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Proceedings Paper

Dosimetry for spectral molecular imaging of small animals with MARS-CT
Author(s): Noémie Ganet; Nigel Anderson; Stephen Bell; Anthony Butler; Phil Butler; Pierre Carbonez; Nicholas Cook; Tony Cotterill; Steven Marsh; Raj Kumar Panta; John Laban; Sophie Walker; Adam Yeabsley; Jérôme Damet
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Paper Abstract

The Medipix All Resolution Scanner (MARS) spectral CT is intended for small animal, pre-clinical imaging and uses an x-ray detector (Medipix) operating in single photon counting mode. The MARS system provides spectrometric information to facilitate differentiation of tissue types and bio-markers. For longitudinal studies of disease models, it is desirable to characterise the system’s dosimetry. This dosimetry study is performed using three phantoms each consisting of a 30 mm diameter homogeneous PMMA cylinder simulating a mouse. The imaging parameters used for this study are derived from those used for gold nanoparticle identification in mouse kidneys. Dosimetry measurement are obtained with thermo-luminescent Lithium Fluoride (LiF:CuMgP) detectors, calibrated in terms of air kerma and placed at different depths and orientations in the phantoms. Central axis TLD air kerma rates of 17.2 (± 0.71) mGy/min and 18.2 (± 0.75) mGy/min were obtained for different phantoms and TLD orientations. Validation measurements were acquired with a pencil ionization chamber, giving an air-kerma rate of 20.3 (±1) mGy/min and an estimated total air kerma of 81.2 (± 4) mGy for a 720 projection acquisition. It is anticipated that scanner design improvements will significantly decrease future dose requirements. The procedures developed in this work will be used for further dosimetry calculations when optimizing image acquisition for the MARS system as it undergoes development towards human clinical applications.

Paper Details

Date Published: 18 March 2015
PDF: 7 pages
Proc. SPIE 9412, Medical Imaging 2015: Physics of Medical Imaging, 94122Y (18 March 2015); doi: 10.1117/12.2081293
Show Author Affiliations
Noémie Ganet, CERN (Switzerland)
Univ. of Canterbury (New Zealand)
Nigel Anderson, Univ. of Otago (New Zealand)
Stephen Bell, MARS Bioimaging Ltd. (New Zealand)
Anthony Butler, CERN (Switzerland)
Univ. of Otago (New Zealand)
MARS Bioimaging Ltd. (New Zealand)
Phil Butler, CERN (Switzerland)
Univ. of Otago (New Zealand)
MARS Bioimaging Ltd (New Zealand)
Pierre Carbonez, CERN (Switzerland)
Nicholas Cook, Canterbury District Health Board (New Zealand)
Tony Cotterill, National Ctr. for Radiation Science (New Zealand)
Steven Marsh, Univ. of Canterbury (New Zealand)
Raj Kumar Panta, Univ. of Otago (New Zealand)
John Laban, National Ctr. for Radiation Science (New Zealand)
Sophie Walker, National Ctr. for Radiation Science (New Zealand)
Adam Yeabsley, National Ctr. for Radiation Science (New Zealand)
Jérôme Damet, CERN (Switzerland)
Lausanne Univ. Hospital (Switzerland)

Published in SPIE Proceedings Vol. 9412:
Medical Imaging 2015: Physics of Medical Imaging
Christoph Hoeschen; Despina Kontos, Editor(s)

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