Automated daily check QA of treatment channel adjustments (TCA), active, and dummy source positioning using bravos...

As HDR afterloader technology evolves, new treatment delivery capabilities create opportunities to reinforce quality assurance (QA) procedures. We present a novel method of automated log file analysis for daily, longitudinal tracking of channel length offsets, and active and dummy source positional accuracy. Leveraging features of the Bravos afterloader system, the method supplements visual inspections and functional tests, enhancing QA accuracy and reliability.

Our clinic utilizes 3 HDR afterloaders across 4 vaults, delivering over 900 treatments annually. Applicators and transfer guide tubes (TGTs) vary in length and connectors. We collected treatment reports and daily Position Verification Test (PVT) logs over 9 months resulting in 694 and 455 treatment reports and PVT logs, respectively. Each TGT is assigned a unique identifier (UID) to monitor readings over time, including dedicated TGTs used in PVT readings. Statistical analysis was performed per afterloader across 3 CamScales, and later grouped by CamScale to assess deviations from expected distances and identify trends in TGT and PVT measurements.

PVT readings for dummy (and active) sources are within 0.05 cm, for 97% (91%), 90% (97%), and 97% (94%) of readings for Afterloaders A1, A2, and A3, respectively, across all CamScales. Postcalibration distances compared to the precalibration distances result in an average difference of <0.03 cm for active and dummy sources. Across 7421 treatment channels adjustments (TCAs), 74 exceeded the overall threshold of 2 mm, decreasing to 7 when group-specific thresholds were applied.

The implementation of an automated QA program of treatment channel adjustments in HDR brachytherapy has benefits in maintaining the accuracy and reliability of TGT measurements and applicators. Daily QA checks provide a comprehensive overview of trends, enabling early detection of potential issues and timely interventions.