I want to know what is the difference between pet scans, mri, ct, and bone/gallium scans?

2 groups: Mri and ct scans are typically looking at the anatomy of a patient, as well as differences in blood flow if contrast is administered. Pet, bone and gallium scans are all looking at the function, or physiology of the patient, and the anatomy is of secondary concern. For example, pet scans are usually using f-18 fdg, a glucose analog, and display differences in glucose use, a main energy source.

Imaging tests: Ct uses radiation, like multiple x-rays. Mri uses magnets, and is very useful in characterizing soft tissue differences such as in the brain or joints, but also is more expensive and takes much more time. Pet is typically used for cancer imaging as it detects glucose usage by tissue (which is greater in tumors). Bone / gallium uses radiotracer.Best i can explain in 400 letters!