ESTRO 2024 - Abstract Book

S380

Beachytherapy - Physics

ESTRO 2024

References:

[1] M. J. Rivard et al., “Update of AAPM Task Group No. 43 Report: A revised AAPM protocol for brachytherapy dose calculations,” Medical Physics, vol. 31, no. 3. John Wiley and Sons Ltd, pp. 633–674, 2004. doi: 10.1118/1.1646040.

[2] R. Nath, L. L. Anderson, G. Luxton, K. A. Weaver, J. F. Williamson, and A. S. Meigooni, “Dosimetry of interstitial brachytherapy sources: Recommendations of the AAPM Radiation Therapy Committee Task Group No. 43,” Med Phys, vol. 22, no. 2, pp. 209–234, 1995, doi: 10.1118/1.597458. [3] L. Beaulieu et al., “Report of the Task Group 186 on model-based dose calculation methods in brachytherapy beyond the TG-43 formalism: Current status and recommendations for clinical implementation,” Medical Physics, vol. 39, no. 10. John Wiley and Sons Ltd, pp. 6208–6236, 2012. doi: 10.1118/1.4747264.

2335

Proffered Paper

International multicentre pilot results of IAEA/WHO dosimetry audit for high-dose rate brachytherapy

Alexis Dimitriadis, Krzysztof Chelminski, Egor Titovich, Godfrey Azangwe, Mauro Carrara, Jamema Swamidas

International Atomic Energy Agency, Dosimetry and Medical Radiation Physics Section, Vienna, Austria

Purpose/Objective:

To assess the accuracy of HDR brachytherapy dosimetry in an international multi-centric pilot test using a dosimetry audit methodology developed as part of IAEA/WHO postal dosimetry audit programme under the framework of a coordinated research project (E24023).

Material/Methods:

The audit methodology aims to assess accuracy of the Reference Air-Kerma Rate for both 60 Co and 192 Ir HDR brachytherapy sources by measuring the dose delivered to a phantom. A compact 16 x 8 x 3 cm PMMA phantom was developed, capable of accommodating two 5 or 6-French interstitial catheters that are 4 cm apart and with a cavity for a centrally placed radiophotoluminescent dosimeter (RPLD) (Asahi Technol Glass Corp, Tokyo, Japan), positioned in the same plane and equidistant from the two catheters. The phantoms were shipped to 48 centres in 11 different countries and the audit methodology was tested on 49 brachytherapy afterloaders, resulting in 59 irradiated dosimeters sets (45 in 192 Ir and 14 in 60 Co), with some centres performing more than one irradiation. Each centre followed a protocol provided by the auditors for generating a treatment plan 1 and calculating the dose using the institution TG-43-based treatment planning system, before delivering to the phantom. The treatment plan was designed to deliver a homogenous dose to the RPLD and the participants reported the dose delivered to a point in the centre of its sensitive volume. The dosimeters were processed upon return to the IAEA Dosimetry Laboratory. All necessary corrections for the dosimeter’s response and irradiation in non-TG43 conditions were applied and the measured dose (D IAEA ) was compared to the dose reported by the users (D USER ).

Results: