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Proceedings Paper

Assessment of light distribution at the photocathode of 5" and 1" position-sensitive photomultiplier tubes
Author(s): Antonio Jorge Soares; Ian Cullum; Fiona Christie; Gary J. Royle; Robert D. Speller; David J. Miller
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Paper Abstract

We present the evaluation of two Position Sensitive Photomultiplier Tubes (PSPMT), the 1' square Hamamatsu R5900- C8 and the 5' circular Hamamatsu R3292, and discuss their suitability as light sensors in a high resolution small gamma camera for in-vivo radioisotope imaging studies. It has been found that there is a strong dependence between the performance of both tubes and the size of the light distribution at the photocathode. For very narrow distributions (1 mm FWHM) from an optical fiber incident on the R5900-C8, most of the area of the tube is insensitive to position changes. This is related to the size of the anodes and the small spread of electron charge in the dynode multiplication process. For wider distributions (2.2 mm FWHM), we achieved a spatial resolution of 1 mm FWHM. The R5900-C8 has also been coupled to a 5 mm thick CsI(Na) crystal which was scanned across by a 1 mm collimated Tc-99m source (140 keV). The results confirm the importance of light spread at the photocathode. The Hamamatsu R5900-C8 was found to be a promising detector for high resolution radionuclide imaging. The results obtained with the R3292 indicate that a high spatial resolution (less than 2 mm FWHM) is achieved for narrow light distributions (less than or equal to 1 mm FWHM).

Paper Details

Date Published: 24 July 1998
PDF: 12 pages
Proc. SPIE 3336, Medical Imaging 1998: Physics of Medical Imaging, (24 July 1998); doi: 10.1117/12.317090
Show Author Affiliations
Antonio Jorge Soares, Univ. College London (United Kingdom)
Ian Cullum, Middlesex Hospital/Univ. College London (United Kingdom)
Fiona Christie, Middlesex Hospital/Univ. College London (United Kingdom)
Gary J. Royle, Univ. College London (United Kingdom)
Robert D. Speller, Univ. College London (United Kingdom)
David J. Miller, Univ. College London (United Kingdom)

Published in SPIE Proceedings Vol. 3336:
Medical Imaging 1998: Physics of Medical Imaging
James T. Dobbins III; John M. Boone, Editor(s)

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