What is a bone scan?

What;s the difference between a bone scan and a PET scan?

• my doctor's have ordered me to have a Cat Scan tomorrow because they are unsure if the growth on my head is related to my battle with testicular cancer during the summer of 2006. ...show more

• Answer:

  CT scan: you only need to fast if they are scanning your abdomen. If they are, you will need to drink oral contrast too. You have to fast to keep your upper digestive tract empty so that you can get a good picture with the oral contrast. If they are just scanning your head, you shouldn't need to fast, but I would just do whatever they tell you too--you don't want your test to be canceled unnecessarily because of an overzealous tech. Bone scan: you will be injected with a chemical that localizes to the bone. It will become concentrated in areas where there is high bone turnover going on, such as tumors, fractures, or infections. Obviously, what they are looking for are tumors. What you will see is a fuzzy picture of your skeleton and any areas of high bone turnover will appear as focal dark spots. PET scan: you will be injected with a modified glucose molecule. Glucose is the primary energy source of cells, so it will become concentrated in parts of your body that are the most metabolically active--such as tumors. A PET scan will usually be done concurrently with a CT scan so that the PET pictures can be overlaid with the CT pictures (otherwise the PET scan just looks like a bunch of fuzzy clouds floating in space). Neither the bone or PET scan should cause you any significant discomfort. Sticking the IV in you should be the worst part. Same for the CT scan, although as your probably know, the oral contrast also has a laxative effect.