Error sensitivity of a log file analysis tool compared with a helical diode array dosimeter for VMAT delivery quality assurance
| Autor: | Patrick Clemens, T. Künzler, M. Meinschad, Philipp Szeverinski, M. Kowatsch, Alexander F. DeVries |
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| Rok vydání: | 2020 |
| Předmět: |
Quality Assurance
Health Care Imaging phantom 030218 nuclear medicine & medical imaging law.invention Root mean square 03 medical and health sciences 0302 clinical medicine law Humans Radiation Oncology Physics log file Radiology Nuclear Medicine and imaging ArcCHECK Instrumentation Mathematics Radiation Dosimeter Phantoms Imaging Radiation Dosimeters business.industry Radiotherapy Planning Computer-Assisted Radiotherapy Dosage Collimator LINACWatch 030220 oncology & carcinogenesis Ionization chamber VMAT delivery quality assurance Radiotherapy Intensity-Modulated Error detection and correction Nuclear medicine business Sensitivity (electronics) Quality assurance |
| Zdroj: | Journal of Applied Clinical Medical Physics |
| ISSN: | 1526-9914 |
| Popis: | Purpose Integrating log file analysis with LINACWatch® (LW) into clinical routine as part of the quality assurance (QA) process could be a time‐saving strategy that does not compromise on quality. The purpose is to determine the error sensitivity of log file analysis using LINACWatch® compared with a measurement device (ArcCHECK®, AC) for VMAT delivery QA. Materials and methods Multi‐leaf collimator (MLC) errors, collimator angle errors, MLC shift errors and dose errors were inserted to analyze error detection sensitivity. A total of 36 plans were manipulated with different magnitudes of errors. The gamma index protocols for AC were 3%/3 mm/Global and 2%/2 mm/Global, as well as 2%/2 mm/Global, and 1.5%/1.5 mm/Global for LW. Additionally, deviations of the collimator and monitor units between TPS and log file were calculated as RMS values. A 0.125 cm3 ionization chamber was used to independently examine the effect on dose. Results The sensitivity for AC was 20.4% and 49.6% vs 63.0% and 86.5% for LW, depending on the analysis protocol. For MLC opening and closing errors, the detection rate was 19.0% and 47.7% for AC vs 50.5% and 75.5% for LW. For MLC shift errors, it was 29.6% and 66.7% for AC vs 66.7% and 83.3% for LW. AC could detect 25.0% and 44.4% of all collimator errors. Log file analysis detected all collimator errors using 1° detection level. 13.2% and 42.4% of all dose errors were detected by AC vs 59.0% and 92.4% for LW using gamma analysis. Using RMS value, all dose errors were detected by LW (1% detection level). Conclusion The results of this study clearly show that log file analysis is an excellent complement to phantom‐based delivery QA of VMAT plans. We recommend a 1.5%/1.5 mm/Global criteria for log file‐based gamma calculations. Log file analysis was implemented successfully in our clinical routine for VMAT delivery QA. |
| Databáze: | OpenAIRE |
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