Diagnostic duo highlights heart damage – technetium-99m sestamibi imaging compound
Kathy A. Fackelmann
Diagnostic duo highlights heart damage
The FDA has approved the use of a new chemical combo to reveal blood-starved cardiac tissue during a heart attack. Called technetium-99m sestamibi, the imaging “dye” consists of a radioactive tracer (technetium-99m) bound to a heart-seeking chemical (sestamibi).
By enabling clinicians to record sharper pictures delineating healthy and damaged areas of the heart, the compound should help physicians assess the need for surgery and evaluate the effectiveness of clot-busting drugs and other heart attack treatments, says Daniel S. Berman of the University of California, Los Angeles. Physicians might also use it to identify outwardly healthy people with blood-flow blockages that place them at risk of sudden heart attack, he suggests. Berman, a nuclear cardiologist, conducted some of the clinical investigations that led to last week’s FDA approval.
Developed by Du Pont Merck Pharmaceutical Co., technetium-99m sestamibi homes in on heart tissue when injected into the bloodstream, binding only to cells that are receiving sufficient blood flow. Because it sticks to the heart cells for about four hours, physicians have plenty of time to stabilize the patient’s condition before taking pictures with a gamma-ray imaging camera, Berman says.
A similar technetium imaging agent, developed by Bristol-Myers Squibb Co., also won FDA approval last month. Until now, the radioisotope thallium has been used as the primary tracer for heart damage, but thallium requires physicians to obtain images within half an hour after the injection or lose the chance to size up the initial damage, Berman says.
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