When I was diagnosed with inflammatory breast cancer in 1998, the first thing my doctors did was order a battery of tests to see if the cancer had spread. The test they did NOT order was a PET scan. Positron emission tomography (PET) was still very expensive and not easy to read. The machine that combined the PET scan with the CT scan went into clinical use at the University of Pittsburg in 1998. Because it was so effective, TIME magazine called it the medical invention of the year in 2000. So for years I read about other people’s experiences with PET scans, but never needed one myself until last fall.
Why have a PET scan when there are so many other ways that doctors can look at our innards these days? The PET is useful because it doesn’t look at the body’s structures. It looks at how our body metabolizes sugar. Cancer cells greedily grab all the nourishment they can find because they are reproducing much faster than the normal body cells. The PET picks up these areas of higher metabolism.
For breast cancer patients, a PET may be ordered as part of initial staging if the doctor is worried that the cancer has already spread, as part of treatment to see if a particular chemo or other treatment is shrinking a tumor, or as part of follow-up care. Because the test is expensive and time-consuming, your doctor may prefer to use other types of imaging tests, especially because PET scans can be prone to false positives. But when another test picks up an area of concern, the PET/CT scan can be useful. It is not useful for routine screening because it does not pick up the tiniest spots of cancer.
I had my PET scan to find out if a nodule near my lung was benign or malignant. It was in a place that would be difficult to biopsy, and the oncologist and radiologist thought a PET could help determine what it was. If you need a PET scan, your experience will probably be similar, but there may be some differences depending on the area the doctor wants to see. PET scans can also be used for other diseases besides cancer, so again the overall procedure will be similar, but perhaps not identical.
Before the test I was told not to eat or drink anything but water. Drinking lots of water is a good idea because it will hydrate your veins and make it easier to insert the IV. You are not allowed to eat because if your body is digesting food, those places will light up on the images. The technicians at the imaging center asked the usual preliminary questions about allergies and medications, but there were some extra questions about whether I was diabetic. If you are diabetic, it is important to discuss your condition with your doctor because of the fasting related to the test and the administration of glucose you are going to receive. It is also essential to let the doctor know if you might be pregnant.