The value of on-site proton audits.

Abstract Purpose To highlight the value and key findings of on-site proton audits. Methods & Materials The authors have performed 38 on-site measurement-based peer reviews of proton centers participating in NCI-funded clinical trials. The reviews covered beam calibration, lateral and depth measurements, mechanical checks, treatment planning and clinical practice, and quality assurance (QA) practices. Program deficiencies were noted and recommendations were made about ways institutions could improve their practices. Results Institutions received an average of 3 [1, 8] recommendations for practice improvements. The number of deficiencies did not decrease over time, highlighting the continued need for this type of peer review. The most common deficiencies were for Task Group recommended QA compliance (97% of centers), CT Number to RLSP conversion (59%), and QA procedures (53%). 32% of institutions assessed failed at least one lateral beam profile measurement ( Conclusions This peer review program has been integral in confirming and promoting consistency and best practice across proton centers for clinical trials, minimizing deviations for outcomes data.