The U.S. Food and Drug Administration (FDA), in collaboration with local health authorities, investigated the issue of radiation overdose from CT perfusion scans of the brain and identified 50 patients who were overexposed to up to eight times the expected dose during CT perfusion scans. Some of these patients reported hair loss or skin reddening after the scans. High doses of radiation can cause cataracts and increase the risk of some types of cancer. Therefore, the FDA requires radiologic technologists to check the display panel of a CT scan subject before an examination to ensure that the amount of radiation to be released is at an appropriate level for the patient. The FDA has provided interim recommendations to imaging facilities, radiologists, and radiologic technologists to help prevent additional overexposures. These recommendations include: 1. Institutions assess whether patients who undergo CT perfusion scans have received an overdose of radiation. 2. institutions review their radiation dose protocols for all CT perfusion studies to ensure that the correct dose is planned for each exam. 3. The institution implements quality control procedures to ensure that dose control protocols are followed and planned radiation doses are given.