Metabolism and autoradiographic evaluation of [(18)F]FE@CIT: a Comparison with [(123)I]beta-CIT and [(123)I]FP-CIT.

Purpose: Since the late 1980s, cocaine analogues based on the phenyltropane structure, such as [(11)C]CFT and [(123)I]beta-CIT have been used for the imaging of the dopamine transporter. FE@CIT (fluoropropyl ester) and FP-CIT (N-fluoropropyl derivative) are further analogues. The aim of this study was to (1) evaluate and compare the metabolic stability of beta-CIT, FP-CIT and FE@CIT against carboxyl esterases and (2) evaluate selectivity of [(18)F]FE@CIT compared to [(123)I]beta-CIT and [(123)I]FP-CIT using autoradiography.

Preparation and first evaluation of [(18)F]FE@SUPPY: a new PET tracer for the adenosine A(3) receptor.

Introduction: Changes of the adenosine A(3) receptor subtype (A3AR) expression have been shown in a variety of pathologies, especially neurological and affective disorders, cardiac diseases and oncological and inflammation processes. Recently, 5-(2-fluoroethyl) 2,4-diethyl-3-(ethylsulfanylcarbonyl)-6-phenylpyridine-5-carboxylate (FE@SUPPY) was presented as a high-affinity ligand for the A3AR with good selectivity. Our aims were the development of a suitable labeling precursor, the establishment of a reliable radiosynthesis for the fluorine-18-labeled analogue [(18)F]FE@SUPPY and a first evaluation of [(18)F]FE@SUPPY in rats.

18F fluoroethylations: different strategies for the rapid translation of 11C-methylated radiotracers.

Introduction: The translation of 11C-labeled compounds into their respective 18F-labeled derivatives is an important tool in the rapid development of positron emission tomography (PET) tracers. Thus, our aim was the development of a general method for the preparation of 18F-fluoroethylated compounds that (a) is applicable to a variety of precursors, (b) can be performed in a fully automated commercially available synthesizer and (c) enables this rapid translation of 11C-methylated tracers into their 18F-fluoroethylated analogs sharing the same precursor molecules.

Methods: Ten methods for the preparation and purification of different 18F-fluoroethylating agents were compared.

Pre vivo, ex vivo and in vivo evaluations of [68Ga]-EDTMP.

Introduction: The objectives of this study were to develop a simple preparation method for [68Ga]-EDTMP and to evaluate the applicability of [68Ga]-EDTMP as a potential positron emission tomography (PET) bone imaging agent using pre vivo, ex vivo and in vivo models.

Methods: [68Ga]-EDTMP was prepared using 68Ga]-gallium chloride eluted from the 68Ge/68Ga generator and commercially available Multibone kits. Binding affinity to bone compartments was evaluated using a recently established pre vivo model.

[18F]FETO: metabolic considerations.

Purpose: 11beta-Hydroxylase is a key enzyme in the biosynthesis of adrenocortical steroid hormones and is a suitable target for the imaging of the adrenal cortex. [(11)C]Metomidate (MTO), [(11)C]etomidate (ETO) and desethyl-[(18)F]fluoroethyl-etomidate (FETO) are potent inhibitors of this enzyme and are used for PET imaging of adrenocortical pathologies. The aims of this study were (1) to evaluate and compare the metabolic stability of MTO, ETO and FETO against esterases and (2) to investigate the metabolic pattern of FETO in vivo.

In vivo disposition of irinotecan (CPT-11) and its metabolites in combination with the monoclonal antibody cetuximab.

Background: The present study was designed to investigate whether a combination of irinotecan and the monoclonal antibody cetuximab shows potential to modulate the pharmacokinetics of irinotecan and its metabolites.

Patients And Methods: All patients, suffering from advanced colorectal cancer, received irinotecan (350 mg/m2) every third week and cetuximab as a loading dose (400 mg/m2) on day 2, followed by a weekly maintenance dose (250 mg/m2). Plasma samples were analysed after the first (MONO) and second (CMAB) irinotecan infusions.

[18F]FETO for adrenocortical PET imaging: a pilot study in healthy volunteers.

Purpose: Functional imaging of the adrenal cortex by means of PET may play an important clinical role. Recently, we presented the synthesis and first evaluation of a novel 11beta-hydroxylase inhibitor, [(18)F]FETO, in rats displaying high tracer accumulation in the adrenals. In this study, we aimed to investigate for the first time the potency of [(18)F]FETO as a PET tracer for the adrenal cortex in humans.

NCA nucleophilic radiofluorination on substituted benzaldehydes for the preparation of [18F]fluorinated aromatic amino acids.

Nucleophilic aromatic substitution is a challenging task in radiochemistry. Therefore, a thorough evaluation and optimisation of this step is needed to provide a satisfactory tool for the routine preparation of [(18)F]fluorinated aromatic amino acids. Two methods, already proposed elsewhere, were evaluated and improved.