Results of a Colorectal Cancer PET/CT Exam

PET/CT use a small amount of a radioactive drug, which is normally FDG: a tracer in combination with a compound such as glucose. Once injected the FDG tracer travels through the body.

FDG emits signals as it travels and eventually collects in the organs targeted for examination. If an area in an organ is cancerous, the signals will be stronger (as shown on the images) since more glucose will be absorbed in those areas. Your physician or surgeon will pick up theses stronger images.

In colon cancer, if the lymph nodes nearby the tumor or if a distant organ such as the liver has become involved by the cancer, they will take up more of the radioactive glucose and again be seen more ‘brightly’ by the surgeon.

In colon cancer, staging how far into the colon the tumor has grown and whether or not it has spread beyond it, either to the lymph nodes or to distant organs is extremely important. Earlier stage may be curable; however, in most cases cancer that has spread to other organs is incurable.

CT scanning looks at the size of the lymph nodes and PET is determines if cancerous cells are alive in that area. In a whole-body scan, the PET scan can look throughout your whole body to see if there are any clumps of the cancer cells that have spread, and the CT can build up an accurate location picture that is superimposed over the PET results, thus aiding complete accuracy in staging and location of a cancer.

PET scan can make the difference in determining whether surgery should be done as well as chemotherapy or radiation therapy.