ESTRO 2025 - Abstract Book

S3616

Physics - Quality assurance and auditing

ESTRO 2025

Results: MicroDiamond orientation and energy variation was negligible. MicroDiamond dose was within 2.5% (+/-5%, k=2) of TPS dose across all tests. The mean gamma passing rate film-measured to TPS-dose for the three centres was 99.0% (range 98.3-99.4) (+/-2%, k=2) at 3% (local), 3 mm. There was a high level of agreement between film and TPS, even between interstitial needles (fig. 2). Differences of TPS-dose to film-dose within the virtual structures was: 0.4 Gy mean deviation (0 to 0.8 Gy range) for CTV D90%; 1.1 Gy mean (0.1-2.5) for CTV D0.02 sq cm; and 0.1 Gy (-0.2 to 0.6) D0.02 sq cm for bladder, bowel, rectum and sigmoid. The gamma passing rate (3% (local) 3mm) film-to-TPS within virtual structures in fig.2 were 92% for HR-CTV and 96% for IRCTV (+/-3%, k=2). Average OAR structures gamma rates were above 95%.