title: On the use of positron counting for radio-Assay in nuclear pharmaceutical production.
abstract: Current techniques for the measurement of radioactivity at various points during PET radiopharmaceutical production and R&D are based on the detection of the annihilation gamma rays from the radionuclide in the labelled compound. The detection systems to measure these gamma rays are usually variations of NaI or CsF scintillation based systems requiring costly and heavy lead shielding to reduce background noise. These detectors inherently suffer from low detection efficiency, high background noise and very poor linearity. They are also unable to provide any reasonably useful position information. A novel positron counting technique is proposed for the radioactivity assay during radiopharmaceutical manufacturing that overcomes these limitations. Detection of positrons instead of gammas offers an unprecedented level of position resolution of the radiation source (down to sub-mm) thanks to the nature of the positron interaction with matter. Counting capability instead of charge integration in the detector brings the sensitivity down to the statistical limits at the same time as offering very high dynamic range and linearity from zero to any arbitrarily high activity. This paper reports on a quantitative comparison between conventional detector systems and the proposed positron counting detector.
authors.affiliation: SUPA School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ, UK. Electronic address: dima.maneuski@glasgow.ac.uk.
authors.forename: D
authors.initials: D
authors.lastname: Maneuski
authors.affiliation: Cyclotron Research Centre, University of Liege, 4000 Liege, Belgium.
authors.forename: F
authors.initials: F
authors.lastname: Giacomelli
authors.affiliation: Cyclotron Research Centre, University of Liege, 4000 Liege, Belgium.
authors.forename: C
authors.initials: C
authors.lastname: Lemaire
authors.affiliation: School of Medicine, University of Glasgow, Glasgow G12 8QQ, UK.
authors.forename: S
authors.initials: S
authors.lastname: Pimlott
authors.affiliation: Cyclotron Research Centre, University of Liege, 4000 Liege, Belgium.
authors.forename: A
authors.initials: A
authors.lastname: Plenevaux
authors.affiliation: PET Radiopharmaceutical Production Unit, Gartnavel General Hospital, Glasgow G12 0YN, UK.
authors.forename: J
authors.initials: J
authors.lastname: Owens
authors.affiliation: SUPA School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ, UK.
authors.forename: V
authors.initials: V
authors.lastname: O'Shea
authors.affiliation: Cyclotron Research Centre, University of Liege, 4000 Liege, Belgium.
authors.forename: A
authors.initials: A
authors.lastname: Luxen
keywords: F18; FDG; Medipix; Nuclear detector; PET; Positron; Radiopharmaceutical; Timepix