ESTRO 2024 - Abstract Book

S4873

Physics - Quality assurance and auditing

ESTRO 2024

Results:

Results of the point dose measurements in terms of the ratio of TPS calculated to RPLD measured doses for all field sizes are presented in Fig 2. Average results with their standard deviations per field size are: 0.985±0.039 for 1×1 cm 2 , 1.003±0.024 for 2×2 cm 2 , 1.001±0.016 for 4×4 cm 2 and 0.995±0.013 for 10×10 cm 2 . Three out of twelve results for the smallest field size were found to be outside the acceptance limits. Results of film profile width measurements as compared with TPS calculations were within 3 mm for all but one case of 2×2 cm 2 field size at 20% dose level where the difference was 4.1 mm.

Figure 2. Results of the point dose measurements in terms of the ratio of TPS calculated to RPLD measured doses for different field sizes. Solid lines indicate 5% acceptance limits.

Conclusion:

The audit was able to identify the deficiencies in small field commissioning of TPSs in participating centres. The audit procedure was easy to follow due to the new holder design.

Keywords: small field dosimetry, remote audit

References:

1) T. Bokulic, P. Kazantsev, P. Wesolowska, W. Lechner, J. Izewska, PO-0998: Feasibility study for high energy photon small beam dosimetry audits using OSL and RPL dosimeters, Radiotherapy and Oncology, 127, Supp 1, 2018, S556