Symposium on molecular radiotherapy dosimetry: The first of a series?

The EFOMP Special Interest Group for Radionuclide Internal Dosimetry (SIG_FRID) organised its first scientific meeting, the Symposium on Molecular Radiotherapy Dosimetry, in Athens on November 9th-11th 2023. The Symposium was hosted by the Hellenic Association of Medical Physicists and the National and Kapodistrian University of Athens. This meeting gathered more than 180 scientists from 28 countries. Scientific, clinical and regulatory aspects were addressed by 8 invited experts. Two continuous professional development sessions were organised. A special round table gathering medical physics experts, physicians regulatory authority experts and patient representatives addressed the possibilities to increase clinical dosimetry dissemination. The event was supported by companies and a specific industry session allowed sponsors to present their products, innovations and future perspective in this field.

Dose-response dependencies of OSL dosimeters in conventional linacs and 1.5T MR-linacs: an experimental and Monte Carlo study.

Objective. This work focuses on the optically stimulated luminescence dosimetry (OSLD) dose-response characterization, with emphasis on 1.5T MR-Linacs.Approach. Throughout this study, the nanoDots OSLDs (Landauer, USA) were considered. In groups of three, the mean OSLD response was measured in a conventional linac and an MR-Linac under various irradiation conditions to investigate (i) dose-response linearity with and without the 1.5T magnetic field, (ii) signal fading rate and its dependencies, (iii) beam quality, detector orientation and dose rate dependencies in a conventional linac, (iii) potential MR imaging related effects on OSLD response and (iv) detector orientation dependence in an MR-Linac. Monte Carlo calculations were performed to further quantify angular dependence after rotating the detector around its central axis parallel to the magnetic field, and determine the magnetic field correction factors,kB,Q,for all cardinal detector orientations.Main results. OSLD dose-response supralinearity in an MR-Linac setting was found to agree within uncertainties with the corresponding one in a conventional linac, for the axial detector orientation investigated. Signal fading rate does not depend on irradiation conditions for the range of 3-30 d considered. OSLD angular (orientation) dependence is more pronounced under the presence of a magnetic field. OSLDs irradiated with and without real-time T2w MR imaging enabled during irradiation yielded the same response within uncertainties.kB,Qvalues were determined for all three cardinal orientations. Corrections needed reached up to 6.4%. However, if OSLDs are calibrated in the axial orientation and then irradiated in an MR-Linac placed again in the axial orientation (perpendicular to the magnetic field), then simulations suggest thatkB,Qcan be considered unity within uncertainties, irrespective of the incident beam angle.Significance. This work contributes towards OSLD dose-response characterization and relevant correction factors availability. OSLDs are suitable for QA checks in MR-based beam gating applications andin vivodosimetry in MR-Linacs.

EFOMP Malaga Declaration 2023: An updated vision on Medical Physics in Europe.

In 2006, the European Federation of Organisations for Medical Physics (EFOMP) adopted the "Malaga Declaration". The declaration asserted the fundamental role of Medical Physics professionals in the radiation protection of patients, workers, general public, carers and comforters and research participants in hospitals. However, since that time the Medical Physics profession has evolved in Europe and new regulations and documentation have been issued, such as directive 2013/59/Euratom and the "European Guidelines on Medical Physics Expert" (RP174). EFOMP has published updated core-curricula and strived towards the recognition of the profession at the European level. In view of this, an update of the original Malaga Declaration was deemed necessary, to define the future vision that will guide the actions of the Federation in the years to come. This Declaration, which has been approved by the national member organizations of EFOMP in April 2023, is much broader than the original Malaga version. This is expected considering the rapid evolution of medical device technology over the last 17 years. The Radiation Protection Expert in hospital settings should be an MPE, since the latter has the highest level of radiation protection knowledge and training. Given the passion and energy that animated the debate, which led to the updating of the Malaga Declaration, we are confident that it represents a solid basis for the development of our profession in Europe which is in consonance with the aspirations of us all.

Statistics in Medical Physics. The 28th European School of Medical Physics Experts.

