PET/CT scans are an important imaging tool that physicians at Franciscan Health order to help detect and diagnose cancer. These specialized images are also used to help determine the best course of treatment.
PET/CT (Positron emission tomography - computed tomography) is a specialized way to create 3D color images of body functions, including growths. While other types of tomography - including CT and MRI - look at body form, PET/CT scans provide helpful clues about your body chemistry and function.
For some types of cancers, PET/CT scans can detect early-stage growths more clearly than CT or MRI. PET/CT images are not as detailed as those generated by CT or MRI; therefore, the doctor may match PET/CT images with additional CT scans to assess the cancer's location and stage of development.
PET/CT scans also are used to help determine the extent of cancerous activity, such as whether or not the cancer is present in multiple locations in the body. A doctor may order a PET/CT scan to determine the best course of treatment.
Twenty hours before the PET/CT scan, you should not:
For eight hours beforehand, you should not eat or drink.
During the test, you will lie still on a table that is attached to a scanner, camera and computer. A sugar-like radioactive substance, called a tracer, is injected into your vein. The sugar substance then collects in cancerous cells.
The donut-shaped scanner will move around the table, taking a complete series of pictures and sending them to the computer screen. The camera detects the location of the tracer, so the physician can identify cancerous areas and determine the stage of cancer.
The scanning process is painless and takes about one to three hours to complete. During the test, you are alone in the scanner room but you can communicate with the technologist through a two-way intercom. For 24 hours after the PET/CT scan, you should drink lots of fluids to flush the low-dose radioactive material out of the body.
As with all tests that use radioactive materials, there is a slight chance that cells or tissues may be damaged by the low levels of radiation injected into your body. However, the benefits of PET/CT far outweigh the risks. Rarely, patients experience soreness or swelling at the tracer injection site. Allergic reactions to the tracer are very rare.