SPECT stands for 'Single Photon Emission Computed Tomography'. It is similar to a PET scan. Before the scan, you have an injection of a very small amount of a radioactive chemical. This is really a tiny amount and not enough to do you any harm at all. The radioactive chemical circulates in your blood and shows up the cancer on the scanner.
A painless procedure that takes a picture of a person's brain, which can help in the diagnosis of Alzheimer's disease, yields somewhat different information from MRI.
a sensitive tool to measure brain function and metabolism