Establishing national diagnostic reference levels for adult nuclear medicine single-photon emission computed tomography imaging in Bahrain.

This study established diagnostic reference levels (DRLs) for common adult single-photon emission computed tomography (SPECT) procedures in Bahrain to support dose optimization and alignment with international radiation protection standards. Data were retrospectively collected from two major nuclear medicine centers, representing most national SPECT services. Administered radiopharmaceutical activities (MBq) for adult patients (70 kg ± 20%) undergoing routine examinations were analyzed. DRLs were calculated as the 75th percentile of administered activity following International Commission on Radiological Protection (ICRP) Publication 135. A total of 1098 studies were included. Variations between centers reflected differences in administration practices. Overall, Bahrain's proposed DRLs were lower than regional values reported in Kuwait and Saudi Arabia and were comparable to European benchmarks. The findings provide a national reference framework for optimization of nuclear medicine practice and support ongoing monitoring to maintain compliance with international radiation safety recommendations from the ICRP and International Atomic Energy Agency.