Radiochemistry for positron emission tomography

Abstract

Positron emission tomography (PET) constitutes a functional imaging technique that is harnessed to probe biological processes in vivo. PET imaging has been used to diagnose and monitor the progression of diseases, as well as to facilitate drug development efforts at both preclinical and clinical stages. The wide applications and rapid development of PET have ultimately led to an increasing demand for new methods in radiochemistry, with the aim to expand the scope of synthons amenable for radiolabeling. In this work, we provide an overview of commonly used chemical transformations for the syntheses of PET tracers in all aspects of radiochemistry, thereby highlighting recent breakthrough discoveries and contemporary challenges in the field. We discuss the use of biologicals for PET imaging and highlight general examples of successful probe discoveries for molecular imaging with PET – with a particular focus on translational and scalable radiochemistry concepts that have been entered to clinical use.

Co-Catalyzed Hydrofluorination of Alkenes: Photocatalytic Method Development and Electroanalytical Mechanistic Investigation

“…PET is a noninvasive imaging technique used to probe biological processes in vivo via the administration of a positron-emitting radiotracer. PET imaging has been used for the purpose of diagnosing and monitoring the progression of diseases, as well as aiding in the development of drugs, both in the preclinical and clinical stages . Thus, the development of new synthetic strategies to prepare PET tracers is highly desirable.…”

“…The percentage of fluorine-containing drug molecules among all pharmaceuticals is estimated to be 20% in recent years, and the broader incorporation of the fluorine atom into drug design depends strongly on the availability of fluorination strategies. Because the half-life of 18 F is favorable compared to alternative radioactive elements, 18 F-labeled tracers are widely used in positron emission tomography (PET) for diseases diagnosis and drug discovery . Necessarily, methods to prepare fluorine-containing molecules are in high demand.…”

Electrochemical (radio)-halodesilylation of aromatic silanes

“…11 Thus, many efforts have been made for radiolabeling methodology development to meet the demands of preclinical and clinical research. 12 Nevertheless, these methods still suffer from similar problems to those of traditional halogenation methods. 13 At present, few methods of electrochemical radioiodine isotopic labeling have been reported.…”

Bioorthogonal Radiolabeling of Azide-Modified Bacteria Using [18F]FB-sulfo-DBCO

“…We believe that this strategy could be used to establish a “pre-targeting” infection imaging method for which a patient-delivered d -amino acid would be followed by a PET tracer used to detect it. Understanding that clinical applications might require a bioorthogonal imaging approach using faster cycloaddition chemistry, we chose strain-promoted azide–alkyne click chemistry (SPAAC) ligation for our proof-of-concept study based on the fluorescence literature . Using a d -amino acid probe with a small side-chain (i.e., d -azido-alanine) would likely facilitate bacterial incorporation due to resemblance to d -alanine itself, whose robust bacterial incorporation is well-established .…”