Pilot evaluation of anti-1-amino-2-[18F] fluorocyclopentane-1-carboxylic acid (anti-2-[18F] FACPC) PET-CT in recurrent prostate carcinoma.
OBJECTIVE
Anti-1-amino-2-[(18)F]fluorocyclopentane-1-carboxylic acid (anti-2-[(18)F]FACPC) is an unnatural alicyclic amino acid radiotracer with high uptake in the DU-145 prostate cancer cell line in vitro. Our goal was to determine if anti-2-[(18)F]FACPC is useful in the detection of prostate carcinoma.


METHODS
Five patients with elevated PSA (1.1-20.5 ng/mL) after curative therapy for prostate carcinoma underwent 60 min dynamic positron emission tomography (PET) of the pelvis after IV injection of 193-340 MBq of anti-2-[(18)F]FACPC. Uptake was compared against PET scans in the same patients with the leucine analog, anti-1-amino-3-[(18)F]fluorocyclobutane-1-carboxylic acid (anti-[(18)F]FACBC), at similar time points and validated via pathology, clinical, and imaging follow-up.


RESULTS
At 5 min, average (±SD) SUVmax of malignant lesions is 4.1(±1.3) for anti-2-[(18)F] FACPC and 4.3(±1.1) for anti-[(18)F]FACBC. Yet, blood pool activity at 5 min is significantly higher for anti-2-[(18)F]FACPC with average (±SD) lesion/blood pool SUVmax/SUVmean ratio of 1.4 (±0.5) vs. 3.0 (±0.9) for anti-[(18)F]FACBC. At 20 min, average (±SD) SUVmax of malignant lesions is 2.6 (±1.0) for anti-2-[(18)F]FACPC and 3.4 (±0.8) for anti-[(18)F]FACBC. Yet, bladder activity at 20 min is significantly more intense for anti-2-[(18)F] FACPC with average (±SD) lesion/bladder SUVmax/SUVmean ratio of 0.3 (±0.8) vs. 2.3 (±1.4) for anti-[(18)F]FACBC.


CONCLUSIONS
While prostate bed lesions are visible on early imaging with anti-2-[(18)F]FACPC, there is high blood pool activity obscuring nodes. As blood pool fades, nodal uptake decreases and high bladder activity then obscures pelvic structures. Compared with anti-[(18)F]FACBC, imaging characteristics for anti-2-[(18)F]FACPC are unfavorable for pelvic recurrent prostate carcinoma detection.
Savir-Baruch
Bital
B
Radiology, Emory University, Atlanta, GA 30322, USA.
Schuster
David M
DM
Jarkas
Nashwa
N
Master
Viraj A
VA
Nieh
Peter T
PT
Halkar
Raghuveer K
RK
Nye
Jonathon A
JA
Lewis
Melinda M
MM
Crowe
Ronald J
RJ
Voll
Ronald J
RJ
Camp
Vernon M
VM
Bellamy
Leah M
LM
Roberts
David L
DL
Goodman
Mark M
MM
D001706:Biopsy; D003515:Cycloleucine / Q000031:analogs & derivatives* / Q000493:pharmacokinetics; D005069:Evaluation Studies as Topic; D005462:Fluorine Radioisotopes; D006801:Humans; D008297:Male; D064847:Multimodal Imaging; D010388:Pelvis / Q000000981:diagnostic imaging; D010865:Pilot Projects; D049268:Positron-Emission Tomography; D011471:Prostatic Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology; D012008:Recurrence; D013997:Time Factors; D014057:Tomography, X-Ray Computed
C552703:1-amino-2-fluorocyclopentyl-1-carboxylic acid; D005462:Fluorine Radioisotopes; D003515:Cycloleucine