Carbon-11 acetate PET imaging in recurrent prostate cancer

Full text: Despite recent developments in radiological as well as nuclear medicine techniques the detection of tumor sites in patients with rising PSA alter radical therapy for prostate cancer (PC) is still challenging. This prospective study aims to assess the clinical value of C-11 acetate whole body PET imaging in detecting clinically occult local/metastatic disease. In 25 clinically asymptomatic patients with rising/elevated PSA alter radical therapy (radical prostatectomy, radiation therapy) indicating the presence of malignant tumor sites were included in the study. C-11 acetate whole body PET scan were performed immediately after i.v injection of 500-700 MBq C-11 acetate with a ring PET scanner. Identified abnormal C-11 acetate foci were compared to bone scan, computed tomography (CT) and /or magnetic resonance imaging (MR). For a better anatomical localization of suspected tumor sites in all PET (+) patients 3D PET-CT/MRI image fusion was done. In 6 out of 25 patients (24 %) C-11 acetate PET studies demonstrated no abnormal tracer accumulation (false negative results). The remaining 19 patients (19/25) demonstrated abnormal C-11 acetate uptake indicating the presence of local and/or metastatic disease (76 %). In 3 patients with non-diagnostic CT/MRI studies significant C-11 acetate accumulation was found in prostatic fossa. In addition, one pulmonary lesion was detected by C-11 acetate PET scan without evidence of disease by spiral CT of the lung. Furthermore, C-11 acetate PET study demonstrated significant lymph node involvement in 3 patients while CT/MRI were not conclusive. This study demonstrate the clinical usefulness of C-11 acetate whole body PET as a promising imaging technique in selecting patients with local PC disease from those having distant metastases. Therefore, C-11 acetate whole body PET can be used to choose the most appropriate therapy option in patients with rising PSA alter radical therapy for PC. (author)