One of the aims of EFOMP is to organise events for education, training and continuous professional development. For this reason, the European Federation of Organisations for Medical Physics has developed a series of schools, called the European School for Medical Physics Experts (ESMPE). These are designed for medical physicists working as Medical Physics Experts (MPE) or in training to become an MPE and the level of training is at EQF level 8. The quality of training offered is accredited by the European Board for Accreditation in Medical Physics.EFOMP schoolstarget new topics included in the revised core curricula and guidelines for Medical Physics Experts in various subspecialties, which are rapidly evolving, as well as areas where the Medical Physicist plays a key role. The 28th ESMPE school was entitled "Statistics in Medical Physics".

The role of medical physicists in clinical trials across Europe.

INTRODUCTION: The roles and responsibilities of medical physicists (MPs) are growing together with the evolving science and technology. The complexity of today's clinical trials requires the skills and knowledge of MPs for their safe and efficient implementation. However, it is unclear to what extent the skillsets offered by MPs are being exploited in clinical trials across Europe. METHODS: The EFOMP Working Group on the role of Medical Physics Experts in Clinical Trials has designed a survey that targeted all 36 current National Member Organisations, receiving a response from 31 countries. The survey included both quantitative and qualitative queries regarding the involvement of MPs in trial design, setup, and coordination, either as trial team members or principal investigators. RESULTS: The extent of MPs involvement in clinical trials greatly varies across European countries. The results showed disparities between the roles played by MPs in trial design, conduct or data processing. Similarly, differences among the 31 European countries that responded to the survey were found regarding the existence of national bodies responsible for trials or the available training offered to MPs. The role of principal investigator or co-investigator was reported by 12 countries (39%), a sign of efficient collaboration with medical doctors in designing and implementing clinical studies. CONCLUSION: Organisation of specific training courses and guideline development for clinical trial design and conduct would encourage the involvement of a larger number of MPs in all stages of trials across Europe, leading to a better standardisation of clinical practice.

Impact of systematic MLC positional uncertainties on the quality of single-isocenter multi-target VMAT-SRS treatment plans.

PURPOSE: To study the impact of systematic MLC leaf positional uncertainties (stemming from mechanical inaccuracies or sub-optimal MLC modeling) on the quality of intracranial single-isocenter multi-target VMAT-SRS treatment plans. An estimation of appropriate tolerance levels is attempted. METHODS: Five patients, with three to four metastases and at least one target lying in close proximity to organs-at-risk (OARs) were included in this study. A single-isocenter multi-arc VMAT plan per patient was prepared, which served as the reference for dosimetric impact evaluation. A range of leaf offsets was introduced (±0.03 mm up to ±0.30 mm defined at the MLC plane) to both leaf banks, by varying the leaf offset MLC modeling parameter in Monaco for all the prepared plans, in order to simulate projected leaf offsets of ±0.09 mm up to ±0.94 mm at the isocenter plane, respectively. For all offsets simulated and cases studied, dose distributions were re-calculated and compared with the corresponding reference ones. An experimental dosimetric procedure using the SRS mapCHECK diode array was also performed to support the simulation study results and investigate its suitability to detect small systematic leaf positional errors. RESULTS: Projected leaf offsets of ±0.09 mm were well-tolerated with respect to both target dosimetry and OAR-sparing. A linear relationship was found between D95% percentage change and projected leaf offset (slope: 12%/mm). Impact of projected offset on target dosimetry was strongly associated with target volume. In two cases, plans that could be considered potentially clinically unacceptable (i.e., clinical dose constraint violation) were obtained even for projected offsets as small as 0.19 mm. The performed experimental dosimetry check can detect potential small systematic leaf errors. CONCLUSIONS: Plan quality indices and dose-volume metrics are very sensitive to systematic sub-millimeter leaf positional inaccuracies, projected at the isocenter plane. Acceptable and tolerance levels in systematic MLC uncertainties need to be tailored to VMAT-SRS spatial and dosimetric accuracy requirements.

The 3rd ESTRO-EFOMP core curriculum for medical physics experts in radiotherapy.

