RT Journal Article
SR Electronic
T1 <sup>18</sup>F-AFETP, <sup>18</sup>F-FET, and <sup>18</sup>F-FDG Imaging of Mouse DBT Gliomas
JF Journal of Nuclear Medicine
JO J Nucl Med
FD Society of Nuclear Medicine
SP 1120
OP 1126
DO 10.2967/jnumed.112.113217
VO 54
IS 7
A1 Kiran Kumar Solingapuram Sai
A1 Chaofeng Huang
A1 Liya Yuan
A1 Dong Zhou
A1 David Piwnica-Worms
A1 Joel R. Garbow
A1 John A. Engelbach
A1 Robert H. Mach
A1 Keith M. Rich
A1 Jonathan McConathy
YR 2013
UL http://jnm.snmjournals.org/content/54/7/1120.abstract
AB The goal of this study was to evaluate the 18F-labeled nonnatural amino acid (S)-2-amino-3-[1-(2-18F-fluoroethyl)-1H-[1,2,3]triazol-4-yl]propanoic acid (18F-AFETP) as a PET imaging agent for brain tumors and to compare its effectiveness with the more-established tracers O-(2-18F-fluoroethyl)-l-tyrosine (18F-FET) and 18F-FDG in a murine model of glioblastoma. The tracer 18F-AFETP is a structural analog of histidine and is a lead compound for imaging cationic amino acid transport, a relatively unexplored target for oncologic imaging. Methods: 18F-AFETP was prepared using the click reaction. BALB/c mice with intracranially implanted delayed brain tumor (DBT) gliomas (n = 4) underwent biodistribution and dynamic small-animal PET imaging for 60 min after intravenous injection of 18F-AFETP. Tumor and brain uptake of 18F-AFETP were compared with those of 18F-FDG and 18F-FET through small-animal PET analyses. Results: 18F-AFETP demonstrated focally increased uptake in tumors with good visualization. Peak tumor uptake occurred within 10 min of injection, with stable or gradual decrease over time. All 3 tracers demonstrated relatively high uptake in the DBTs throughout the study. At late time points (47.5–57.5 min after injection), the average standardized uptake value with 18F-FDG (1.9 ± 0.1) was significantly greater than with 18F-FET (1.1 ± 0.1) and 18F-AFETP (0.7 ± 0.2). The uptake also differed substantially in normal brain, with significant differences in the standardized uptake values at late times among 18F-FDG (1.5 ± 0.2), 18F-FET (0.5 ± 0.05), and 18F-AFETP (0.1 ± 0.04). The resulting average tumor-to-brain ratio at the late time points was significantly higher for 18F-AFETP (7.5 ± 0.1) than for 18F-FDG (1.3 ± 0.1) and 18F-FET (2.0 ± 0.3). Conclusion: 18F-AFETP is a promising brain tumor imaging agent, providing rapid and persistent tumor visualization, with good tumor–to–normal-brain ratios in the DBT glioma model. High tumor-to-brain, tumor-to-muscle, and tumor-to-blood ratios were observed at 30 and 60 min after injection, with higher tumor-to-brain ratios than obtained with 18F-FET or 18F-FDG. These results support further development and evaluation of 18F-AFETP and its derivatives for tumor imaging.