Synthesis of the European ALARA network 20th workshop 'ALARA for interventional radiology and nuclear medicine'.

The European as low as reasonably achievable(ALARA) network regularly organises workshops on topical issues in radiation protection (RP). The topic of the 20th workshop was: 'ALARA for interventional radiology (IR) and nuclear medicine (NM)'. The objective was to examine the challenges faced when applying the optimisation principle (ALARA) in IR and NM and to consider how ALARA could be better implemented for patient and staff exposures. This memorandum provides a synthesis of the workshop sessions, and recommendations coming from the working groups discussion. Parallels are drawn with the recommendations arising from the 13th EAN workshop on 'ALARA and the medical sector (2011)' to consider how the optimisation challenges in IR and NM have evolved over the past decade. Current levels of exposure are presented along with operational practice and the challenges and opportunities for improvement, both in monitoring and practice. Whilst RP challenges remain, the application of ALARA appears more established in IR compared with experiences reported in 2011. The application of ALARA to emerging technologies in the NM setting is in need of further development to ensure that RP is considered at all stages in the development process of new radiopharmaceuticals. Besides the obvious technical and operational aspects, the importance of education and training, human factors and broadly the RP 'culture' were deemed fundamental to the success of the application of ALARA and where further emphasis is needed. All concerned parties, medical physics experts (MPEs), radiation protection experts, clinical staff, manufacturers and regulators have a role to play in the application of ALARA and this is discussed in the memorandum. Many of the recommendations from the 13th EAN workshop remain applicable today and overlap with the recommendations arising from the 20th workshop. This should prompt attention given that the use of IR and the development of novel radiopharmaceuticals for NM is only anticipated to increase with time.

ICRP workshop on the review and revision of the system of radiological protection: a focus on research priorities-feedback from the international community.

In September 2022, the International Commission on Radiological Protection (ICRP) organised a workshop in Estoril, Portugal, on the 'Review and Revision of the System of Radiological Protection: A Focus on Research Priorities'. The workshop, which was a side event of the European Radiation Protection Week, offered an opportunity to comment on a recent paper published by ICRP on areas of research to support the System of Radiological Protection. Altogether, about 150 individuals participated in the workshop. After the workshop, 16 of the 30 organisations in formal relations with ICRP provided written feedback. All participants and organisations followed ICRP's view that further research in various areas will offer additional support in improving the System in the short, medium, and long term. In general, it was emphasised that any research should be outcome-focused in that it should improve protection of people or the environment. Many research topics mentioned by the participants were in line with those already identified by ICRP in the paper noted above. In addition, further ideas were expressed such as, for example, that lessons learned during the COVID-19 pandemic with regards to the non-radiological social, economic and environment impacts, should be analysed for their usefulness to enhance radiological protection, and that current protection strategies and application of current radiological protection principles may need to be adapted to military scenarios like those observed recently during the military conflict in the Ukraine or the detonation of a nuclear weapon. On a broader perspective, it was discussed how radiation research and radiological protection can contribute towards the Sustainable Development Goals announced by the United Nations in 2015. This paper summarises the views expressed during the workshop and the major take home messages identified by ICRP.

Application of the ALARA principle for radon at work: feedback from the European ALARA network.

The Council Directive 2013/59/Euratom has introduced binding requirements for the management of radon in the workplace in Member States of the European Union. How does it work in practice? In 2021, the European ALARA Network created a working group on ALARA for Radon at Work with the objective of collecting and sharing experiences from the field. A survey was developed to detail each step of the national regulations for the control of radon and to describe case studies showing implementation. This article presents a qualitative analysis of the answers received from seven countries. There are no two similar national regulations and, at each step, different provisions, protocols, techniques etc are applicable or recommended. This diversity contributes to the richness of the results and can inform about interesting and good practices, where 'good' is defined by what is appropriate in the nationally and locally prevailing circumstances. All national regulations follow a graded approach, which is a key component for the implementation of the optimisation (ALARA) principle, yet several potential weak points that may be challenging to ALARA have been identified and are discussed, namely the radon risk assessment, the focus on numerical values, uncertainties in the measurement, how to obtain economically efficient remediation, and the interface with other regulations. Strengthening collaboration between risk prevention and radiation protection actors could help to provide and build expertise on radon management in the workplace, especially when exposure is managed as a planned exposure situation.

A new two-strip TLC method for the quality control of technetium-99m mercaptoacetyl-triglycine (99mTc-MAG3).

BACKGROUND: 99mTc-mercaptoacetyl-triglycine (99mTc-MAG3) has been used for dynamic renal imaging since about 30 years. Free pertechnetate (99mTcO4), colloidal 99mTc ((99mTcO2)n), 99mTc-tartrate (precursor), precomplexes (99mTc-(MAG3)x) and lipophilic 99mTc-MAG2 are the main radiochemical impurities that may occur in the preparation. The total amount of these impurities has to be identified before release of the product for patient administration to guarantee patient safety and good image quality. The European Pharmacopoeia suggests a method based on high-pressure liquid chromatography analysis in combination with a paper chromatography. This analytical method is time consuming, expensive and requires specially trained technicians. As a consequence, it is not widely applied in nuclear medicine radiopharmacies. RESULTS: We developed a simple method for radiochemical purity testing of 99mTc-MAG3. The method is based on thin layer chromatography with two strips to be developed in parallel. Method validation was carried out in comparison to the official methods of the companies and to the European Pharmacopoeia method. It was tested on specificity, accuracy, robustness and precision. CONCLUSION: The proposed method is able to identify and quantify the sum of all impurities occurring in the preparation, respecting the acceptance criteria for the radiochemical purity defined by the official methods. Hydrophilic and lipophilic compounds are identified separately and results are obtained within less than 20 minutes. Our method is simple, cost effective, fast and is suitable for employing dose calibrators or radiometric scanners.

Swiss survey on hybrid imaging CTs doses in Nuclear Medicine and proposed national dose reference levels.

A multidisciplinary working group led by the Swiss Federal Office of Public Health was formed to plan and perform a nationwide survey of patient radiation exposure from computed tomography (CT) in hybrid devices across Nuclear Medicine departments. The survey included 16 departments (of which 5 were university hospitals) and the submitted responses included 10,673 entries for the 33 different protocols proposed (11 in PET and 22 in SPECT). The working group determined the selection and exclusion criteria applied to the analysis. This work presents the survey preparation and data analysis including the exclusion criteria used. The results are used to inform recommendations for National Diagnostic Reference Levels (DRL) for CT procedures in Nuclear Medicine in Switzerland. Of the 33 protocols initially proposed, 10 protocols for both PET and SPECT modalities were retained after exclusion criteria and thresholds were applied. The results obtained in terms of volume-weighted computed tomography dose index (CTDIvol) and dose length product (DLP) have been put forward as recommendations for national Diagnostic Reference Levels for protocols in hybrid imaging devices in Nuclear Medicine in Switzerland and will be published by the Federal Office of Public Health.