Abstract

Micro-imaging cancer morphology, microvasculature and stiffness based on optical coherence tomography

David Sampson, Head, University of Western Australia

Tools to image cancer in vivo are important for biological and biomedical research based on animal models, and also important for next-generation diagnosis and surgical guidance in the medical setting. Whilst advanced confocal and multiphoton microscopy continue to make advances on the cellular scale, and medical imaging tools, such as positron emission tomography and magnetic resonance imaging, are well established on the scale of the whole tumour and organ, imaging the tumour environment on the micro-scale, between that of cells and whole tissues, is currently challenging. Our group has been exploring the potential of optical coherence tomography for imaging cancer in whole tissues, on the resolution scale of 2-20 ?m and over fields of view from 1-50 mm per dimension. We have been developing the capacity to perform such imaging using hand-held probes and from within a hypodermic needle, which can be delivered to locations deep in tissues not normally accessible to optical imaging. The intrinsic contrast provided by scattering from the tissue reveals many morphological features of tumours, but is, on occasions, insufficient. For example, it does not readily reveal microvasculature, and it can be difficult to distinguish tumour from uninvolved stroma. We have been developing a range of advances aimed at improving the basic optical coherence tomography approach. These include speckle decorrelation to image tissue microvasculature and parametric approaches that extract, from a three-dimensional optical coherence tomography data set, a two-dimensional image of an optical parameter, such as attenuation or birefringence, or extract a mechanical parameter, stiffness. The combination of these approaches promises a comprehensive means of characterising the tumor microenvironment.