Background: Neuroendocrine tumors (NET) are neoplasms that secrete peptides and neuroamines. For gastroenteropancreatic (GEP) NET, surgical resection represents the only curative option. Ten-year imaging surveillance programs are recommended due to long time-to-recurrence following resection. We performed retrospective chart review evaluating radiation exposure and practice patterns from surveillance of completely resected GEP NET. Methods: We performed a retrospective cohort study of cases with well-differentiated GEP NET from January 2005 to July 2020. Location of primary, modality of imaging, and duration of follow-up were collected. Dosimetry data was collected to calculate effective dose. Results: 62 cases were included with 422 surveillance scans performed. Cross-sectional imaging was used in 82% and functional imaging was used in 18% of scans. Mean number of scans per year was 1.25 (0.42–3). Mean total effective dose was 56.05 mSv (SD 45.56; 0 to 198 mSv) while mean total effective dose per year was 10.62 mSv (SD 9.35; 0 to 45 mSv). Over the recommended ten years of surveillance the estimated total effective dose was 106 mSv. Conclusions: Surveillance of completely resected GEP NET results in cumulative radiation doses in the range associated with secondary malignancy development. Strategies to minimize radiation exposure in surveillance should be considered in future guideline development.

Introduction: Diagnosis and treatment of acute stroke depends upon imaging, namely non-contrast CT (NCCT), CT angiography (CTA), CT perfusion (CTP), and MRI. We sought to i) examine available data from around the world on six categories related to acute stroke imaging: utilization, time to imaging, radiation exposure, contrast dose, availability, and cost, and ii) compare that information with similar data from our province (Alberta). Methods: Using a scoping review methodology, six categories related to acute stroke diagnostic imaging were examined: utilization, time to imaging, radiation exposure, contrast dose, availability, and cost. Metadata for these categories in Alberta were collected from Alberta Health Services administrative records for comparison. Results: A total of 6693 articles/documents were initially identified through database searches, of which 83 were included for analysis. CT (range = 55-100%) was used more frequently than MRI (range = 23.6-94.0%) in acute stroke, with high CTA use in Alberta (55.7%) compared to other centres (range = 8.6-36.0%; Table 1). CT time to imaging was < 25 min (target time) in most centres, but not in Alberta (mean = 3.2 hr, median = 2.0 hr). MRI was not used urgently in most centres (mean = 0.4-21.0 hr), including Alberta (mean = 15.4 hr, median = 13.0 hr). CTA radiation exposure was greater in Alberta compared to other centres (5.7 mSv vs 2.8-5.4 mSv) whereas it was similar for NCCT and CTP. Contrast doses for CTA and CTP were similar between Alberta (CTA = 50-70 mL, CTP = 45 mL) and other centres (CTA = 40-150 mL, CTP = 30-60 mL). Lastly, the number of CT and MRI scanners per million population and cost of operating them was similar worldwide. Conclusions: In conclusion, no studies were identified that provide a comprehensive overview of all six factors relevant to diagnostic imaging in acute stroke. The Alberta metadata fills in this literature gap, specifically in the context of Canadian stroke care. Download figure