ESTRO 2024 - Abstract Book

S4948

Physics - Quality assurance and auditing

ESTRO 2024

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[3] McCaw TJ, Barraclough BA, Belanger M, Besemer A, Dunkerley DA, Labby ZE. Diagnosing atmospheric communication of a sealed monitor chamber. J Appl Clin Med Phys. 2020; 21(8): 309-314. https://doi.org/10.1002/acm2.12975

[4] Hossain M. Output trends, characteristics, and measurements of three megavoltage radiotherapy linear accelerators. J Appl Clin Med Phys. 2014; 15(4): 137-151. https://doi.org/10.1120/jacmp.v15i4.4783

[5] Matsumoto K, Tarutani K. Characteristics of Monitor Chamber for Photon Energy Mounted on Linear Accelerators. Nihon Hoshasen Gijutsu Gakkai Zasshi. 2019 ;75(10):1135-1140. https://doi.org/10.6009/jjrt.2019_jsrt_75.10.1135

3215

Digital Poster

Biological basis for dosimetric audit criteria for Head&Neck radiotherapy

Vanessa Panettieri 1,2,3 , Paige Taylor 4,5 , Stephen F Kry 4,5

1 Peter MacCallum Cancer Centre, Physical Sciences, Melbourne, Australia. 2 The University of Melbourne, Sir Peter MacCallum Department of Oncology, Melbourne, Australia. 3 Monash University, Central Clinical School, Melbourne, Australia. 4 Imaging and Radiation Oncology Core, ,, Houston, USA. 5 MD Anderson Cancer Center, Department of Radiation Physics, Houston, USA

Purpose/Objective:

Current clinical trial credentialing criteria solely relies on physical quantities (such as dose and dose distribution), which act as surrogate of the biological response [1]. In North American trials involving IMRT, credentialing is required based on irradiation of a phantom based on H&N anatomy provided by the Imaging and Radiation Oncology Core (IROC). In order to be successful, measured and planned dose must agree within 7% at each of the 6 locations of point dose measurement. This “maximum point-dose disagreement” fails to account for the dose distribution, and is independent of the actual anatomical site of the trial. As such, this approach could potentially mask the true sensitivity to inaccurate dose delivery.

The aim of this work is to evaluate credentialing criteria guided directly by biological variations in the anatomy treated, using biological indices.

Material/Methods: