Dynamic 18Fluoroethylcholine-PET in primary prostate cancer. Is there a use?

Objectives Detecting primary prostate cancer by imaging still remains a challenge because of heterogeneity of the prostate, variable uptake of contrast agents and even of radiolabeled choline. Within the scope of a prospective clinical FEC-PET/MRI trial (EudraCT-No. 2006-003933-33) we investigate a dynamic acquisition protocol for detecting localized primary. Initial results are presented.

Methods Patients with prostate cancer proven by needle biopsy obtain an FEC-PET-Scan starting immediately after injection. Emissionscans are performed with 10 frames over the first 10 minutes. Images are compared visually with the delayed (70 minutes p.i.) and fused PET/endorectalMRI images that are acquired within the scope of the clinical trial. Tumor foci are proven by reconstructed holoptical histologic slices after radical prostatectomy.

Results In 14 patients dynamic PET showed early increased tumor uptake in 8 cases. Because of low spatial resolution of dynamic images, a differentiation between multiple tumor foci was not possible. Delayed imaging detected tumor foci in all of these cases and could differentiate 29 of 35 main tumor foci at multifocal localization.

Conclusions In our preliminary results dynamic FEC-PET imaging seems not to provide substantial information about primary localized prostate carcinoma. Delayed images detect more tumor foci and give additional information about intraprostatic tumor localization.