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.

UK experience of professional registration in radiation protection.

The UK Radiation Protection Council (RPC) was established in 2019, under the Royal Charter of the Society for Radiological Protection. The RPC holds the registers for three grades of professional registration-Chartered, Incorporated and Technical Radiation Protection Professional. Individual radiation protection practitioners may apply for registration through any society or organisation that has been accepted as a Licensee of the RPC. This paper will give an overview of the criteria used for registration at each level, along with the benefits of professional registration to individuals, employers, the radiation protection profession and the public. We will discuss the operation of the RPC and share the experience of its establishment, identifying key issues and potential pitfalls for other Societies wishing to go down this route. Future expectations for professional registration will be considered.

Developing and Implementing an Imaging Optimization Study in Pediatric Nuclear Medicine: Experience and Recommendations from an IAEA-Coordinated Research Project.

The International Atomic Energy Agency instituted a coordinated research project on the evaluation and optimization of pediatric imaging, addressing the lack of consistency in this field. The purpose was to develop and test an optimization schema for the practices of pediatric radiology and nuclear medicine. Methods: A 5-step optimization schema was developed. Once a protocol optimization is identified, the steps are as follows: identification of the imaging situation; collection of administered-activity data and evaluation of the diagnostic image quality at baseline; comparison of baseline administered activity data with published standards or other benchmarks; identification of intervention, if necessary; and implementation of intervention and evaluation. Results: Within the coordinated research project, two sites considered optimization projects regarding nuclear medicine. In this work, renal imaging using 99mTc-dimercaptosuccinic acid (DMSA) projects are presented as examples. Site 1 acquired its standard 300-s static 99mTc-DMSA studies as 5-frame dynamic studies in 29 children. Frames were added to simulate different levels of administered activity. Image quality was subjectively judged on a 3-point Likert scale. A 30% reduction in administered activity with increased imaging duration (350 s) across all age groups was shown to be acceptable. This reduction was implemented and evaluated in 31 subsequent children, yielding administered activities significantly lower than baseline (mean relative differences of 30%, 37%, and 38% for children aged 0-5, 5-10, and 10-15 y, respectively). Site 2 performed a phantom study to determine the impact of lowering administered activity on image noise, finding that administered activities could be significantly lowered if longer imaging times were used. This led to a 50%-70% reduction from baseline with no loss in image quality. Conclusion: A dose optimization approach was applied successfully for several procedures commonly performed in pediatric nuclear medicine. Results are reported for renal cortical imaging using 99mTc-DMSA, leading to significant reductions in administered activity (and thus radiation dose). This optimization schema can be successfully implemented by nuclear medicine clinics seeking to improve their approach to imaging children.

Cancer incidence among children and young adults who have undergone x-ray guided cardiac catheterization procedures.

Children and young adults with heart disease appear to be at increased risk of developing cancer, although the reasons for this are unclear. A cohort of 11,270 individuals, who underwent cardiac catheterizations while aged ≤ 22 years in the UK, was established from hospital records. Radiation doses from cardiac catheterizations and CT scans were estimated. The cohort was matched with the NHS Central Register and NHS Transplant Registry to determine cancer incidence and transplantation status. Standardized incidence ratios (SIR) with associated confidence intervals (CI) were calculated. The excess relative risk (ERR) of lymphohaematopoietic  neoplasia was also calculated using Poisson regression. The SIR was raised for all malignancies (2.32, 95% CI 1.65, 3.17), lymphoma (8.34, 95% CI 5.22, 12.61) and leukaemia (2.11, 95% CI 0.82, 4.42). After censoring transplant recipients, post-transplant, the SIR was reduced to 0.90 (95% CI 0.49, 1.49) for all malignancies. All lymphomas developed post-transplant. The SIR for all malignancies developing 5 years from the first cardiac catheterization (2 years for leukaemia/lymphoma) remained raised (3.01, 95% CI 2.09, 4.19) but was again reduced after censoring transplant recipients (0.98, 95% CI 0.48, 1.77). The ERR per mGy bone marrow dose for lymphohaematopoietic neoplasia was reduced from 0.541 (95% CI 0.104, 1.807) to 0.018 (95% CI - 0.002, 0.096) where transplantation status was accounted for as a time-dependent background risk factor. In conclusion, transplantation appears to be a large contributor to elevated cancer rates in this patient group. This is likely to be mainly due to associated immunosuppression, however, radiation exposure may also be a contributing factor.

UK guidance on the management of personal dosimetry systems for healthcare staff working at multiple organizations.

There has been concern expressed by the UK regulator, the Health & Safety Executive, regarding the management of occupation dose for healthcare radiation workers who work across multiple organizations. In response to this concern, the British Institute of Radiology led a working group of relevant professional bodies to develop guidance in this area. The guidance addresses issues of general system management that would apply to all personal dosimetry systems, regardless of whether or not the workers within that system work across organizational boundaries, along with exploring efficient strategies to comply with legislation where those workers do indeed work across organizational boundaries. For those specific instances, the guidance discusses both system requirements to enable organizations to co-operate (Ionising Radiation Regulations 1999 Regulation 15), as well as specific instances of staff exposure. This is broken down into three categories-low, medium and high risk. A suggested approach to each is given to guide employers and their radiation advisers in adopting sensible strategies for the monitoring of their staff and the subsequent sharing of dosimetry data to ensure overall compliance with both dose limits and optimization requirements.

Radiation Safety Culture in the UK Medical Sector: A Top to Bottom Strategy.

