Reduction in SPECT MPI Radiation Dose
How effective are contemporary radiation dose reduction strategies for single photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI) in clinical practice?
The authors retrospectively reviewed radiation exposures for 18,162 SPECT MPI studies performed at four nuclear cardiology laboratories in the Midwestern United States from January 2009 to September 2016. Effective radiation doses were computed using standard conversion factors for thallium-201, technetium-99m sestamibi, and technetium-99m tetrofosmin. Average and median effective radiation doses were analyzed in changes in protocols and scanner technologies.
Elimination of thallium-201 protocols in 2009 resulted in a decreased effective radiation dose from a mean of 17.9 mSv to 12.1 mSv. Transition from large field of view cameras to small field of view cameras with advanced reconstruction software was associated with a further reduction to 5.6 mSv, while use of cadmium-zinc-telluride (CZT) cameras was associated with mean effective dose of 2.8 mSv. Overall, mean effective doses decreased from 17.9 mSv in 2009 to 7.2 mSv in 2016.
Comprehensive radiation dose reduction strategies comprising elimination of thallium-201 protocols and use of advanced technologies is associated with a dramatic reduction in effective radiation exposures.
This study demonstrates that nuclear cardiology methods need not be associated with a high radiation burden in the current era if modern protocols and technologies are utilized. Unfortunately, effective dose data from accreditation organizations and large international surveys suggest that these technologies are not being utilized broadly. Increased efforts at education and, perhaps, realignment of financial incentives are likely necessary to achieve the goal of minimizing patient effective radiation doses from SPECT MPI while maintaining or improving diagnostic performance.
Keywords: Cadmium, Cardiac Imaging Techniques, Myocardial Perfusion Imaging, Nuclear Medicine, Radiation, Radiation Dosage, Technetium, Technetium Tc 99m Sestamibi, Thallium, Tomography, Emission-Computed, Single-Photon
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