[show abstract][hide abstract] ABSTRACT: Quality assurance data from five centres were analysed to assess the reliability of RapidArc radiotherapy delivery in terms of machine and dosimetric performance.
A large group of patients was treated with RapidArc radiotherapy and treatment data recorded. Machine quality assurance was performed according to Ling et al (Int J Radiat Oncol Biol Phys 2008;72:575-81). In addition, treatment to a typical clinical case was delivered biweekly as a constancy check. Pre-treatment dosimetric validation of plan delivery was performed for each patient. All measurements and computations were performed at the depth of the maximum dose in water according to the GLAaS method using electronic portal imaging device measurements. Evaluation was carried out according to a gamma agreement index (GAI, the percentage of field area passing the test); the threshold dose difference was 3% and the threshold distance to agreement was 3 mm.
A total of 275 patients (395 arcs) were included in the study. Mean delivery parameters were 31.0±20.0° (collimator angle), 4.7±0.5° s(-1) (gantry speed), 343±134 MU min(-1) (dose rate) and 1.6±1.4 min (beam-on time) for prescription doses ranging from 1.8 to 16.7 Gy/fraction. Mean deviations from the baseline dose rate and gantry speed ranged from -0.61% to 1.75%. Mean deviations from the baseline for leaf speed variation ranged from -0.73% to 0.41%. The mean GAI of repeated clinical fields was 99.2±0.2%. GAI varied from 84.7% to 100%; the mean across all patients was 97.1±2.4%.
RapidArc can provide a reliable and accurate delivery of radiotherapy for a variety of clinical conditions.
The British journal of radiology 06/2011; 84(1002):534-45. · 2.11 Impact Factor
[show abstract][hide abstract] ABSTRACT: A planning study was performed to evaluate RapidArc (RA), a volumetric modulated arc technique, on malignant pleural mesothelioma. The benchmark was conventional fixed-field intensity-modulated radiotherapy (IMRT).
The computed tomography data sets of 6 patients were included. The plans for IMRT with nine fixed beams were compared against double-modulated arcs with a single isocenter. All plans were optimized for 15-MV photon beams. The dose prescription was 54 Gy to the planning target volume. The planning objectives for the planning target volume were a minimal dose of >95% and maximal dose of <107%. For the organs at risk, the parameters were as follows: contralateral lung, percentage of volume receiving 5 Gy (V(5 Gy)) <60%, V(20 Gy) < 10%, mean <10.0 Gy; liver, V(30 Gy) <33%, mean <31 Gy; heart, V(45 Gy) <30%, V(50 Gy) <20%, dose received by 1% of the volume (D(1%)) <60 Gy; contralateral kidney, V(15 Gy) <20%; spine, D(1%) <45 Gy; esophagus, V(55 Gy) <30%; and spleen, V(40 Gy) <50%. The monitor units (MUs) and delivery time were scored to measure the treatment efficiency. The pretreatment portal dosimetry scored delivery to the calculation agreement with the Gamma Agreement Index.
RA and IMRT provided equivalent coverage and homogeneity. Both techniques fulfilled objectives on organs at risk with a tendency of RA to improve sparing. The conformity index was 1.9 +/- 0.1 for RA and IMRT. The number of MU/2 Gy was 734 +/- 82 for RA and 2,195 +/- 317 for IMRT. The planning vs. delivery agreement revealed a Gamma Agreement Index for IMRT of 96.0% +/- 2.6% and for RA of 95.7% +/- 1.5%. The treatment time was 3.7 +/- 0.3 min for RA and 13.4 +/- 0.1 min for IMRT.
RA demonstrated compared with conventional IMRT, similar target coverage and better dose sparing to the organs at risks. The number of MUs and the time required to deliver a 2-Gy fraction were much lower for RA, allowing the possibility to incorporate this technique in the treatment options for mesothelioma patients.
International journal of radiation oncology, biology, physics 04/2010; 77(3):942-9. · 4.59 Impact Factor
[show abstract][hide abstract] ABSTRACT: The radiation oncology process along with its unique therapeutic properties is also potentially dangerous for the patient, and thus it should be delivered under a systematic risk control. To this aim incident reporting and analysis are not sufficient for assuring patient safety and proactive risk assessment should also be implemented. The paper accounts for some methodological solutions, lessons learned and opportunities for improvement, starting from the systematic application of the failure mode effects and criticality analysis (FMECA) technique to the radiotherapy process of an Italian hospital.
The analysis, performed by a working group made of experts of the radiotherapy unit, was organised into the following steps: (1) complete and detailed analysis of the process (integration definition for function modelling); (2) identification of possible failure modes (FM) of the process, representing sources of adverse events for the patient; (3) qualitative risk assessment of FMs, aimed at identifying priorities of intervention; (4) identification and planning of corrective actions.
Organisational and procedural corrective measures were implemented; a set of safety indexes for the process was integrated within the traditional quality assurance indicators measured by the unit. A strong commitment of all the professionals involved was observed and the study revealed to be a powerful "tool" for dissemination of patient safety culture.
