What is a pet scan? What is a pet scan and how is it different from other breast imaging procedures?
Anatomy vs Physiolog. Mri and ct look at the structure of the body, the anatomy, and the way diseases change or distort it. Pet looks at the physiology, or how the body uses, or metabolizes something. For pet, the most common metabolism pathway looked at is how glucose is used. Ct is used to correlate anatomy to the pet pet images the whole body, while mri, us and mammography are limited to a portion of the body.
Positron emission. Pet stands for positron emission tomography. Radioactive material is injected that emits positrons that are measured by a detector. This is placed over the region of the body that is desired to study. Mammography and self exam may detect a lump or mass, and then the pet can look for abnormal uptake suggesting that it is cancerous.
PET. Pet stands for positron emission tomography. This involves injection of a radiopharmaceutical (fluorine 18 labeled fluorodeoxyglucose = fdg). This sugar molecule is taken up by metabolically active cells throughout the body. Tumors and metastases are generally very metabolically active and uptake a disproportionately large amount of fdg. The radioactive fluorine 18 that is attached to the FDG sugar molecule emits radiation which can be detected by a special radiation detector. The detected information is then used to generate an image of metabolic activity throughout the body which highlights tumors because of their high metabolism. This exposes the patient to a significantly larger radiation dose than mammography. It is generally used in combination with ct to evaluate the entire body for metastatic disease after breast cancer is discovered. Pem (positron emission mammography) is being developed to image only the breast for breast cancer, but this is not widely available and still being researched and developed.