New Fully Automated Preparation of High Apparent Molar Activity Ga-FAPI-46 on a Trasis AiO Platform.

A large number of applications for fibroblast activation protein inhibitors (FAPI)-based PET agents have been evaluated in conditions ranging from cancer to non-malignant diseases such as myocardial infarction. In particular, Ga-FAPI-46 was reported to have a high specificity and affinity for FAP-expressing cells, a fast and high accumulation in tumor lesions/injuries together with a fast body clearance when investigated in vivo. Due to the increasing interest in the use of the agent both preclinically and clinically, we developed an automated synthesis for the production of Ga-FAPI-46 on a Trasis AiO platform.

F-meta-fluorobenzylguanidine (F-mFBG) to monitor changes in norepinephrine transporter expression in response to therapeutic intervention in neuroblastoma models.

Targeted radiotherapy with I-mIBG, a substrate of the human norepinephrine transporter (NET-1), shows promising responses in heavily pre-treated neuroblastoma (NB) patients. Combinatorial approaches that enhance I-mIBG tumour uptake are of substantial clinical interest but biomarkers of response are needed. Here, we investigate the potential of F-mFBG, a positron emission tomography (PET) analogue of the I-mIBG radiotracer, to quantify NET-1 expression levels in mouse models of NB following treatment with AZD2014, a dual mTOR inhibitor.

Automated radiosynthesis of GMP quality [18F]HX4 for PET imaging of hypoxia.

Introduction: [(18)F]HX4 is a 2-nitroimidazole based investigational radiotracer for imaging hypoxia.

Methods: A two-step, one-pot synthetic procedure was developed on a GE Tracerlab MX-FDG with a disposable cassette. Nucleophilic substitution of a nosylate group with [(18)F]fluoride was followed by solvent evaporation and acidic removal of the acetyl protecting group.

Radiosynthesis of the D2/3 agonist [3-11C]-(+)-PHNO using [11C]iodomethane.

We report here a radiosynthesis for the D(2/3) agonist (+)-4-([3-(11)C]propyl)-3,4,4a,5,6,10b-hexahydro-2H-naphtho[1,2-b][1,4]oxazin-9-ol (3-[(11)C]-(+)-PHNO) labelled at the terminal carbon of the N-propyl chain. The protocol is based on (11)C-methylation of an N-acetyl precursor. This initial step is followed by a reduction with LiAlH(4) to give ([3-(11)C]-(+)-PHNO).

Evaluation of deuterated 18F- and 11C-labeled choline analogs for cancer detection by positron emission tomography.

Purpose: (11)C-Choline-positron emission tomography (PET) has been exploited to detect the aberrant choline metabolism in tumors. Radiolabeled choline uptake within the imaging time is primarily a function of transport, phosphorylation, and oxidation. Rapid choline oxidation, however, complicates interpretation of PET data.

Further evaluation of the carbon11-labeled D(2/3) agonist PET radiotracer PHNO: reproducibility in tracer characteristics and characterization of extrastriatal binding.

[(11)C]-(+)-PHNO is a new dopamine D(2/3) receptor agonist radiotracer which has been successfully used to measure D(2/3) receptor availability in experimental animals and man. Here we report in vivo evaluation in the rat of the biodistribution, metabolism, specificity, selectivity, and dopamine sensitivity of carbon11-labeled PHNO ([(11)C]-3-PHNO) produced by an alternative radiochemical synthesis method. [(11)C]-3-PHNO showed rapid metabolism and clearance from most peripheral organs and tissues.

Methods for 18F-labeling of RGD peptides: comparison of aminooxy [18F]fluorobenzaldehyde condensation with 'click labeling' using 2-[18F]fluoroethylazide, and S-alkylation with [18F]fluoropropanethiol.

Three strategies for chemoselective labeling of RGD peptides with (18)F have been compared. Aminooxy [(18)F]fluorobenzaldehyde conjugation provided 40 +/- 12% decay-corrected radiochemical yield using a fully automated method. An one-pot protocol for 'click labeling' of the RGD scaffold with 2-[(18)F]fluoroethylazide afforded 47 +/- 8% decay-corrected radiochemical yield.

Quantification of [11C]GB67 binding to cardiac alpha1-adrenoceptors with positron emission tomography: validation in pigs.

Introduction: An increase in human cardiac alpha(1)-adrenoceptor (alpha(1)-AR) density is associated with various diseases such as myocardial ischemia, congestive heart failure, hypertrophic cardiomyopathy and hypertension. Positron emission tomography (PET) with an appropriate radioligand offers the possibility of imaging receptor function in the normal and diseased heart. [(11)C]GB67, an analogue of prazosin, has been shown in rats to have potential as a PET ligand with high selectivity to alpha(1)-AR.