test?

CT scan is like a black and white TV, PET scans are like flat screen color TV with internet access! That's just my analogy.
Basically, there's just a world of difference in how well and what all they can see with the PET vs. CT scan. Mainly, for cancer patients, CT will show a mass or tumor as a density different from surrounding tissue, and sometimes they don't see that till it gets pretty big. With PET scans they usually inject radioactive glucose by IV, tumors then pick up glucose, it shows up on scan, therefore they can detect cancer cells at a much earlier stage. Hope this helps. hummer