F-18 FDOPA scan is superior to both F-18 FLT and F-18 FDG for visualization of primary and recurrent low grade gliomas. F-18-FLT should not be considered for evaluation of recurrent low grade gliomas.
Correct staging is the most crucial for the treatment outcome in cancer management. Molecular imaging with 18F-fluoroestradiol (FES) positron emission tomography-computed tomography (PET-CT) targets estrogen receptor (ER) and may have a higher incremental value in diagnosis by aiding specificity. We enrolled 12 female breast cancer patients prospectively and did 18F-FES PET-CT and 18F-fluorodeoxyglucose (FDG) PET-CT within 1 week interval time. Lesion detection sensitivity was compared for a total number of lesions and for nonhepatic lesions only by McNemar test. 18F-FES PET-CT was taken as reference in case of indeterminate lesions. The incremental value reported by identifying 18F-FES exclusive lesions and by characterization of 18F-FDG indeterminate lesions. Spearman rank test was used to correlate ER expression and maximum standardized uptake value (SUVmax). Two ER-negative patients with no 18F-FES uptake were excluded. Ten ER-positive patients with 154 disease lesions were finally analyzed. 18F-FDG picked-up 142 lesions (sensitivity 92.21%), whereas 18F-FES picked-up 116 lesions (sensitivity 75.32%) and this difference was statistically significant. For nonhepatic lesions (n = 136) detectability, 18F-FDG picked-up 124 (sensitivity 91.18%), whereas 18F-FES picked-up 116 (sensitivity 85.29%) lesions and this difference was not statistically significant. Beside 12 exclusive lesions, 18F-FES characterized 41 (27.5%) 18F-FDG indeterminate lesions. Overall 18F-FES impacted 20% patient management. The positive trend was also seen with 18F-FES SUVmax with ER expression and negative with 18F-FDG SUVmax. We conclude, 18F-FDG has overall better sensitivity than 18F-FES PET-CT, however for nonhepatic metastasis difference was not significant. 18F-FES PET-CT better-characterized lesions and impacted 20% patient management. Therefore, 18F-FES PET-CT should be used with 18F-FDG PET-CT in strongly ER expressing patients for better specificity.
In an attempt to explore use of PET radioisotope, (68)Ga, in the diagnosis of Alzheimer's disease, a metal-based homodimeric ligand exhibiting high affinity towards Aβ aggregates was designed by conjugating two chalcone units with the chelating system, diethylenetriaminepentaacetic acid. Bischalcone derivative, 5,8-bis(carboxymethyl)-13-(4-((E)-3-(4-(dimethylamino)phenyl)acryloyl)phenoxy)-2-(2-(2-(4-((E)-3-(4-(dimethylamino)phenyl)acryloyl)phenoxy)ethylamino)-2-oxoethyl)-10-oxo-2,5,8,11-tetraazatridecane-1-carboxylic acid, DT(Ch)2 was synthesized in 95% yield with high purity. It was radiolabelled with (68)Ga under mild conditions with 85.4% efficiency and 9.5-10 MBq nmol(-1) specific activity. An in vitro binding assay on Aβ42 aggregates displayed high binding affinity of (68)Ga-DT(Ch)2 and inhibition constant of 4.18 ± 0.62 nM. The fluorescent properties of the ligand with peaks of absorption/emission at 410/540 nm exhibited a blue shift with 5.5-fold increase in emission intensity on binding with Aβ aggregates. Blood kinetics of the complex performed on normal rabbit exhibited fast clearance (t1/2(F) = 24 ± 0.08 min; t1/2(S) = 2 h 40 ± 0.04 min). Ex vivo biodistribution analysis demonstrated blood-brain barrier penetration with brain uptake of 1.24 ± 0.31% ID g(-1) at 2 min p.i. and rapid washout with negligible activity (0.36% ID g(-1)) left at 30 min p.i. These preliminary studies reveal that the bivalent approach of synthesis had minimal effect on binding affinity, signifying that the developed (68)Ga-complex, (68)Ga-DT(Ch)2, may offer a new perspective in generator produced PET imaging probes for Alzheimer's disease.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.