ESTRO 2024 - Abstract Book

S4847

Physics - Quality assurance and auditing

ESTRO 2024

Cause of Investigation

Plans

Corrective Action

Incorrect panel position

14.0%

Repeat transit

Data/images missing

1.3%

Retrieve missing data

TPS export

3.3%

Re-export plan

14.0% of transits were repeated due to an error in panel position. For a small minority, the repeat took more than one attempt which highlighted a correctable issue in the method used to centre the panel. 3.3% of results had errors relating to TPS export procedures and 1.3% of results had not retrieved the EPID data; both issues could be corrected before the next fraction. PerFRACTION provided improvements in efficiency compared to the previous system; post-processing was performed automatically which reduced calculation time by 30 minutes per patient. The number of measurements requiring investigation due to technical error significantly decreased (previously accounting for up to 2/3 of transit measurements) and in all cases the cause was identified. Some errors were due to unfamiliarity with a new system and decreased in frequency as users gained more experience. The audit highlighted potential weaknesses both in the software and local workflow, such as incorrect plan labelling and version number, which helped to inform investigation/contingency protocols. The system detected genuine changes in CBCT images and there were no patients with "Level 1" results that should have been referred for investigation. Issues detected by the system had not been referred for investigation based on the on-treatment CBCT review, indicating that where there is ambiguity PerFRACTION will act as a safety net.

Conclusion:

The PerFRACTION system enabled early identification of issues such as changes in patient anatomy and set-up, leading to prompt clinical review and corrective actions. A quantifiable improvement was found in workflow efficiency when compared with the previous system, including reduction in the time needed for post-processing and investigation. The integrated design of the software enabled monitoring across the treatment pathway and provisional audit results enabled evidence-based improvements to the current workflow.

Keywords: Transit dosimetry, PerFRACTION, dose verification

References:

1. Bossuyt E, Weytjens R, Nevens D, De Vos S, Verellen D. Evaluation of automated pre-treatment and transit in-vivo dosimetry in radiotherapy using empirically determined parameters. Phys Imaging Radiat Oncol. 2020 Nov 9;16:113-129.

1893

Proffered Paper