PET/CT with C-11 acetate has higher sensitivity compared to 18F-FDG imaging in detecting primary prostate cancer, local recurrence and apparent nodal spread of the disease in both the staging and re-staging patient populations, according to research presented at the 2009 Radiological Society of North America (RSNA) annual conference in Chicago earlier this month.

“The role of 18F-FDG has been successful in other cancers but limited in prostate cancers due to various factors— slow growing cancerous cells which do not take up FDG efficiently as other tumors and significant urinary excretion,” said Muhammad Chaudhry, MBBS, from the division of nuclear medicine at Johns Hopkins University in Baltimore.

In the study, clinical patients with prostate cancer underwent dual radiotracer PET/CT imaging utilizing 11C-acetate and 18F-FDG on the same day. A total of 26 studies in 26 patients (age range 40-84 years) were performed over a one-year period, from March 2008-March 2009.

Chaudhry and colleagues found that, 11C-acetate imaging was positive in 6/8 patients in the staging population. By contrast, 18F-FDG was falsely negative in 7/8 studies while correctly identifying intraprostatic disease in only one patient.

Also, Chaudhry said that he and his colleagues found: "11C-acetate imaging was able to detect apparent nodal disease in one staging patient, while 18F-FDG was negative in all 8 staging studies."

Also, 11C-acetate imaging was positive in identifying apparent local recurrence in the prostate bed in six of 17 patients and nodal spread of the disease in five of 17 patients, while, 18F-FDG imaging was negative in all 17 patients and was unable to detect any nodal disease, according to the researchers.

“C-11 acetate PET/CT is superior to FDG in terms of staging and restaging including local recurrencem,” concluded Chaudhry.