ArticleLiterature Review

Radiation-Induced Cataractogenesis: A Critical Literature Review for the Interventional Radiologist

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Abstract

Extensive research supports an association between radiation exposure and cataractogenesis. New data suggests that radiation-induced cataracts may form stochastically, without a threshold and at low radiation doses. We first review data linking cataractogenesis with interventional work. We then analyze the lens dose typical of various procedures, factors modulating dose, and predicted annual dosages. We conclude by critically evaluating the literature describing techniques for lens protection, finding that leaded eyeglasses may offer inadequate protection and exploring the available data on alternative strategies for cataract prevention.

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... Recent epidemiologic studies have yielded new evidence of radiation-induced cataract at lower doses (16), leading the International Commission on Radiological Protection to lower the assumed threshold to 0.5 Gy (17). However, investigators in some literature reviews focused on more recent epidemiologic and biologic study findings (18,19) have questioned whether the data are still consistent with the theory that cataract is a tissue reaction and have described potential stochastic phenomena linked to DNA damage as an explanation for the increased risks at lower radiation ...
... Although an increased risk of cataract among medical workers who were occupationally exposed to radiation has been previously reported (19), mainly among those who performed fluoroscopically guided interventional procedures, to our knowledge such a risk increase has never been reported for NM workers. The radiation doses to the eyes of NM workers are expected to be low because only photon emitters of low energy and/or beta emitters with energy levels higher than 0.7 MeV penetrate deep enough to reach the lens. ...
... Bernier et al tomography use in recent decades may have contributed to higher eye lens doses in technologists who perform NM procedures (30,31). In addition, in recent reviews in the epidemiologic literature, there has been discussion of a potential effect on cataract development from radiation doses lower than the previously accepted threshold of 0.5 Gy (18,19). We observed modest increases in cataract risk in association with everas opposed to never-performing diagnostic (7% risk increase) and therapeutic (10% risk increase) NM procedures. ...
Article
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Purpose To estimate the risk of cataract in a cohort of nuclear medicine (NM) radiologic technologists on the basis of their work histories and radiation protection practices. Materials and Methods In the years 2003-2005 and 2012-2013, 42 545 radiologic technologists from a U.S. prospective study completed questionnaires in which they provided information regarding their work histories and cataract histories. Cox proportional hazards models, stratified according to birth-year cohort (born before 1940 or born in 1940 or later) and adjusted for age, sex, and race, were used to estimate hazard ratios (HRs) for the risk of cataract in radiologic technologists according to NM work history practices according to decade. Results During the follow-up period (mean follow-up, 7½ years), 7137 incident cataracts were reported. A significantly increased risk of cataract (HR, 1.08; 95% confidence interval [CI]: 1.03, 1.14) was observed among workers who performed an NM procedure at least once-as opposed to never. Risks of cataract were increased in the group who had performed a diagnostic (HR, 1.07; 95% CI: 1.01, 1.12) or therapeutic (HR, 1.10; 95% CI: 1.04, 1.17) NM procedure. Risks were higher for those who had first performed diagnostic NM procedures in the 1980s to early 2000s (HR, 1.30; 95% CI: 1.08, 1.58) and those who had performed therapeutic NM procedures in the 1970s (HR, 1.11; 95% CI: 1.01, 1.23) and in the 1980s to early 2000s (HR, 1.14; 95% CI: 1.02, 1.29). With the exception of a significantly increased risk associated with performing therapeutic NM procedures without shielding the radiation source in the 1980s (HR, 1.32; 95% CI: 1.04, 1.67), analyses revealed no association between cataract risk and specific radiation protection technique used. Conclusion An increased risk of cataract was observed among U.S. radiologic technologists who had performed an NM procedure at least once. This association should be examined in future studies incorporating estimated lens doses. (©) RSNA, 2017.
... The crystalline lenses of the eyes are of the most radiosensitive tissues in the body [6]. Data suggest that cataractogenesis may be stochastic rather than deterministic in effect and that changes may occur even at very low radiation dose exposure [7]. The pathogenesis of radiation-induced cataracts may be due to oxidation processes or damage to proteins [8]. ...
... This finding is consistent with that of interventionalists in a UK study where lead glasses were underutilized compared with other PPE [22]. The use of lead glasses reduces the radiation dose to the eye by 70e98% based on various studies [7,23]. It is, thus, imperative that employers provide appropriately fitting lead glasses for the interventionalists to reduce cataracts [24]. ...
Article
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Objective: This study explored personal protective equipment (PPE) availability and PPE utilization among interventionalists in the catheterization laboratory, which is a highly contextualized workplace. Methods: This is a cross-sectional study using mixed methods. Participants (108) completed a survey. A hyperlink was sent to the participants, or they were asked to complete a paper-based survey. Purposively selected participants (54) were selected for individual (30) or group (six) interviews. The interviews were conducted at conferences, or appointments were made to see the participants. Logistic regression analysis was performed. The qualitative data were analyzed thematically. Results: Lead glasses were consistently used 10.2% and never used 61.1% of the time. All forms of PPE were inconsistently used by 92.6% of participants. Women were 4.3 times more likely to report that PPE was not available. PPE compliance was related to fit and availability. Conclusions: PPE use was inconsistent and not always available. Improving the culture of radiation protection in catheterization laboratories is essential to improve PPE compliance with the aim of protecting patients and operators. This culture of radiation protection must include all those involved including the users of PPE and the administrators and managers who are responsible for supplying sufficient, appropriate, fitting PPE for all workers requiring such protection.
... Due to these advantages, CT has been used with increased frequency for pain-relieving injections at the spine 15 . However, the broader use of CT has also raised concerns regarding radiation exposure for patients as well as for the performing interventionalists [16][17][18][19][20][21] . One of the main disadvantages of CT-guided procedures compared with the conventional fluoroscopy procedure is the risk of a distinctly higher radiation exposure to patients 15 . ...
... However, not only the diagnostic use but also the use of CT in interventional radiology for image guidance and navigation purposes has increased over time, which is mostly due to an increasing trend to minimally invasive medicine 14,37 . This is a development that comes at cost of higher radiation exposure and, as a consequence, at potentially increased estimated cancer risk ratios for patients and interventionalists exposed to CT [16][17][18][19][20][21] . Hence, it should be the aim to perform these CT scans with the lowest reasonable radiation exposure but, at the same time, without losing sight of the clinical usefulness of generated images with respect to the "as low as reasonably achievable" (ALARA) principle 38,39 . . ...
Article
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Abstract Periradicular infiltrations are frequently performed in daily neuroradiological routine and are often guided by multi-detector computed tomography (MDCT), thus leading to radiation exposure. The purpose of this study was to evaluate MDCT with low dose (LD) and model-based iterative reconstruction for image-guided periradicular infiltrations at the cervical and lumbosacral spine. We retrospectively analyzed 204 MDCT scans acquired for the purpose of cervical or lumbosacral periradicular interventions, which were either derived from scanning with standard dose (SD; 40 mA and 120 kVp) or LD (20–30 mA and 120 kVp) using a 128-slice MDCT scanner. The SD cases were matched to the LD cases considering sex, age, level of infiltration, presence of spinal instrumentation, and body diameter. All images were reconstructed using model-based iterative image reconstruction and were evaluated by two readers (R1 and R2) using 5- or 3-point Likert scales (score of 1 reflects the best value per category). Furthermore, noise in imaging data was quantitatively measured by the standard deviation (StDev) of muscle tissue. The dose length product (DLP) was statistically significantly lower for LD scans (6.75 ± 6.43 mGy*cm vs. 10.16 ± 7.70 mGy*cm; p 0.05 for all items). This resulted in high confidence for intervention planning as well as periprocedural intervention guidance for both SD and LD scans. The inter-reader agreement was at least substantial (weighted Cohen’s κ ≥ 0.62), except for confidence in intervention planning for LD scans (κ = 0.49). In conclusion, considerable dose reduction for planning and performing periradicular infiltrations with MDCT using model-based iterative image reconstruction is feasible and can be performed without clinically relevant drawbacks regarding image quality or confidence for planning.
... Although radiation-induced cataracts are a well-known effect of exposure to radiation, recent debates focus on whether they are formed deterministically or stochastically. [1][2][3] In previous studies, [4][5][6] it was believed that radiation-induced cataracts develop deterministically and a threshold dose was required for detectable lens opacities. Recent data reveal that radiation-induced cataracts may occur stochastically; they may develop at a lower dose level or potentially with no dose threshold. ...
... It is reported that because of discomfort, <30% of operators wear protective eyewear. 3 There is a tradeoff between efficacy and comfort when choosing appropriate eyewear. Radiologist's head posture also has an influence on the efficacy of protective eyewear. ...
... Finding strategies to limit the use of fluoroscopy during MIO has clear advantages on safety. [27][28][29] The purpose of this study was to test if the TVS could be safely applied percutaneously without fluoroscopic guidance in a feline cadaveric gap fracture model. We hypothesized that (1) TVS could be safely applied with MIO technique with or without fluoroscopy to humeral, femoral and tibial fractures simulated in a feline cadaver model; (2) there would be no difference in surgical time, intraoperative complications and fracture alignment between bones fixated using fluoroscopy and without fluoroscopy. ...
... However, the benefits of intraoperative fluoroscopy should also be carefully weighed against potential safety concerns. [27][28][29] The frequent use of ionizing radiation may have long-term insidious health effects and therefore the fluoroscopic unit should only be used if the advantages clearly outweigh the disadvantages. 25 The rate of iatrogenic fractures that we observed, especially in the humerus, is even higher than previously reported in a clinical study using the TVS. ...
Article
Objectives The Targon Vet System (TVS) is a 2.5-mm interlocking nail that can be applied minimally invasively. The purpose of this study was to test if the TVS could be safely applied percutaneously to different feline long bones without fluoroscopic guidance. Methods A gap fracture was created in 96 feline humeri, femora and tibiae (n = 32/group). Paired bones were randomly assigned to two treatment groups: (1) TVS inserted percutaneously with fluoroscopy and (2) TVS inserted percutaneously without fluoroscopy. Intraoperative evaluation (complications, procedure time, attempts), radiographs (pre-/postoperative alignment, length) and anatomical dissection (neurovascular injury, rotational alignment) were compared between treatment groups. Results The use of fluoroscopy did not lead to significant differences in any of the outcome measures. Intraoperative complications predominantly occurred in the distal humerus (12/32) and the proximal femur (7/32). In total, 20/96 complications occurred with no complications for the tibia. Neurovascular structures were only damaged at the medial side of the distal humerus (10/32). Clinical Significance We conclude that the TVS can be safely applied percutaneously to the tibia and with limitations to the femur in normal cadaveric cats without fluoroscopy. Despite the limitations of a cadaveric study, the high number of complications is leading us to consider the humerus not safe for the TVS. A learning curve has to be expected and technical recommendations should be respected to decrease complications.
... Aside from the risk of carcinogenesis, radiation dose to the eye can result in the formation of cataracts. 25 Doses as low as 0.5 Gy can promote increased and earlier cataract development, 26 and research suggests that cataractogenesis may be a stochastic effect rather than deterministic as previously thought. 25 However, it is likely that cataract formation is determined by whether or not the treatment beam passes through the lens, and that the relatively low concomitant imaging dose will not contribute significantly to this. ...
... 25 Doses as low as 0.5 Gy can promote increased and earlier cataract development, 26 and research suggests that cataractogenesis may be a stochastic effect rather than deterministic as previously thought. 25 However, it is likely that cataract formation is determined by whether or not the treatment beam passes through the lens, and that the relatively low concomitant imaging dose will not contribute significantly to this. ...
Article
Full-text available
Objectives This paper uses clinical audit to determine the extent and dosimetric impact of additional imaging for patients undergoing ocular proton beam therapy who have no clips visible in the collimated beam. Methods An audit was conducted on 399 patients treated at The National Centre for Eye Proton Therapy between 3 July 2017 and 14 June 2019. The mean total number of image pairs over the course of treatment for patients with and without clips visible in the collimated beam were compared. Results Among 364 evaluable patients, 333 had clips visible in the collimated beam and 31 did not. There was a statistically significant increase of five image pairs required for patients with no clips visible compared with those with clips visible (mean 14.6 vs 9.6 image pairs, respectively; p = 2.74 × 10 –6 ). This equated to an additional 1.5 mGy absorbed dose, representing an increase in secondary cancer induction risk from 0.0004 to 0.0007%. Conclusions The small increase in concomitant dose and set-up time for patients with no clips visible in the collimated beam is not clinically significant. Advances in knowledge This novel work highlights clinical audit from real on-treatment geometric verification data and frequencies, rather than protocols, for ocular proton beam therapy; something not present in the literature. The simple and straightforward methodology is easily and equally applicable to clinical audits (especially those under Ionising Radiation (Medical Exposure) Regulations) for photon techniques.
... The poor use of protective eyewear among interventionalists may be because of insufficient understanding of the health risks, but encouraging radiation safety practices may have a positive effect on the eye health of interventionalists. 11 The aim of this study was to describe the ophthalmological changes in a group of doctors occupationally exposed to IR. ...
