Radiation effects on bone architecture in mice and rats resulting from in vivo micro-computed tomography scanning

Klinck, R. Josh; Campbell, Graeme M.; Boyd, Steven K.

doi:10.1016/j.medengphy.2007.11.004

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Volume 30, Issue 7 , Pages 888-895, September 2008

Radiation effects on bone architecture in mice and rats resulting from in vivo micro-computed tomography scanning

R. Josh Klinck
- Department of Mechanical and Manufacturing Engineering, University of Calgary, Calgary, Canada
- Roger Jackson Centre for Health and Wellness Research, University of Calgary, Calgary, Canada
Graeme M. Campbell
- Department of Mechanical and Manufacturing Engineering, University of Calgary, Calgary, Canada
- Roger Jackson Centre for Health and Wellness Research, University of Calgary, Calgary, Canada
Steven K. Boyd
- Department of Mechanical and Manufacturing Engineering, University of Calgary, Calgary, Canada
- Roger Jackson Centre for Health and Wellness Research, University of Calgary, Calgary, Canada
- Corresponding author at: Department of Mechanical and Manufacturing Engineering, University of Calgary, 2500 University Drive, N.W., Calgary, Alberta T2N 1N4, Canada. Tel.: +1 403 220 4173; fax: +1 403 282 8406.

Received 10 April 2007; received in revised form 12 November 2007; accepted 22 November 2007. published online 15 January 2008.

Abstract

Recently established techniques for performing in vivo micro-computed tomography (micro-CT) provide the capability of monitoring bone changes in a living animal at various points in time. However, radiation exposure from repeated micro-CT scans may have an effect on skeletal growth in normal or disease-model animals. The purpose of this study is to test a high resolution (∼10μm) in vivo micro-CT protocol on mice and rats used for bone research to understand the impact of micro-CT radiation exposure on bone architecture.

Ovariectomy (OVX) or sham-OVX surgery was performed on groups (n=6–8/group) of 12-week-old C3H/HeJ, C57BL/6J, and BALB/cByJ mice, and one strain of rat (Wistar, retired breeders). The right proximal tibiae were scanned at weekly intervals while the contralateral left limbs were not scanned until the endpoint of the protocol. Trabecular and cortical bone morphology was compared between radiated and non-radiated limbs at the endpoint to quantify the radiation effect.

No effects of radiation were observed in OVX or sham rats. Lower trabecular bone volume was observed in the radiated limbs (−8 to −20% relative to non-radiated limb) of all mice groups except sham BALB/cByJ mice and normal control C57BL/6J mice, however, the observed effects were much less than the observed effects of ovariectomy (∼40–50% total bone volume reduction, depending on mouse strain), and no interactions between radiation and OVX treatment were observed (p>0.2). Using an internal non-radiated control within each animal is a potential method to elucidate the effect of radiation exposure for any in vivo protocol. Thus, although in vivo micro-CT is a valuable tool for bone-related research, the impact of radiation in skeletally immature mice should be considered, particularly for strains with low bone volume at the measured site.

Keywords: In vivo micro-computed tomography, Radiation, Trabecular micro-architecture