Effective Dose to Patients from SPECT and CT During Myocardial Perfusion Imaging

Area of Science:

• Nuclear Medicine
• Radiology
• Medical Imaging

Background:

• Patient radiation dose is a critical factor in medical imaging, requiring regular assessment for risk-benefit analysis.
• Optimization of imaging protocols is essential for minimizing radiation exposure while maintaining diagnostic accuracy.

Purpose of the Study:

• To estimate the effective dose (ED) to patients undergoing SPECT myocardial perfusion imaging (MPI) with CT attenuation correction.
• To analyze radiation dose variations based on patient demographics, scanner models, and imaging centers.

Main Methods:

• Reviewed SPECT and CT acquisition parameters (administered activity, CTDIvol, dose-length product) for 415 patients.
• Calculated effective doses for SPECT, CT, and the combined procedure.
• Performed statistical comparisons across sexes, BMIs, scanner models, and imaging centers.

Main Results:

• Mean ED for SPECT MPI was 8.8 mSv (men) and 10.4 mSv (women).
• Mean ED for CT attenuation correction was 0.8 mSv (men) and 1.1 mSv (women).
• Total mean ED was 9.6 mSv (men) and 11.5 mSv (women); CTDIvol depended on scanner model, not BMI.

Conclusions:

• The total effective dose for SPECT/CT MPI is approximately 11 mSv, with SPECT contributing the majority.
• CT attenuation correction poses a small additional radiation risk compared to the significant diagnostic benefits.
• Findings support the continued use of CT for attenuation correction in SPECT MPI due to its value in accurate diagnosis.