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ABSTRACT: This planning study was performed to compare stereotactic linac based radiosurgery of Arteriovenous Malformations (AVM) with current Helical Tomotherapy (HT) and future HT techniques. For 10 patients with AVM, dose distributions and treatment times of "regular" HT delivery (Reg 2.5/1/0.6 cm field width), Running-Start-Stop Treatment (RSS 5/2.5 cm), Axial Mode (Axial 5 cm) and Dynamic Jaw/Dynamic Couch delivery with a maximum field width of 5 cm (DJDC 5) were analysed and compared to linac-based stereotactic radiosurgery. Axial produced the fastest treatment (Axial 4:47 min vs. Linac 32:42 min) at the cost of large brain exposure (V10% 289 ml). Except for Reg 0.6, all other HT techniques achieved significantly shorter treatment times than linac-based treatment (e.g. Reg 1, 19:42 min, DJDC 6:30 min). However, high-dose brain exposure (V60%) was higher in all HT plans (e.g. Reg 0.6, 10 ml, Linac 9 ml), and only Reg 0.6 showed better low-dose exposure (V10% of 167 ml vs. 199 ml, not significant). Neither current nor future HT modes in their current version outperformed linac-based stereotactic radiosurgery. However, AVM with special geometry might still benefit from HT.
Technology in cancer research & treatment 03/2013; · 2.02 Impact Factor
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ABSTRACT: Purpose: Evaluation of different calculation methods for dose modification due to intrafraction prostate motion using film measurements as ground truth. Methods: We acquired intrafraction motion data with the Calypso tumor tracking system by Varian Medical Systems Inc for 4 prostate IMRT patients treated with 35 fractions each. These motion data were transferred to a phantom platform which reproduces the observed motion and has a 20 cm diameter cylindrical solid water phantom mounted. For each patient all fractions were irradiated on one radiochromic MD-V2-55 film placed in the isocentric transversal slice of this phantom. These films serve as ground truth for three calculation Methods: 1) Recalculation of the plan with shifted target point for every segment with the segment's mean Calypso position. 2)+3) Convolution of the static dose distribution with a probability density function of the observed positions. For 2) only Calypso positions with activated beam on signal were used whereas for 3) all Calypso positions between the first and the last beam on signal for all fractions were employed. The comparisons between films and calculated dose distributions were made with the verification software VeriSoft 3.2 (PTW, Freiburg, Germany) where an 8×8 cm^2 ROI around the isocenter was selected for gamma evaluation. Results: The segment shifted plans reach 3%/3mm gamma values above 90% against the films for all four patients. For both convolution methods three values are above 90%, only for the patient with the largest intrafraction motion they decrease to 89%. Conclusions: Shifting of the target point for every segment is well suited to estimate the dosimetric consequences of intrafraction prostate motion. This may facilitate the evaluation of different margin sizes or dose prescribing recipes under different motion conditions. If such a lengthy calculation is not possible, a convolution with motion data can be used for acceptable results, too. Our work was partially supported by Siemens Healthcare and Varian Medical Systems Inc.
Medical Physics 06/2012; 39(6):3686. · 2.83 Impact Factor
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ABSTRACT: Preserving lung, heart, and the contralateral breast from toxicity is a technical challenge in women with funnel chest, who require breast irradiation. The purpose of this study was to determine whether helical tomotherapy (HT) offers an advantage compared to three-dimensional (3D) conformal radiotherapy (CRT) for patients with pectus excavatum with regard to its shape.
Ten breast cancer patients with pectus excavatum were graded into a low or high deformation group using different indices, measured and calculated by using the planning CT. A planning comparison was performed, creating plans for CRT and HT. Target uniformity, target conformity, and exposure to the organs at risk (OARs) were compared.
The uniformity and conformity of the target dose distribution and the median/average dose of the planning target volume (PTV) was inferior in CRT compared to HT in both deformation groups. By using tomotherapy, the volume of the lungs, the contralateral breast, and the heart, which received high dose exposure, could be significantly reduced. Tomotherapy plans led to a significantly higher low dose exposure to the lungs and contralateral breast.
