Nuclear medicine

The researches find that the Reducing radiation exposure from myocardial perfusion imaging (MPI) is a key priority, especially for congenital heart disease (CHD) patients who face repetitive scanning. Which nuclear imaging modality and radiotracer are best for this task is the subject of a study publish in the Journal of Nuclear Cardiology. Researchers from Brigham and Women’s Hospital in Boston and Boston Children’s Hospital paired technetium-99m (Tc-99m) sestamibi SPECT and SPECT/CT against rubidium-82 (Rb-82) and N-13 ammonia with PET and found that radiation dose was lowest with N-13 ammonia PET.

The Reducing radiation exposure

That finding certainly is helpful in directing MPI strategies, bit it might not always be the best option. Nuclear medicine practitioners still must balance radiation risk against an exam’s optimal clinical benefit for the patient, the researchers noted. “The key is to make sure that the clinical question is clear and to understand in discussion with the congenital heart disease physician that the answers give by the test are likely to change a patient’s management;” said study co-author Dr. Sharmila Dorbala, from the division of nuclear medicine and molecular imaging at Brigham and Women’s Hospital.

“The risk-benefit ratio should always be consider. The future small potential risk of radiation-related side effects should be weighed against a present life-changing clinical benefit from treatment if heart problems are found on these scans.” Patients with complex congenital heart disease could undergo one of several stress imaging modalities, including echocardiography, cardiac MRI; and radionuclide scans.

Potential risk of radiation

The latter approach  perform with an exercise stress test and is often prefer over cardiac MRI; which requires a pharmacological stress test, and echocardiography, which has shortcomings in spatial resolution and image quality; particularly in hearts with complex anatomy. At the same time, radiation exposure remains an “overarching concern” with radionuclide MPI, particularly among pediatric patients with complex congenital heart disease who are likely to undergo multiple imaging scans to monitor their progress after surgery and any subsequent treatment; the study authors noted (J Nucl Cardiol, August 12, 2019).

“Because treatments have improved over the past several decades, patients with complex congenital heart disease are now living longer, growing up to become adults; and these adults need close monitoring;” Dorbala told “Most of them have undergone surgical repair procedure as neonates or in their infancy. They need long-term surveillance for possible complications and treatments for their heart conditions.”

A number of pediatric patients also undergo coronary angiography or other imaging procedures; so their lifetime exposure to imaging-relate radiation may sometimes be high. For this reason; Dorbala and colleagues wanted to explore different methods and improve their techniques so they could accurately evaluate for ischemia related ;to coronary artery pathology with the lowest possible radiation dose.