ABSTRACT
OBJECTIVE: This study aims to establish a local diagnostic reference level (LDRL) for single-photon emission tomography/computed tomography (SPECT/CT) and positron emission tomography/CT (PET/CT) with respect to myocardial perfusion imaging (MPI). MATERIALS AND METHODS: The acquisition protocol and dosimetry data on the MPI procedures of five SPECT/CT scans and one PET/CT scan were collected. Data on technitum-99m sestamibi (99mTc-sestamibi), 99mTc-tetrofosmin, thallium-201 (201Tl), and rubidium-82 (82RB) were all collected from one centre via questionnaire booklets. Descriptive data analysis was used to analyse all variables, and the 50th percentile was used to analyse each radiation dose quantity. RESULTS: The reported 50th percentile dose for a one-day stress/rest protocol using 99mTc-sestamibi (445/1147 MBq) and 99mTc-tetrofosmin (445/1147 MBq) and for a two-day stress/rest protocol using 99mTc-sestamibi (1165/1184 MBq) and 99mTc-tetrofosmin (1221/1184 MBq) are in good agreement with reported national diagnostic reference levels (NDRLs). However, the dose from the study data on a one-day stress/rest protocol using 99mTc-sestamibi was more than the 50th percentile dose from the Brazilian data (370/1110 MBq) on a similar protocol, and the dose from the study data on a two-day stress/rest protocol using 99mTc-tetrofosmin was more than the 50th percentile dose (1084/1110 MBq) from the United States data on MPI scans. Regarding the computed tomography (CT) portion of the SPECT/CT framework, the 50th percentile doses were lower than all the identified doses in the data considered in the literature reviewed. However, regarding the CT component of the PET/CT MPI scans, the 82RB dose was more than the recorded doses in the CT data in the published literature. CONCLUSION: This study determined the LDRL of five SPECT/CT protocols and one PET/CT MPI protocol. The results suggest that there may be opportunities to optimise the patient radiation burden from administered activities in patients undergoing SPECT examinations and the CT components associated with 82RB PET/CT scans without compromising diagnostic image quality.