... There is a need to improve the awareness of the health risk to the eye among interventionalists so as to reduce the complications associated with occupational IR exposure. 11 General practitioners, ophthalmologists and occupational health physicians should also be vigilant in considering this risk as part of routine screening and examination of interventionalists. ...
Article
Full-text available
Background: Ionising radiation (IR) is an occupational hazard for interventionalists. Dry eye syndrome may develop. There may be damage to the corneal epithelium, causing irritation and ulceration. Radiation-induced cataracts commonly develop in the posterior sub-capsular (PSC) region of the lens and are more common in the left eye. Aim: The aim of this study was to describe the ophthalmological findings in South African interventionalists occupationally exposed to IR. Setting: This study was conducted in South Africa. Methods: A prospective cross-sectional study was conducted. Interventional radiologists (25), adult cardiologists (42) and paediatric cardiologists (31) were recruited at conferences and included in the study. Convenience sampling was used. Participants completed a survey that collected data on their demographics, their cataract risk factors and co-morbid diseases, their occupational history, their radiation safety practices and their training in occupational history. Participants’ eyes were examined using a slit lamp after dilation of the eyes. Ethics clearance was obtained and each participant gave informed consent. A descriptive analysis was done. Results: The median age of the 98 interventionalists screened was 43.5 years. They worked with radiation for a median of 7.5 years. Cataracts occurred in the left eye of 17 (17.3%) participants and in the right eye of nine (9.2%). There were five (5.1%) PSC cataracts in the left eye and one (1%) in the right eye. The vitreous was abnormal in 19.4% of participants. The tear break-up time was abnormal in 48% of participants. Conclusion: Ionising radiation is an occupational hazard posing a risk to interventionalists’ eyes. They are at increased risk of cataracts and dry eye syndrome, which can affect their occupational performance and quality of life. Education can positively influence the radiation safety practices of interventionalists that could reduce the detrimental effects of IR on their eyes.
... A reanalysis of epidemiological studies upon which these historical thresholds were founded was recommended, based on increased knowledge of latency periods and statistical analysis, suggesting that these historical studies were carried out too soon post-exposure, making judgements on low dose difficult to extrapolate and conclude. cardiologists and individuals involved in nuclear medicine production who are also most at risk of frequent exposure (Frey 2014;Seals 2015;Bitarafan Rajabi 2015;Ciraj-Bjelac 2012). ...
... mSv for the radiologist (Paulson 2001) -are widespread throughout the world and are often conducted in dedicated large departments allowing high patient throughput required by these procedure types in modern medical care. Seals et al (2015) reviewed the recent literature relating specifically to exposures of interventional radiologists and drew general conclusions regarding the risk of radiation-induced cataractogenesis in this cohort. The study found that with current workloads and radiation protective measures in place, there was a potential for lens doses to exceed the recommended limit of 20 mSv/y. ...
Thesis
The lens of the eye is thought to be one of the most radiosensitive tissues. Cataracts were one of the first observed biological effects following ionising radiation exposure. The recent change in regulations for eye lens dose limits has led to the urgent need to make sure our biological understanding is sufficient. The anterior of the lens is covered by lens epithelial cells (LEC), that are critical to maintaining normal lens function and producing fibre cells. Damage or disruption to LECs can have detrimental consequences to the lens. Low dose (<500 mGy) radiation-induced DNA damage and repair, cell proliferation and lens opacity were investigated post-exposure in or amongst four mouse strains (C57BL/6,129S2, BALB/c and CBA/Ca). Mice were sacrificed up to 24 hours post-exposure and lenses removed and epithelia isolated for analyses. Immunofluorescent staining for DNA double strand break (DSB) repair (53BP1) and cell proliferation (Ki67) were performed. Dose, dose-rates were varied during exposures to seek experimental evidence to support the epidemiological studies. Peripheral blood lymphocytes were collected for comparison with LEC. 120 female mice were irradiated and their lenses analysed for opacity at monthly intervals over 18 months. An inverse dose-rate effect was observed in the DSB repair response, as well as slower repair at low IR doses and a significant strain dependency. A nonlinear response to IR was observed for LEC proliferation that was bimodal; inhibition at low dose (<50 mGy), and a significant interaction effect between dose-rate and region. Lens opacity also increased over time. These results give the first biological evidence for an inverse dose-rate response in the lens. They highlight the importance of dose-rate in low-dose cataract formation represent the first evidence that LECs process radiation damage differently to blood lymphocytes. More work is needed to support lens dose limits.
... The European Union (EU) responded to the new ICRP recommendation by incorporating the new dose limits into the current European basic safety standard, while in the United States the National Council on Radiation Protection and Measurements (NCRP) has not advocated a reduction from the 7.5 fold higher annual limit of 15,000 mrem (150 mSv) [6] [7]. This information has led interventional radiologists, interventional cardiologists and radiological technologists to revisit protective measures to combat radiation-induced cataractogenesis [4] [5] [8] [9]. A 2015 study concluded that any lens exposure may have associated cataract risk and suggested that interventional radiology work increases probability of cataract development [9]. ...
... This information has led interventional radiologists, interventional cardiologists and radiological technologists to revisit protective measures to combat radiation-induced cataractogenesis [4] [5] [8] [9]. A 2015 study concluded that any lens exposure may have associated cataract risk and suggested that interventional radiology work increases probability of cataract development [9]. Employing protective measures such as leaded glasses, patient-supported protective blankets, and suspended ceiling shields have shown to reduce lens doses [7]. ...
... Therefore, in our study, we chose the latter method to obtain the eye lens dose through calculations from air kerma free-in-air by considering a fixed photon energy and 0 � incidence angle. Lead glasses are the most fundamental equipment for the protection of the eye lens in clinical operations and could distinctly reduce the lens dose for physicians (Carinou et al., 2015;Domienik et al., 2016;Seals et al., 2016). Nevertheless, we observed that the lateral shielding of lead glasses is more crucial than the thickness of the lead equivalent material in front of the lead glasses for eye lens protection in clinical situations. ...
... In general, radiation protective lead glasses could provide significant radiation protection efficiency to the eye lens of physicians from interventional radiology departments. The amount of scattered photons was remarkably reduced by the attenuation of lead glasses (Domienik et al., 2016;Hu et al., 2017;Seals et al., 2016). Furthermore, the mean energy of penetrated photons through lead glasses increased from the beam hardening effect. ...
Article
Physicians tend to receive extended radiation exposure given the complexity and machine settings of procedures in interventional radiology departments, which involve neurovascular interventional radiology (neuro-IR) and interventional radiology of body regions (general-IR). The eye lens dose was evaluated with direct measurements from the EYE-DTM, Hp(3), and indirect estimation from doses measured with over-apron collar dosimeters, Hp(0.07) and Hp(10). The median value of Hp(3) for general-IR procedures was approximately 3.6 times larger than that for neuro-IR procedures. The median value of Hp(3)/kerma-area product (KAP) for physicians who did not wear lead glasses was 1.4 and 2.9 times higher than that for those who wore glasses in neuro-IR and general-IR procedures, respectively. The median value of Hp(3)/KAP for type B glasses (no lateral shielding) wearers was 6.6 and 1.5 times higher than that for type A glasses wearers for neuro-IR and general-IR procedures, respectively. Radiation protective lead glasses can reduce lens dose by 28% and 65% in neuro-IR and general-IR procedures, respectively. Proper lateral shielding is more necessary for radiation protection to the eye lens in clinical situations than is the thickness of the lead equivalent in front of the glasses. Indirect measurements from over-apron collar dosimeters could be a preliminary option for eye lens dose monitoring. However, the underestimation would be 33% of the maximum, which should be specially noted. Dedicated eye lens dosimeters are essential for accurate radiation dose monitoring in neuro-IR and general-IR procedures.
... This paper reviews the most important tissue injuries observed after FGI. The main contribution of this paper is the observation and analysis of skin injuries, as radiation-induced cataractogenesis was just recently covered by a review article in this journal [19]. Moreover, some practical advice is given regarding the effective avoidance of skin injuries. ...
... The results of Seals et al. indicate that cataractogenesis tends to be a stochastic and not a deterministic effect as was long assumed [13]. ...
Article
Background The increasing number of minimally invasive fluoroscopy-guided interventions is likely to result in higher radiation exposure for interventional radiologists and medical staff. Not only the number of procedures but also the complexity of these procedures and therefore the exposure time as well are growing. There are various radiation protection means for protecting medical staff against scatter radiation. This article will provide an overview of the different protection devices, their efficacy in terms of radiation protection and the corresponding dosimetry. Method The following key words were used to search the literature: radiation protection, eye lens dose, radiation exposure in interventional radiology, cataract, cancer risk, dosimetry in interventional radiology, radiation dosimetry. Results and Conclusion Optimal radiation protection always requires a combination of different radiation protection devices. Radiation protection and monitoring of the head and neck, especially of the eye lenses, is not yet sufficiently accepted and further development is needed in this field. To reduce the risk of cataract, new protection glasses with an integrated dosimeter are to be introduced in clinical routine practice. Key Points: Citation Format
... The latter are mostly exposed to scattered radiation. This remains a much-discussed topic because possible stochastic and in case of the eye lens also deterministic damage caused by ionizing radiation has raised concerns (8)(9)(10)(11). ...
Article
Background: Computed tomography (CT) is widely used not only for diagnostic purposes but also for image guidance during different types of interventions. Therefore, radiation exposure of both patients and interventional radiologists remains a much-discussed topic. Purpose: To quantify radiation exposure of interventional radiologists during multiple CT-guided interventions using dosimeters placed under and outside standard protective lead clothing. Material and methods: A total of 113 consecutive interventions covering three different types of procedures (grouped as periradicular infiltration therapy, biopsies, and drain placement) and performed using routine clinical protocols were prospectively analyzed. The interventions were performed by two radiologists of different experience levels with identically placed dosimeters outside and underneath their protective clothing. Personal doses (right hand, eye lens, thyroid gland, thorax, gonads) were cumulatively measured for each type of intervention and separately for the two radiologists. Results: Personal dose was below the detection limit of the dosimeters during periradicular infiltration therapy. In the biopsy and drain placement groups, the highest dose was found for the right hand (maximum cumulative dose = 1.84 ± 1.30 mSv in 19 consecutive drain placements). Under the protective gear, exposure was only observed for drain placements performed by the less experienced radiologist (maximum = 0.05 ± 0.04 mSv for the eye lens). Conclusion: Personal doses measured here were far below annual thresholds published by the International Commission on Radiological Protection. Therefore, performing multiple CT-guided interventions appears to be safe for interventional radiologists in terms of radiation exposure.
... Aktuelle Untersuchungen zeigen zudem, dass eine Strahlenexposition der Orbita negative Folgen haben kann. Schon bei geringen Strahlendosen kann es dabei nämlich in der Linse zu einer Kataraktbildung kommen[26][27][28] . Somit ist eine routinemäßige Darstellung beider Kieferhöhlen oder auch einer ganzen Kiefer-höhle unter Einschluss des ostiomeatalen Komplexes -und dadurch auch zumindest eine teilweise Exposition der Orbita ein-oder beidseitig -nicht gerechtfertigt22 . ...
Article
The maxillary sinus is a symmetric and pyramid-shaped, air-filled space in the facial skeleton that is regularly depicted on oral radiographs. For dental indications and especially prior to implant therapy, cone beam computed tomography (CBCT) is the recommended imaging modality for 3-dimensional visualizations of the sinus. Although considered desirable, depiction of the natural sinus ostium on the respective field of view (FOV) of the CBCT is not mandatory. Thus, for most CBCT scans performed for implant treatment-planning purposes, a small- to medium-sized FOV depicting only the maxillary sinus intended for surgery is sufficient. Knowledge of the possibilities and limitations in diagnostic imaging helps the practitioner to make adequate decisions and to avoid radiographic modalities that may result in unnecessary radiation exposure to the patient. Changes and pathologies of the maxillary sinuses are rather frequent findings and exhibit a wide variability, from harmless anatomical variants to malignant neoplasias. Benign and malignant lesions tend to grow in the lumen of the maxillary sinus without any clinical symptoms for quite some time and may only be incidentally diagnosed on dental radiographs. This underlines the importance of a proper initial clinical and radiographic assessment of patients referred for dental implant treatment planning-especially with regard to the health or pathology of the maxillary sinus. If further diagnostic imaging or treatment of unclear sinus conditions is deemed necessary, referral to a medical specialist such as an ear, nose, and throat specialist must be considered.
... While the peak age is between 40 and 50, there is an increasing number of patients under 30 years that are treated with periradicular infiltration to avoid surgery at a young age [5]. At the same time, however, there is growing concern about the associated radiation exposure to patients and interventional radiologists alike [6,7]. ...
