[11C]-Acetate PET/CT imaging of prostate cancer: A multiparametric MR imaging histopathological correlation study

Objectives [11C]-Acetate is a PET agent which has been shown to uptake in prostate cancer. In this study, the uptake of [11C]-Acetate was evaluated in intra-prostatic tumor foci and compared with multiparametric MRI and whole mount step section histopathology.

Methods In this ongoing prospective study, to date, data from 10 patients with biopsy documented prostate cancer who underwent dynamic [11C]-Acetate PET/CT and multiparametric 3T MRI, have been analysized. All patients then underwent robotic prostatectomy and the prostate was sliced for pathology in the orientation of the MR images. Regions of interest in tumor and normal prostate tissues were outlined on MR images, retrospectively, using whole-mount histopathology maps. The PET/CT images were registered to the MR studies using the pelvic bones for initial rotation and translation. Final visual adjustments were made to account for interval prostate motion and deformation due to the MR rectal coil. The MR ROIs were then applied to reoriented [11C]-Acetate PET/CT images and SUVmax/mean and tumor:background ratios were obtained.

Results The average SUVmax (n=9) of the histopathology defined intraprostatic tumors was 3.6±1.6 [range 2.0 to 7.1]. This was statistically higher than that of background (normal prostate tissue) 2.3±1.2 [p=0.005,n=10]. The average tumor:background ratio was 1.9±0.8 [range 1.1 to 2.7].

Conclusions [11C]-Acetate PET/CT demonstrates higher uptake in prostate malignacy than in normal prostate tissue. It is projected that combined imaging with [11C]-Acetate PET/CT and multiparametric MR will be useful in localizing intraprostatic tumor sites; potentially setting the stage for localized prostate therapy in low risk patients.

Research Support NCI Contract No. HHSN261200800001