Status of cardiovascular PET radiation exposure and strategies for reduction: An Information Statement from the Cardiovascular PET Task Force

Abstract

Cardiovascular positron emission tomography (PET) imaging provides high-quality visual and quantitative myocardial perfusion and function images. In addition, cardiovascular PET can assess myocardial viability, myocardial inflammatory disorders such as cardiac sarcoid, and infections of implanted devices including pacemakers, ventricular assist devices, and prosthetic heart valves. As with all nuclear cardiology procedures, the benefits need to be considered in relation to the risks of exposure to radiation. When performed properly, these assessments can be obtained while simultaneously minimizing radiation exposure. The purpose of this information statement is to present current concepts to minimize patient and staff radiation exposure while ensuring high image quality.

EANM procedural guidelines for PET/CT quantitative myocardial perfusion imaging

“…82 Rb: 1.1 mSv/GBq [ 26 , 33 ]. The effective dose depends on the exact protocol used, but two injections of 10 MBq/kg result in an effective dose of approximately 1.5 mSv.…”

“…[ 13 N]NH 3 : 2 mSv/GBq [ 26 , 33 ]. A typical protocol consisting of two injections of 400 MBq will result in an effective dose lower than 1.8 mSv.…”

Ten things to know about ten imaging studies: A preventive cardiology perspective (“ASPC top ten imaging”)

“…If unable to physically exercise, then an A2A adenosine receptor agonists (i.e., regadenoson coronary vasodilator for cardiolite stress test) can be injected to mimic exercise 10 -15 mSv with technetium-99 [48] 25 – 30 mSv with thallium-201 [48] (seldom used in current clinical practice) • PET perfusion imaging Requires injection of radiotracer (e.g., 50 mCi of 82 rubidium or 20 mCi of 13 ammonia for rest and stress perfusion). [47] If unable to physically exercise, then pharmacologic stress testing can be achieved via the vasodilators regadenoson, adenosine, dipyridamole, or inotropic/chronotropic agents such as dobutamine with or without atropine 4 mSv with 82 rubidium or 13 ammonia [49] (older reports suggest higher radiation exposure) [ 48 , 47 ] • MUGA ventricular imaging (seldom use in current clinical practice) Requires injection of radiotracer 5 – 10 mSv with technetium-99m-pertechnetate [50] CMR Most cardiac protocols involve injection of contrast (i.e., gadolinium) 0.00 mSv (no radiation) Cardiac catheterization Cardiac catheterization involves insertion of a catheter tube into the artery or vein in the groin, neck, or arm, which is then threaded into the heart. 2 – 7 mSv for diagnostic cardiac catheterization [51] 10 mSv or higher for interventional catheterization [ 52 , 52 ] DXA total body composition scan Noninvasive ≤ 0.001mSv for typical body composition (minimal radiation; technicians not required to wear garments to protect from radiation) Hepatic imaging• Ultrasound of liver• VCTE/fibroscan• CT• MRI-PDFF• MRS NoninvasiveNoninvasiveMay involve injection of contrast (e.g., iohexol)May involve injection of contrast (i.e., gadolinium)May involve injection of contrast (i.e., gadolinium) 0.00 mSv (no radiation)0.00 mSv (no radiation)3.0 mSv0.00 mSv (no radiation)0.00 mSv (no radiation) Carotid ultrasound, peripheral doppler imaging, ultrasound flow-mediated dilation, and pulse amplitude tonometry Fingertip infrared light transmission photoplethysmograpy for endothelial function Noninvasive 0.00 mSv (no radiation) Daily background radiation 0.007 mSv Yearly background radiation ...…”

Contemporary Cardiac SPECT Imaging—Innovations and Best Practices: An Information Statement from the American Society of Nuclear Cardiology

“…It also requires the use of radiation doses much higher than what is used in other modalities for similar procedures. 18,19 Iterative reconstruction algorithms utilize a stepwise approach to determine the source distribution; the most common of these is the maximum likelihood/expectation maximization (MLEM) algorithm. 20 This algorithm uses a model for the statistics of the image to iteratively improve the source activity estimate.…”