Article
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Purpose: To develop and evaluate a technical approach for CT-guided periradicular infiltration using quantitative needle access and guidance parameters extracted from CT scout images. Methods: Five 3D-printed phantoms of the abdomen mimicking different patients were used to develop a technical approach for scout-guided periradicular infiltration. The needle access point, puncture depth, and needle angulation were calculated using measurements extracted from anterior-posterior and lateral CT scout images. Fifty needle placements were performed with the technique thus developed. Dose exposure and number of image acquisitions were compared with ten procedures performed using a conventional free-hand technique. Data were analyzed with the Mann-Whitney U test. Results: Parameters derived solely from scout images provided adequate guidance for successful and reliable needle placement. Needle guidance was performed with the same equipment as the standard periradicular infiltration. Two scout images and 3.5 ± 2.3 (mean ± SD) single-shot images for needle positioning were acquired. Mean DLP ± SD was 3.8 ± 2.5 mGy cm. The number of single-shot acquisitions was reduced by 68% and the overall dose was reduced by 84% in comparison with the conventional free-hand technique (p < 0.0001). Conclusion: Scout-guided needle placement for periradicular infiltration is feasible and reduces radiation exposure significantly.
... This paper reviews the most important tissue injuries observed after FGI. The main contribution of this paper is the observation and analysis of skin injuries, as radiation-induced cataractogenesis was just recently covered by a review article in this journal [19]. Moreover, some practical advice is given regarding the effective avoidance of skin injuries. ...
Article
Full-text available
For a long time, radiation-induced skin injuries were only encountered in patients undergoing radiation therapy. In diagnostic radiology, radiation exposures of patients causing skin injuries were extremely rare. The introduction of fast multislice CT scanners and fluoroscopically guided interventions (FGI) changed the situation. Both methods carry the risk of excessive high doses to the skin of patients resulting in skin injuries. In the early nineties, several reports of epilation and skin injuries following CT brain perfusion studies were published. During the same time, several papers reported skin injuries following FGI, especially after percutaneous coronary interventions and neuroembolisations. Thus, CT and FGI are of major concern regarding radiation safety since both methods can apply doses to patients exceeding 5 Gy (National Council on Radiation Protection and Measurements threshold for substantial radiation dose level). This paper reviews the problem of skin injuries observed after FGI. Also, some practical advices are given how to effectively avoid skin injuries. In addition, guidelines are discussed how to deal with patients who were exposed to a potentially dangerous radiation skin dose during medically justified interventional procedures.
... There is a significant body of literature establishing a link between ionizing radiation exposure and cataract formation in interventionalists, 14 with several reports showing cataract development occurring at cumulative doses as low as 100 mGy. [15][16][17] Given that lens opacification can have a profound impact on a surgeon's ability to operate, it is of paramount importance that effective radiation safety eyewear be available to all practicing interventionalists. ...
Article
Introduction Ocular radiation exposure from fluoroscopically-guided-interventions (FGIs) can cause cataracts. Standard lead eyewear may not significantly reduce eye radiation dose, as the majority of scattered radiation penetrates the operator’s eye obliquely. Our aim was to evaluate the efficacy of standard leaded eyewear and a customized eyewear design in lowering eye radiation dose to vascular surgeons. Methods The attenuating efficacy of three forms of leaded eyewear (standard eyewear, eyewear with built-in leaded side-shields, and our modified eyewear) were tested in both a simulated setting and clinical practice. The modified design consisted of safety eyewear with 0.75 mm of added lead shielding attached to the lateral and inferior borders of the eyewear frame to attenuate oblique radiation. We performed simulated experiments using an anthropomorphic head phantom (ATOM model-701:CIRS, Norfolk, VA) positioned to represent a primary operator performing right femoral access. Optically stimulated, luminescent nanoDot detectors (Landauer, Glenwood, IL) were placed inside the phantom’s ocular spaces, and at the surface of the left eye within and outside the leaded glasses to measure the eye radiation dose reduction provided by each eyewear type. All 3 eyewear types were also tested during clinical FGIs by placing nanoDots below the operator’s left eye, inside and outside of the eyewear coverage. Means and standard errors were calculated using a pooled linear mixed model with repeated measurements. Results This prospective, single-center study included 60 FGIs; 30 with traditional eyewear and 30 with our modified design. There was no significant eye radiation dose reduction (p>0.05) with the standard eyewear or leaded side-shield eyewear in both the simulated and clinical settings. In the simulated environment, our modified design resulted in an 86% radiation dose reduction to the surface of the left eye, and an 80% reduction in left lens radiation dose (p<.0001). In the clinical FGIs, the modified eyewear led to a 62% left ocular radiation dose reduction (p<.0001). Conclusions Standard lead-equivalent glasses are ineffective at reducing ocular radiation dose during FGIs. Eyewear modification with lateral and inferior lead shielding molded to the operator’s face significantly decreases eye radiation exposure to the eye closest to the x-ray source.
... Several cases of radiation-induced lens opacity and cataracts have been reported among interventional practitioners, [1][2][3][4][5] suggesting that interventional practices increase the risk of cataracts. 6 The International Commission on Radiological Protection has published recommendations for fluoroscopy-guided procedures to prevent patient and professional radiation injuries, [7][8][9] and a number of these recommendations have been adopted by European regulations, establishing new occupational dose limits and the requirement for optimizing procedures to keep occupational doses as low as possible. 10 A number of international programs have promoted actions to assess lens doses during medical procedures. ...
Article
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Purpose: This study presents a prototype smartphone application for occupational dosimetry in interventional practices based on electronic personal dosimeters to assist in dose monitoring. Methods: The prototype receives and records information from the Occupational Dose Report containing the cumulative dose of electronic personal dosimeters worn over the apron at chest level and electronic area dosimeters located on C-arms (reference dosimeters), for each fluoroscopy-guided procedure. Using their smartphones, personnel involved in interventional practices can review and compare their occupational records with an investigation level, the dose limits and their department colleagues (anonymously). The ratio between Hp (10) measured by the personal and the reference dosimeters at the C-arm is presented as an indicator of consistent use of suspended operator shield. Some general results extracted from the first months of use are presented. Results: The reference dosimeter located at the C-arm (without lead protection and acting as an ambient dosimeter) recorded in one of the laboratories 217 mSv during 308 procedures over 5 months, showing an indication of the radiation risk present in an interventional laboratory. The ratio between the personal cumulative dose and the dose at a reference C-arm dosimeter ranged from 0.2% to 1.67% (a factor of 8.5) for different interventionalists. These differences suggest different protection habits among interventional operators, as well as a target for dose reduction. Conclusions: With this system, professionals have easy access to their occupational dosimetry records (including information on the workload) in the setting of their interventional departments, to thereby actively engage in the protection process.
... With the introduction of new medical interventional procedures such as fluoroscopy, that employ ionizing radiation (IR), reported injuries to the eye have increased (Vano et al 2008, Barnard et al 2016, Seals et al 2016. The lens of the eye is known to be highly sensitive to IR due to the enhanced proliferation and differentiation status of the cells as well as slow DNA repair (Hamada 2017). ...
Article
Recent findings in populations exposed to ionizing radiation (IR) indicate dose-related lens opacification occurs at much lower doses (< 2Gy) than indicated in radiation protection guidelines. As a result, research efforts are now being directed towards identifying early predictors of lens degeneration resulting in cataractogenesis. In this study, Raman micro-spectroscopy was used to investigate the effects of varying doses of radiation, ranging from 0.01 Gy to 5 Gy, on human lens epithelial (HLE) cells which were chemically fixed 24 hrs post-irradiation. Raman spectra were acquired from the nucleus and cytoplasm of the HLE cells. Spectra were collected from points in a 3 x 3 grid pattern and then averaged. The raw spectra were preprocessed and principal component analysis followed by linear discriminant analysis (PCA-LDA) was used to discriminate between dose and control for 0.25, 0.5, 2, and 5 Gy. Using leave-one-out cross-validation (LOOCV) accuracies of greater than 74% were attained for each dose/control combination. The ultra-low doses 0.01 and 0.05 Gy were included in an analysis of band intensities for Raman bands found to be significant in the linear discrimination, and an induced repair model survival curve was fit to a band-difference-ratio plot of this data, suggesting HLE cells undergo a nonlinear response to low-doses of IR. A survival curve was also fit to clonogenic assay data done on the irradiated HLE cells, showing a similar nonlinear response.
... The new threshold is now considered to be 0.5 Gy and the occupational annual equivalent dose limit is recommended to be 20 mSv, averaged over defined periods of 5 years, with no single annual dose exceeding 50 mSv (12) . Nonetheless, some investigators express the view that radiation-induced cataract may be a non-threshold effect (3,9,10,13) . ...
Article
The aim of the study was to measure and evaluate the radiation dose to the eye lens and forehead of interventional radiologists (IRs). The study included 96 procedures (lower-limb percutaneous transluminal angioplasties, embolisations/chemoembolisations and vertebroplasties) performed by 6 IRs. A set of seven thermoluminescence dosemeters was allocated to each physician. The highest dose per procedure was found for the left eye lens of the primary operator in vertebroplasties (1576 μSv). Left and right eye doses were linearly correlated to left and right forehead doses, respectively. A workload-based estimation of the annual dose to participating IRs revealed that the occupational dose limit for the eye lens can be easily exceeded. The left eye dose of ΙRs must be routinely monitored on a personalised basis. Τhe left eye dose measurement provides a reliable assessment of the ipsilateral forehead dose, along with valid estimations for the right eye and right forehead doses.
... 23 Although radiation exposure during fluoroscopically assisted procedures typically remains below acceptable levels, 24 repeated exposure to low level radiation is a serious concern in the medical community because of its insidious, cumulative effects and its correlation with increased risk of malignant neoplasia (stochastic effect) or cataracts (nonstochastic effect). 13,25 This concern is exacerbated when the C-arm is used in cine mode (also referred to as live fluoroscopy). Although an argument could be made that using cine mode could further reduce surgical time in MIO of SIL/F by forgoing stepping away as spot films (normal fluoroscopy) are taken, this approach leads to significantly higher levels of radiation exposure. ...
Article
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Objective: To describe a novel Sacroiliac Luxation Instrument System (SILIS™) and its application in minimally invasive osteosynthesis (MIO) of sacroiliac luxations/fractures (SIL/F). The SILIS was designed to provide stable SIL/F reduction and accurate sacral screw placement while reducing personnel exposure to ionizing radiation during intraoperative fluoroscopy. Study design: Descriptive, proof of concept cadaveric study. Methods: A right SIL and a left SIL/F were created on a Labrador Retriever that had died of natural causes. Bilateral sacroiliac lag screw fixation was performed under fluoroscopic guidance with the SILIS, which consists of dedicated reduction and fixation instruments rigidly linked to table-bound 6-axis arms. Results: Throughout surgery, the SILIS facilitated and maintained stable reduction and allowed accurate placement of a custom designed drill guide over the sacral body without the surgeon's manual holding of any reduction or fixation instruments. The surgical team was therefore able to step away from the C-arm when acquiring fluoroscopic images, thus reducing exposure to radiation. Dorsoventral and craniocaudal screw deviation from an ideal trajectory ranged from 0.9° to 3.8°. Both screws were fully located within the sacral body. Conclusion: The SILIS addresses limitations associated with MIO of SIL/F, including maintenance of reduction throughout surgery along with reliable and accurate sacral screw placement. Distance from the X-ray source is the most effective protection against radiation. Use of the SILIS allows the surgical team to move away from the C-arm during fluoroscopy, thereby reducing personnel exposure to dangerous direct and back-scattered ionizing radiation.
... The ICRP still classifies cataract formation as a deterministic effect, which means that a threshold dose needs to be reached before the reaction occurs. Recent epidemiologic evidence suggests that radiation-induced cataracts may form stochastically, without a threshold and at low radiation doses (Ainsbury et al., 2009;Bouffler et al., 2012;Dauer et al., 2010;Martin, 2011;Neriishi et al., 2012;Seals, Lee, Cagnon, Al-Hakim, & Kee, 2016) with increased exposure levels resulting in more severe effects (Worgul et al., 1996). This is significant to staff working in fluoroscopic suites because if precautions are not taken to limit radiation exposure to their eyes, they will develop subcapsular opacities that may become an impairment to vision. ...
Article
Continuing improvements in both catheterization and imaging equipment have resulted in greater numbers and increasingly more complex angiographic cases being performed, which has led to higher patient and staff doses. Occupational radiation exposure to staff within fluoroscopic suites has been demonstrated to elevate the risk of carcinogenesis and radiation-induced cataracts. A survey was undertaken to compare the accessibility and utilization of radiation protective equipment by staff within a selection of cardiovascular suites throughout Australia. A number of Australian cardiovascular suites were invited to complete an online survey comprising 10 questions. The survey questions focused on the availability and use of head, thyroid, and eye radiation protection by doctors and nurses present in the room during cardiac angiography procedures. The study identified that the utilization of ceiling-mounted lead and thyroid shields was adequate within the surveyed departments but has highlighted that there are areas that staff could further reduce their risk of the occupational exposure. There is very strong evidence proving the importance of additional shielding such as lead caps and glasses in minimizing dose, and there needs to be a focus on education to ensure that staff are cognizant of the benefit of wearing them. It is advisable that staff working within angiography suites have access to appropriate radiation protection devices to minimize their exposure to ionizing radiation. In addition, training should be provided to staff regarding the risk of occupational exposure and dose optimization.
