A new radio-HPLC detection system for measuring radioactivity in plasma samples during Positron Emission Tomography [PET] studies was developed. It is based on detecting both the positron and one of the annihilation photons. The system focused on improving the measurement of radioactivity concentrations on an unmetabolized positron emitting a radiopharmaceutical [PER] in the presence of its radioactive metabolites, all containing the same positron emitter. This paper presents a new detection configuration that improves the minimal detectible activity (MDA), simplify the measuring systems and reduces the error caused by the metabolites. The detector is based on a plastic scintillator and a BGO scintillation crystal, that produces different light output spectra for signal and noise events. By summing the positron and the annihilated photon light outputs, different spectra are obtained for the metabolite and for the parent compound tracer and for tracer marked by different positron emitting isotopes. This new detection system can improve quantitative analysis of plasma samples. The spectrum change provides up to a three-fold improvement in sensitivity compared to the currently used detection systems that measure only the annihilation coincidence events. Results showed that for 11C the MDA was improved by approximately 520%. Furthermore, it provides the additional advantage of reliability by providing a method for separating the signal and noise readings from the gross detector readout. Accurate reconstruction algorithm of the signal was achieved over a wide measuring range even when the signal was only 5% of the gross measurement.

Journal of Labelled Compounds and RadiopharmaceuticalsVolume 44, Issue S1 p. S863-S865 Article Selectivity of [18F]F2 towards L-α-methyltyrosine and L-tyrosine: A radiochemical and NMR spectroscopic study N. Vasdev, N. Vasdev Department of Chemistry, McMaster University, Hamilton, Ontario, L8S 4M1, Canada Department of Nuclear Medicine, McMaster University Medical Centre, Hamilton Health Sciences Corporation, Hamilton, Ontario, L8N 3Z5, CanadaSearch for more papers by this authorR. Chirakal, R. Chirakal Department of Chemistry, McMaster University, Hamilton, Ontario, L8S 4M1, Canada Department of Nuclear Medicine, McMaster University Medical Centre, Hamilton Health Sciences Corporation, Hamilton, Ontario, L8N 3Z5, CanadaSearch for more papers by this authorG. J. Schrobilgen, G. J. Schrobilgen Department of Chemistry, McMaster University, Hamilton, Ontario, L8S 4M1, CanadaSearch for more papers by this authorC. Nahmias, C. Nahmias Department of Nuclear Medicine, McMaster University Medical Centre, Hamilton Health Sciences Corporation, Hamilton, Ontario, L8N 3Z5, CanadaSearch for more papers by this author N. Vasdev, N. Vasdev Department of Chemistry, McMaster University, Hamilton, Ontario, L8S 4M1, Canada Department of Nuclear Medicine, McMaster University Medical Centre, Hamilton Health Sciences Corporation, Hamilton, Ontario, L8N 3Z5, CanadaSearch for more papers by this authorR. Chirakal, R. Chirakal Department of Chemistry, McMaster University, Hamilton, Ontario, L8S 4M1, Canada Department of Nuclear Medicine, McMaster University Medical Centre, Hamilton Health Sciences Corporation, Hamilton, Ontario, L8N 3Z5, CanadaSearch for more papers by this authorG. J. Schrobilgen, G. J. Schrobilgen Department of Chemistry, McMaster University, Hamilton, Ontario, L8S 4M1, CanadaSearch for more papers by this authorC. Nahmias, C. Nahmias Department of Nuclear Medicine, McMaster University Medical Centre, Hamilton Health Sciences Corporation, Hamilton, Ontario, L8N 3Z5, CanadaSearch for more papers by this author First published: 23 April 2012 https://doi.org/10.1002/jlcr.25804401303AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume44, IssueS1Supplement: Journal of Labelled Compounds and RadiopharmaceuticalsMay 2001Pages S863-S865 RelatedInformation

