Data from: Beauty is more than skin deep: a non-invasive protocol for in vivo anatomical study using micro-CT

Microcomputed tomography (μCT) is a widely used tool in biomedical
research, employed to investigate tissues and bone structures of small
mammals in vivo. The application of in vivo μCT scanning in non-medical
studies greatly lags behind the rapid advancements made in the biomedical
field wherein the methodology has evolved to allow for longitudinal
studies and eliminate the need to sacrifice the animal. Ecological and
evolutionary studies often involve morphological measurements of a large
sample of live animals; however, the potential of in vivo μCT imaging as a
method for data acquisition has yet to be delineated. Here, we describe a
protocol for in vivo μCT imaging of the internal anatomy of reptiles and
amphibians, commonly used study organisms in ecological and evolutionary
research. We consider the skeletal and extraskeletal (i.e. osteoderms)
bones of a lizard as a case study to elucidate the potential of in vivo
μCT imaging. First, we explore the effects of various parameter settings
on radiation dose, scan time and image quality. Secondly, we develop a
protocol to immobilize and restrain study organisms during scanning
without need for the administration of anaesthetics and compare the
results of the in vivo protocol to images obtained post-mortem. To
immobilize animals, we replace the use of anaesthetics by cooling, thereby
allowing the use of previously unsuitable rotating gantry μCT scanners
that are readily available in scientific institutions. The resultant image
quality of in vivo μCT scans is similar to that of post-mortem μCT scans,
especially in the abdominal region. We discuss the effect of tube voltage,
distance to X-ray source and metal filtration on radiation dose, and how
these parameters could be altered to reduce the cumulative radiation dose
while maintaining optimal image quality. The proposed in vivo μCT protocol
offers a new approach to acquire anatomical information for non-biomedical
studies. We offer specific suggestions as to how the protocol can be
employed to suit a variety of model organisms.