... Osłony osobiste -okulary, maski i czapki ołowiowe Autorzy wielu artykułów naukowych podkreślali konieczność ochrony soczewek oczu przed promieniowaniem jonizującym oraz monitorowania dawki na soczewki oczu w ramach dozymetrii indywidualnej (głównie podczas zabiegów interwencyjnych) [12][13][14][15][16][17][18][19][20][21][22][23][24]. Opisywane we wspomnianych artykułach badania dotyczyły pomiaru ekspozycji na soczewki oczu, który wcześniej nie był prowadzony w ramach dozymetrii indywidualnej ze względu na wysoki, nieprzekraczany w miejscach pracy limit dawki (150 mSv/rok). ...
Article
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Ionizing radiation as a scientific achievement provides a variety of advantages, e.g., in the medical field. However, it also causes a risk of some illnesses, e.g., cataract or cancer. This results in the need to measure radiation doses and to reduce the unnecessary risk. There are 3 main methods of dose reduction, i.e., shortening the time of exposure, working as far as possible from the X-ray source, and using radioprotective shields. Together with the development of science and technology, dose reduction methods and radioprotection methods have also evolved. Besides improved shielding, the ergonomics is also more advanced, e.g., the zero-gravity shielding or light, and non-lead aprons. What is more, the awareness of using radiological protection and conducting the surgery in the safest way for both the staff and the patient is growing up. The goal of this article is to discuss the newest methods of radiation protection against the background of 3 main protection principles. Med Pr. 2021;72(1).
... 5 Katarak radiasi umumnya terjadi pada bagian PSC (posterior subcapsular) dari lensa mata. 6 Berbagai studi telah menunjukkan kenaikan insidensi katarak pada para pekerja radiasi intervensi medic. [7][8][9] Studi terbaru memperkirakan bahwa lebih dari 800 tindakan per tahun dan per operator diperlukan untuk mencapai nilai batas dosis lensa mata. ...
Article
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Aplikasi radiasi di bidang medik merupakan penyumbang terbesar dari paparan radiasi yang diterima oleh populasi dunia. Tujuan: Mengetahui tingkat dosis radiasi yang diterima pekerja dan pasien pada saat dilakukan tindakan intervensi yang dilakukan di Rumah Sakit Umum Pusat (RSUP) Dr. M. Djamil, Padang. Metode: Penelitian dilakukan pada bulan Februari sampai Maret 2018 dengan mengukur dosis pekerja menggunakan dosimeter termoluminesensi (TLD) dalam bentuk chip, dan merekam kerma dan KAP (kerma-area product) pasien yang ditampilkan pada layar monitor pesawat sinar-X. Hasil: Perawat yang terlibat dalam tindakan PAC menerima dosis efektif, dosis tiroid dan dosis ovarium tertinggi sebesar masing-masing 0,1043 mSv, 0,1141 mSv dan 0,1040 mSv, sementara dosis lensa mata tertinggi sebesar 0,3020 mSV diterima perawat dalam tindakan pemasangan pacu jantung, dan dosis ekstremitas jari tertinggi sebesar 0,3964 mSv diterima dokter yang melakukan tindakan angio dan PTCA elektif. Untuk pasien, kerma tertinggi sebesar 3053 mGy dan KAP tertinggi sebesar 16443 cGy cm2 diterima oleh pasien yang menjalani tindakan PAC diikuti PTCA. Simpulan: Dosis radiasi tertinggi yang diterima pekerja radiasi menyiratkan bahwa tidak hanya dokter namun perawat juga dapat menerima dosis radiasi tertinggi, sedangkan pasien diduga menerima risiko efek deterministik dan efek stokastik terbesar saat menjalani tindakan PAC diikuti PTCA.Kata kunci: dosis pasien, dosis pekerja, tindakan intervensi, paparan medik
... They are exposed to both, ionizing radiation dose scattered from the patient and radiation leakage from the X-ray tube. 3 Epidemiologic studies on radiation-induced cataract formation have shown that the eye lens may be a more radiosensitive tissue than previously considered. 4 The International Commission of Radiological Protection (IRCP) has used this evidence to propose a new occupational dose limit for the eye lens of 20 mSv (vs 150 mSv previously), averaged over a defined period of 5 years, with no single year exceeding 50 mSv. 5 These new dose limits are also affecting operators performing EVARs and primarily those who perform fenestrated and branched EVARs. ...
Article
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Introduction While the operator radiation dose rates are correlated to patient radiation dose rates, discrepancies may exist in the effect size of each individual radiation dose predictors. An operator dose rate prediction model was developed, compared with the patient dose rate prediction model, and converted to an instant operator risk chart. Materials and Methods The radiation dose rates (DR operator for the operator and DR patient for the patient) from 12,865 abdomen X-ray acquisitions were selected from 50 unique patients undergoing standard or complex endovascular aortic repair (EVAR) in the hybrid operating room with a fixed C-arm. The radiation dose rates were analyzed using a log-linear multivariable mixed model (with the patient as the random effect) and incorporated varying (patient and C-arm) radiation dose predictors combined with the vascular access site. The operator dose rate models were used to predict the expected radiation exposure duration until an operator may be at risk to reach the 20 mSv year dose limit. The dose rate prediction models were translated into an instant operator radiation risk chart. Results In the multivariate patient and operator fluoroscopy dose rate models, lower DR operator than DR patient effect size was found for radiation protocol (2.06 for patient vs 1.4 for operator changing from low to medium protocol) and C-arm angulation. Comparable effect sizes for both DR operator and DR patient were found for body mass index (1.25 for patient and 1.27 for the operator) and irradiated field. A higher effect size for the DR operator than DR patient was found for C-arm rotation (1.24 for the patient vs 1.69 for the operator) and exchanging from femoral access site to brachial access (1.05 for patient vs 2.5 for the operator). Operators may reach their yearly 20 mSv year dose limit after 941 minutes from the femoral access vs 358 minutes of digital subtraction angiography radiation from the brachial access. Conclusion The operator dose rates were correlated to patient dose rate; however, C-arm angulation and changing from femoral to brachial vascular access site may disproportionally increase the operator radiation risk compared with the patient radiation risk. An instant risk chart may improve operator dose awareness during EVAR.
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For years, the dose limit for occupational exposure of the eye lens to ionising radiation was rarely exceeded. Early 2018, this dose limit was reduced from 150 to 20 mSv per year. The reduction of this dose limit has significant implications for the protection of the eye lens. When category A workers are liable to receive significant exposures to the lens of the eye, an adequate system for monitoring shall be set up to ensure that the dose does not exceed the dose limit. The purpose of this NCS report is to support radiation protection experts in the Netherlands and Belgium with the implementation of the new legislation in their practice. Download this report from: https://doi.org/10.25030/ncs-031 or https://radiationdosimetry.org/ncs/documents/ncs-31-radiation-protection-and-dosimetry-of-the-eye-lens
Article
Purpose CT-guided periradicular infiltration of the cervical spine is an effective symptomatic treatment in patients with radiculopathy-associated pain syndromes. This study evaluates the robustness and safety of a low-dose protocol on a CT scanner with iterative reconstruction software. Materials and Methods A total of 183 patients who underwent periradicular infiltration therapy of the cervical spine were included in this study. 82 interventions were performed on a new CT scanner with a new intervention protocol using an iterative reconstruction algorithm. Spot scanning was implemented for planning and a basic low-dose setup of 80 kVp and 5 mAs was established during intermittent fluoroscopy. The comparison group included 101 prior interventions on a scanner without iterative reconstruction. The dose-length product (DLP), number of acquisitions, pain reduction on a numeric analog scale, and protocol changes to achieve a safe intervention were recorded. Results The median DLP for the whole intervention was 24.3 mGy*cm in the comparison group and 1.8 mGy*cm in the study group. The median pain reduction was –3 in the study group and –2 in the comparison group. A 5 mAs increase in the tube current-time product was required in 5 patients of the study group. Conclusion Implementation of a new scanner and intervention protocol resulted in a 92.6 % dose reduction without a compromise in safety and pain relief. The dose needed here is more than 75 % lower than doses used for similar interventions in published studies. An increase of the tube current-time product was needed in only 6 % of interventions. Key Points: Citation Format
Article
Purpose: To compare outcomes of percutaneous robot-assisted uterine fibroid embolization (UFE) using two different endovascular robotic catheters. Methods: Twenty-one patients with a symptomatic uterine fibroid were prospectively enrolled in a single-center study to be treated with a percutaneous robot-assisted embolization using the Magellan system. Fourteen patients were treated using a first generation steerable robotic catheter, version 1.0 (group 1), and seven were treated using the new version 1.1 (group 2). Demographic, pathologic, and procedural variables were recorded. Dose Area Product (DAP) and physician equivalent doses were registered for each procedure. Procedural related complications and clinical midterm outcomes were also evaluated. Results: Successful robot-assisted UFE was obtained in eight patients (57.1%) in group 1 and 7 patients (100%) in group 2 (p = 0.01). A successful robot-assisted catheterization of the internal iliac artery anterior branch was performed in all patients of both groups. Median selective target vessel catheterization time was 21.0 ± 12.8 vs 13.4 ± 7 min (p = 0.04) and total fluoroscopy time was 30.3 ± 11.2 vs 19.3 ± 5.9 min, respectively, in group 1 and 2. Mean DAP decreased from 18472.6 ± 15622 to 5469.1 ± 4461.0 cGy·cm(2) (p = 0.04). All patients obtained a symptoms relief at 6 months follow-up. Conclusions: Robot-assisted uterine fibroid embolization is safe and effective. New version of steerable robotic catheter allows performing a faster procedure without related adverse events compared to old version.
Article
Objectives: There is potential for high radiation exposure during neurointerventional procedures. Increasing regulatory requirements mandate dose monitoring of patients and staff, and justification of high levels of radiation exposure. This paper demonstrates the potential to use radiation dose-tracking software to establish local diagnostic reference levels. Methods: Consecutive neurointerventional procedures, performed in a single institution within a one-year period, were retrospectively studied. Dose area product (DAP) data were collected using dose-tracking software and clinical data obtained from a prospectively generated patient treatment database. Results: Two hundred and sixty-four procedures met the selection criteria. Median DAP was 100 Gy.cm2 for aneurysm coiling procedures, 259 Gy.cm2 for arteriovenous malformation (AVM) embolisation procedures, 87 Gy.cm2 for stroke thrombolysis/thrombectomy, and 74 Gy.cm2 for four-vessel angiography. One hundred and nine aneurysm coiling procedures were further studied. Six significant variables were assessed using stepwise regression analysis to determine effect on DAP. Aneurysm location (anterior vs posterior circulation) had the single biggest effect (p = 0.004). Conclusions: This paper confirms variable radiation exposures during neurointerventional procedures. The 75th percentile (used to define diagnostic reference levels) of DAP measurements represents a reasonable guidance metric for monitoring purposes. Results indicate that aneurysm location has the greatest impact on dose during coiling procedures and that anterior and posterior circulation coiling procedures should have separate diagnostic reference levels. Key points: • Dose-tracking software is useful for monitoring patient radiation dose during neurointerventional procedures • This paper provides a template for methodology applicable to any interventional suite • Local diagnostic reference levels were defined by using the 75th percentile of DAP as per International Commission on Radiological Protection recommendations • Aneurysm location is the biggest determinant of radiation dose during coiling procedures. • Anterior and posterior circulation coiling procedures should have separate diagnostic reference levels.
Article
The use of radiological activity in operating room (OR) and regulatory decrease of lens eyes dose warrant assessing how medical staff is protected from radiation. This study aims at evaluating practices and knowledge in radiation protection (RP) for OR doctors before and after training. A descriptive study of surgeons and anesthetists in a French public hospital center was conducted in 2016. An ad-hoc questionnaire concerning occupational practices and knowledge about RP was distributed before and one month after RP training. Among 103 doctors attending training 90 answered the questionnaire before. Results showed a lack of knowledge and good practices in RP. Most of the participants (86.7%) have never been trained to RP and recognize insufficient knowledge. Most of them (92.2%) wear a leaded apron, 50.0 % a thyroid-shield, 5.6% leaded glasses, 53.3% a passive dosimeter and 17.8% an electronic dosimeter. None of them benefit collective protective equipment such as ceiling suspended screen. The questionnaire after was completed by 35 doctors only. Comparison before and after training results show improvement in knowledge (scores of correct responses: 5.5/16 before and 9.5/16 after training) but not in RP good practices (scores of correct responses: 3.2/7 before and 3.3/7 after training). One training session appears to be not sufficient to improve the application of the safety rules when X-rays are used. It needs to improve communication about RP among the anesthetists and surgeons such as training renewal, workstation analysis in OR related to X-rays use and occupational medical follow-up. Otherwise, it needs to better consider radiological risks in OR such as radio-induced cataract risk. It is necessary to encourage the use of dosimeters and protective equipment and strengthen access to leaded glasses and collective protective equipment such as ceiling suspended screen. All these recommendations permit to reduce the received dose as low as reasonably achievable.
