PET-CT is considered particularly effective in identifying whether cancer is present or not, if it has spread, if it is responding to treatment, and if a person is cancer free after treatment. Cancers for which PET-CT is considered particularly effective include lung, head and neck, colorectal, oesophageal, lymphoma, melanoma, breast, thyroid, cervical, pancreatic, and brain as well as other less-frequently-occuring cancers.
The risks associated with a PET scan are minimal. Most studies are conducted with an injection made up of radioactive glucose (sugar). The radiation exposure associated with PET is similar to a conventional whole-body diagnostic CT scan.
The main use of PET/CT is the detection and evaluation of primary and metastatic cancer. It is used to determine the correct stage of the cancer at the beginning and to evaluate the response to treatment as well as recurrence of disease after treatment.
PET/CT combines anatomical imaging (CT) with physiological and pathological imaging (PET).
A radioactive isotope, which is bound to sugar, is injected into the body. This concentrates in areas with a high metabolic rate, in other words which uses a large amount of sugar. This is the case in most primary cancers and ca