PURPOSE: To update the 2011 ESTRO-EFOMP core curriculum (CC) for education and training of medical physics experts (MPE)s working in radiotherapy (RT), in line with recent EU guidelines, and to provide a framework for European countries to develop their own curriculum. MATERIAL AND METHODS: Since September 2019, 27 European MPEs representing ESTRO, EFOMP and National Societies, with expertise covering all subfields of RT physics, have revised the CC for recent advances in RT. The ESTRO and EFOMP Education Councils, all European National Societies and international stakeholders have been involved in the revision process. RESULTS: A 4-year training period has been proposed, with a total of 240 ECTS (European Credit Transfer and Accumulation System). Training entrance levels have been defined ensuring the necessary physics and mathematics background. The concept of competency-based education has been reinforced by introducing the CanMEDS role framework. The updated CC includes (ablative) stereotactic-, MR-guided- and adaptive RT, particle therapy, advanced automation, complex quantitative data analysis (big data/artificial intelligence), use of biological images, and personalized treatments. Due to the continuously increasing RT complexity, more emphasis has been given to quality management. Clear requirements for a research project ensure a proper preparation of MPE residents for their central role in science and innovation in RT. CONCLUSION: This updated, 3rd edition of the CC provides an MPE training framework for safe and effective practice of modern RT, while acknowledging the significant efforts needed in some countries to reach this level. The CC can contribute to further harmonization of MPE training in Europe.

Early career medical physicist groups in Europe: An EFOMP survey.

INTRODUCTION: Training, educating, and fostering of young professionals are key requisites for the progress of any profession. The young medical physicists (MPs) of today are the medical physics professionals and leaders of tomorrow. It is, therefore, essential that they learn to work collectively and in a coordinated manner at both national and European levels at an early stage in their career. In view of this, EFOMP is planning to create a special interest group (SIG) encompassing early career MPs from across Europe. METHODS: A survey was developed by EFOMP and circulated to all National Member Organisations (NMOs) to gather information on the status of early career groups in their respective societies and on the interest to partake in such group within the Federation. RESULTS: Of the 36 NMOs that are part of EFOMP, 32 responded to the survey. Only 9 NMOs have established early career MPs groups within their NMOs, while the remaining countries are either considering setting up young MPs groups in the future (15 NMOs) or do not show such interest (8 NMOs). Of all responders, 59% expressed interest in the creation of the EFOMP SIG, 34% remained neutral towards this issue by not answering the question and for two NMOs the SIG idea had no appeal. CONCLUSION: Most NMOs showed interest in the creation of an early career MPs group within EFOMP and offered constructive feedbacks on the roles they envisage for the group. EFOMP will use and implement this information when establishing the special interest group.

Education, training and registration of Medical Physics Experts across Europe.

From its inception, EFOMP has pursued a policy to improve and coordinate education and training of medical physicists across all its participating European countries. Several EFOMP policy statements on education and training have been published and surveys have been held to get an overview of the actual situation. At the beginning of 2020 a new survey was distributed amongst the 36 National Member Organizations (NMOs), in which questions were based on recommendations published in the most recent policy statements. Thirty-three of the NMOs (91%) responded, of which 22 indicated having a National Registration Scheme (NRS) for Medical Physics Experts (MPEs) in place. Another 6 indicated considering such a scheme. Results of the questionnaire showed that there was good correspondence between education and training programmes, i.e. a division between a BSc phase, an MSc phase and a clinical phase after completion of the MSc. Differences between NRSs were primarily seen in the availability and composition of a supervising committee and in the availability of guidelines for handling professional misconduct. In addition, some differences were seen in the topics that were part of the education and training programme. The goal of a universal (registered) MPE accepted by all European countries is still far away despite the progress being made. The new procedure for approving an existing NRS, which fulfils all EFOMP criteria is seen as an important step forward. Exchange of experience, knowledge, ideas and, above all, MPE trainees between European countries is seen as the best approach to achieve this goal.

Towards an updated ESTRO-EFOMP core curriculum for education and training of medical physics experts in radiotherapy - A survey of current education and training practice in Europe.

PURPOSE: ESTRO-EFOMP intend to update the core curriculum (CC) for education and training of medical physicists in radiotherapy in line with the European Commission (EC) guidelines on Medical Physics Experts (MPE), the CanMEDS methodology and recent developments in radiotherapy. As input, a survey of the current structure of radiotherapy MPE national training schemes (NTS) in Europe was carried out. METHODS: A 35-question survey was sent to all European medical physics national societies (NS) with a focus on existence of an NTS, its format and duration, required entry-level education, and financial support for trainees. RESULTS: Twenty-six of 36 NS responded. Twenty had an NTS. Minimum required pre-training education varied from BSc in physics or related sciences (5/2) to MSc in medical physics, physics or related sciences (6/5/2) with 50-210 ECTS in fundamental physics and mathematics. The training period varied from 1 to 5 years (median 3 years with 50% dedicated to radiotherapy). The ratio of time spent on university lectures versus hospital training was most commonly 25%/75%. In 14 of 20 countries with an NTS, a research project was mandatory. Residents were paid in 17 of 20 countries. The recognition was mostly obtained by examination. Medical physics is recognised as a healthcare profession in 19 of 26 countries. CONCLUSIONS: The NTS entrance level, duration and curriculum showed significant variations. This survey serves to inform the design of the updated CC to define a realistic minimum training level for safe and effective practice aiming at further harmonization in line with EC guidelines.

