A Pre-implementation Study of Volumetric Modulated Arc Therapy for Same-day Planning and Treatment of Vertebral Bone Metastases Within a Rapid-access Palliative Radiotherapy Programme
| Autor: | Julie Renaud, Karl G. Linden, Marc Gaudet, D. Granville, Robert Zohr, E. Ali, Kristopher Dennis, C. McGrath, Miller MacPherson |
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| Rok vydání: | 2020 |
| Předmět: |
Contouring
Palliative care business.industry Radiotherapy Planning Computer-Assisted Radiotherapy Dosage Radiosurgery Volumetric modulated arc therapy 030218 nuclear medicine & medical imaging 03 medical and health sciences 0302 clinical medicine Lumbar Oncology Palliative radiotherapy 030220 oncology & carcinogenesis Rapid access Medicine Humans Radiology Nuclear Medicine and imaging Radiotherapy Intensity-Modulated business Nuclear medicine Quality assurance Monte Carlo Method Vertebral bone |
| Zdroj: | Clinical oncology (Royal College of Radiologists (Great Britain)). 33(10) |
| ISSN: | 1433-2981 |
| Popis: | We aimed to develop a process for same-day contouring, planning, quality assurance and delivery of volumetric modulated arc therapy (VMAT) for vertebral bone metastases within our institution's rapid-access palliative radiotherapy programme.Two thoracic (T6-7, T3-7) and two lumbar (L2-3, L1-5) targets were contoured on computed tomography images acquired from an anthropomorphic phantom and five patient scans. Inverse planning aimed to provide coverage of a prescribed dose of 8 Gy with a combined lung V2Gy25% and a combined kidney mean dose2 Gy. Serial plans were created to identify an efficient combination of six main planning variables specific to our treatment planning system: (i) voxel size (3 mm versus 5 mm), (ii) Monte Carlo statistical uncertainty (1% per calculation versus 3% per control point), (iii) fluence smoothing (medium versus high), (iv) number of iterations of segment shape changes during optimisation (1 versus 5), (v) dose calculation algorithm (Monte Carlo versus pencil beam) and (vi) number of arcs (single versus multiple). Contouring, planning, quality assurance and treatment delivery were timed.The combination of planning variables deemed efficient and appropriate was: a 3 mm voxel size, statistical uncertainty of 1% per calculation, medium fluence smoothing, five iterations of segment shape changes, Monte Carlo dose calculation and single full arc delivery. Patient scan contouring times ranged from 7 to 9 min (T6-7), 11-13 min (T3-7), 5-7 min (L2-3) and 8-10 min (L1-5) and planning times ranged from 9 to 15 min (T6-7), 13-25 min (T3-7), 18-25 min (L2-3) and 21-31 min (L1-5). Physics quality assurance times ranged from 15 to 21 min and beam-on times ranged from 3 to 6 min.The combined elements of VMAT for thoracic and lumbar vertebral bone metastases were completed in under 2 h. This new process makes same-day contouring, planning, quality assurance and treatment delivery of VMAT feasible within our rapid-access palliative radiotherapy programme. |
| Databáze: | OpenAIRE |
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