Treatment planning of VMAT and step‐and‐shoot IMRT delivery techniques for single fraction spine SBRT: An intercomparative dosimetric analysis and phantom‐based quality assurance measurements
| Autor: | Ping Xia, Zi Ouyang, Danielle LaHurd, John H. Suh, Samuel T. Chao, Ehsan H. Balagamwala |
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| Rok vydání: | 2019 |
| Předmět: |
Organs at Risk
treatment planning spine SBRT Quality Assurance Health Care VMAT quality assurance Radiosurgery Imaging phantom 030218 nuclear medicine & medical imaging 03 medical and health sciences 0302 clinical medicine Lumbar Statistical significance Humans Radiation Oncology Physics Medicine Radiology Nuclear Medicine and imaging IMRT Radiation treatment planning Instrumentation Retrospective Studies Spinal Neoplasms Radiation Phantoms Imaging business.industry Radiotherapy Planning Computer-Assisted Cauda equina Radiotherapy Dosage Spinal cord medicine.anatomical_structure 030220 oncology & carcinogenesis Mann–Whitney U test Radiotherapy Intensity-Modulated business Nuclear medicine Quality assurance |
| Zdroj: | Journal of Applied Clinical Medical Physics |
| ISSN: | 1526-9914 |
| DOI: | 10.1002/acm2.12788 |
| Popis: | Purpose To retrospectively compare clinically treated step-and-shoot intensity modulated radiotherapy (ssIMRT) and volumetric modulated arc therapy (VMAT) spine stereotactic body radiotherapy (SBRT) plans in dosimetric endpoints and pretreatment quality assurance (QA) measurements. Methods Five single fraction spine SBRT (18 Gy) cases - including one cervical, two thoracic, and two lumbar spines - clinically treated with ssIMRT were replanned with VMAT, and all plans were delivered to a phantom for comparing plan quality and delivery accuracy. Furthermore, we analyzed 98 clinically treated plans (18 Gy single fraction), including 34 ssIMRT and 29 VMAT for cervical/thoracic spine, and 19 ssIMRT and 16 VMAT for lumbar spine. The conformality index (CI) and homogeneity index (HI) were calculated, and QA measurement records were compared. For the spinal cord/cauda equina, the maximum dose to 0.03 cc (D0.03cc ) and volume receiving 10 or 12 Gy (V10Gy /V12Gy ) were recorded. Statistical significance was tested with the Mann-Whitney U test. Results Compared to ssIMRT, replanned VMAT plans had lower V10Gy /V12Gy and D0.03cc to the spinal cord/cauda equina in all five cases, and better CI in three out of five cases. The VMAT replans were slightly less homogeneous than those of ssIMRT plans. Both modalities passed IMRT QA with >95% passing rate with (3%, 3 mm) gamma criteria. With the 98 clinical cases, for cervical/thoracic ssIMRT and VMAT plans, the median V10Gy of spinal cord was 4.15% and 1.85% (P = 0.004); the median D0.03cc of spinal cord was 10.85 Gy and 10.10 Gy (P = 0.032); the median CI was 1.28 and 1.08 (P = 0.009); the median HI were 1.34 and 1.33 (P = 0.697), respectively. For lumbar spine, no significant dosimetric endpoint differences were observed. The two modalities were comparable in delivery accuracy. Conclusion From our clinically treated plans, we found that VMAT plans provided better dosimetric quality and comparable delivery accuracy when compared to ssIMRT for single fraction spine SBRT. |
| Databáze: | OpenAIRE |
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