Federal Office for Radiation Protection

The radiopharmaceutical 223Ra-dichloride (Xofigo®) has been approved for palliative treatment of metastatic castration-resistant prostate cancer. During the treatment and caregiving, patients who received 223Ra-dichloride can exhale the progeny 219Rn, a radioactive gas. This causes a potential risk for medical staff and caregivers who might inhale the 219Rn gas and its airborne decay products. As an addition to the strategies of developing devices for measuring 219Rn gas and its daughter nuclides in treatment rooms, this work tried to estimate the amount of exhaled 219Rn and of its airborne progeny using biokinetic modelling. The biokinetic models and parameters for 223Ra and its progeny 219Rn, as published by the International Commission of Radiological Protection, were adopted for this analysis. Without consideration of room ventilation, the model predicted that the amount of 219Rn gas in the room air can reach a maximum activity of 5.8∙10− 2 Bq at approximately 1.5 min after infusion of one Bq of 223RaCl2. The summed activities of 219Rn and its airborne progeny do not exceed 1.2∙10− 1 Bq per infused Bq of 223RaCl2. In the breathing air of the patients, the activities at 1 and 5 min after the infusion were estimated to be approximately 2∙10− 2 Bq and 1.8∙10− 2 Bq per Bq of 223RaCl2, respectively. The values at 1 min are comparable to the measured results reported in the literature. The effective dose from inhalation of 219Rn gas and its airborne progeny due to a treatment of 4015 kBq of 223RaCl2, was estimated to be 232.6 nSv for medical staff and 7.5 µSv for caregivers.

PurposeThe standard modality for the diagnosis of ventriculoperitoneal (VP) shunt failure is the radiographic shunt series (RSS). However, ultra-low dose computed tomography (ULD-CT) may replace RSS. The aim of this study was to compare the radiation doses of RSS and ULD-CT in the diagnosis of mechanical shunt failure in human phantoms including pediatric phantoms and to further reduce the total CT dose by reducing the topogram radiation.MethodsMechanical VP shunt complications were placed on human phantoms representing ages of 1, 5, 10 and 30 years. RSS and ULD-CT were performed on each phantom with different radiation doses of the topogram with varying tube currents (10, 20, 30, 40 and 50 mAs). Effective doses of RSS and ULD-CT were estimated by using conversion factors.ResultsULD-CT demonstrated lower effective doses than RSS in phantoms representing ages 5, 10 and 30 years, while successfully depicting all mechanical shunt complications. However, higher effective doses were assessed for ULD-CT scans of the 1-year phantom than RSS. The effective doses for RSS and ULD-CT (utilizing 10 mAs topograms), respectively, were estimated as follows: 1-year: 0.056 vs. 0.133 mSv; 5-year: 0.186 vs. 0.123 mSv; 10-year: 0.240 vs. 0.107 mSv; 30-year: 0.641 vs. 0.076 mSv.ConclusionThis study demonstrated ULD-CT as an alternative to RSS for the detection of mechanical VP shunt complications, reducing radiation doses in phantoms equivalent to 5 years of age and older while demonstrating the complications equally to RSS. This may be of clinical interest, especially in children due to the reduction of radiation risks.

Light exposure over 24 h is a modifiable environmental influence on human physiology and behavior with significant implications for health and well-being, yet the field lacks coordinated research infrastructure, standardized methodologies, and translational pathways. To address this, we convened a multi-disciplinary consensus workshop and expert consultation process with 13 experts from academia, public health, radiation protection, and occupational health institutions. The aim was to identify key research gaps and to define priority areas to guide future work. Through an in-person and hybrid meeting, followed by iterative refinement and feedback, we identified nine critical gaps: (1) lack of standardized measurement tools, (2) inadequate exposure estimation infrastructure, (3) inconsistent descriptors and metrics, (4) absence of outcome standards, (5) limited dose–response evidence beyond the laboratory, (6) insufficient data on intervention effectiveness, (7) poor characterization of globally representative and vulnerable populations, (8) fragmented data harmonization, and (9) limited integration into public health frameworks. To address these gaps, we propose 11 research priority areas spanning measurement, methodology, data infrastructure, ethics, and implementation, as well as four capacity-building priority areas. This agenda provides a strategic foundation for building an integrated and evidence-based approach to studying and understanding light exposure as a determinant of health.

To enhance patient safety in nuclear medicine (NM) across Europe by operationalising MARLIN recommendations for implementing incident learning systems (ILSs), including barriers/enablers and practical implementation guidance. A mixed‑methods study (combining a survey, semi‑structured interviews, and a targeted literature review) was performed within the MARLIN project. This was a 24‑month initiative conducted under the European Commission’s Strategic Agenda for Medical Ionising Radiation Applications (SAMIRA) Action Plan, involving European organisations such as EANM, EIBIR, ESTRO, and EFOMP. Surveys were distributed to Clinical Facilities (CFs), Competent Authorities (CAs), and professional societies (PSs). Interviews were used to explore implementation barriers and examples of good practice. Data were analysed using descriptive statistics and thematic analysis. The study revealed significant variability in the criteria for defining and reporting significant radiation events in NM across Europe. While all surveyed countries had designated authorities for managing reported events, only 11/23 had specific criteria for NM. The study identified key enablers and barriers to ILS implementation, including the need for a just culture to encourage reporting without fear of punitive measures. The guidelines recommended criteria for significant radiation events in NM and the organisation of ILSs. The MARLIN study provides a comprehensive framework for the systematic implementation of ILSs in NM, highlighting the importance of standardised reporting criteria in several categories, multidisciplinary involvement, and a culture of safety. Addressing the identified barriers and promoting a coordinated effort among stakeholders are crucial for enhancing patient safety in NM across Europe.

In diagnostic radiology, it is essential to ensure that image quality is sufficiently good to support accurate diagnosis and patient safety. This is in accordance with the ALARA principle of keeping radiation exposure as low as reasonably achievable - taking into account economic and societal factors. Further, the detection of subtle low-contrast differences is critical for early disease detection, particularly in cases such as liver metastases. Iterative reconstruction algorithms have improved medical imaging by reducing noise, but their non-linear nature challenges traditional assessment metrics. Model observers like the Channelized Hotelling Observer provide task-specific evaluations suitable for non-linear systems. This study employs a previously proposed method for determining the dose-averaged detectability in computed tomography (CT) systems, focusing on minimizing systematic errors from measurement processes and phantom specimen variations. We conducted two repeatability analyses: intra-specimen, using the same CT scanner and phantom, and inter-specimen, using different specimens of the same phantom type. The study utilized a GE Brightspeed 16 scanner. The analyses revealed significant variations among different specimens, necessitating corrections for consistent comparison. The main correction underscores the importance of experimental verification of actual contrast values for accurate determination of the figure of merit (FOM) with multiple phantom specimens.