PET - Positron Emission Tomography

Positron Emission Tomography, also called PET, is a diagnostic imaging exam which is most often used to detect disease in very early stages. PET can often detect disease before the condition is visible on other imaging methods. 

Clinical indications for PET include:

1.   diagnosing  disease

2.   staging cancer  

3.   evaluating for metastatic disease 

4.   monitoring treatment plan

"PET is a very powerful tool to sensitively detect and evaluate many types of cancers."

 - Adam V. Ratner, M.D.

Advanced Medical Imaging San Saba PET/CT Scanner

Case Study

The patient is a 48 year-old female with a history of sigmoid colon resection for cancer of the colon. 

At surgery, the margins of resection were free of tumor, and fourteen out of fourteen lymph nodes had no evidence of tumor involvement.  The surgeon sent several samples of tissue to the pathology department which revealed that there was local invasion of the tumor through the colon’s muscularis and subserosal layers. 

The patient had a  two month follow-up enhanced CT scan. The CT scan showed no evidence of recurrent tumor in the lower abdomen or pelvis.  There were, however, two solid nodules identified in the liver. 

PET/CT was then performed for additional evaluation and restaging.  Coronal PET, CT and PET/CT fusion images (figures 1,2 & 3 – see arrows) demonstrate the two liver lesions to be hypermetabolic.   There were also two additional areas of tumor involvement in the liver that were identified on the whole-body PET/CT (not shown on these views).  The liver lesions were biopsied and were consistent with metastatic cancer originating from the colon.

Provided by Dr. Gerald Growcock