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Dynamic Collimator Angle Adjustments During Volumetric Modulated Arc Therapy to Account for Prostate Rotations
- Source :
- International journal of radiation oncology, biology, physics, 91(5), 1009-1016. Elsevier Inc.
- Publication Year :
- 2015
- Publisher :
- Elsevier BV, 2015.
-
Abstract
- Purpose: Rotations of the prostate gland induce considerable geometric uncertainties in prostate cancer radiation therapy. Collimator and gantry angle adjustments can correct these rotations in intensity modulated radiation therapy. Modern volumetric modulated arc therapy (VMAT) treatments, however, include a wide range of beam orientations that differ in modulation, and corrections require dynamic collimator rotations. The aim of this study was to implement a rotation correction strategy for VMAT dose delivery and validate it for left-right prostate rotations. Methods and Materials: Clinical VMAT treatment plans of 5 prostate cancer patients were used. Simulated left-right prostate rotations between +15 degrees and -15 degrees were corrected by collimator rotations. We compared corrected and uncorrected plans by dose volume histograms, minimum dose (D-min) to the prostate, bladder surface receiving >= 78 Gy (S78) and rectum equivalent uniform dose (EUD; n=0.13). Each corrected plan was delivered to a phantom, and its deliverability was evaluated by gamma-evaluation between planned and delivered dose, which was reconstructed from portal images acquired during delivery. Results: On average, clinical target volume minimum dose (D-min) decreased up to 10% without corrections. Negative left-right rotations were corrected almost perfectly, whereas Dmin remained within 4% for positive rotations. Bladder S78 and rectum EUD of the corrected plans matched those of the original plans. The average pass rate for the corrected plans delivered to the phantom was 98.9% at 3% per 3 mm gamma criteria. The measured dose in the planning target volume approximated the original dose, rotated around the simulated left-right angle, well. Conclusions: It is feasible to dynamically adjust the collimator angle during VMAT treatment delivery to correct for prostate rotations. This technique can safely correct for left-right prostate rotations up to 15 degrees. (C) 2015 Elsevier Inc. All rights reserved
- Subjects :
- Male
Cancer Research
Rotation
Movement
medicine.medical_treatment
Urinary Bladder
Planning target volume
Radiation Dosage
Imaging phantom
law.invention
Prostate cancer
law
Prostate
medicine
Humans
Radiology, Nuclear Medicine and imaging
Radiation
Phantoms, Imaging
business.industry
Radiotherapy Planning, Computer-Assisted
Rectum
Prostatic Neoplasms
Collimator
medicine.disease
Volumetric modulated arc therapy
Radiation therapy
medicine.anatomical_structure
Oncology
Calibration
Feasibility Studies
Radiotherapy, Intensity-Modulated
Nuclear medicine
business
Radiotherapy, Image-Guided
Subjects
Details
- ISSN :
- 03603016
- Volume :
- 91
- Database :
- OpenAIRE
- Journal :
- International Journal of Radiation Oncology*Biology*Physics
- Accession number :
- edsair.doi.dedup.....972a81dc680670502d406eaa28790dc7