Heart after heart attack. False-colour computer enhanced gamma scan of a human heart (seen in transverse section) which has suffered a myo- cardial infarction. During a heart attack, the heart muscle is starved of oxygen and necrosis (cell death) occurs in places. Here, red areas show healthy myocardial tissue which normally is continuous in a semi-circle around the left ven- tricle. Due to myocardial infarction, the red areas are separated, with scarred tissue occurring between & beneath the red areas. Gamma scanning (scintigraphy) involves introducing radioactive substances into the body, which are taken up by certain organs and detected by a gamma camera.