Variation in accumulated dose of volumetric‐modulated arc therapy for pancreatic cancer due to different beam starting phases
| Autor: | Mitsuhiro Nakamura, Makoto Sasaki, Y. Ishihara, Yoko Goto, Takashi Mizowaki, Manabu Nakata, Naozo Sugimoto, Nobutaka Mukumoto |
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| Rok vydání: | 2019 |
| Předmět: |
Organs at Risk
pancreatic cancer Planning target volume VMAT Computed tomography Dose distribution 030218 nuclear medicine & medical imaging 03 medical and health sciences 0302 clinical medicine Interplay effect Humans Radiation Oncology Physics Arc therapy Medicine Radiology Nuclear Medicine and imaging Four-Dimensional Computed Tomography Instrumentation Aged Retrospective Studies Aged 80 and over Radiation medicine.diagnostic_test beam starting phase business.industry Radiotherapy Planning Computer-Assisted DICOM‐RT plan file Radiotherapy Dosage Middle Aged Prognosis Volumetric modulated arc therapy Pancreatic Neoplasms 030220 oncology & carcinogenesis interplay effect Radiotherapy Intensity-Modulated business Nuclear medicine Algorithms Beam (structure) |
| Zdroj: | Journal of Applied Clinical Medical Physics |
| ISSN: | 1526-9914 |
| DOI: | 10.1002/acm2.12720 |
| Popis: | Purpose To assess the effects of different beam starting phases on dosimetric variations in the clinical target volume (CTV) and organs at risk (OARs), and to identify the relationship between plan complexity and the dosimetric impact of interplay effects in volumetric‐modulated arc therapy (VMAT) plans for pancreatic cancer. Methods Single and double full‐arc VMAT plans were generated for 11 patients. A dose of 50.4 Gy in 28 fractions was prescribed to cover 50% of the planning target volume. Patient‐specific Digital Imaging and Communications in Medicine–Radiation Therapy plan files were divided into 10 files based on the respiratory phases in four‐dimensional computed tomography (4DCT) simulations. The phase‐divided VMAT plans were calculated in consideration of the beam starting phase for each arc and were then combined in the mid‐ventilation phase of 4DCT (4D plans). The dose‐volumetric parameters were compared with the calculated dose distributions without consideration of the interplay effects (3D plans). Additionally, relationships among plan parameters such as modulation complexity scores, monitor units (MUs), and dose‐volumetric parameters were evaluated. Results Dosimetric differences in the median values associated with different beam starting phases were within ± 1.0% and ± 0.2% for the CTV and ± 0.5% and ± 0.9% for the OARs during single and double full‐arc VMAT, respectively. Significant differences caused by variations in the beam starting phases were observed only for the dose‐volumetric parameters of the CTV during single full‐arc VMAT (P |
| Databáze: | OpenAIRE |
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