National Diagnostic Reference Level (DRL) for nuclear medicine computed tomography–positron emission tomography hybrid imaging studies for kuwait population: second phase dose audit-2019

Objective: Diagnostic reference levels (DRLs) for CT part of positron emission tomography-CT (PET-CT) examinations are limited. The study was aiming to execute the second phase of the national DRL in support of optimisation and dose reduction in State of KW. Methods: In this multicentre collaborative PET-CT study, oncology patient data were exclusively collected due to the National MOH Ethical Committee recommendation and limitation of the other studies. Median, Mean, SD, 75th, 25th percentiles as well as whole body (WB) effective dose (ED) were calculated. The study was UK-IPEM-based methodology and it was the second phase of the study in Kuwait. Results: Half body (HB) and WB scans were 65 and 35% of the total enterers (309). The third quartile dose–length product (DLP) (mGy x cm) and volumetric CT dose index (mGy) values for the HB (537, 5) were higher than the UK NDRL (400, 4.3) but were lower than the Swiss NDRL (620, 6) and the France NDRL (762, 7.7). Comparatively, the proposed NDRLs for the WB (684, 4.1) were lower than Swiss National Data (720, 5.0) though, the Swiss had about 5000 (HB) & 706 (WB), the UK had 370 (HB) and France had 1000 (HB) entries. Calculated ED varied from 4.1 to 10.2 mSv, (mean values = 6.9 mSv) for HB and from 2.6 to 7 mSv (mean value = 4.6 mSv). Conclusions: There was 9.1% improvement in NDRL for 2019, compared to 2018, but there is a continuous need for improving NDRL. Advances in knowledge: Data provided a trend of NDRL that is served as a national data bank for continuous optimisation.