JNM: Scintigraphic techniques detect cardio toxicity of anticancer agents
New anti-tumor agents result in significant benefits for cancer patients, but may have serious cardiovascular side effects which can be detected early using scintigraphic techniques, according to an article published in the April issue of the Journal of Nuclear Medicine.

To measure the cardiovascular side effects of anti-tumor agents, physicians have relied on 99mTc multigated radionuclide angiography, which visualizes the mechanical function of the heart as the gold standard. This approach monitors left ventricular ejection fraction (LVEF); however, it generally detects cardiovascular damage in a relatively late stage.

Nuclear cardiologic techniques that visualize pathophysiologic and neurophysiologic processes at the tissue level have the potential to detect cardiovascular injury at earlier stages, according to Lioe-Fee de Geus-Oei, MD, PhD, nuclear medicine physician at the department of nuclear medicine, Radboud University Nijmegen Medical Centre in Nijmegen, the Netherlands.

“These techniques may give the opportunity for timely intervention to prevent further damage and could provide insights into the mechanisms and pathophysiology of cardiotoxicity caused by anticancer agents,” wrote Geus-Oei and colleagues.

Both first-order functional imaging techniques such as 99mTc multigated radionuclide angiography and 99mTc gated blood-pool SPECT, and third-order functional imaging techniques (visualizing pathophysiologic and neurophysiologic processes at the tissue level) were discussed in the review.

Third-order functional imaging techniques comprise 123I-metaiodobenzylguanidine scintigraphy, which images the efferent sympathetic nervous innervations; sympathetic neuroneuronal PET, with its wide range of tracers; 111In-antimyosin, which is a specific marker for myocardial cell injury and necrosis; 99mTc-annexin V scintigraphy, which visualizes apoptosis and cell death; fatty-acid-use scintigraphy, which visualizes the storage of free fatty acids in the lipid pool of the cytosol (which can be impaired by cardiotoxic agents); and 111In-trastuzumab imaging, to study trastuzumab targeting to the myocardium.

"Fully exploring these pathophysiologic and neurophysiologic imaging strategies is not only important for the prevention of cardiac morbidity and mortality, but also for the development of newer strategies to prevent cardiac injury, either through new dosing schedules, less toxic analogues or addition of protecting agents," said Geus-Oei.

She added that using molecular imaging and nuclear medicine to detect cardio toxicity can help provide cost savings for hospitalization, additional treatment and other indirect costs. Further, imaging strategies are not only of relevance to approved drugs--they also can be applied to new targeted drugs currently under development.