What is CT- PET Fusion Imaging?
It is the very latest imaging technology that combines the anatomical detail of 16-slice CT (Computerized Tomography) technology with the molecular metabolic information derived from PET (Positron Emission Tomography).
Almost everyone is familiar with CT or "CAT" scans, which have been commonplace in medicine for approximately 30 years. Today's CT scanners are better and faster than ever, capable of producing up to 64 "slices" of imaging in 0.5 seconds. Still, they are sometimes unable to detect tiny, often sub-clinical malignancies. Left undetected (and therefore untreated), these malignancies will grow and possibly metastasize, making their eventual treatment more challenging. Even when they are detectable on CT scans, they merely appear as abnormal masses and there is often uncertainty with regard to whether they are malignant or benign.
Dedicated PET imaging is a nuclear medicine procedure in which a radioactive isotope, 18-fluorodeoxyglucose (FDG), is injected intravenously. The glucose, or "sugar" component of the FDG allows it to be "taken up" in cells seeking sugar. Because cancer cells are sugar-seekers, a disproportionate amount of FDG is captured within malignancies, making even tiny tumors visible during the scanning process.
PET therefore, succeeds where conventional CT fails, because it provides for the imaging of very small tumors, and while a diagnosis of cancer cannot be made without a biopsy, PET can prove to be a strong indicator. PET has also proven very useful in staging cancer patients, sometimes eliminating the need for surgery.
Unfortunately though, PET scans do not show nearly the anatomical detail that CT scans do, and while physicians can often identify potential malignancies, they are sometimes unsure of their exact location. This conundrum has led to the development of software technology that combines PET and CT imaging simultaneously and creating "fused" the best features of both CT and PET on a single image. In essence, it provides the best of both the CT and PET worlds.
PET-CT fusion is covered by most insurances and by Medicare. Medicare is continually adding to its lists of approved clinical indications for PET and PET-CT. Currently, Medicare authorizes PET and PET-CT for:
- Solitary pulmonary nodules
- Non-small cell lung cancer
- Colorectal cancer
- Lymphoma (Hodgkin's and Non-Hodgkin's)
- Head and neck cancer (excludes CNS)
- Esophageal cancer
- Breast cancer
- Certain neurologic and cardiac indications
Several other cancers are currently under review:
PET-CT fusion is useful for more than just "finding" and staging cancers; it can play an important role in monitoring a tumor's response to chemotherapy or radiation therapy. In many instances a follow-up PET-CT scan can be performed after the first cycle of therapy to gauge the impact that the therapy regimen has had. If there has been a significant reduction in the tumor's size, it can safely be said that the therapy has been successful and if indicated, can be effectively continued. On the other hand, should a follow-up PET-CT show little or no tumor response, a change in treatment might be indicated. This, obviously, can significantly improve treatment outcomes, shorten treatment durations and provide substantial cost savings.
If you would like to learn more about PET-CT fusion or would like for a Florida Institute for Advanced Diagnostic Imaging representative to speak about PET-CT to a group that you belong to, please contact us at (727) 849-8492.