A procedure in which a small amount of C-11 choline (a radioactive form of the vitamin choline) is injected into a vein. A scanner and a computer are used to make detailed pictures of areas inside the body where the C-11 choline collects. Cancer cells take up more C-11 choline than normal cells, so the pictures can be used to find cancer cells in the body. Also called carbon-11 choline PET-CT scan.