Dosimetry for spectral molecular imaging of small animals with MARS-CT

Type of content
Conference Contributions - Published
Thesis discipline
Degree name
Publisher
University of Canterbury. Physics and Astronomy
Journal Title
Journal ISSN
Volume Title
Language
Date
2015
Authors
Ganet, N.
Anderson, N.
Bell, S.
Butler, A.
Butler, P.
Carbonez, P.
Cook, N.
Cotterill, T.
Marsh, S.
Kumar, R.
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.

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Citation
Ganet, N., Anderson, N., Bell, S., Butler, A., Butler, P., Carbonez, P., Cook, N., Cotterill, T., Marsh, S., Kumar, R., Laban, J., Walker, S., Yeabsley, A., Damet, J. (2015) Dosimetry for spectral molecular imaging of small animals with MARS-CT. Orlando, FL, USA: SPIE 2015, 21-26 Feb 2015. Proceedings of SPIE, Medical Imaging, 9412.
Keywords
dosimetry, computed tomography, thermoluminescent, molecular imaging, spectral imaging, medipix, longitudinal, small-animal
Ngā upoko tukutuku/Māori subject headings
ANZSRC fields of research
Field of Research::11 - Medical and Health Sciences::1103 - Clinical Sciences::110320 - Radiology and Organ Imaging
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