Article
Purpose: There is limited understanding of the mechanistic effects of ionizing radiation (IR) exposure in cataract formation. In this study, we explored the effects of IR on reactive oxygen/nitrogen species (ROS and RNS) generation in human lens epithelial (HLE) cells as an early key event to long-term damage. Materials and methods: HLE cell-line was exposed to X-rays at varied doses (0-5 Gy) and dose-rates. Cell lysates and supernatants were collected 20 h post-exposure and analysed for viability, cell cycling and metabolites of ROS (p, m-, o-, tyrosines, 3-chlorotyrosine (cl-tyrosine), 8-hydroxy deoxyguanosine, (8-OH-dG) and RNS (3-nitrotyrosine). Results and conclusions: HLE cell-line exhibited a bi-phasic response in terms of cell viability, ROS and RNS profiles. At doses <0.5 Gy, ROS and RNS levels were lower than control and at higher doses (>0.5 Gy) a steady increase was observed in each metabolite. This response was observed irrespective of dose-rate. Among the associations tested, cl, p, m-tyrosine and 3-nitrotyrosine revealed changes (p < 0.05) at 5 Gy compared exclusively to 0.05 and 0.01 Gy. In addition, dose-rate related differences were observed. Overall, the data suggests that ROS and RNS are key events in radiation induced damage and this response dependant on the dose and dose-rate of IR exposure.
Article
A systematic review was conducted to provide an overview of the health effects of occupational radiation exposure from interventional fluoroscopy procedures on medical radiation workers. Among the 34 studies that met the inclusion criteria, most studies were cross-sectional (76%) and published after 2011 (65%) in a handful of countries. Although diverse outcomes were reported, most studies focused on cataracts. Radiation health effects were rarely assessed by risk per unit dose. Interventional radiation medical workers represent a small subset of the population studied worldwide. Further epidemiologic studies should be conducted to evaluate health outcomes among interventional radiation medical workers.
Article
The ocular lens is one of the most susceptible structures in the body to radiation damage. Unfortunately, much of the traditional academic and regulatory thinking on thresholds to develop radiation-induced opacities or cataracts has proven to be false. Individual vulnerability to the effects of radiation is extremely variable, largely because each individual is variably genetically equipped to repair the damage caused by radiation. Therefore many people, including some unsuspecting interventional radiologists may have no, or almost no, threshold at all for cataract development after radiation injury. For most others, if there is a threshold it is a fraction of what was previously thought. These new data have become apparent during the same time period when unprecedented numbers of physicians and medical staff have been exposed to unprecedented doses of scatter radiation as the number and complexity of fluoroscopic guided procedures has exploded. Increased rates of radiation lens damage have already been documented in physicians and support staff working in interventional medicine. As there is a latency period of years to decades for lens injury to fully evolve it is quite possible the true incidence will not be known for some time. Strategies to minimize the potential risks encountered in interventional medicine include radiation safety best practices, passive and personal barrier protection, and philosophical approach to interventional radiology practice. Ignore this article at your peril.
Article
Purpose: The International Commission on Radiological Protection (ICRP) recently recommended reducing the occupational equivalent dose limit for the lens of the eye. Based primarily on a review of epidemiological data, the absorbed dose threshold is now considered to be 0.5 Gy independent of dose-rate and severity of opacifiction, reduced from the previous threshold of 2 Gy. However, direct mechanistic evidence to support an understanding of the underlying molecular mechanisms of damage is still lacking. To this end, we explored the effects of a broad dose-range of ionizing radiation exposure on gene expression changes in a human lens epithelial (HLE) cell-line in order to better understand the shape of the dose-response relationship and identify transcriptional thresholds of effects. Methods: HLE cells were exposed to doses of 0, 0.01, 0.05, 0.25, 0.5, 2, and 5 Gy of X-ray radiation at two dose rates (1.62 cGy/min and 38.2 cGy/min). Cell culture lysates were collected 20 h post-exposure and analysed using whole-genome RNA-sequencing. Pathways and dose-thresholds of biological effects were identified using benchmark dose (BMD) modeling. Results: Transcriptional responses were minimal at doses less than 2 Gy. At higher doses there were a significant number of differentially expressed genes (DEGs) (p ≤ 0.05, fold change ≥ |1.5|) at both dose rates, with 1308 DEGs for the low dose rate (LDR) and 840 DEGs for the high dose rate (HDR) exposure. Dose-response modeling showed that a number of genes exhibited non-linear bi-phasic responses, which was verified by digital droplet PCR. BMD analysis showed the majority of the pathways responded at BMD median values in the dose range of 1.5-2.5 Gy, with the lowest BMD median value being 0.6 Gy for the HDR exposure. The minimum pathway BMD median value for LDR exposure, however, was 2.5 Gy. Although the LDR and HDR exposures shared pathways involved in extracellular matrix reorganization and collagen production with BMD median value of 2.9 Gy, HDR exposures were more effective in activating pathways associated with DNA damage response, apoptosis, and cell cycling relative to LDR exposure. Conclusion: Overall, the results suggest that radiation induces complex non-linear transcriptional dose-response relationships that are dose-rate dependent. Pathways shared between the two dose rates may be important contributors to radiation-induced cataractogenesis. BMD analysis suggests that the majority of pathways are activated above 0.6 Gy, which supports current ICRP identified dose thresholds for deterministic effects to the lens of the eye of 0.5 Gy.
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Objectives This retrospective study evaluated the visibility, location, and morphology of the primary maxillary ostium (PMO), as well as the presence and number of accessory maxillary ostia (AMO) in the maxillary sinus using cone beam computed tomography (CBCT). Materials and methods CBCT scans with a large field of view with both maxillary sinuses entirely visible, acquired from February 2016 to February 2018, were initially screened. Patients were included if there was no history of surgical intervention/trauma in the sinus region. Two observers evaluated the CBCTs for PMO and AMOs independently. PMO and AMOs were evaluated in axial, coronal, and sagittal CBCT views. In case of disagreement, a third observer served as a referee. The findings were correlated with age, gender, condition of the sinus mucosa, and status of the dentition to assess for potential influencing factors. Results A total of 184 patients (368 maxillary sinuses) were included. PMO was present and patent in 346 (94.0%) of the 368 analyzed sinuses. Most of the PMOs were located above the attachment of and in the middle third of the inferior turbinate (76.1%) and exhibited a slit shape (71.1%). An AMO was present in 167 (45.5%) of the 368 analyzed sinuses, and 66 (17.9%) sinuses had multiple AMOs. Gender and sinus mucosa morphology were found to be influencing factors for the patency of the PMO. Furthermore, gender seems to be influencing the presence of an AMO. Conclusions Most of the analyzed maxillary sinus cavities in the present population had a patent PMO. Being male and having morphological changes of the sinus mucosa were factors associated with a reduced prevalence of a patent PMO. Clinical relevance A maxillary sinus with pathological findings of the mucosa seems to have a reduced prevalence of patent PMOs. Therefore, clinicians should take care to assess any clinical and radiographical sign indicating a potential maxillary sinusitis prior to surgical interventions in this region, especially in cases with planned sinus floor elevation.
Article
CT-Befunde an den Augen sind häufig Nebenbefunde bei Hals- oder Schädeluntersuchungen. Eine gezielte CT der Augen ist z. B. bei einer vermuteten Bulbusperforation oder zur Suche intraokulärer Fremdkörper indiziert. Der vorliegende Artikel behandelt Veränderungen des Bulbus oculi, die in der CT festgestellt werden können und geht auch auf den Strahlenschutz ein, der bei jeder CT in besonderer Weise zu berücksichtigen ist.
Article
Objectives Interventional professionals tend to receive extended radiation exposure given the complexity and machine settings of procedures in interventional cardiology departments, resulting in a high eye lens dose. This study developed a method for estimating the occupational radiation dose to the eye lens based on the personal dose equivalent to the skin at 0.07-mm depth [Hp(0.07)] obtained using an over-apron dose badge, investigated whether glasses with lateral shielding but a thin Pb-equivalent material could adequately protect the eye lens from radiation in clinical situations, and identified factors affecting the occupational radiation dose to the eye lens. Methods The occupational radiation dose was prospectively measured using dosimeters near the eye and over the lead apron at the collar level in 26 interventional professionals performing 444 procedures in interventional cardiology departments. Type A (0.07-mm front and lateral Pb equivalence) and type B (0.5-mm front Pb equivalence and 0.25-mm lateral Pb equivalence) glasses were worn by the operators during operation to protect the eye lens. Results The median personal dose equivalent to the eye lens at 3-mm depth [Hp(3)/dose area product (DAP)] of the primary operator was the highest (7.6 μSv/Gycm²) for upper limb percutaneous transluminal angioplasty among all examined procedures. The secondary operator's median Hp(3)/DAP values ranged from 17% to 41% of that of the primary operator. The median Hp(3)/DAP values did not significantly differ between the primary operators wearing type A glasses and those wearing type B glasses for percutaneous coronary intervention or diagnostic cardiology studies (all p > 0.05). The Pearson correlation test results revealed significant positive correlations between the Hp(3) and Hp(0.07). The estimated annual Hp(3) values ranged from 3.3 ± 0.6 to 62.4 ± 8.3 mSv and from 6.0 to 8.0 ± 4.6 mSv for the cardiologists and radiographers, respectively. Conclusions The Hp(3) value can be estimated from the Hp(0.07) value obtained using an over-apron dose badge at the collar level. Glasses with 0.07-mm front and lateral Pb equivalence provide satisfactory radiation protection to the eye lens. Regularly using appropriate radiation-protective lead glasses, adopting small angles for left anterior oblique projections, and undertaking moderate workloads are highly recommended to prevent cardiologists from receiving excessive radiation doses to the eye lens.
Article
The reduction in the occupational dose limit of the eye lens has created the need for optimizing eye protection and dose assessment, in particular for interventional clinicians. Lead glasses are one of the protection tools for shielding the eyes, but assessing the eye lens dose when these are in place remains challenging. In this study, we evaluated the impact of the position of Hp(3) dosemeters on the estimated eye lens dose when lead glasses are used in interventional settings. Using the Monte Carlo method (MCNPX), an interventional cardiology setup was simulated for two models of lead glasses, five beam projections and two patient access routes. Hp(3) dosemeters were placed at several positions on the operator and the obtained dose was compared to the dose to the sensitive part of the eye lens (Hlens). Furthermore, to reproduce an experimental setup, a reference dosemeter, Hp(3)ref, was placed on the surface of the eye. The dose measured by Hp(3)ref was, on average, only 60% of Hlens. Dosemeters placed on the glasses, under their shielding, underestimated Hlens for all parameters considered, by from 10% up to 90%. Conversely, dosemeters placed on the head or on the glasses, over their shielding, overestimated Hlens, on average, up to 60%. The presence or lack of side shielding in lead glasses affected mostly dosemeters placed on the forehead, at the left side. Results suggest that both use of a correction factor of 0.5 to account for the presence of lead glasses in doses measured outside their shielding and placing an eye lens dosemeter immediately beneath the lenses of lead glasses may lead to underestimation of the eye lens dose. Most suitable positions for eye lens dose assessment were on the skin, unshielded by the glasses or close to the eye, with no correction to the dose measured.
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Scattered dose radiation to occupational in interventional cardiology cannot be neglected due to the long time for each procedure. The limit dose for occupational is 20 mSv per year or 0.01 mSv/h. The aim of this study is to calculate the effective dose of occupational and to analyse the optimization of radiation protection in the Cath lab. The simulation has been done using Rando phantom as a patient and Unfors Xi as scattered dose measuring instrument (in mGy/h). The data is collected in 6 different positions from altitudes 25 cm to 75 cm with a range of 15 cm without protective shielding. Field size of primary beam is varied to 20×20 cm and 25×25 cm, while gantry tilt is varied to caudal, cranial, and Left Anterior Oblique (LAO). The obtained data is multiplied by weighting factor base on its height. The result shows that the effective dose of occupational is in the range of 0.18-0.94 mSv/h, which is exceed the limit dose. To accommodate the limit dose for occupational, we propose the limitation of procedure time to 21-110 hours a year or the use of protective shielding as thick as 1-1.6 mm lead.