This is the first study which evaluates a group of 10 breast cancer patients with funnel chest. Better uniformity and conformity combined with a significant reduction of high dose exposure to the OARs can be reached using tomotherapy. However, tomotherapy plans have a significantly larger volume of low dose to the lungs and contralateral breast. Therefore, the stochastic risk should be considered after low dose exposure in women with low deformation.
Strahlentherapie und Onkologie 01/2012; 188(2):127-35. · 3.56 Impact Factor
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ABSTRACT: With the development of modern radiation techniques, such as intensity-modulated radiotherapy (IMRT), a dose escalation in the definitive radiotherapy of prostate cancer and a consecutive improvement in biochemical recurrence-free survival (BFS) could be achieved. Among others, investigators at the Memorial Sloan-Kettering Cancer Center (MSKCC) saw 5-year BFS rates of up to 98%. A further gain in effectiveness and safety is expected of hypofractionation schedules, as suggested by data published by Kupelian et al., who saw a low 5-year rate of grade ≥2 rectal side-effects of 4.5%. However, randomized studies are just beginning to mature. Patients with intermediate or high-risk tumors should receive neoadjuvant (NHT) and adjuvant (AHT) androgen deprivation. Bolla et al. could show an increase in 5-year overall survival from 62-78%. The inclusion of the whole pelvis in the treatment field (WPRT) is still controversial. The RTOG 94-13 study showed a significant advantage in disease-free survival after 60 months but long-term data did not yield significant differences between WPRT and irradiation of the prostate alone.The German Society of Urology strongly recommends adjuvant radiotherapy of the prostate bed for pT3 N0 tumors with positive margins. In a pT3 N0 R0 or pT2 N0 R+ situation, adjuvant radiotherapy should at least be considered. So far, no randomized data on NHT and AHT have been published, so androgen deprivation remains an individual decision in the postoperative setting. In a retrospective analysis Spiotto et al. reported a positive effect for adjuvant WPRT and biochemical control.This article summarizes the essential publications on definitive and adjuvant radiotherapy and discusses the additional use of androgen deprivation and WPRT.
Der Radiologe 11/2011; 51(11):955-61. · 0.61 Impact Factor
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ABSTRACT: Accurate and reproducible patient setup is a prerequisite to fractionated radiotherapy. To evaluate the applicability and
technical performance of a commercial 3Dsurface imaging system (Galaxy, LAP Laser, Lüneburg, Germany) for patient alignment,
measurements were performed in a rigid anthropomorphic phantom as well as in a healthy volunteer. In addition, we launched
a study, which investigates the 3D-laser surface imaging system as a function of the treatment location for its clinical applicability
to determine the inter-fractional setup error in radiotherapy patients. The 3D-laser surface imaging system creates a 3D-surface
model by scanning the patient surface with laser beams. This model is used to compare the current setup with a pre-defined
reference setup. As a result, a couch adjustment is calculated and displayed. We compared the couch adjustments indicated
by the Galaxy system with setup corrections performed by an image guided radiation therapy unit (Tomotherapy (tomo) Hi Art
System, TomoTherapy, Madison, WI, USA). The optical surface imaging system showed a high stability and detected predefined
3D-translations of a phantom with an accuracy of 0.17 ± 0.35 mm and those of a healthy volunteer with an accuracy of 1.96
± 2.12 mm, respectively.