EFOMP survey results on national radiotherapy dosimetry audits.

PURPOSE: The Council Directive 2013/58/EURATOM entered into force in 2014, and its transposition into national legislations became applicable in 2018. The Council Directive 2013/58/EURATOM strengthened the importance of clinical audits, and stated that Member States should ensure dosimetry audit compliance in accordance with national procedures. Therefore, the purpose of this work was to picture the status of the implementation of dosimetry audits in European countries. METHODS: A questionnaire was designed to describe dosimetry audit standards in radiotherapy across European countries. The questionnaire was sent to 33 EFOMP National Member Organizations (NMO). RESULTS: Nineteen NMOs responded to the survey (14 EU members). For 58% of the participating countries national regulations required dosimetry audits in radiotherapy departments. In 37% of the participating countries there were implemented regulations for independent/secondary dose verification, and in 21% of the participating countries similar procedures for dose verification were already implemented although not regulated by law. In 42% of the participating countries there were implemented mechanisms to review updates and advances in the field of radiotherapy. CONCLUSIONS: The transposition and further implementation of the Council Directive 2013/59/EURATOM was scarce, leading to heterogeneities in national policies about dosimetry audits.

Dosimetric impact of rotational errors on the quality of VMAT-SRS for multiple brain metastases: Comparison between single- and two-isocenter treatment planning techniques.

PURPOSE: In the absence of a 6D couch and/or assuming considerable intrafractional patient motion, rotational errors could affect target coverage and OAR-sparing especially in multiple metastases VMAT-SRS cranial cases, which often involve the concurrent irradiation of off-axis targets. This work aims to study the dosimetric impact of rotational errors in such applications, under a comparative perspective between the single- and two-isocenter treatment techniques. METHODS: Ten patients (36 metastases) were included in this study. Challenging cases were only considered, with several targets lying in close proximity to OARs. Two multiarc VMAT plans per patient were prepared, involving one and two isocenters, serving as the reference plans. Different degrees of angular offsets at various orientations were introduced, simulating rotational errors. Resulting dose distributions were evaluated and compared using commonly employed dose-volume and plan quality indices. RESULTS: For single-isocenter plans and 1° rotations, plan quality indices, such as coverage, conformity index and D95% , deteriorated significantly (>5%) for distant targets from the isocenter (at> 4-6 cm). Contrarily, for two-isocenter plans, target distances to nearest isocenter were always shorter (≤4 cm), and, consequently, 1° errors were well-tolerated. In the most extreme case considered (2° around all axes) conformity index deteriorated by on-average 7.2%/cm of distance to isocenter, if one isocenter is used, and 2.6%/cm, for plans involving two isocenters. The effect is, however, strongly associated with target volume. Regarding OARs, for single-isocenter plans, significant increase (up to 63%) in Dmax and D0.02cc values was observed for any angle of rotation. Plans that could be considered clinically unacceptable were obtained even for the smallest angle considered, although rarer for the two-isocenter planning approach. CONCLUSION: Limiting the lesion-to-isocenter distance to ≤4 cm by introducing additional isocenter(s) appears to partly mitigate severe target underdosage, especially for smaller target sizes. If OAR-sparing is also a concern, more stringent rotational error tolerances apply.

Dosimetric comparison of five different techniques for craniospinal irradiation across 15 European centers: analysis on behalf of the SIOP-E-BTG (radiotherapy working group).

