By Nick Nelson, RT (R)(N) ARRT CNMT , PET/CT Technologist and Mary Kay Holloway, RDN CSO LDN Oncology Dietitian
Your doctor just said one of the dreaded statements, “You have cancer.” Then you are sent off for a CT and PET scan. You say “okay,” but in your head you are wondering just what this doctor is talking about. He is not talking about a scan for your pet, but a PET scan. PET is short for Positron Emission Tomography, and CT is short for Computed Tomography. Just what does it have to do with cancer? Read on for that answer.
PET and CT are both standard imaging tools that physicians use to reveal the presence and severity of cancers. While a PET scan reveals the way the body works, the CT scan provides information about the body’s anatomy such as size, shape, and location. The images from these two powerful technologies are fused into one non-invasive technique called PET/CT. The accuracy of PET/CT images allows a physician to examine an entire body at once and provides information that helps physicians:
- locate the site of the cancer.
- determine the size of the tumor.
- evaluate the extent of the disease.
- select the most appropriate treatments.
- monitor the success of therapy.
- detect any recurrent tumors.
Scans must be interpreted carefully because noncancerous conditions can look like cancer. The types of cancer most likely to show up on PET scans include breast, cervical, colorectal, esophageal, head and neck, lung, lymphoma, melanoma, pancreatic, prostate, and thyroid.
A PET/CT scan is painless, with no side effects. After fasting for at least four hours, a patient receives an intravenous (IV) injection of a radioactive glucose. Following the injection, the patient is asked to rest quietly for approximately 90 minutes while the glucose is metabolized and distributed throughout the body. After the distribution time is complete, the patient will then be asked to lie on a table that slowly passes through the scanner. The entire process can be expected to take two to three hours. After the organ being studied processes the radioactive tracer and the scanner records the information, a trained radiologist interprets the images. Upon completion of the scan there are no special instructions and patients may go back to their usual routines. The small amount of radioactive material present in the body is short-lived and will exit the body through urine or stool, losing radioactivity over 2 to 10 hours with no physical effects.
Hopefully, you never hear the words “You have cancer.” However, if you do, you can be assured that the technology available right here in Bloomington/Normal is state of the art. The PET/CT is here to help your doctor provide the best treatment plan to help you in the fight.
The Community Cancer Center offers a variety of supportive and educational groups and programs, free of charge, to help patients and families cope with cancer and its effects. For more information go to our website at www.cancercenter.org.