Uptake of cis-4-[18F]fluoro-L-proline in urologic tumors.

Tumor uptake of the amino acid cis-4-[18F]fluoro-L-proline (cis-FPro) was studied with PET in eight patients with urologic tumors.

METHODS

Three patients had primary renal cell carcinomas (RCCs), one had a local recurrence of RCC, one had squamous RCC, one had an adrenal hemangioma, one had inguinal metastases of penile squamous carcinoma, and one had suspected metastatic disease from prostate cancer. PET scans of the trunk were acquired at 1 and 3-5 h after intravenous injection of 400 MBq cis-FPro and compared with 18F-FDG PET scans and CT.

RESULTS

None of the tumors or metastases showed significant uptake of cis-FPro. FDG uptake was seen in one of the three primary RCCs, in the local recurrence of RCC, in the squamous RCC, and in the metastases of penile cancer.

CONCLUSIONS

Cis-FPro appears not to be a promising PET tracer in oncology.