Imaging Techniques in CT: Technical Development

Study Summary

Background: \- Computed tomography (CT) scanning is a procedure that helps doctors with diagnoses. It uses X-ray radiation to produce an image in three dimensions. Researchers want to study how to get the best quality CT scans using the lowest possible radiation dose. Objective: \- To determine how to improve CT scanning. Eligibility: \- Adults 45 years of age and older who have not had a CT scan in the past year and do not have kidney disease. Design: * Participants will be screened with a medical history and blood and urine tests. * Nurses will put an intravenous (IV) line into an arm or hand vein. It will stay in for several hours during the magnetic resonance imaging (MRI) and CT scans. Through this IV, blood will be taken, dye will be injected, and medicine will be given. * Participants may have a CT scan of the heart, head, chest, abdomen, and/or pelvis. Participants will lie on their back on a table. The table will slide into a donut-shaped machine. An X-ray tube will move around the body, taking pictures. * Participants may be given a drug called a beta blocker by mouth or through the IV tube. * Participants heart rate and blood pressure will be monitored. * Participants may have an MRI scan. The MRI is a large hollow tube. The participant will lie on a table that will be moved into the tube, which contains a magnetic field. When the imaging starts, a thumping sound will be heard. Headphones or earplugs will be provided to muffle the sound. * Participants will give blood samples.