PET Scans

CT PET Scanning and the Valley PET Institute
As physicians began looking for ways to better diagnose the extent of disease and to better measure the results of cancer treatment, some investigators found that cancers have more active metabolism and take up and use sugar more than their normal tissue counterparts. CT-PET scanning depends on how actively a tumor takes up radioactive sugar (FDG) and incorporates it into the cancer cells. This shows up on the resulting scan as being ‘hot’ in comparison to the surrounding organs, and thus is visible.

How is the CT PET used?
What is staging?
If the tumor is treated with cancer therapy, a scan can help the clinician determine whether the treatment has worked, and if the tumor has spread elsewhere. The first use is in determining how wide spread a particular cancer is. Can it be surgically removed or treated with a local treatment such as radiation. If it can not, than some form of chemotherapy is most likely to be used, although there are many uses of both surgery and radiation, even though the tumor is wide spread. This scan done before therapy is begun is called a staging scan.

What is restaging?
After therapy is completed in some cases, and while treatment is still ongoing in others, a scan may be performed to help determine whether the treatment is working. In some cases it is used quite early in treatment to find out if the tumor is responding to the treatment. This later area is more controversial, But using scanning following treatment is commonly done.

What are the approved indications for PET scanning for initial diagnosis and for follow up?
For primary diagnosis and staging…All solid tumors one time

Specific indications for PET use- diagnosis and follow up of select solid tumors

• Breast Cancer
• Lung- Single pulmonary nodule
• Lung- Non small cell cancer
• Esophagael- Diagnosis, staging and detecting residual post therapy
• Melanoma- Diagnosis, staging and restaging
• Lymphoma- Diagnosis, staging and restaging
• Head and Neck- Diagnosis, staging and restaging
• Ovarian- Detect recurrent/residual tumor prior to surgery or chemo
• Brain Tumors- Not mets. Tumor vs. radiation necrosis
• Thyroid- Restaging after definitive initial therapy post surgery
• Colorectal-Anal – Diagnosis, staging and restaging
• Hodgkins Disease- Initial staging and restaging
• Cervical Cancer- Diagnosis, staging and restaging
• Myeloma- Diagnosis, staging and restaging
• Musculoskeletal Tumors- Staging, restaging

Lung cancer- The PET shows a fusion scan of PET and CT that demonstrates a right sided lung cancer in the right hilum of the lung only. It is the yellow-white area. The heart, brain, kidneys and the bladder always light up as well.

The next image shows a patient with one kidney and a mass next to the spinal column in the chest. Cancers take up more radioactive sugar than most normal tissues.