KeywordsRadiotherapy-3D surface imaging-setup errors-patient alignment-repositioning accuracy
12/2009: pages 295-298;
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ABSTRACT: Helical tomotherapy is a form of image-guided intensity-modulated radiotherapy that introduces the ring gantry concept into radiation oncology. The system is a combination of a therapeutic linear accelerator and a megavoltage CT-scanner. This work describes the clinical experience with megavoltage CT with 456 patients in more than 11000 fractions. It also provides a review of the current literature of the possibilities and limitations of megavoltage CT. Between July 2006 and October 2008 456 patients were treated with helical tomotherapy and a pretreatment megavoltage CT was performed in 98.1% of the 11821 fractions to perform position control and correction. CT image acquisition was done with 3.5 MV x-rays in the helical tomotherapy machine. MVCT was used for dose recalculations to quantify doses distributions in cases of changing geometry, tumor shrinkage or presence of metal implants. Inverse treatment planning for prostate cancer patients with bilateral hip replacements was performed based upon an MVCT. A mean 3D-correction vector of 7.1mm with a considerable variation was detected and immediately corrected. Mean shifts were lateral 0.9mm (sd 5.0mm), mean longitudinal shift 1.0mm (sd 5.1mm) and mean vertical shift 3.2mm (sd 5.2mm). The MVCT enables imaging of anatomical structures in the presence of dental metal or orthopedic implants. Especially in these cases, dose recomputations can increase the precision of dose calculations. Due to a mean 3d correction vector of more than 7mm and a variation of corrections of more than 5mm daily image-guidance is recommended to achieve a precise dose application. The MVCT shows evident advantages in cases with metal implants but has limitations due to a reduced soft tissue contrast. Compared with megavoltage cone-beam-CT the tomotherapy fan beam CT adds less extra dose fore the patient and has a better soft tissue contrast.
Technology in cancer research & treatment 10/2009; 8(5):343-52. · 2.02 Impact Factor
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DMW - Deutsche Medizinische Wochenschrift 09/2009; 134(39):1953-5. · 0.53 Impact Factor
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ABSTRACT: Technical developments in radiation oncology have led to major improvements in the treatment of locally advanced prostate cancer. This article summarizes the publications on dose escalation, including the side effects. The effect of additional hormonal therapy and irradiation of the pelvic lymphatics is also discussed.
Der Urologe 10/2008; 47(11):1424-30. · 0.50 Impact Factor
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ABSTRACT: Retrobulbar metastases from transitional cell carcinoma of the urinary bladder are very rare. This is a case report of palliative radiotherapy successfully reducing acute clinical symptoms such as proptosis, dysfunction of the eye muscles and diplopia in a 50-year-old male patient with a retrobulbar metastasis from transitional cell carcinoma. Radiotherapy quickly ameliorated the proptosis and dysfunction of the eye muscles without side effects. The patient's quality of life was clearly improved.
Der Ophthalmologe 03/2008; 105(2):170-2. · 0.62 Impact Factor
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ABSTRACT: Durch weitreichende technische Weiterentwicklung der Strahlentherapie konnten in den letzten Jahren die Heilungsraten beim Durch weitreichende technische Weiterentwicklung der Strahlentherapie konnten in den letzten Jahren die Heilungsraten beim
lokal fortgeschrittenen Prostatakarzinom deutlich gesteigert werden. Der Artikel fasst die entscheidenden Publikationen zur lokal fortgeschrittenen Prostatakarzinom deutlich gesteigert werden. Der Artikel fasst die entscheidenden Publikationen zur
Dosiseskalation zusammen, erfasst die Nebenwirkungen und diskutiert den zusätzlichen Einsatz einer Hormontherapie oder der Dosiseskalation zusammen, erfasst die Nebenwirkungen und diskutiert den zusätzlichen Einsatz einer Hormontherapie oder der
Bestrahlung der Lymphabflusswege. Bestrahlung der Lymphabflusswege.
Technical developments in radiation oncology have led to major improvements in the treatment of locally advanced prostate Technical developments in radiation oncology have led to major improvements in the treatment of locally advanced prostate
cancer. This article summarizes the publications on dose escalation, including the side effects. The effect of additional cancer. This article summarizes the publications on dose escalation, including the side effects. The effect of additional
hormonal therapy and irradiation of the pelvic lymphatics is also discussed. hormonal therapy and irradiation of the pelvic lymphatics is also discussed.
