The flare phenomenon is an increased activity uptake, seen in scintigraphic procedures in the early phases of therapy or due to healing processes.

A perfusion scintigraphy records the organ blood circulation usually directly or during the first two minutes after the injection of a radioactive tracer.
Different types of radiopharmaceuticals are used, depending on the target organ.

Typical perfusion scans include:
See also First Pass Scintigraphy, Myocardial Scintigraphy, Heart Scintigraphy, Whole Body Scintigraphy, and Flare Phenomenon.