Results of an international survey of SunCHECK Patient users: consensus and benchmark data for plan verification, pre-treatment quality assurance and in vivo dosimetry tolerances.

Abstract

ObjectivesElectronic portal imaging devices (EPID) are well suited to radiotherapy in-vivo dosimetry (IVD), but limited guidance remains a barrier to routine clinical use. This SunCHECK (Sun Nuclear Corporation) user survey captured real-world configurations and tolerances for EPID-based patient-specific verification, as well as other aspects of patient-related QA, to establish consensus benchmark data and inform guidance for new and existing users.MethodsA structured survey was distributed to SunCHECK Patient users across the UK and Europe. Respondents reported current clinical practice for treatment plan verification, patient-specific quality assurance (PSQA), and IVD, including calibration methods, analysis modes, and investigation tolerances.ResultsSixty-four responses were received from 18 countries. Linear accelerator manufacturer, treatment planning algorithm, and level of SunCHECK experience had minimal influence on applied tolerances. Point dose difference is no longer widely used as a pass-fail metric. Most centres use gamma analysis for calibration with global normalisation, a 10% threshold, and a 95% pass rate. Plan verification and PSQA are almost universally assessed using gamma criteria of 3%/3 mm with a 95% passing tolerance. IVD tolerances fall into two main approaches: gamma criteria of 10%/5 mm for detecting gross errors, and tighter criteria of either 3%/3 mm or 5%/5 mm for identifying smaller, clinically relevant discrepancies.ConclusionsDespite extensive configurability within SunCHECK, there is strong consistency across centres in selected settings and investigation tolerances. These benchmark data provide practical guidance for reviewing and optimising local configurations.Advances in knowledgeThis work provides consensus-based guidance for configuring EPID IVD systems to reliably identify treatment delivery inconsistencies in clinical practice.