What is the difference between PET/CT/Bone Scan

[Cal-Gal]

Hi there--

Can someone explain the difference --
or actually what shows and what doesn't in these different tests:



PET
CT
Bone Scans


I had a PET and a CT right aft my surgery and subsequently 2 more CT scans--have not had a bone scan--

Thanks---

[Rich66]

PET shows areas of metabolic activity (sugar uptake), usually of cancer cells. judged as to whether an area "lights up".

CT gives a "picture" of masses, good for tracking size of tumor. Often done with contrast injection to give clearer image.
PET and CT are sometimes done separately and matched up, whereas sometimes done together on the same PET/CT machine. PET is thought to show changes in cancer before it is visible on CT.

Cancer bone scan shows bone metastases activity. Not to be confused with bone density scan for osteoporosis.

[Cal-Gal]

Thanks Rich-

I had the combo PET/CT scan in January and the CT w/dye the last 2 times-

Thanks for clarification on bone scans--I have never had one--and didnt know if that is an area or possibly area of concern that is covered in the CT or PET--

[Rich66]

I think it may be possible to pick up certain bone mets on a PET but not reliably.
I will also mention that CTs have varying resolutions or "slices", typically between 16 and 64. In cases of tracking mets during chemo, it may be helpful to have a higher slice machine since minute changes may be indistinguishable from differences in where the slices occurred.

[Cal-Gal]

Thanks Rich for this info--