Article
Purpose Radiation exposure during coronary angiography is potentially harmful to patients and operators. However, there are limited data on the effects of a low-dose radiation angiography. We evaluated the feasibility and effectiveness of a reduced radiation dose protocol during invasive coronary angiography. Methods One hundred three consecutive patients who underwent coronary angiography were enrolled and randomized to low- or conventional dose protocols (LDP versus CDP). The LDP consists of 10 frames per second during fluoroscopy and half the radiation dose of CDP during cineangiography. Image quality was assessed using a Likert rating scale by an independent radiologist. The radiation dose was estimated with dose-area product (DAP) and air-kerma (AK). Results Body weight and waist circumference are well correlated with the level of DAP and AK. Exposure time and total images and frame counts in cineangiography were similar in both groups. There was a marked reduction of the estimated radiation dose (DAP and AK) in the LDP group compared to the CDP group without significant compromise in image quality (total DAP: LDP 1980.1 ± 1163.7 vs. CDP 3434.2 ± 2188.1 μGym² p = 0.001; total AK: 279.6 ± 159.3 vs. 493.8 ± 280.6 mGy, p < 0.001). Conclusion The LDP reduced the total estimated radiation dose compared to the CDP without a significant loss of diagnostic information. A LDP may be a viable strategy to protect patients and medical staff from the hazards of radiation in the cardiac catheterization laboratory.
Chapter
Reported rates of major complications following contemporary catheter ablation procedures vary by as much as five- to eight­fold between various types of ablation procedures, ranging from 0.8% for supraventricular tachycardia, 3.4% for idiopathic ventricular tachycardia, 5.2% for atrial fibrillation, and 6.0% for ventricular tachycardia associated with structural heart disease. Death is a rare complication of catheter ablation, occurring in 0.11% to 0.30% of patients with regular supraventricular tachycardia, and in 0.31% of those with ventricular tachycardia. Transsep­tal catheterization appears to contribute to the cause of death in 0.2% of procedures. Complications related to vascular access are among the most common problems observed following catheter ablation proce­dures. Other complications include iatrogenic arrhythmias, cardiac perforation, thromboembolism, air embolism, coronary artery injury, radiation exposure, as well as damage to surrounding extracardiac structures such as the esophagus and phrenic nerves. The optimal management of these complications is prevention. Several strategies have been employed to minimize the risk of complications. Early detection and prompt treatment are essential to improve the outcome after the occurrence of a complication.
Article
Purpose: To assess occupational lens exposure in a mixed interventional radiology department, comparing pediatric and adult procedures. To analyze the correlation between the lens dose and the doses measured at the chest and collar level and the kerma-area product (PKA ). Methods: For 17 months, three radiologists performing both pediatric and adult interventions were monitored by means of 14 dosimeters per worker: 12 single-point optically stimulated luminescent (OSL) dosimeters calibrated in terms of Hp (0.07) were placed on the inside and outside of two pairs of lead glasses, one for pediatric procedures and one for adult interventions; another whole-body OSL dosimeter calibrated in terms of Hp (10) was placed over the thyroid shield; finally, an additional active solid-state dosimeter, also calibrated for Hp (10), was worn on the chest, over the apron. Furthermore, a database was created to register the demographic and dosimetric data of the procedures, as well as the name of the radiologist acting as first operator. Results: For the three radiologists, who performed 276-338 procedures/year (20% pediatric), cumulative annual doses to the left bare eye exceeded 20 mSv (21-61 mSv). Considering the glasses' protection, annual doses exceeded 6 mSv (13-48 mSv) for both eyes. No important differences were observed in lens dose per procedure between pediatric and adult interventions (0.16 vs. 0.18, 0.12 vs. 0.09, and 0.07 vs. 0.07 mSv), although lens dose per PKA was 4.1-4.5 times higher in pediatrics (5.8 vs. 1.3, 3.3 vs. 0.8, and 2.6 vs 0.6 µSv/Gy·cm2 ) despite a similar use of the ceiling-suspended screen. Lens doses were highly correlated with collar readings (with Pearson coefficients [r] ranging from 0.86 to 0.98) and with chest readings (with r ranging from 0.75 to 0.93). However, slopes of the linear regressions varied greatly among radiologists. Conclusions: There is real risk of exceeding the occupational dose limit to the eye lens in mixed interventional radiology rooms if radiation protection tools are not used properly. Regular monitoring of the lens dose is recommended, given lens exposure might easily exceed 6 mSv/year. Using a collar dosimeter for this purpose might be suitable if it is preceded by an individualized regression analysis. The same radiation protection measures should be applied to interventional radiologists regardless of whether they are treating pediatric or adult patients.
Chapter
There has been an increasing use of medical imaging and interventional procedures associated with a dramatic increase in the human exposure to ionizing radiation from all sources. The increased application of endovascular techniques warrants that interventionalists are well trained in the risks involved to themselves and their patients and are educated in techniques and technology to protect themselves from radiation. Biologic and clinical effects of radiation should be understood and recognized by physicians using radiation. Dose limits and methods to protect the patient and the operator from adverse exposure are established. Special considerations regarding protection of the pregnant patient, operator, and the fetus are discussed. New technologies are described as they impact the increasing complexity of endovascular procedures. Quality improvement and radiation safety monitoring are considered in the context of building a successful endovascular practice.
Article
Data suggest that radiation-induced cataracts may form without a threshold and at low-radiation doses. Staff involved in interventional radiology and cardiology fluoroscopy-guided procedures have the potential to be exposed to radiation levels that may lead to eye lens injury and the occurrence of opacifications have been reported. Estimates of lens dose for various fluoroscopy procedures and predicted annual dosages have been provided in numerous publications. Available tools for eye lens radiation protection include accessory shields, drapes and glasses. While some tools are valuable, others provide limited protection to the eye. Reducing patient radiation dose will also reduce occupational exposure. Significant variability in reported dose measurements indicate dose levels are highly dependent on individual actions and exposure reduction is possible. Further follow-up studies of staff lens opacification are recommended along with eye lens dose measurements under current clinical practice conditions.
Article
Introduction and objectives: It is relevant to estimate the uncertainties in the estimation of eye lens doses from a personal dosimeter over the protective apron without using additional dosimetry near the eyes. Additional dosimetry for interventionists represents a difficulty for routine clinical practice. This study analyses the estimated eye doses from dosimeter values taken at chest level over the apron and their uncertainties. Methods: Measurements of Hp(0.07) using OSL dosimeters located on the chest over the apron and on the glasses (in the inner and outer part of the protection) were taken from 10 interventionalists in a university hospital, in the period 2018-2019 during standard clinical practice. Results: For a total sample of 133 interventional procedures included in our study, the ratio between the Hp(0.07) on the glasses (left-outer side) and on the chest over the apron had an average of 0.74, with quartiles of 0.47, 0.64, 0.88. Statistically significant differences were found among operators using the U-Mann-Whitney test. The average transmission factor for the glasses was 0.30, with quartiles of 0.21, 0.25, 0.32. Conclusion: Different complexity in the procedures, in the quality of the scatter radiation and in the individual operational practices, involve a relevant dispersion in the results for lens dose estimations from the over apron dosimeter. Lens doses may be between a 64% and an 88% of the over apron dosimeter values (using median or 3rd quartile). The use of 88% may be a conservative approach.
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Background: Due to the drastic reduction of the eye lens dose limit from 150 mSv per year to 20 mSv per year since 2018, the prospective investigation of the estimated dose of the eye lens by radiological imaging procedures at the surgical site during trauma surgery in the daily work process was carried out. This was also necessary because, as experience shows, with changes in surgical techniques, there are also changes in the use of radiological procedures, and thus an up-to-date inventory can provide valuable information for the assessment of occupationally induced radiation exposure of surgical personnel under the current conditions. Methods: The eye lens radiation exposure was measured over three months for five trauma surgeons, four hand surgeons and four surgical assistants with personalized LPS-TLD-TD 07 partial body dosimeters Hp (0.07). A reference dosimeter was deposited at the surgery changing room. The dosimeters were sent to the LPS (Landesanstalt für Personendosimetrie und Strahlenschutzausbildung) measuring institute (National Institute for Personal Dosimetry and Radiation Protection Training, Berlin) for evaluation after 3 months. The duration of the operation, occupation (assistant, surgeon, etc.), type of surgery (procedure, diagnosis), designation of the X-ray unit, total duration of radiation exposure per operation and dose area product per operation were recorded. Results: Both the evaluation of the dosimeters by the trauma surgeons and the evaluation of the dosimeters by the hand surgeons and the surgical assistants revealed no significant radiation exposure of the eye lens in comparison to the respective measured reference dosimeters. Conclusions: Despite the drastic reduction of the eye lens dose limit from 150 mSv per year to 20 mSv per year, the limit for orthopedic, trauma and hand surgery operations is well below the limit in this setting.
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Purpose: Despite its carcinogenic potential X-ray remains indispensible for EP procedures. In this randomized clinical trial we evaluate dose reduction as well as image quality (IQ) of a novel X-ray dose reduction technology, based on improved noise reduction (Allura Clarity, Philips) in a state of the art EP-lab. Methods: We performed a randomized, non-blinded trial in 136 consecutive patients undergoing ablations for complex arrhythmias (atrial fibrillation, atypical flutter or ventricular tachycardia). In the X-ray system (Philips Allura FD20) Allura Clarity was either switched ON (A; 68 patients) or OFF (N; 68 patients). Primary endpoint was overall procedural patient dose (expressed in Dose Area Product, DAP and Air Kerma, AK). Physician dose, procedural success and necessity to switch to higher dose settings, in order to improve IQ were used as secondary endpoints. Additionally, fluoro time, number of exposure frames and procedure duration were recorded. In case of non-normal distribution, the Mann-Whitney test was applied. Results: Baseline characteristics were similar, except for age. Patients in A-group were younger (56 vs 65 years old, P<0.001); BMI was equal (26 vs 26 kg/m2). Median DAP and AK were 40% and 47% lower in the A-group, compared to the N-group (median DAP 8723 vs 14608 mGycm2, AK 66 vs 123 mGy, P<0.001). Additionally, a significant physician dose reduction of 42% (median 3.5 vs 6 μSv, P<0.001) was achieved. Equivalence of fluoro time (21 vs 25 min), number of exposure frames (41 vs 35), and procedure duration (168 vs 163 min) indicate that IQ in the A-group is as adequate as in the N-group. Also, in all cases in both groups IQ was judged as adequate for the entire procedure. In both groups procedural success could not be achieved in 5 patients; in the A-group 1 tamponade occurred. Conclusion: A novel x-ray dose reduction technology (Allura Clarity, Philips) significantly reduces both patient and physician dose, while maintaining comparable image quality. Use of this technology will further improve safety of electrophysiological interventions.
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Three protective eyewear models were evaluated to determine effectiveness in reducing radiation dose to a fluoroscopist’s eyes. The performance of the protective eyewear was measured using radiation dosimeters in a fluoroscopy suite. An Eyewear Protection Factor was determined for each model in each of three exposure orientations. The protection was strongly influenced by the location of the radiation source. When the source was in front of the fluoroscopist, the lead equivalence was important. When the source was to the side of the fluoroscopist, the cross section of the side shield had a significant influence on protection. Protective eyewear selection needs to include consideration of job task and head orientation to the radiation source as well as the possibility that face shape and eyewear fit may also impact the radiation dose to the eye.
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Monte Carlo calculations were used to investigate the efficiency of radiation protection equipment in reducing eye and whole body doses during fluoroscopically guided interventional procedures. Eye lens doses were determined considering different models of eyewear with various shapes, sizes and lead thickness. The origin of scattered radiation reaching the eyes was also assessed to explain the variation in the protection efficiency of the different eyewear models with exposure conditions. The work also investigates the variation of eye and whole body doses with ceiling-suspended shields of various shapes and positioning. For all simulations, a broad spectrum of configurations typical for most interventional procedures was considered. Calculations showed that 'wrap around' glasses are the most efficient eyewear models reducing, on average, the dose by 74% and 21% for the left and right eyes respectively. The air gap between the glasses and the eyes was found to be the primary source of scattered radiation reaching the eyes. The ceiling-suspended screens were more efficient when positioned close to the patient's skin and to the x-ray field. With the use of such shields, the Hp(10) values recorded at the collar, chest and waist level and the Hp(3) values for both eyes were reduced on average by 47%, 37%, 20% and 56% respectively. Finally, simulations proved that beam quality and lead thickness have little influence on eye dose while beam projection, the position and head orientation of the operator as well as the distance between the image detector and the patient are key parameters affecting eye and whole body doses.
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Because of the increasing number of interventional endovascular procedures with fluoroscopy and the corresponding high annual dose for interventionalists, additional dose-protecting measures are desirable. The purpose of this study was to evaluate the effect of disposable radiation-absorbing surgical drapes in reducing scatter radiation exposure for interventionalists and supporting staff during an endovascular aneurysm repair (EVAR) procedure. This was a randomized control trial in which 36 EVAR procedures were randomized between execution with and without disposable radiation-absorbing surgical drapes (Radpad: Worldwide Innovations & Technologies, Inc., Kansas City, US, type 5511A). Dosimetric measurements were performed on the interventionalist (hand and chest) and theatre nurse (chest) with and without the use of the drapes to obtain the dose reduction and effect on the annual dose caused by the drapes. Use of disposable radiation-absorbing surgical drapes resulted in dose reductions of 49%, 55%, and 48%, respectively, measured on the hand and chest of the interventionalist and the chest of the theatre nurse. The use of disposable radiation-absorbing surgical drapes significantly reduces scatter radiation exposure for both the interventionalist and the supporting staff during EVAR procedures.
