Radionuclide angiography with 99m technetium-RBCs.

When properly labeled 99mTc-RBCs are injected into a patient, these labeled cells are fairly stable in the circulation thus allowing scintigraphic studies on cardiovascular system. Among various modified techniques published for 99mTc-RBCs labeling, incubation of RBCs with 99mTc pertechnetate then with tin yielded 99mTc-RBCs most stable in the circulation. Average labeling efficiency of 99mTc-RBCs was 66%. After an injection of about 10 mCi 99mTc-RBCs, clear images of the heart chambers and major vessels could be obtained using a gamma camera. Resolution of vascular structures improved significantly when images were taken using gamma camera equipped with pinhole collimator. Radionuclide angiography with 99mTc-RBCs was very useful in detection of abdominal aortic aneurysm, evaluation of mediastinal mass--thoracic aortic aneurysm, and detection of abnormality in a smaller vessel such as carotid artery. Advantages of this procedure are (1) the technique is simple and noninvasive; (2) it has capability of functional evaluation by obtaining flow study; and (3) multiple and repetitive static views can be obtained even several hours after an injection.