Monte Carlo verification of the holder correction factors for the radiophotoluminescent glass dosimeter used by the IAEA in international dosimetry audits.

The International Atomic Energy Agency (IAEA), jointly with the World Health Organization (WHO), has operated a postal dosimetry audit program for radiotherapy centers worldwide since 1969. In 2017 the IAEA introduced a new methodology based on radiophotoluminescent dosimetry (RPLD) for these audits. The detection system consists of a phosphate glass dosimeter inserted in a plastic capsule that is kept in measuring position with a PMMA holder during irradiation. Correction factors for this holder were obtained using experimental methods. In this work these methods are described and the resulting factors are verified by means of Monte Carlo simulation with the general-purpose code PENELOPE for a range of photon beam qualities relevant in radiotherapy. The study relies on a detailed geometrical representation of the experimental setup. Various photon beams were obtained from faithful modeling of the corresponding linacs. Monte Carlo simulation transport parameters are selected to ensure subpercent accuracy. The simulated correction factors fall in the interval 1.005-1.008 (±0.2%), with deviations with respect to experimental values not larger than 0.2(2)%. This study corroborates the validity of the holder correction factors currently used for the IAEA audits.

[Training of medical physicists in radiation therapy at the International Educational Center of the Association of Medical Physicists in Russia].

The efficiency of radiotherapy treatment for cancer patients and use of the state-of-the-art accelerator facilities, in the first place, depends on the qualification and number of medical physicists. The need for the training and continuing professional development (CPD) of medical radiation physicists in Russia and CIS countries has dramatically increased today. The article considers the system of refresher training which should provide the continuing professional development and advance training of medical radiation physicists. The authors analyze the experience of the International Educational Center of the Association of Medical Physicists in Russia involved in the CPD of medical physicists under the IAEA TC projects, RMAPO and N.N. Blokhin RCRC joint educational programs.

WE-E-213AB-01: Medical Physics Challenges for Implementation of New Technologies in External Beam Radiotherapy.

The AAPM has signed two formal Educational Exchange Agreements with the Spanish (SEFM) and the Russian (AMPR) medical physics societies. While the primary purpose of the Agreements is to provide educational opportunities for young medical physicists, the Agreements also contemplate holding joint sessions at scientific congresses. The purpose of this professional AAPM/SEFM/AMPR Joint Symposium is to explore the challenges that medical physicists in the three countries face when new external beam radiotherapy technologies are introduced in their facilities and to suggest potential solutions to limitations in testing equipment and lack of familiarity with protocols. Speakers from the three societies will present reviews of the technical aspects of IMRT, Arc EVIRT (IMAT/VMAT/Rapid Arc), SRS/SRBT, and IGRT/Adaptive radiotherapy, and will describe the status of these technologies in their countries, including the challenges found in tasks such as developing anatomical and biological dose optimization techniques and implementing QA management, risk assessment and patient safety programs. The SEFM will offer AAPM and AMPR members the possibility to participate in collaborative proposals for future research bids in UE and USA based on an ongoing Spanish project for adaptive radiotherapy using functional imaging. A targeted discussion will debate three propositions: the cost/benefit ratio of IGRT, whether IMRT requires IGRT, and the use of non-ionizing radiation technologies for realtime monitoring of prostate IGRT. For these debates, each society has designated one speaker to present and defend either "For" or "Against" the proposition, followed by discussion by all participants. The Symposium presentations and the country-tailored recommendations drawn will be made available to each society for inclusion in their websites. The WGNIMP, the AAPM Work Group charged with executing the AAPM/SEFM and AAPM/AMPR Agreements, will follow up on the commitments made by the AAPM.Di Yan's research on adaptive radiotherapy has been financially supported by: 1) NIH Research Grants, 2) Elekta Research Grants 3) Philips Research GrantConflicts of interest for Cedric X Yu: 1) Board Member of Prowess, Inc., 2) Shareholder of Xcision Medical Systems, LLC, 3) Inventor on patents licensed by Varian Medical Systems, Inc. LEARNING OBJECTIVES: 1. Describe fundamental aspects for four advanced radiotherapy techniques: IMRT, IGRT, SBRT, and adaptive radiotherapy. 2. Review technical and professional challenges for implementation of advanced techniques as a function of resources and capabilities available within each scientific society: AAPM, SEFM, and AMPR. 3. Discuss and plan a proposal for an international trial on IMRT/IGRT based on functional imaging. 4. Debate important implementation aspects of IMRT and IGRT according to country-specific resources.