What are the differences between pet scans, mri, ct, and bone/gallium scans?

Precision: Ct is a great screening tool for imaging the organs. Mri images certain tissues more accurately. Pet uses radioactive material to light up specific tissues. Bone scans use activated agents that are taken up selectively by abnormal tissues. Each technique has it's benefits, risks, and degree of precision.

Many differences: Mri (magnetic resonance) does not utilize ionizing radiation(ir) characterize tissues, extent of tumor, infection, damage to cartilage/ligaments.Bone scan (ir) finds changes in bone reflecting tumors, fxs, infection( sensitive not specific) .Ct (ir) can localize traumatic changes, tumors, appendicitis, kidney disease.Pet/ct (ir) combo isotope /ct finds subtle metastases and recurrent malignancy, .

Anatomy vs Physiolog: 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.