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The ICRP has recently recommended that the occupational exposure limit for the lens of the eye be reduced to 20 mSv in a year, averaged over defined periods of 5 years, with no single year exceeding 50 mSv. There has been concern amongst some groups of individuals, particularly interventional cardiologists and radiologists as well as relevant professional bodies, that implementation of these recommendations into UK law will adversely affect working patterns. However, despite a number of informative European studies, there is currently little UK dosimetry data available upon which judgements can effectively be based. In order to address this knowledge gap, Public Health England has carried out a small, targeted survey of UK lens doses to medical staff undertaking procedures likely to involve the highest levels of radiation exposure. Two out of a total of 61 individuals surveyed had projected annual doses which could be close to 20 mSv, measured outside lead glasses. Use of protective equipment was generally good; however, lead glasses were only used by 9 participants. The results of this survey suggest that compliance with the ICRP recommendations is likely to be possible for most individuals in the UK medical sector.
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The purpose of this study was to quantify the reduction in patient radiation dose by X-ray imaging technology using image noise reduction and system settings for neuroangiography and to assess its impact on the working habits of the physician. Radiation dose data from 190 neuroangiographies and 112 interventional neuroprocedures performed with state-of-the-art image processing and reference system settings were collected for the period January-June 2010. The system was then configured with extra image noise reduction algorithms and system settings, which enabled radiation dose reduction without loss of image quality. Radiation dose data from 174 neuroangiographies and 138 interventional neuroprocedures were collected for the period January-June 2012. Procedures were classified as diagnostic or interventional. Patient radiation exposure was quantified using cumulative dose area product and cumulative air kerma. Impact on working habits of the physician was quantified using fluoroscopy time and number of digital subtraction angiography (DSA) images. The optimized system settings provided significant reduction in dose indicators versus reference system settings (p<0.001): from 124 to 47 Gy cm(2) and from 0.78 to 0.27 Gy for neuroangiography, and from 328 to 109 Gy cm(2) and from 2.71 to 0.89 Gy for interventional neuroradiology. Differences were not significant between the two systems with regard to fluoroscopy time or number of DSA images. X-ray imaging technology using an image noise reduction algorithm and system settings provided approximately 60% radiation dose reduction in neuroangiography and interventional neuroradiology, without affecting the working habits of the physician.
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Within the ORAMED project (Optimization of Radiation Protection of Medical Staff) a coordinated measurement program for occupationally exposed medical staff was performed in different hospitals in Europe (www.oramed-fp7.eu). The main objective was to obtain a set of standardized data on extremity and eye lens doses for staff involved in interventional radiology and cardiology and to optimize radiation protection. Special attention was given to the measurement of the doses to the eye lenses. In this paper an overview will be given of the measured eye lens doses and the main influence factors for these doses. The measured eye lens doses are extrapolated to annual doses. The extrapolations showed that monitoring of the eye lens should be performed on routine basis.
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Ionizing radiation is a well-known but little understood risk factor for lens opacities. Until recently, cataract development was considered to be a deterministic effect occurring at lens doses exceeding a threshold of 5-8 Gy. Substantial uncertainty about the level and the existence of a threshold subsists. The International Commission on Radiation Protection recently revised it to 0.5 Gy. Based on a systematic literature review of epidemiological studies on exposure to low levels of ionizing radiation and the occurrence of lens opacities, a list of criteria for new epidemiological studies was compiled, and a list of potential study populations was reviewed. Among 24 publications finally identified, six report analyses of acute exposures in atomic bomb survivors and Chernobyl liquidators, and the others report analyses of protracted exposures in occupationally, medically or accidentally exposed populations. Three studies investigated a dose threshold: in atomic bomb survivors, the best estimates were 1 Sv (95 % CI <0-0.8 Sv) regarding lensectomies; in survivors exposed as children, 0.6 Sv (90 % CI <0.0-1.2 Sv) for cortical cataract prevalence and 0.7 Sv (90 % CI 0.0-2.8 Sv) for posterior subcapsular cataract; and in Chernobyl liquidators, 0.34 Sv (95 % CI 0.19-0.68 Sv) for stage 1 cataract. Current studies are heterogeneous and inconclusive regarding the dose-response relationship. Protracted exposures and high lens doses occur in several occupational groups, for instance, in physicians performing fluoroscopy-guided interventional procedures, and in accidentally exposed populations. New studies with a good retrospective exposure assessment are feasible and should be initiated.
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Purpose: To test the hypothesis that an image noise reduction algorithm designed for digital subtraction angiography (DSA) in interventional neuroradiology enables a reduction in the patient entrance dose by a factor of 4 while maintaining image quality. Materials and methods: This clinical prospective study was approved by the local ethics committee, and all 20 adult patients provided informed consent. DSA was performed with the default reference DSA program, a quarter-dose DSA program with modified acquisition parameters (to reduce patient radiation dose exposure), and a real-time noise-reduction algorithm. Two consecutive biplane DSA data sets were acquired in each patient. The dose-area product (DAP) was calculated for each image and compared. A randomized, blinded, offline reading study was conducted to show noninferiority of the quarter-dose image sets. Overall, 40 samples per treatment group were necessary to acquire 80% power, which was calculated by using a one-sided α level of 2.5%. Results: The mean DAP with the quarter-dose program was 25.3% ± 0.8 of that with the reference program. The median overall image quality scores with the reference program were 9, 13, and 12 for readers 1, 2, and 3, respectively. These scores increased slightly to 12, 15, and 12, respectively, with the quarter-dose program imaging chain. Conclusion: In DSA, a change in technique factors combined with a real-time noise-reduction algorithm will reduce the patient entrance dose by 75%, without a loss of image quality.
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Scatter radiation during interventional radiology procedures can produce cataracts in participating medical personnel. Standard safety equipment for the radiologist includes eye protection. The typical configuration of fluoroscopy equipment directs radiation scatter away from the radiologist and toward the anesthesiologist. This study analyzed facial radiation exposure of the anesthesiologist during interventional neuroradiology procedures. Radiation exposure to the forehead of the anesthesiologist and radiologist was measured during 31 adult neuroradiologic procedures involving the head or neck. Variables hypothesized to affect anesthesiologist exposure were recorded for each procedure. These included total radiation emitted by fluoroscopic equipment, radiologist exposure, number of pharmacologic interventions performed by the anesthesiologist, and other variables. Radiation exposure to the anesthesiologist's face averaged 6.5 ± 5.4 μSv per interventional procedure. This exposure was more than 6-fold greater (P < 0.0005) than for noninterventional angiographic procedures (1.0 ± 1.0) and averaged more than 3-fold the exposure of the radiologist (ratio, 3.2; 95% CI, 1.8-4.5). Multiple linear regression analysis showed that the exposure of the anesthesiologist was correlated with the number of pharmacologic interventions performed by the anesthesiologist and the total exposure of the radiologist. Current guidelines for occupational radiation exposure to the eye are undergoing review and are likely to be lowered below the current 100-150 mSv/yr limit. Anesthesiologists who spend significant time in neurointerventional radiology suites may have ocular radiation exposure approaching that of a radiologist. To ensure parity with safety standards adopted by radiologists, these anesthesiologists should wear protective eyewear.
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The aim of this study was to determine occupational dose levels in interventional radiology and cardiology procedures. The study covered a sample of 25 procedures and monitored occupational dose for all laboratory personnel. Each individual wore eight thermoluminescent dosemeters next to the eyes, wrists, fingers and legs during each procedure. Radiation protection shields used in each procedure were recorded. The highest doses per procedure were recorded for interventionists at the left wrist (average 485 μSv, maximum 5239 μSv) and left finger (average 324 μSv, maximum 2877 μSv), whereas lower doses were recorded for the legs (average 124 μSv, maximum 1959 μSv) and the eyes (average 64 μSv, maximum 1129 μSv). Doses to the assisting nurses during the intervention were considerably lower; the highest doses were recorded at the wrists (average 26 μSv, maximum 41 μSv) and legs (average 18 μSv, maximum 22 μSv), whereas doses to the eyes were minimal (average 4 μSv, maximum 16 μSv). Occupational doses normalised to kerma area product (KAP) ranged from 11.9 to 117.3 μSv/1000 cGy cm² and KAP was poorly correlated to the interventionists' extremity doses. Calculation of the dose burden for interventionists considering the actual number of procedures performed annually revealed that dose limits for the extremities and the lenses of the eyes were not exceeded. However, there are cases in which high doses have been recorded and this can lead to exceeding the dose limits when bad practices are followed and the radiation protection tools are not properly used.
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The prevailing belief for some decades has been that human radiation-related cataract occurs only after relatively high doses; for instance, the ICRP estimates that brief exposures of at least 0.5-2 Sv are required to cause detectable lens opacities and 5 Sv for vision-impairing cataracts. For protracted exposures, the ICRP estimates the corresponding dose thresholds as 5 Sv and 8 Sv, respectively. However, several studies, especially in the last decade, indicate that radiation-associated opacities occur at much lower doses. Several studies suggest that medical or environmental radiation exposure to the lens confers risk of opacities at doses well under 1 Sv. Among Japanese A-bomb survivors, risks for cataracts necessitating lens surgery were seen at doses under 1 Gy. The confidence interval on the A-bomb dose threshold for cataract surgery prevalence indicated that the data are compatible with a dose threshold ranging from none up to only 0.8 Gy, similar to the dose threshold for minor opacities seen among Chernobyl clean-up workers with primarily protracted exposures. Findings from various studies indicate that radiation risk estimates are probably not due to confounding by other cataract risk factors and that risk is seen after both childhood and adult exposures. The recent data are instigating reassessments of guidelines by various radiation protection bodies regarding permissible levels of radiation to the eye. Among the future epidemiological research directions, the most important research need is for adequate studies of vision-impairing cataract after protracted radiation exposure.
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To quantify the reduction in equivalent dose at operator's hand that can be achieved by placement of a radiation-absorbing drape (RADPAD) during long-lasting cardiac resynchronization therapy (CRT) procedures. This is a prospective observational study that included 22 consecutive patients with drug-refractory heart failure who underwent implantation of a CRT device. The cases were randomly assigned to Group A (11 cases), performed without RADPAD, and to Group B (11 cases), performed using RADPAD. Dose equivalent at the examiner's hand was measured as H(p)(0.07) and as a time-adjusted H(p)(0.07) rate (mGy/min) with a direct reading dosimeter. The mean fluoroscopy time was 20.8 ± 7.7 min and the mean dose area product (DAP) was 118.6 ± 45.3 Gy cm(2). No significant differences were found between body mass index, fluoroscopy time, and DAP between patients examined with or without RADPAD. The correlation between the fluoroscopy time and the DAP was high (R(2) = 0.94, P < 0.001). Mean dose and dose rate measurement without the RADPAD at the finger and hand were H(p)(0.07) = 1.27 ± 0.47 mGy per procedure and H(p)(0.07) rate = 0.057 ± 0.011 mGy/min, respectively. The dosage was reduced with the RADPAD to H(p)(0.07) = 0.48 ± 0.20 (P < 0.05) and to H(p)(0.07) rate = 0.026 ± 0.008 (P < 0.001), respectively. A mean reduction of 54% in the equivalent dose rate to the operator's hand can be achieved with the use of RADPAD. The use of the RADPAD in CRT devices implantation will make unlikely the necessity of limiting the yearly number of implants for high volume operators.
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Coronary angioplasties can be performed with either single-plane or biplane imaging techniques. The aim of this study was to determine whether biplane imaging, in comparison to single-plane imaging, reduces radiation dose and contrast load and shortens procedural time during (i) primary and elective coronary angioplasty procedures, (ii) angioplasty to the main vascular territories and (iii) procedures performed by operators with various levels of experience. This prospective observational study included a total of 504 primary and elective single-vessel coronary angioplasty procedures utilising either biplane or single-plane imaging. Radiographic and clinical parameters were collected from clinical reports and examination protocols. Radiation dose was measured by a dose-area-product (DAP) meter intrinsic to the angiography system. Our results showed that biplane imaging delivered a significantly greater radiation dose (181.4±121.0 Gycm2) than single-plane imaging (133.6±92.8 Gycm2, p<0.0001). The difference was independent of case type (primary or elective) (p=0.862), vascular territory (p=0.519) and operator experience (p=0.903). No significant difference was found in contrast load between biplane (166.8±62.9 ml) and single-plane imaging (176.8±66.0 ml) (p=0.302). This non-significant difference was independent of case type (p=0.551), vascular territory (p=0.308) and operator experience (p=0.304). Procedures performed with biplane imaging were significantly longer (55.3±27.8 min) than those with single-plane (48.9±24.2 min, p=0.010) and, similarly, were not dependent on case type (p=0.226), vascular territory (p=0.642) or operator experience (p=0.094). Biplane imaging resulted in a greater radiation dose and a longer procedural time and delivered a non-significant reduction in contrast load than single-plane imaging. These findings did not support the commonly perceived advantages of using biplane imaging in single-vessel coronary interventional procedures.
