ESTRO 2023 - Abstract Book

S526

Sunday 14 May 2023

ESTRO 2023

Conclusion Using the software the source tracking measurements can be translated into clinical parameters, and the clinical relevance of deviations can be assessed. Results show that the uncertainty of our IVD system has a small impact on the DVHs, even when an offset happened during the treatment. However, more clinical cases with different treatment errors still have to be evaluated. This is essential to fully understand the uncertainties of the proposed IVD method in a clinical context, and help define action limits for error detection. OC-0636 GEC-ESTRO Recommendations on Calibration and Traceability of HE HDR-PDR Photon Brachytherapy Sources J. Perez Calatayud 1,2 , F. Ballester 3 , Å. Carlsson Tedgren 4 , L.A. DeWerd 5 , P. Papagiannis 6 , M.J. Rivard 7 , F. Siebert 8 , J. Vijande 3 1 Hospital La Fe, Radiation Oncology, Valencia, Spain; 2 Hospital Clinica Benidorm, Radiation Oncology, Alicante, Spain; 3 Valencia University, Departament of Atomic, Molecular and Nuclear Physics, Valencia, Spain; 4 , Linköping University Sweden, Radiation Physics, Department of Medicine and Health (IMH), , Linköping, Sweden; 5 University of Wisconsin– Madison, Department of Medical Physics, School of Medicine and Public Health, Madison, USA; 6 National and Kapodistrian University of Athens, Medical Physics Laboratory, Medical School, Athens Greece, Greece; 7 Alpert Medical School of Brown University, Department of Radiation Oncology, Providence, USA; 8 UKSH, Campus Kiel, Klinik für Strahlentherapie (Radioonkologie), Kiel, Germany Purpose or Objective The vast majority of radiotherapy departments in Europe using brachytherapy (BT) perform temporary implants of high- or pulsed-dose rate (HDR-PDR) sources with photon energies higher than 50 keV. Such techniques are successfully applied to diverse pathologies and clinical scenarios. In this communication, we present the GEC-ESTRO recommendations on Calibration and Traceability of high energy HDR-PDR Photon-Emitting Brachytherapy Sources at the Hospital Level. Materials and Methods These recommendations are the result of Working Package 21 (WP-21) initiated within the BRAchytherapy PHYsics Quality Assurance System (BRAPHYQS) GEC-ESTRO working group with a focus on HDR-PDR source calibration. They provide guidance on the calibration of such sources, including practical aspects and issues not specifically accounted for in well-accepted societal recommendations, complementing the BRAPHYQS WP-18 report dedicated to low energy BT photon emitting sources (seeds). Results Recommendations are offered on the preferred equipment for source assay (well-type chamber), the establishment of a redundancy program, the periodicity of assay, source model specific calibrations and source design constancy, contamination testing, source certification and of course assay tolerance. Key points are that the responsibility to assay sources remains with the medical physicist and administrators must provide the required resources, and that a tighter tolerance level of 3% difference between source assay and source certificate provided by the vendor is established for HE BT sources.