The study recruited all adult Saudi patients who suffered from CVD and were eligible to undergo SPECT/CT or PET/CT MPI scans between 2020 and 2021. Ethical approval (IRB log number: 21-204E) was acquired before commencing the study. The data were gathered from scans conducted on one SPECT/CT scanner and one PET/CT scanner in Riyadh, Saudi Arabia. Five SPECT/CT MPI scans were selected for this study: one-day stress/rest (99mTc-Sestamibi and 99mTc-Tetrofosmin), two-day stress/rest (99mTc-Sestamibi and 99mTc-Tetrofosmin), and stress/rest and reinjection 201Tl. For PET/CT MPI scans, one stress/rest rubidium-82 (82RB) was selected for this study. A retrospective data collection approach was implemented to collect all the required information for this project. Two NM technologists were assigned to collect all the data-based booklet questionnaires used in this study. All the required data had been registered on hospital radiology systems and picture archiving communication systems (PACS).
The first part of the data collection aspect of this study focused primarily on obtaining information on the MPI protocol used at the study facility, such as the model and brand name of the SPECT/CT and PET/CT scanners, the manufacturer, commission date, detector material, and recommended administration method for radioactivity. The second part of the LDRL audit focused on collecting individual demographic data and radiation dose information on each patient who underwent the MPI SPECT/CT and PET/CT protocols considered in this study. The demographic data include the clinical indication, gender, age, weight, and height. Radiation dose information includes the type of administered activity during each SPECT and PET examination and CT dose quantity in CTDIvol and DLP. Details on the acquisition time, matrix size, and collimator were collected for SPECT MPI scans, while scanning time and number of bed/positions was collected for PET MPI scans. CT parameters in the axillary of SPECT and PET MPI were collected, including tube rotation time, kilovoltage, scan length, pitch, and slice thickness. The data collection approach followed the non-weight restricted protocol consistent with the NDRL method for adult common SPECT/CT and PET/CT scans used in a published international study implemented by the Australian Radiation Protection and Nuclear Safety Agency [19 ].
All the CT data related to the SPECT/CT MIP scans were used for AC, and the CT portion of the PET/CT scan was used for AC-AL. The CT equipment was calibrated by the manufacturer using a 32 cm body phantom for CT components associated with all identified SPECT MPI protocols and the PET MPI protocol. Automatic exposure control software was utilised for all identified CT MPI acquisition protocols. The scanner installation data were collected in June 2012 for the SPECT/CT scanner and 2017 for the PET/CT scanner.
Regarding the statistical data analysis, all the collected data were transferred to an Excel sheet. Then, after data entry, they were transferred to SPSS software version 18.0 (PASW, Chicago, IL, USA). The LDRL value for administered activity, CTDIvol, and DLP in frameworks of SPECT/CT and PET/CT MPI were determined based on 50th percentiles. Moreover, the SPECT, PET, and CT data were analysed using descriptive statistics, such as mean, minimum, maximum, and standard deviation (SD). The SPECT and PET radiopharmaceuticals data were analysed and compared with the 50th and 75th percentiles of international published MPI data. Likewise, the CT components associated with SPECT/CT and PET/CT MPI scans were analysed and compared with 50th and 75th percentiles of published international NDRL studies.
Alkhybari E., Albeshan S., Alanazi B., Alfarraj R., Alduhaim R., El Bez Chanem I, & Tulbah R. (2023). Radiation Dose Assessment for Myocardial Perfusion Imaging: A Single Institution Survey. Tomography, 9(1), 264-273.