PURPOSE: Conventional techniques (3D-CRT) for craniospinal irradiation (CSI) are still widely used. Modern techniques (IMRT, VMAT, TomoTherapy®, proton pencil beam scanning [PBS]) are applied in a limited number of centers. For a 14-year-old patient, we aimed to compare dose distributions of five CSI techniques applied across Europe and generated according to the participating institute protocols, therefore representing daily practice. MATERIAL AND METHODS: A multicenter (n = 15) dosimetric analysis of five different techniques for CSI (3D-CRT, IMRT, VMAT, TomoTherapy®, PBS; 3 centers per technique) was performed using the same patient data, set of delineations and dose prescription (36.0/1.8 Gy). Different treatment plans were optimized based on the same planning target volume margin. All participating institutes returned their best treatment plan applicable in clinic. RESULTS: The modern radiotherapy techniques investigated resulted in superior conformity/homogeneity-indices (CI/HI), particularly in the spinal part of the target (CI: 3D-CRT:0.3 vs. modern:0.6; HI: 3D-CRT:0.2 vs. modern:0.1), and demonstrated a decreased dose to the thyroid, heart, esophagus and pancreas. Dose reductions of >10.0 Gy were observed with PBS compared to modern photon techniques for parotid glands, thyroid and pancreas. Following this technique, a wide range in dosimetry among centers using the same technique was observed (e.g., thyroid mean dose: VMAT: 5.6-24.6 Gy; PBS: 0.3-10.1 Gy). CONCLUSIONS: The investigated modern radiotherapy techniques demonstrate superior dosimetric results compared to 3D-CRT. The lowest mean dose for organs at risk is obtained with proton therapy. However, for a large number of organs ranges in mean doses were wide and overlapping between techniques making it difficult to recommend one radiotherapy technique over another.

Participation of women medical Physicists in European scientific events: The European experience.

PURPOSE: Though the number of women scientists is increasing over the years, studies show that they are still under-represented in leadership roles. The purpose of this work is to establish the percentage of women Medical Physicists (wMPs) that have participated in European scientific events and evaluate it as an indication of the current position of women in the field of Medical Physics in Europe and to propose possible ways to encourage their participation. MATERIALS AND METHODS: Data regarding the participants in European scientific events of Medical Physics were collected. The participants were divided into categories according to the program of the events and their gender was identified. The percentage of wMPs in each category was evaluated. RESULTS: The participation of wMPs attending courses is greater than 50%. The categories with the greatest participation are "Organizing Committees", "Chairpersons-Moderators" and "Oral Presentations". The categories with the lower participation of wMPs are "Scientific Committee", "Symposiums" and "Invited Speakers". None of wMPs were represented as "Course Directors". CONCLUSIONS: The attendance of wMPs in courses is slightly greater than average. However, wMPs do not have an equally important recognition in special invited roles in conferences. They are still under-represented in "Scientific Committees", "Invited Speakers", "Symposiums" and "Course directors". wMPs should be encouraged to participate even more actively in European conferences and the organizing committees should invite more wMPs in special roles. More studies concerning the status of female MPs in each country separately should be encouraged as they will help in understanding the position of wMPS in Europe.

Anatomy- vs. fluence-based planning for prostate cancer treatments using VMAT.

The purpose of this study was to compare the planning approaches used in two treatment planning systems (TPS) provided by Elekta for VMAT treatments. Ten prostate patients were studied retrospectively. Plan comparison was performed in terms of delivery efficiency and accuracy, as well as in terms of target coverage and critical organ protection by utilizing physical and radiobiological indices. These include: DVH (dose volume histogram) values, CI (conformity index), HI(%) (homogeneity index) and TCP (tumor control probability) for target coverage; mean doses, DVH values, dose to the normal non-target tissue, NTCP (normal tissue complication probability) and GI (gradient index) for critical organ sparing; MU/fraction and treatment time for delivery efficiency. The comparisons were performed using the two-sided Wilcoxon matched-pair signed rank test. Plans generated using the anatomy-based approach in ERGO++ and fluence-based approach in Monaco were found similar in terms of target coverage and TCP values, as well as in terms of rectum protection and corresponding NTCP values. The former exhibited increased delivery efficiency (comparable to that of 3D conformal radiotherapy) due to the relatively larger segments used. On the other hand advantages of the fluence-based approach in Monaco include increased conformity, better target dose homogeneity and higher dose gradient (lower dose to normal non-target-tissue) mainly due to the higher degree of modulation offered by the fluence-based approach, while the Monte Carlo algorithm used for dose calculation provides plans with increased accuracy despite the relatively small segments used.