Real-world estimated effective radiation doses from commonly used cardiac testing and procedural modalities

The volume of cardiac diagnostic tests that are performed has increased significantly in recent years. The benefits of these tests should be weighed against the risks, including exposure to ionizing radiation. We sought to determine the effective radiation doses associated with common cardiac imaging studies performed at a provincial referral heart centre in Vancouver, Canada, between January 1, 2009 and December 31, 2009.

Effective radiation dose was calculated for all patients who underwent clinically indicated cardiac computed tomography angiography (CCTA), myocardial perfusion imaging (MPI), and diagnostic catheter coronary angiography (CCA) in 2009. The dose from CCTA and CCA studies was estimated from dose-length product and dose area product values, respectively. A conversion factor of 0.014 mSv/(mGy × cm) was used for CCTA and MPI CT attenuation correction. The conversion factor for CCA was 0.22 mSv/(Gy × cm(2)). The effective radiation dose for MPI was calculated using: E = (E/A) × A(o) where E = effective dose, E/A is an effective dose coefficient, and A(o) is the radiotracer activity.

There were 673 CCTA studies and 2306 MPI studies performed with average effective doses of 3.7 mSv and 16.8 mSv, respectively. There were 2628 diagnostic CCA studies performed with an average effective dose of 11.4 mSv.

There was a wide range of effective radiation doses between imaging modalities. These tests provide different clinical information and the appropriate test must be chosen with radiation dose in mind. The implementation of dose reduction strategies has the potential to significantly reduce these doses.