Guidance on medical physics expert support for nuclear medicine.

The Ionising Radiation (Medical Exposure) Regulations require employers to appoint suitable medical physics experts (MPE) for nuclear medicine services, and they also define the areas where MPEs are required to provide advice and specify matters that they must contribute towards. Applications for employer licences under IR(ME)R require employers to specify the level of MPE support available and if this is provided by onsite MPEs or remotely. Assessment of these applications by the Administration of Radioactive Substances Advisory Committee (ARSAC) has highlighted variability in the levels of MPE support being provided for similar services across the UK. A working party including representatives from IPEM, ARSAC, BIR and BNMS was formed and has produced these recommendations on MPE support. Nuclear medicine services were divided into seven broad categories and MPE support for each category has been considered. However, some services that differ from the scenarios provided in this guidance may require different levels of MPE support. Positron emission tomography (PET)/CT and gamma camera imaging have been considered separately here, although it is recognised that both PET/CT and gamma cameras are often sited within the same department in many centres. The separation has been done for pragmatic purposes, as there are felt to be sufficient differences in the MPE role requirements. This guidance sets out recommendations for MPE support, and broader physics support, to run a safe nuclear medicine service and defines the responsibilities of these staff for a range of clinical nuclear medicine services. The recommendations on MPE support made are advice, but will assist employers in meeting regulatory requirements.

The challenges of radioiodine treatment for incontinent paediatric patients with complex care needs.

OBJECTIVE: A thyrotoxic paediatric patient with incontinence, autism and Down's syndrome was referred for radioiodine therapy. Here, the risk assessment methodology and measures taken to deliver a legally compliant treatment that was acceptable to the family are described. METHODS: Prior risk assessment indicated that the most active incontinence waste would require decay storage until it could be transported for disposal. The Health and Safety Executive (HSE) indicated that school staff would be occupationally exposed under the Ionising Radiations Regulations (2017) based on the patient's retained activity. To avoid the need for HSE registration, it was advised that the patient's return to school may need to be delayed slightly. Post-treatment, confirmatory waste and patient dose rate measurements were made to refine the advised time scales. RESULTS: Domestic waste disposal resumed at 28 days. The patient recommenced schooling a few days after their school reopened after the summer break. The school underwent HSE notification. CONCLUSION: Careful planning allowed us to provide a safe, compliant treatment regarding waste management and occupational exposure. ADVANCES IN KNOWLEDGE: Incontinent 131I outpatient treatments require detailed, patient specific waste management. The HSE considered school staff as occupationally exposed by the patient well after normal social restrictions had ended.

Hepatic selective internal radiation therapy: how well does pretreatment 99mTc-macroaggregated albumin activity distribution and quantification agree with post-therapy bremsstrahlung imaging?

AIM: The aim of this study was to examine the agreement of pretreatment Tc-macroaggregated albumin imaging performed for selective internal radiation therapy (SIRT) workup with Y percentage lung shunt (PLS) and regional hepatic distribution in subsequent post-therapy bremsstrahlung imaging. PATIENTS AND METHODS: Planar images were used to calculate PLS. The significant Y bremsstrahlung scatter required background correction. Results using both Y lung background regions of interest (ROI) reported in previous studies and extended ROIs (reflecting lung background variation) were compared with Tc-MAA PLS. Lesion and healthy liver volumes were outlined on diagnostic computed tomography scans and registered to Tc-MAA and Y single-photon emission computed tomography/computed tomographydata. Single-photon emission computed tomography voxel values were normalized to injected Y activity. Volume mean activities were calculated, and converted into the mean absorbed dose. Agreement was quantified using Bland-Altman analysis. RESULTS: PLS: The bias using previous studies' lung background ROIs was -10.71%, with a 95% confidence interval (CI) of -18.79 to -2.64%. The extended ROI yielded a bias of 0.77% (95% CI: -2.23 to 3.70%). Liver: The healthy liver bias was 0.01 MBq/ml (0.17 Gy), with a -0.05 to 0.06 MBq/ml (95% CI:0.80 -1.93 Gy). The lesion mean activity/ml bias was -0.02 MBq/ml (3.71 Gy), with a -0.81 to 0.76 MBq/ml (95% CI: -35.49 to 28.07 Gy). CONCLUSIONS: The PLS agreement was sensitive to the Y lung background correction ROI, potentially explaining a previously published controversy. The mean activity and absorbed dose agreement for the metastatic lesions was poorer than the healthy liver volumes studied here.