ESTRO meets Asia 2024 - Abstract Book

S342

Physics – Quality assurance and auditing

ESTRO meets Asia 2024

Hiroshima, Japan. 5 Department of Radiation Oncology, Hiroshima Prefectural Hospital, Hiroshima, Japan. 6 Department of Radiological Technology, Hiroshima City Hiroshima Citizens Hospital, Hiroshima, Japan. 7 Central Radiology Department, Department of Radiology, Hiroshima Red Cross Hospital & Atomic-bomb Survivors Hospital, Hiroshima, Japan

Purpose/Objective:

In July 2016, the Radiotherapy Technical Support Working Group (RTSWG) was established in Hiroshima, Japan, with a mission to elevate the standards of physics Quality Assurance (QA) in radiotherapy across various facilities. The RTSWG consists of 19 members, including medical physicists, radiological technologists, and administrative staff, under the Steering Council, the governing body of Hiroshima High-Precision Radiotherapy Cancer Center. Serving as an impartial entity, the RTSWG undertakes rigorous audits to ensure that each aspect of QA is meticulously managed within participating facilities, culminating in the issuance of validation certificates.

Material/Methods:

The core activities of the RTSWG are encapsulated within Task Groups (TG) #1, #2, and #4, each focusing on distinct yet critical areas of physics QA for radiotherapy.

TG-1: This group is dedicated to the auditing of photon beam outputs from linear accelerators (linacs), adhering to Japanese standard dosimetry protocol (Standard Dosimetry 12). Utilizing a custom Excel template and an online data registration system, TG-1 ensures precise beam calibration and the consistency between the linac output and the radiotherapy treatment planning systems (RTPS). TG-2: Focuses on the verification of heterogeneity correction in RTPS based on the stoichiometric CT number calibration method, leveraging a unique mailing phantom (Fig. 1) alongside an online data registration platform include uploading DICOM data of the mailing phantom scanned by CT scanner in each radiotherapy facility [1]. TG-2 performs independent verification of CT number calibration curves registered in RTPS. TG-4: Concentrates on the accuracy of image-guided radiation therapy (IGRT), employing a specialized mailing phantom (Fig. 1) and online data registration including DICOM data of the mailing phantom acquired from EPID on linac to validate the quality of IGRT [2].

Fig. 1 The original phantom of TG-2 and TG-4. The three on the right are TG-2 phantoms and the leftmost is the TG-4 phantom.

The committee also holds various quality control workshops and symposiums to provide basic lectures and up to-date information on physics QA for radiotherapy to medical physicists and radiological technologists as well as students and other medical staff interested in radiotherapy.

Results: