Gail Distefano1, Jonny Lee2, Shakardokht Jafari3, Clare Gouldstone4, Colin Baker5, Helen Mayles2, Catharine H Clark6. 1. Department of Medical Physics, Royal Surrey County Hospital NHS Trust, Guildford, UK. Electronic address: gail.distefano@nhs.net. 2. Clatterbridge Cancer Centre, Liverpool, UK. 3. Department of Physics, University of Surrey, Guildford, UK; Radiology Department, Faculty of Medicine, Kabul Medical University, Afghanistan. 4. National Physical Laboratory, Teddington, UK. 5. Clatterbridge Cancer Centre, Liverpool, UK; Radiotherapy Physics, Royal Berkshire NHS Foundation Trust, Reading, UK. 6. Department of Medical Physics, Royal Surrey County Hospital NHS Trust, Guildford, UK; Department of Physics, University of Surrey, Guildford, UK; National Physical Laboratory, Teddington, UK.
Abstract
BACKGROUND AND PURPOSE: A UK national dosimetry audit was carried out to assess the accuracy of Stereotactic Ablative Body Radiotherapy (SABR) lung treatment delivery. METHODS AND MATERIALS: This mail-based audit used an anthropomorphic thorax phantom containing nine alanine pellets positioned in the lung region for dosimetry, as well as EBT3 film in the axial plane for isodose comparison. Centres used their local planning protocol/technique, creating 27 SABR plans. A range of delivery techniques including conformal, volumetric modulated arc therapy (VMAT) and Cyberknife (CK) were used with six different calculation algorithms (collapsed cone, superposition, pencil-beam (PB), AAA, Acuros and Monte Carlo). RESULTS: The mean difference between measured and calculated dose (excluding PB results) was 0.4±1.4% for alanine and 1.4±3.4% for film. PB differences were -6.1% and -12.9% respectively. The median of the absolute maximum isodose-to-isodose distances was 3mm (-6mm to 7mm) and 5mm (-10mm to +19mm) for the 100% and 50% isodose lines respectively. CONCLUSIONS: Alanine and film is an effective combination for verifying dosimetric and geometric accuracy. There were some differences across dose algorithms, and geometric accuracy was better for VMAT and CK compared with conformal techniques. The alanine dosimetry results showed that planned and delivered doses were within ±3.0% for 25/27 SABR plans.
BACKGROUND AND PURPOSE: A UK national dosimetry audit was carried out to assess the accuracy of Stereotactic Ablative Body Radiotherapy (SABR) lung treatment delivery. METHODS AND MATERIALS: This mail-based audit used an anthropomorphic thorax phantom containing nine alanine pellets positioned in the lung region for dosimetry, as well as EBT3 film in the axial plane for isodose comparison. Centres used their local planning protocol/technique, creating 27 SABR plans. A range of delivery techniques including conformal, volumetric modulated arc therapy (VMAT) and Cyberknife (CK) were used with six different calculation algorithms (collapsed cone, superposition, pencil-beam (PB), AAA, Acuros and Monte Carlo). RESULTS: The mean difference between measured and calculated dose (excluding PB results) was 0.4±1.4% for alanine and 1.4±3.4% for film. PB differences were -6.1% and -12.9% respectively. The median of the absolute maximum isodose-to-isodose distances was 3mm (-6mm to 7mm) and 5mm (-10mm to +19mm) for the 100% and 50% isodose lines respectively. CONCLUSIONS:Alanine and film is an effective combination for verifying dosimetric and geometric accuracy. There were some differences across dose algorithms, and geometric accuracy was better for VMAT and CK compared with conformal techniques. The alanine dosimetry results showed that planned and delivered doses were within ±3.0% for 25/27 SABR plans.
Authors: Alexis Dimitriadis; Antony L Palmer; Russell A S Thomas; Andrew Nisbet; Catharine H Clark Journal: Br J Radiol Date: 2017-05-25 Impact factor: 3.039
Authors: Carles Muñoz-Montplet; Rafael Fuentes-Raspall; Diego Jurado-Bruggeman; Sebastià Agramunt-Chaler; Albert Onsès-Segarra; Maria Buxó Journal: Adv Radiat Oncol Date: 2021-05-19