MEDRADSC 2Z03 Chapter Notes - Chapter 5: Hounsfield Scale, Molecular Probes, Barium
27 Jun 2016
School
Department
Course
Professor
Document Summary
Due to small differences in the hounsfield unit between soft tissues and, importantly, between normal and pathologic tissues for many disease processes, The patient will be injected with a contrast agent, also called dye, before the scan. The dye highlights specific areas inside the body, resulting in clearer pictures. Barium and iodine are two dyes commonly used in ct scanning. Similar to the molecular probes used in other imaging modalities, the performance of x-ray contrast agents is dictated by the relationship between the change in imaging signals (in this case, x-ray attenuation) induced by the compound versus its concentration. The design of x-ray ct contrast agents involves the selection of atoms with large mass attenuation coefficients for use as attenuators. For tomographic imaging, suspensions containing 5 10 g barium sulfate are commonly used. The taste of the barium suspension is generally considered unpleasant, with a mild acidic burning sensation.