Der Urologe 01/2008; 47(11):1424-1430. · 0.50 Impact Factor
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ABSTRACT: Brain metastases represent the most common intracranial neoplasia. The lung, breast and kidney are the primary tumor locations most often associated with brain metastasis. Seizures and neurological impairment are typical manifestations of neoplastic cerebral dissemination, which, when untreated, usually lead to death within a few months. In this review, we discuss whole brain radiotherapy, surgical resection and stereotactic radiosurgery as the currently used therapeutic options for renal cell cancer metastasis in the brain.
Der Urologe 02/2007; 46(1):36-9. · 0.50 Impact Factor
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ABSTRACT: Hirnmetastasen sind die am hufigsten auftretenden intrakranialen Neoplasien. Meist sind es Metastasen von Lungen-, Brust- oder Nierentumoren. Das Auftreten von Krmpfen und neurologischen Ausfllen stellen die typischen klinischen Manifestationen der zerebralen Dissemination dar, welche unbehandelt in wenigen Monaten zum Tod fhrt. In dieser bersicht besprechen wir die aktuellen therapeutischen Optionen der Hirnmetastasen ausgehend vom Nierenzellkarzinom. Dies sind im Einzelnen: Ganzhirnbestrahlung, chirurgische Resektion und stereotaktische Radiochirurgie.Brain metastases represent the most common intracranial neoplasia. The lung, breast and kidney are the primary tumor locations most often associated with brain metastasis. Seizures and neurological impairment are typical manifestations of neoplastic cerebral dissemination, which, when untreated, usually lead to death within a few months. In this review, we discuss whole brain radiotherapy, surgical resection and stereotactic radiosurgery as the currently used therapeutic options for renal cell cancer metastasis in the brain.
Der Urologe 12/2006; 46(1):36-39. · 0.50 Impact Factor
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12/2005: pages 373-450;
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ABSTRACT: The purpose of this study was to monitor liver metastases after radiotherapy using contrast-enhanced ultrasound (CEUS). In 15 patients, follow-up examinations after stereotactic, single-dose radiotherapy were performed using CEUS (low mechanical index (MI), 2.4-ml SonoVue) and computed tomography (CT). Besides tumor size, the enhancement of the liver and the metastases was assessed at the arterial, portal venous, and delayed phases. The sizes of the tumor and of a perifocal liver reaction after radiotherapy measured with CEUS significantly correlated with those measured at CT (r=0.93, p<0.001). CEUS found a significant reduction of the arterial vascularization in treated tumors (p<0.05). In the arterial phase, the perifocal liver tissue was hypervascularized compared to the treated tumor (p<0.001); in the late phase, it was less enhanced than the liver (p<0.001) and more than the tumor (p<0.01). The perifocal liver reaction was also seen in CT, but with a variable enhancement at the arterial (50% hyperdense compared to normal liver tissue), venous, or delayed phase (each with 70% hyperdense reactions). CEUS allows for the assessment of tumor and liver perfusion, in addition to morphological tumor examination, which was comparable with CT. Thus, changes of tumor perfusion, which may indicate tumor response, as well as the perifocal liver reaction after radiotherapy, which must be differentiated from perifocal tumor growth, can be sensitively visualized using CEUS.
European Radiology 05/2005; 15(4):677-84. · 3.22 Impact Factor
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ABSTRACT: Stereotactic irradiation of lung tumors is a relatively new technique aiming at increased applicable radiation doses by a reduction of normal tissue involvement. As a result of adequate patient immobilization, three dimensional treatment planning and highly precise target point definition, the safety margins generally used in conventional radiotherapy can be reduced significantly. Increased fraction doses, which have an amplified biological effect, can be used and lead to a shortening of the overall treatment time. Especially for localized early-stage non-small-cell lung cancer the achieved dose escalation is proven to correlate with an increased local tumor control. But also the utilization for the therapy of lung metastases of solid tumors is possible. In spite of small patient cohorts and limited long-term data compared to conventional radiotherapy the results are promising.