The feasibility of FMECA in fostering radiotherapy safety was proven; nevertheless, some lessons learned as well as weaknesses of current practices in risk management open to future research for the integration of retrospective methods (e.g. incident reporting or root cause analysis) and risk assessment.
Radiotherapy and Oncology 03/2010; 94(3):367-74. · 4.52 Impact Factor
[show abstract][hide abstract] ABSTRACT: When local recurrences arise within an irradiated region involving metastatic spinal cord compression, the dose limit to the spinal cord reduces the chance to re-treat the patient by 3D-conformational RT technique. The possibility of using volumetric modulated arc RT by RapidArc was evaluated for dose sparing at spinal cord level and preserving target coverage. A clinically satisfactory PTV coverage and dose sparing to the spinal cord were obtained. An upcoming trial on patients will provide clinical outcomes.
Radiotherapy and Oncology 12/2009; 94(1):67-70. · 4.52 Impact Factor
[show abstract][hide abstract] ABSTRACT: To evaluate the efficacy of different radiotherapy treatment modalities in radioresistant brain metastasis.
A retrospective analysis was conducted on 78 patients with brain metastases from melanoma, sarcoma, or renal cell carcinoma primary tumours who underwent radiosurgery (20 Gy) and/or hypofractionated stereotactic radiotherapy (6x4 Gy or 7x4 Gy) with or without whole-brain radiotherapy at our Center.
The actuarial median survival times for melanoma, renal cell carcinoma and sarcoma were 23, 22 and 7 months respectively, with a significant correlation to recursive partitioning analysis class.
Our results show that these treatments were effective both in symptom palliation and in improving survival, suggesting that although outcomes generally remained poor in this study population, it is possible and important to control intracranial brain metastases.
Anticancer research 10/2009; 29(10):4259-63. · 1.71 Impact Factor
[show abstract][hide abstract] ABSTRACT: A planning study was performed comparing volumetric modulated arcs, RapidArc (RA), fixed beam IMRT (IM), and conformal radiotherapy (CRT) with multiple static fields or short conformal arcs in a series of patients treated with hypofractionated stereotactic body radiation therapy (SBRT) for solitary or oligo-metastases from different tumors to abdominal lymph nodes.
Fourteen patients were included in the study. Dose prescription was set to 45 Gy (mean dose to clinical target volume [CTV]) in six fractions of 7.5 Gy. Objectives for CTV and planning target volume (PTV) were as follows: Dose(min) >95%, Dose(max) <107%. For organs at risk the following objectives were used: Maximum dose to spine <18 Gy; V(15Gy) <35% for both kidneys, V(36Gy) <1% for duodenum, V(36Gy) <3% for stomach and small bowel, V(15Gy) <(total liver volume--700 cm(3)) for liver. Dose-volume histograms were evaluated to assess plan quality.
Planning objectives on CTV and PTV were achieved by all techniques. Use of RA improved PTV coverage (V(95%) = 90.2% +/- 5.2% for RA compared with 82.5% +/- 9.6% and 84.5% +/- 8.2% for CRT and IM, respectively). Most planning objectives for organs at risk were met by all techniques except for the duodenum, small bowel, and stomach, in which the CRT plans exceeded the dose/volume constraints in some patients. The MU/fraction values were as follows: 2186 +/- 211 for RA, 2583 +/- 699 for IM, and 1554 +/- 153 for CRT. Effective treatment time resulted as follows: 3.7 +/- 0.4 min for RA, 10.6 +/- 1.2 min for IM, and 6.3 +/- 0.5 min for CRT.
Delivery of SBRT by RA showed improvements in conformal avoidance with respect to standard conformal irradiation. Delivery parameters confirmed logistical advantages of RA, particularly compared with IM.
International journal of radiation oncology, biology, physics 10/2009; 75(5):1570-7. · 4.59 Impact Factor
[show abstract][hide abstract] ABSTRACT: Non-small cell lung cancer (NSCLC) is the leading cause of cancer death worldwide. Stereotactic body irradiation offers a non-invasive treatment modality for patients with early stage NSCLC who are not amenable to surgery or other invasive approaches because of their poor medical condition.
Forty-three inoperable patients with NSCLC were treated with SBRT at our institution. A mean total dose of 30.5 Gy in 1-4 fractions was applied. The median follow-up duration was 14 months (range 6-36 months).
The actuarial survival at two years was 53%: two patients died from cancer progression whereas a further 8 patients died from comorbidities. Acute toxicity was practically absent, with 7 (16.3%) patients suffering from grade 1 symptoms and two from (4.6%) grade II effects. At the time of this report, only 1 patient had grade II and 6 patients (13.9%) grade I chronic symptoms.
Our results compare favourably with recently published studies and confirm that stereotactic radiotherapy has the potential to produce high local control rates with a low risk of lung toxicity in patients not amenable to curative resection. The low grade of side-effects is encouraging for shortening the treatment using a greater dose per fraction.
Anticancer research 27(5B):3615-9. · 1.71 Impact Factor