A CT Scan vs. a PET scan; how do they differ? CT scans and PET scans are actually very different and often serve a different diagnostic purpose. While your doctor will prescribe the scan that most effectively addresses your needs, you might be curious about how they work. Here is a quick guide to help you understand the basics.
How CT Scans Work
A CT (computed tomography) scan uses x-ray technology to create detailed images of the body and inner body structures. CT scans usually take about five to ten minutes to complete and are generally less expensive than other types of diagnostic scans like MRIs or PET scans. CT scans expose the body to a moderate amount of radiation and are therefore not recommended for children or pregnant women unless absolutely necessary. CT scans are quick, painless, and completely noninvasive. Your doctor may order a CT scan after an injury or to diagnose a potential illness.
How PET Scans Work
PET (positron emission tomography) scans are utilized to diagnose and keep careful tabs on a variety of illnesses. PET scans are most commonly used to detect cancers, heart problems, brain disorders, and problems with the nervous system. PET scans utilize molecular imaging. Molecular imaging is a very precise way of detecting disease on the cellular and molecular level. PET scans work by injecting a tiny amount of radioactive tracers into the bloodstream, which the PET scan machine can then detect and analyze via 3D images. PET scans take between 2-4 hours to complete, and are significantly more expensive than CT scans. The radiation exposure of a PET scan is about the same as an x-ray. PET scans are excellent at analyzing the biological processes of the body and at detecting pathology such as cancer at the very earliest stages.
A CT Scan vs. a PET Scan
Your doctor will prescribe the scan that addresses your needs.