A Single Photon Emission Computed Tomogram (SPECT) is a test that evaluates blood flow within the brain. The test is performed during PHASE I monitoring. There are two parts to the test. During both, a small amount of radioactive tracer is injected into the bloodstream. In the first part the tracer is injected while the person is having a seizure. During a seizure, blood flow is increased in the region of brain where the abnormal electrical activity occurs. In areas where blood flow is increased, more tracer accumulates. The second part of the test is done in between seizures. A tracer is injected as before, and the results of the two tests are compared. Any area, which shows increased uptake, represents the area of brain that is causing the seizures.