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Implications of Medical Low Dose Radiation Exposure

Periodic Reporting for period 2 - MEDIRAD (Implications of Medical Low Dose Radiation Exposure)

Reporting period: 2018-12-01 to 2020-05-31

MEDIRAD aims to enhance the scientific bases and clinical practice of radiation protection (RP) in the medical field and addresses the need to better understand and evaluate the health effects of low-dose ionising radiation (IR) exposure from diagnostic and therapeutic imaging and from off-target effects in radiotherapy (RT).
MEDIRAD pursues 3 major operational objectives:
• To improve organ dose estimation and registration to inform clinical practice, optimise doses, set recommendations and provide adequate dosimetry for clinical-epidemiological studies of effects resulting from exposures to IR in medicine;
• To evaluate and understand the effects of medical exposures, focusing on two major endpoints of public health relevance: cardiovascular effects of low to moderate doses of radiation from RT in breast cancer treatment including understanding of mechanisms, and long-term carcinogenic effects of low doses from CT in children;
• To develop science-based consensus recommendations for the effective protection of patients, workers and the general public.
To fulfil these, the MEDIRAD project relies on a multi-disciplinary consortium involving 34 partners from 14 European countries, a Scientific Advisory Board (with world-renowned experts in the fields of imaging, radiobiology, dosimetry, medical physics, epidemiology and ethics), a Stakeholder Board (with representatives from the medical associations EANM, EFOMP, EFRS, ESR and ESTRO, as well as the EURADOS, EURAMED and MELODI platforms on RP research, and the EPF), and a Stakeholder Forum (including health professionals, patients, nuclear scientists, policy-makers, competent authorities and representatives from international organisations).
The second reporting period of MEDIRAD was mainly devoted to the development of the studies involved in the project (in particular patient recruitment and preliminary data analysis), the establishment of an imaging and dose biobank and the preparation of pre-clinical models for biomarkers.
WP1 took care of the project governance and management procedures and organised several project meetings. Moreover, communication and dissemination activities were developed. Risks and quality assurance were continuously monitored, and the Knowledge Management and Exploitation Plan was prepared.
WP2 focused on state-of-the-art computed tomography (CT), fluoroscopically-guided interventional procedures and hybrid systems. Detailed dosimetric data have been produced, which will be valuable for optimising radiation protection of patients from high-dose diagnostic and interventional procedures. An imaging and dose biobank is being developed to address research needs.
WP3 has established the first European network of centres to perform standardised quantitative imaging of radioiodine, used for the treatment of differentiated thyroid cancer. This will allow sufficient recruitment of patients for clinical studies to address the ongoing controversies regarding the use of radioiodine. Ethical approval has been obtained and recruitment of 100 patients across four centres has started for a multi-centre clinical study to establish the absorbed doses delivered to patients undergoing treatment.
Under WP4, the clinical trial EARLY-HEART and the retrospective study BRACE were started and included all patients necessary. Data analysis is in progress and models are in development. For the biomarkers studies, the pre-clinical models have been performed and data are being analysed. The first biomarkers are available. Moreover, methods are being developed for the network analysis and mechanistic modelling of the envisaged data.
Under WP5, the follow-up of the Dutch, French, Spanish and UK cohorts was successfully implemented with ethics approvals obtained in all countries and linkage to registries currently being performed. The case-control study of brain and haematological malignancies nested within EPI-CT mainly focused on developing the protocol, online questionnaire, informed consent forms and documents with information for cases and controls with successful obtaining of ethics approvals in France and Spain. In parallel, protocols for analysis of genes associated to radiosensitivity and epigenetic analyses were optimised.
Under WP6, a Stakeholder Board and Forum were set-up. A first web-consultation of the Stakeholder Forum was organised and the top 10 topics for MEDIRAD recommendations were identified. In parallel, based on the first scientific results of WPs 2-5, a first list of 23 preliminary topics for recommendation was collected. A first cross analysis of these topics will help to draft the first set of MEDIRAD recommendations.
MEDIRAD aims to achieve significant progress in the interaction between the RP and medical scientific communities at EU level, leading to cross-fertilisation of research efforts and provision of more consolidated and robust science-based policy recommendations to decision makers in both sectors. MEDIRAD was designed specifically, through consortium composition and choice of scientific goals, to illustrate the potential innovative results achievable through joint research efforts between these communities. It is the first time they work together on RP oriented objectives, thus considerably strengthen relations and interactions between them.
Under WP2, novel tools for patient dose optimisation in chest CT and fluoroscopically-guided procedures are being developed. DRLs for specific applications of CT in PET/CT and SPECT/CT have been established. An imaging and dose biobank is being developed to address needs of MEDIRAD researchers.
It has been considered that response to radioiodine therapy for thyroid cancer patients depends largely on the radiation doses delivered to thyroid tissue or disease, rather than on the amounts of radioactive iodine that are administered. Multi-centre clinical studies are essential to recruit sufficient patients to achieve the statistical significance required to address the controversies. The set-up of a European imaging network under WP3 is essential to ensure optimisation and standardisation of data acquisition and processing to allow for accurate patient dosimetry and investigations into the potential of patient-tailored treatment planning.
The predictive model developed under WP4 based on both dose distribution and biomarkers will be unprecedented. It will have a high impact on the radiation oncology field and will reduce the health burden of breast cancer survivors on the long term. Developed network analysis and mechanistic modelling tools have the potential for gaining deeper insights into cardiovascular disease development even beyond radiation-induced disease.
WP5 of MEDIRAD will provide an updated estimation of cancer risk following CT scanning in young people with additional insights and analyses on factors that may modify this risk, i.e. genetic and epigenetic variants and potential confounders.
WP6 aims to transfer to a wider community (researchers, practitioners, authorities, stakeholders) the operational results reached by the MEDIRAD project, by seeking consensus on proposed recommendations, lessons learnt and solutions. Therefore, four recommendation papers will be prepared covering different topics relevant to the RP and medical scientific communities to strengthen their interaction.