Standard Myocardial Perfusion and Cardiac FDG PET Protocols and Associated Patient Radiation Doses

Sharmila Dorbala, MD Brigham and Women’s Hospital, Boston, MA

Myocardial perfusion positron emission tomography (PET) using 82Rb or 13N ammonia is an accurate method to evaluate rest and stress myocardial perfusion, to detect significant coronary artery disease, and to risk-stratify patients with regard to cardiac event-free survival. Compared to myocardial perfusion SPECT, PET usually provides superior image quality due to higher photon energy and inherent soft tissue attenuation correction. Coronary flow reserve may be quantified, providing a means to detect “balanced” myocardial ischemia in patients without regional perfusion abnormalities. However, because myocardial perfusion requires pharmacologic stress, exercise capacity and associated electrocardiographic abnormalities cannot be assessed. Combined with myocardial perfusion imaging, 18F-2-fluoro-2-deoxy-D-glucose (FDG) PET identifies areas of resting ischemia of viable, jeopardized myocardium where regional ischemia has resulted in a shift from fatty acid to glucose metabolism.

 Study Injected Activity  Effective Dose Estimate
 Scout scan/Localizing scan1    

  Radionuclide: 82Rb

10 mCi 0.46 mSv2

  Radionuclide: 13N ammonia

1 mCi 0.10 mSv3 

  Radionuclide: 18F FDG

Use injected FDG activity to localize the heart No additional dose
 CT scout   0.73 mSv
 CT transmission scan   0.04 mSv
 Emission scan1    
 Rest/stress 82Rb -2D 40 mCi rest
40 mCi stress
 3.76 mSv2,4
 Rest/stress 82Rb -3D 20 mCi rest
20 mCi stress
 1.88 mSv2,4
 Rest/stress 13N ammonia -2D 20 mCi rest
20 mCi stress
 3.98 mSv3
 Rest/stress 13N ammonia -3D 10 mCi rest
10 mCi stress
 1.99 mSv3
 Stress-only 82Rb -2D 40 mCi stress  1.89 mSv4
 Stress-only 82Rb -3D 20 mCi stress  0.95 mSv4
 Stress-only 13N ammonia -2D 20 mCi stress  1.99 mSv3
 Stress-only 13N ammonia -3D 10 mCi stress  0.99 mSv3
 18F FDG- 2D 10 mCi  7.03 mSv3
 18F FDG- 3D 5 mCi  3.51 mSv3

Total Patient Dose/study = (Scout dose+ transmission dose+ emission dose) + Calcium score dose (if applicable) + CT coronary angiogram dose (if applicable)

Recommendations to Decrease/Limit Patient Radiation Exposure