Molar activity – The keystone in ¹¹C-radiochemistry

Author(s)

Verena Pichler, Thomas Zenz, Cécile Philippe, Chrysoula Vraka, Neydher Berrotéran-Infante, Sarah Pfaff, Lukas Nics, Marius Ozenil, Oliver Langer, Matthäus Willeit, Tatjana Traub-Weidinger, Rupert Lanzenberger, Markus Mitterhauser, Marcus Hacker, Wolfgang Wadsak

Abstract

Introduction: Radiochemists/radiopharmacists, involved in the preparation of radiopharmaceuticals are regularly confronted with the requirement of continuous high quality productions in their day-to-day business. One of these requirements is high specific or molar activity of the radiotracer in order to avoid e.g. receptor saturation and pharmacological or even toxic effects of the applied tracer for positron emission tomography. In the case of

¹¹C-labeled radiotracers, the reasons for low molar activity are manifold and often the search for potential

¹²C-contaminations is time-consuming. Methods: In this study, diverse

¹²C-contaminations were analyzed and quantified, which occurred during >450 syntheses of six PET tracers using [

¹¹C]CO

₂ or [

¹¹C]CH

₃I generated via the gas phase method in a commercially available synthesizer. Additionally, non-radioactive syntheses were performed in order to identify the origins of carbon-12. Results: The manifold contributions to low molar activity can be attributed to three main categories, namely technical parameters (e.g. quality of target gases, reagents or tubings), inter/intralaboratory parameters (e.g. maintenance interval, burden of the module, etc.) and interoperator parameters (e.g. handling of the module). Conclusion: Our study provides a better understanding of different factors contributing to the overall carbon load of a synthesis module, which facilitates maintenance of high molar activity of carbon-11-labeled radiopharmaceuticals.

Organisation(s)

External organisation(s)

Medizinische Universität Wien, Ludwig Boltzmann Intitute Applied Diagnostics, Centre for Biomarker Research in Medicine – CBmed GmbH

Journal

Nuclear Medicine and Biology

Volume

67

Pages

21-26

No. of pages

6

ISSN

0969-8051

DOI

https://doi.org/10.1016/j.nucmedbio.2018.09.003

Publication date

12-2018

Peer reviewed

Yes

Austrian Fields of Science 2012

104020 Radiochemistry

Keywords

ASJC Scopus subject areas

Molecular Medicine, Radiology Nuclear Medicine and imaging, Cancer Research

Portal url

https://ucrisportal.univie.ac.at/en/publications/cf3cc4d9-6a04-4d77-a79b-5eb564698769