The study, conducted at Hahnemann University Hospital and Mercy Hospital in Philadelphia, evaluated the efficacy of whole body 18FDG-PET (Fluorodeoxyglucose-positron emission tomography) imaging compared to conventional CT imaging, which "has been used for many years to detect cancer spread in soft tissues," Dr. Dadparvar says.
Dr. Dadparvar and her colleagues studied 35 patients between the ages of 40 and 83 with various stages of colon cancer. The patients underwent 39 sets of PET and CT scans. CT imaging with contrast was performed on all patients and whole body PET imaging was performed 45-60 minutes after intravenous injection of 18FDG.
PET had a sensitivity rate of 93% compared to 46% for CT and specificity of 100% compared to 73%, and accuracy of 93% compared to 56%, says Dr. Dadparvar.
In addition to its superior performance, PET also has many advantages over CT, says Dr. Dadparvar. "Radiation exposure is lower than CT, because CT examinations require multiple scans, and since one PET scan can produce the same results as multiple CT scans, PET can also cost much less than CT," Dr. Dadparvar says.
Although PET is currently not available everywhere--usually only in major cities--Dr. Dadparvar says she recommends using PET over CT for staging of patients with suspected cancer spread, restaging of patients who have already been treated for cancer, and evaluation of patients with "rising CEA as a tumor marker" for recurrent colon cancer. "CT, which is able to detect anatomical features, must be done during initial staging to localize the tumor site as a guide for surgery," she says.
The study will be presented May 6, during the American Roentgen Ray Society Annual Meeting in San Diego.
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