ESTRO meets Asia 2024 - Abstract Book

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Invited Speaker

ESTRO meets Asia 2024

Applicator materials can produce artifacts in MRI and CT, necessitating preclinical evaluation. Scanning applicators in a tissue-equivalent medium phantom helps quantify these artifacts, with CT-MRI image registration providing further insights. This step becomes more significant if needles are being used for interstitial brachytherapy. Needle visualization in CT and MRI needs to be assessed for evaluation of the artifacts. This information aids in accurate applicator and needle reconstruction during clinical use. Verification of source dwell positions is conducted using a source dummy wire (CT) and water line markers (MRI). Imaging scans with these markers allow for precise verification of distances and source positions using the treatment planning station.

The final step in implementing a new applicator involves standardizing the loading pattern.

Applicator commissioning is performed before clinical use of a new applicator and can be repeated annually as part of the quality assurance protocol. The results of applicator commissioning can be utilized to validate the library of applicators provided by the vendor. Errors in commissioning can lead to systematic reconstruction errors, highlighting the importance of its meticulous planning and execution. The process of applicator commissioning fosters confidence in brachytherapy treatment planning and execution among oncologists and medical physicists, supporting a seamless clinical workflow.

In summary, applicator commissioning is a vital component of the IGBT workflow, essential for reducing DVH parameter and treatment uncertainties in clinical practice.

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Dosimetry audit projects for safe and effective radiotherapy treatments

Krzysztof Chelminski 1 , Alexis Dimitriadis 1 , Roua Abdulrahim 1 , Anna Becker 1 , Egor Titovich 1 , Liset de la Fuente Rosales 1 , Jonathan Kalinowski 2,3 , Shirin Abbasi Enger 2,3 , Evelyn Granizo-Roman 1 , Benjamin Kellogg 1 , Pavel Kazantsev 1 , Godfrey Azangwe 1 , Mauro Carrara 1 , Jamema Swamidas 1 1 Department of Nuclear Sciences and Applications, Division of Human Health, International Atomic Energy Agency, Vienna, Austria. 2 Department of Oncology, Medical Physics Unit, McGill University, Montreal, Canada. 3 Lady Davis Institute for Medical Research, Jewish General Hospital, Montreal, Canada Background and Purpose: The International Atomic Energy Agency/World Health Organisation (IAEA/WHO) dosimetry audit programme operates since 1969 and provides dosimetry audit services in various processes of radiotherapy, prioritizing Low- and Middle-income Member States (MS). In response to MS’s requests to extend the current audit service to brachytherapy, a Coordinated Research project (CRP-E24023) was launched in 2021, with the aim to develop a multi-level dosimetry audit methodology for High Dose Rate (HDR) brachytherapy including evaluation of Reference Air Kerma Rate (RAKR), source position verification and an end-to-end dosimetry audit for cervical cancer. Material and Methods: Under the framework of this CRP, a simple, light weight, cost-effective phantom suitable for remote postal dosimetry audits was proposed. The audit methodology aims to assess accuracy of the RAKR for both 60 Co and 192 Ir sources by measuring the dose delivered to the phantom. Correction factors accounting for deviations from AAPM TG-43 full scatter conditions, non-water equivalent of the phantom and the detector material, were Abstract