Der Radiologe 06/2004; 44(5):484-90. · 0.61 Impact Factor
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ABSTRACT: Die stereotaktische Bestrahlung von Lungentumoren ist eine relativ neue Technik mit dem Ziel einer Erhhung der applizierbaren Strahlendosis durch Reduktion der Strahlenbelastung des Normalgewebes. Durch adquate Patientenimmobilisation, dreidimensionale Bestrahlungsplanung und eine hohe Przision in der Zielpunktdefinition lassen sich die bei der konventionellen Bestrahlung erforderlichen Sicherheitssume deutlich verringern. Gesteigerte Strahleneinzeldosen, die eine erhhte biologische Wertigkeit besitzen, sind einsetzbar und fhren zu einer deutlichen Verkrzung der Gesamttherapiedauer. Insbesondere beim lokalisierten nichtkleinzelligen Bronchialkarzinom ist die so zu erzielende Dosiseskalation erwiesenermaen mit einer erhhten Tumorkontrolle korreliert. Aber auch der Einsatz bei der Therapie einzelner Lungenmetastasen solider Tumoren ist mglich. Trotz bisher kleiner Patientenkollektive und begrenzter Langzeitdaten sind die Ergebnisse im Vergleich zur konventionellen Bestrahlung ermutigend.Stereotactic irradiation of lung tumors is a relatively new technique aiming at increased applicable radiation doses by a reduction of normal tissue involvement. As a result of adequate patient immobilization, threedimensional treatment planning and highly precise target point definition, the safety margins generally used in conventional radiotherapy can be reduced significantly. Increased fraction doses, which have an amplified biological effect, can be used and lead to a shortening of the overall treatment time. Especially for localized early-stage non-small-cell lung cancer the achieved dose escalation is proven to correlate with an increased local tumor control. But also the utilization for the therapy of lung metastases of solid tumors is possible. In spite of small patient cohorts and limited long-term data compared to conventional radiotherapy the results are promising.
Der Radiologe 04/2004; 44(5):484-490. · 0.61 Impact Factor
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ABSTRACT: To evaluate the setup accuracy that can be achieved with a novel noninvasive patient fixation technique based on a body cast attached to a recently developed stereotactic body frame during fractionated extracranial stereotactic radiotherapy.
Thirty-one CT studies (> or = 20 slices, thickness: 3 mm) from 5 patients who were immobilized in a body cast attached to a stereotactic body frame for treatment of paramedullary tumors in the thoracic or lumbar spine were evaluated with respect to setup accuracy. The immobilization device consisted of a custom-made wrap-around body cast that extended from the neck to the thighs and a separate head mask, both made from Scotchcast. Each CT study was performed immediately before or after every second or third actual treatment fraction without repositioning the patient between CT and treatment. The stereotactic localization system was mounted and the isocenter as initially located stereotactically was marked with fiducials for each CT study. Deviation of the treated isocenter as compared to the planned position was measured in all three dimensions.
The immobilization device can be easily handled, attached to and removed from the stereotactic frame and thus enables treatment of multiple patients with the same stereotactic frame each day. Mean patient movements of 1.6 mm+/-1.2 mm (laterolateral [LL]), 1.4 mm+/-1.0 mm (anterior-posterior [AP]), 2.3 mm+/-1.3 mm (transversal vectorial error [VE]) and < slice thickness = 3 mm (craniocaudal [CC]) were recorded for the targets in the thoracic spine and 1.4 mm+/-1.0 mm (LL), 1.2 mm+/-0.7 mm (AP), 1.8 mm+/-1.2 mm (VE), and < 3 mm (CC) for the lumbar spine. The worst case deviation was 3.9 mm for the first patient with the target in the thoracic spine (in the LL direction). Combining those numbers (mean transversal VE for both locations and maximum CC error of 3 mm), the mean three-dimensional vectorial patient movement and thus the mean overall accuracy can be safely estimated to be < or = 3.6 mm.
The presented combination of a body cast and head mask system in a rigid stereotactic body frame ensures reliable noninvasive patient fixation for fractionated extracranial stereotactic radiotherapy and may enable dose escalation for less radioresponsive tumors that are near the spinal cord or otherwise critically located while minimizing the risk of late sequelae.
International Journal of Radiation OncologyBiologyPhysics 10/1999; 45(2):521-7. · 4.11 Impact Factor
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ABSTRACT: We wished to investigate the circadian rhythm and pulsatility of parathyroid hormone (PTH) secretion in man, as conflicting results have been published.
To investigate the circadian rhythm during daytime, we sampled (a) peripheral blood at hourly intervals in 12 healthy young men from 0900 h until 1700 h. For observation of pulsatility, we sampled (b) peripheral blood at 1-minute intervals for 1 hour in three healthy men and three healthy women (mean 27.7 years, range 21-56 years) and (c) at 1-minute intervals for 30 minutes in 21 patients with surgically confirmed primary hyperparathyroidism (pHPT).
The serum levels of intact PTH were measured by two-site immunoradiometric assay and special care was taken to reduce intra-assay variability, especially at the normal PTH concentration. In series (a), ionized calcium, total calcium and phosphate were also determined.
A circadian rhythm during daytime was found for intact PTH in healthy men and women with a nadir at 0930 h and a peak in the afternoon. Ionized calcium and total calcium (protein-adjusted) decreased and phosphate increased in the afternoon. These changes were all statistically significant (P < 0.02). Pulsatility of PTH: Statistical cluster analysis of the data showed no pulsatility either in healthy persons or in patients with primary hyperparathyroidism. In two healthy women and one healthy man slight changes of longer duration were discovered, but no complete pulses. In five patients with primary hyperparathyroidism, larger differences between the highest and lowest concentrations of intact PTH were found, but no complete pulses.
Our data show a significant circadian rhythm during daytime of intact PTH and only minor changes from minute to minute. The alterations in PTH-levels occurred at longer time intervals in healthy persons. In some patients with primary hyperparathyroidism, decreases of PTH-levels were found. The circadian rhythm of PTH may be due to slight changes in calcium or phosphate concentration.
Clinical Endocrinology 01/1993; 37(6):511-9. · 3.17 Impact Factor
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ABSTRACT: The aim of this study was to determine the changes in serum calcium concentration and in the concentrations of calcium regulating hormones after a single oral or intravenous calcium administration. Standard dosages of calcium, as used in routine patient care, were employed. Intact parathyrin, calcitonin, calcitriol, calcidiol, total calcium, ionized calcium, total protein and phosphate were determined in 12 healthy young men before and up to 8 h after oral and intravenous administration of calcium. During a fortnight there were four study days with 1000 mg calcium orally (p.o.), 2000 mg orally, 180 mg calcium intravenous (i.v.) and a control day without calcium. During the study the men were on a low calcium diet. We observed a sharp increase in the calcium concentration after i.v. administration (15 min: total Ca: + 0.48 +/- 0.32 mmol/l; ionized Ca: + 0.25 +/- 0.15 mmol/l; p < 0.01). The concentration increase after the two oral loads was nearly identical. The maximal concentration of total calcium was reached after 120 min (1000 mg: + 0.1 +/- 0.04 mmol/l; p < 0.001; 2000 mg: + 0.12 +/- 0.04 mmol/l; p < 0.001). There was a significant increase in urinary calcium after all modes of calcium administration. Calcitonin increased significantly only after i.v. injection of calcium (+ 9.2 +/- 3.4 pmol/l; p < 0.001) while parathyrin decreased significantly after all modes of calcium administration (i.v.: 15 min: -1.9 +/- 0.88 pmol/l; p < 0.01; 1000 mg: 90 min: -0.78 +/- 0.75 pmol/l; p < 0.001; 2000 mg: 90 min: -1.02 +/- 0.57 pmol/l; p < 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)
European journal of clinical chemistry and clinical biochemistry: journal of the Forum of European Clinical Chemistry Societies 12/1992; 30(12):815-22.
