Preparing a patient for a gamma scan of the heart using a tracer containing the radioisotope thallium-201. So-called cold-spot" scanning with thallium-201 is used to image the uptake of the tracer by the myocardium (the heart muscle) & check for defects. The radioactive tracer is injected into the bloodsteam prior to scanning. The concentration of thallium-201 in heart muscle depends on a normal blood flow and the integrity of the membranes surrounding the muscle cells of the heart. Comparison of scans made during exercise & at rest may reveal areas deficient in blood supply (ischaemic) or infarcts - areas of inactive heart tissue caused by a heart attack. Photo taken in a Kuwait hospital prior to the Iraqi invasion of August 1990. This equipment was reportedly looted & removed to Baghdad."