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The lens of the eye is recognized as one of the most radiosensitive tissues in the human body, and it is known that cataracts can be induced by acute doses of less than 2 Gy of low-LET ionizing radiation and less than 5 Gy of protracted radiation. Although much work has been carried out in this area, the exact mechanisms of radiation cataractogenesis are still not fully understood. In particular, the question of the threshold dose for cataract development is not resolved. Cataracts have been classified as a deterministic effect of radiation exposure with a threshold of approximately 2 Gy. Here we review the combined results of recent mechanistic and human studies regarding induction of cataracts by ionizing radiation. These studies indicate that the threshold for cataract development is certainly less than was previously estimated, of the order of 0.5 Gy, or that radiation cataractogenesis may in fact be more accurately described by a linear, no-threshold model.
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The study aim was to determine the risk of cataract among radiologic technologists with respect to occupational and nonoccupational exposures to ionizing radiation and to personal characteristics. A prospective cohort of 35,705 cataract-free US radiologic technologists aged 24-44 years was followed for nearly 20 years (1983-2004) by using two follow-up questionnaires. During the study period, 2,382 cataracts and 647 cataract extractions were reported. Cigarette smoking for >or=5 pack-years; body mass index of >or=25 kg/m(2); and history of diabetes, hypertension, hypercholesterolemia, or arthritis at baseline were significantly (p <or= 0.05) associated with increased risk of cataract. In multivariate models, self-report of >or=3 x-rays to the face/neck was associated with a hazard ratio of cataract of 1.25 (95% confidence interval: 1.06, 1.47). For workers in the highest category (mean, 60 mGy) versus lowest category (mean, 5 mGy) of occupational dose to the lens of the eye, the adjusted hazard ratio of cataract was 1.18 (95% confidence interval: 0.99, 1.40). Findings challenge the National Council on Radiation Protection and International Commission on Radiological Protection assumptions that the lowest cumulative ionizing radiation dose to the lens of the eye that can produce a progressive cataract is approximately 2 Gy, and they support the hypothesis that the lowest cataractogenic dose in humans is substantially less than previously thought.
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Ten types of lenses were tested for their radiation protection properties in three experimental circumstances: (a) Their good geometry (scatter free) attenuation was determined as a function of HVL in a direct x‐ray beam. (b) Their dose reducing properties were determined under simulated clinical fluoroscopic conditions, using both ion chambers and thermoluminescent dosimeters (TLD’s) while the lenses, mounted in frames, were worn by a head phantom. The head was oriented in four different directions to simulate clinical conditions in a fluoroscopic room. (c) Their dose reducing properties were measured with TLD’s while the glasses were worn by radiologists during clinical fluoroscopic procedures. Although several of the lenses could attenuate a direct x‐ray beam several thousand times, none of the glasses offer more than a factor of 8 reduction in eye exposure when the glasses are worn during fluoroscopy. This is attributed to backscatter from the fluoroscopist’s head and deficient lateral shielding. Some of the glasses may even be causing an increase in eye exposure when the TV monitor is located 90° or more from the patient.
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Objective: The purpose of this study was to validate the hypothesis that image quality of digital subtraction angiography (DSA) in pediatrics is not impaired when using a low-dose acquisition protocol. Materials and methods: Three piglets corresponding to common pediatric population sizes were used. DSA was performed in the aorta and renal, hepatic, and superior mesenteric arteries using both the commonly used reference standard and novel radiographic imaging noise reduction technologies to ensure pairwise radiation dose and image quality comparison. The air kerma per frame at the interventional reference point for each DSA acquisition was collected as a radiation dose measure, and image quality was evaluated by five interventional radiologists in a randomized blinded fashion using a 5-point scale. Results: The mean air kerma (± SD) at the interventional reference point with the novel x-ray imaging noise reduction technology was significantly lower (1.1 ± 0.8 mGy/frame) than with the reference technology (4.2 ± 3.0 mGy/frame, p = 0.005). However, image quality was statistically similar, with average scores of 3.2 ± 0.4 and 3.1 ± 0.5 for the novel and reference technologies, respectively (p = 0.934); interrater absolute agreement was 0.77. Conclusion: The DSA radiation dose for pediatrics can be reduced by a factor of four with a novel x-ray imaging noise reduction technology without deterioration of image quality.
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The atomic bomb and other studies have established with certainty that moderate-to-high doses of radiation cause many types of solid cancer and leukemia. Moving down the dose range to the vicinity of 100-200 mSv, the risks become fuzzy and then unknown at low doses on the order of 10-20 mSv. Nor have low-dose experimental studies provided definitive answers: some have suggested there may be adverse biological effects in the range of 5-50 mSv, while others support a "no risk" interpretation. Epidemiologic data contain intrinsic "noise" (variation by known and unknown factors related to genetics, lifestyle, other environmental exposures, sociodemographics, diagnostic accuracy, etc.) so are generally too insensitive to provide compelling answers in the low-dose range. However, there have been recent provocative reports regarding risk from relatively low-dose occupational and medical radiation exposures that warrant careful consideration. Summaries of the largest studies with low-dose or low dose-rate radiation exposure provide suggestive evidence of risk for solid cancer and stronger evidence for leukemia risk. Recently, interest in health endpoints other than cancer also has risen sharply, in particular the degree of cardiovascular and cataract risk following doses under 1 Sv. Data regarding cardiovascular disease are limited and fuzzy, with suggestions of inconsistencies, and the risk at low doses is essentially unknown. The evidence of cataract risk after low dose-rate exposures among those conducting interventional medical radiological procedures is becoming strong. The magnitude of radiation impacts on human health requires fuller documentation, especially for low-dose or low dose-rate exposures. From the epidemiologic vantage point, this will require longer observation of existing irradiated cohorts and development of new informative cohorts, improved accuracy in dose assessments, more attention to confounding variables, and more biosamples from irradiated groups to enable translational radiobiological studies. Introduction of Radiation Impacts on Human Health (Video 2:02, http://links.lww.com/HP/A35).
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This study was designed to evaluate the reduction of the eye lens dose when wearing protective eyewear in interventional radiology and to identify conditions that optimize the efficacy of radiation safety glasses. The dose reduction provided by different models of radiation safety glasses was measured on an anthropomorphic phantom head. The influence of the orientation of the phantom head on the dose reduction was studied in detail. The dose reduction in interventional radiological practice was assessed by dose measurements on radiologists wearing either leaded or no glasses or using a ceiling suspended screen. The different models of radiation safety glasses provided a dose reduction in the range of a factor of 7.9-10.0 for frontal exposure of the phantom. The dose reduction was strongly reduced when the head is turned to the side relative to the irradiated volume. The eye closest to the tube was better protected due to side shielding and eyewear curvature. In clinical practice, the mean dose reduction was a factor of 2.1. Using a ceiling suspended lead glass shield resulted in a mean dose reduction of a factor of 5.7. The efficacy of radiation protection glasses depends on the orientation of the operator's head relative to the irradiated volume. Glasses can offer good protection to the eye under clinically relevant conditions. However, the performance in clinical practice in our study was lower than expected. This is likely related to nonoptimized room geometry and training of the staff as well as measurement methodology.
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To investigate radiation exposure in computed tomography (CT)-guided interventions, to establish reference levels for exposure, and to discuss strategies for dose reduction. We analyzed 1576 consecutive CT-guided procedures in 1284 patients performed over 4.5 years, including drainage placements; biopsies of different organs; radiofrequency and microwave ablations (RFA/MWA) of liver, bone, and lung tumors; pain blockages, and vertebroplasties. Data were analyzed with respect to scanner settings, overall radiation doses, and individual doses of planning CT series, CT intervention, and control CT series. Eighy-five percent of the total radiation dose was applied during the pre- and post-interventional CT series, leaving only 15% applied by the CT-guided intervention itself. Single slice acquisition was associated with lower doses than continuous CT-fluoroscopy (37mGycm vs. 153mGycm, p<0.001). The third quartile of radiation doses varied considerably for different interventions. The highest doses were observed in complex interventions like RFA/MWA of the liver, followed by vertebroplasty and RFA/MWA of the lung. This paper suggests preliminary reference levels for various intervention types and discusses strategies for dose reduction. A multicenter registry of radiation exposure including a broader spectrum of scanners and intervention types is needed to develop definitive reference levels.
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Despite its carcinogenic potential, X-ray remains indispensable for electrophysiological (EP) procedures. To evaluate the dose reduction and image quality (IQ) of a novel X-ray technology using advanced image processing and dose-reduction technology in an EP laboratory. In this single-center, randomized, unblinded, parallel controlled trial, consecutive patients undergoing catheter ablation for complex arrhythmias were eligible. The Philips Allura FD20 system used allowed switching between the reference (Allura Xper) and the novel X-ray imaging technology (Allura Clarity). Primary endpoint was overall procedural patient dose, expressed in dose area product (DAP) and air kerma (AK). Operator dose, procedural success, and necessity to switch to higher dose settings were secondary endpoints RESULTS: A total of 136 patients were randomly assigned to the novel imaging (n = 68) or reference (n = 68) groups. Baseline characteristics were similar except patients in the novel imaging group were younger (58 vs 65 years; P < .01). Median DAP and AK were, respectively, 43% and 40% lower in the novel imaging group (P < .0001). A 50% operator dose reduction was achieved in the novel imaging group (P < .001). Fluoroscopy time, number of exposure frames, and procedure duration were equivalent between the two groups indicating that the IQ was similarly adequate in both groups. Procedural success was achieved in 91% of patients in both groups; 1 pericardial tamponade occurred in the novel imaging group. The novel imaging technology, Allura Clarity, significantly reduces patient and operator dose in complex EP procedures while maintaining IQ.
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In the past decade the number of computed tomography (CT)-guided procedures performed by interventional radiologists have increased, leading to a significantly higher radiation exposure of the interventionalist's eye lens. Because of growing concern that there is a stochastic effect for the development of lens opacification, eye lens dose reduction for operators and patients should be of maximal interest. To determine the interventionalist's equivalent eye lens dose during CT-guided interventions and to relate the results to the maximum of the recommended equivalent dose limit. During 89 CT-guided interventions (e.g. biopsies, drainage procedures, etc.) measurements of eye lens' radiation doses were obtained from a dedicated dosimeter system for scattered radiation. The sensor of the personal dosimeter system was clipped onto the side of the lead glasses which was located nearest to the CT gantry. After the procedure, radiation dose (µSv), dose rate (µSv/min) and the total exposure time (s) were recorded. For all 89 interventions, the median total exposure lens dose was 3.3 µSv (range, 0.03-218.9 µSv) for a median exposure time of 26.2 s (range, 1.1-94.0 s). The median dose rate was 13.9 µSv/min (range, 1.1-335.5 µSv/min). Estimating 50-200 CT-guided interventions per year performed by one interventionalist, the median dose of the eye lens of the interventional radiologist does not exceed the maximum of the ICRP-recommended equivalent eye lens dose limit of 20 mSv per year.
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This study investigated the relationship between the absorbed dose to the lens of the eye and the absorbed dose at different measurement positions near the eye of interventional radiologists. It also visualised the dose distribution inside the head, both when protective eyewear were used and without such protection. The best position for an eye lens dosimeter was found to be at the side of the head nearest to the radiation source, close to the eye. Positioning the dosimeter at the eyebrow could lead to an underestimation of the lens dose of as much as 45%. The measured dose distribution showed that the absorbed dose to the eye lenses was high compared to the other parts of the head, which stresses the importance of wearing protective eyewear. However, many models of eyewear were found to be deficient as the radiation could slip through at several places, e.g. at the cheek. The relationship between the absorbed dose to the lens and the kerma-area-product (PKA) delivered to the patient was also studied.
Article
Purpose: To estimate ocular radiation doses and prevalence of lens opacities in a group of interventional catheterization professionals and offer practical recommendations based on these findings to avoid future lens damage. Materials and methods: Subjects included 58 physicians and 69 nurses and technicians attending an interventional cardiology congress and appropriate unexposed age-matched controls. Lens dose estimates were derived from combining experimental measurements in catheterization laboratories with questionnaire responses regarding workload, types of procedures, and use of eye protection. Lens opacities were observed by dilated slit lamp examination using indirect illumination and retroillumination. The frequency and severity of posterior lens changes were compared between the exposed and unexposed groups. The severity of posterior lens changes was correlated with cumulative eye dose. Results: Posterior subcapsular lens changes characteristic of ionizing radiation exposure were found in 50% of interventional cardiologists and 41% of nurses and technicians compared with findings of similar lens changes in<10% of controls. Estimated cumulative eye doses ranged from 0.1-18.9 Sv. Most lens injuries result after several years of work without eye protection. Conclusions: A high prevalence of lens changes likely induced by radiation exposure in the study population suggests an urgent need for improved radiation safety and training, use of eye protection during catheterization procedures, and improved occupational dosimetry.