UK professional bodies have established a number of sectorial working parties to provide guidance on the improvement of radiation safety (RS) culture in the workplace. The medical sector provides unique challenges in this regard, and the remit of the medical group was to review the current state of RS culture and to develop a framework for improvement. The review of current RS culture was based on measurable indicators, including data from regulatory inspections, personal monitoring data and incident data. An online survey to capture the RS-related views and experience of hospital staff at all levels was carried out, and the responses provided a wealth of information on RS awareness and implementation across the country. The framework for improving RS culture includes both 'top-down' initiatives to engage management and regulators, and 'bottom-up' initiatives relating to engagement and training of different staff groups. A 'Ten-point Assessment' on what constitutes a good approach to medical RS culture has been proposed, which provides a tool for management to assess RS culture in the workplace and has potential use in regulatory inspections in the UK.

Survival adjusted cancer risks attributable to radiation exposure from cardiac catheterisations in children.

OBJECTIVES: To estimate the risk of developing cancer in relation to the typical radiation doses received from a range of X-ray guided cardiac catheterisations in children, taking variable survival into account. METHODS: Radiation doses were estimated for 2749 procedures undertaken at five UK hospitals using Monte Carlo simulations. The lifetime attributable risk (LAR) of cancer incidence was estimated using models developed by the Biological Effects of Ionising Radiation committee, based on both normal life expectancy, and as a function of attained age, from 20 to 80 years, to take reduced life expectancy into account. RESULTS: The radiation-related risks from these procedures are dominated by lung and breast cancer (for females). Assuming normal life expectancy, central LAR estimates for cancer incidence, based on median doses, ranged from <1 in 2000 for atrial septal defect occlusions to as high as 1 in 150 for valve replacements. For a reduced life expectancy of 50 years, estimated risks are lower by a factor of around 7. For conditions with especially poor survival (age 20 years), such as hypoplastic left heart syndrome, estimated cancer risks attributable to radiation were <1 in 20 000. CONCLUSIONS: Based on recent UK radiation dose levels, the risk of cancer following cardiac catheterisations is relatively low and strongly modified by survival and the type of procedure. The risk of breast cancer, especially following pulmonary artery angioplasty and valve replacements, is the greatest concern.

Reduction in radiation doses from paediatric CT scans in Great Britain.

OBJECTIVE: Although CT scans provide great medical benefits, concerns have been raised about the magnitude of possible associated cancer risk, particularly in children who are more sensitive to radiation than adults. Unnecessary high doses during CT examinations can also be delivered to children, if the scan parameters are not adjusted for patient age and size. We conducted the first survey to directly assess the trends in CT scan parameters and doses for paediatric CT scans performed in Great Britain between 1978 and 2008. METHODS: We retrieved 1073 CT film sets from 36 hospitals. The patients were 0-19 years old, and CT scans were conducted between 1978 and 2008. We extracted scan parameters from each film including tube current-time product [milliampere seconds (mAs)], tube potential [peak kilovoltage (kVp)] and manufacturer and model of the CT scanner. We estimated the mean mAs for head and trunk (chest and abdomen/pelvis) scans, according to patient age (0-4, 5-9, 10-14 and 15-19 years) and scan year (<1990, 1990-1994, 1995-1999 and ≥2000), and then derived the volumetric CT dose index and estimated organ doses. RESULTS: For head CT scans, mean mAs decreased by about 47% on average from before 1990 to after 2000, with the decrease starting around 1990. The mean mAs for head CTs did not vary with age before 1990, whereas slightly lower mAs values were used for younger patients after 1990. Similar declines in mAs were observed for trunk CTs: a 46% decline on an average from before 1990 to after 2000. Although mean mAs for trunk CTs did not vary with age before 1990, the value varied markedly by age, from 63 mAs for age 0-4 years compared with 315 mAs for those aged >15 years after 2000. No material changes in kVp were found. Estimated brain-absorbed dose from head CT scans decreased from 62 mGy before 1990 to approximately 30 mGy after 2000. For chest CT scans, the lung dose to children aged 0-4 years decreased from 28 mGy before 1990 to 4 mGy after 2000. CONCLUSION: We found that mAs for head and trunk CTs was approximately halved starting around 1990, and age-specific mAs was generally used for paediatric scans after this date. These changes will have substantially reduced the radiation exposure to children from CT scans in Great Britain. ADVANCES IN KNOWLEDGE: The study shows that mAs and major organ doses for paediatric CT scans in Great Britain began to decrease around 1990.

The state of radiological protection; views of the radiation protection profession: IRPA13, Glasgow, May 2012.

The IRPA13 Congress took place from 14-18 May 2012 in Glasgow, Scotland, UK, and was attended by almost 1500 radiological protection professionals. The scientific programme of the Congress was designed to capture a snapshot of the profession's views of the current state of knowledge, and of the challenges seen for the coming years. This paper provides a summary of these results of the Congress in twelve key scientific areas that served as the structural backbone of IRPA13.

Radiation dose in videofluoroscopic swallow studies.

Videofluoroscopy has become an increasingly important armament in the investigation and assessment of swallowing disorders. However, very little work has been published on the radiation dose used in such examinations and currently there is no national diagnostic reference level in the United Kingdom. Videofluoroscopy in our hospital is performed predominantly by one radiologist (IZM) in a single fluoroscopy room. We recorded the screening times of 230 patients over a 45-month period. Screening time ranged from 18 to 564 s (median = 171 s) associated with a median dose-area product of 1.4 Gy cm(2). This is below the third quartile level of 2.7 Gy cm(2) for all such examinations performed across the northern England. The effective dose associated with a typical videofluoroscopy dose-area product is 0.2 mSv. Videofluoroscopy is the most appropriate instrumental examination for assessing oropharyngeal swallow biomechanics and intervention strategies. This data set is based on the largest number of videofluoroscopy swallow studies published to date. Our results show that videofluoroscopy can be performed using minimal radiation doses.