Fluorinated derivatives of L-tyrosine and L-alpha -methyltyrosine (L-alpha -MT) are known to be useful tracers for medical imaging with positron emission tomography. Direct fluorination of L-tyrosine and L-alpha -MT with [F-18]F-2 in different acidic media show increases in the radiochemical yield of the 3-fluoro isomers as the acidity of the reaction medium is increased. Lower radiochemical yields and increased production of the 3,5-difluoro isomers of the tyrosine derivatives resulted when solvent mixtures containing BF3 added to anhydrous HF (aHF) were used. Lower yields in BF3/aHF have been studied by use of low-temperature (-70 degreesC) H-1 and C-13 NMR spectroscopy Of L-alpha -MT, which showed deactivation of the aromatic ring in BF3/aHF. Improved isocratic preparative and analytical HPLC methods for the separation of the fluorinated tyrosine derivatives were also developed. All compounds synthesized in this study were characterized by NMR spectroscopy and mass spectrometry. (C) 2001 Elsevier Science B.V. All rights reserved.

Journal of Labelled Compounds and RadiopharmaceuticalsVolume 44, Issue S1 p. S219-S221 Article A comparative study of the in vivo behaviour of [18F] 2-, 5- and 6-fluoro-L-dopa in the human brain R. Chirakal, R. Chirakal Department of Nuclear Medicine, Hamilton Health Sciences Corporation, 1200 Main St. West, Hamilton, Ontario, Canada L8N 3Z5 Department of Chemistry, McMaster University, Hamilton, Ontario, Canada L8S 4M1Search for more papers by this authorN. Vasdev, N. Vasdev Department of Nuclear Medicine, Hamilton Health Sciences Corporation, 1200 Main St. West, Hamilton, Ontario, Canada L8N 3Z5 Department of Chemistry, McMaster University, Hamilton, Ontario, Canada L8S 4M1Search for more papers by this authorG. J. Schrobilgen, G. J. Schrobilgen Department of Chemistry, McMaster University, Hamilton, Ontario, Canada L8S 4M1Search for more papers by this authorS. Amano, S. Amano Department of Nuclear Medicine, Hamilton Health Sciences Corporation, 1200 Main St. West, Hamilton, Ontario, Canada L8N 3Z5Search for more papers by this authorC. Nahmias, C. Nahmias Department of Nuclear Medicine, Hamilton Health Sciences Corporation, 1200 Main St. West, Hamilton, Ontario, Canada L8N 3Z5Search for more papers by this author R. Chirakal, R. Chirakal Department of Nuclear Medicine, Hamilton Health Sciences Corporation, 1200 Main St. West, Hamilton, Ontario, Canada L8N 3Z5 Department of Chemistry, McMaster University, Hamilton, Ontario, Canada L8S 4M1Search for more papers by this authorN. Vasdev, N. Vasdev Department of Nuclear Medicine, Hamilton Health Sciences Corporation, 1200 Main St. West, Hamilton, Ontario, Canada L8N 3Z5 Department of Chemistry, McMaster University, Hamilton, Ontario, Canada L8S 4M1Search for more papers by this authorG. J. Schrobilgen, G. J. Schrobilgen Department of Chemistry, McMaster University, Hamilton, Ontario, Canada L8S 4M1Search for more papers by this authorS. Amano, S. Amano Department of Nuclear Medicine, Hamilton Health Sciences Corporation, 1200 Main St. West, Hamilton, Ontario, Canada L8N 3Z5Search for more papers by this authorC. Nahmias, C. Nahmias Department of Nuclear Medicine, Hamilton Health Sciences Corporation, 1200 Main St. West, Hamilton, Ontario, Canada L8N 3Z5Search for more papers by this author First published: 23 April 2012 https://doi.org/10.1002/jlcr.2580440176AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume44, IssueS1Supplement: Journal of Labelled Compounds and RadiopharmaceuticalsMay 2001Pages S219-S221 RelatedInformation