An innovative non-invasive technique for subcutaneous tumour measurements

In oncological drug development, animal studies continue to play a central
role in which the volume of subcutaneous tumours is monitored to assess
the efficacy of new drugs. The tumour volume is estimated by taking the
volume to be that of a regular spheroid with the same
dimensions. However, this method is subjective, insufficiently
traceable, and is subject to error in the accuracy of volume estimates as
tumours are frequently irregular. This paper reviews the standard
technique for tumour volume assessment, calliper measurements, by
conducting a statistical review of a large dataset consisting of 2,500
tumour volume measurements from 1,600 mice by multiple operators across 6
mouse strains and 20 tumour models. Additionally, we explore the impact of
six different tumour morphologies on volume estimation and the detection
of treatment effects using a computational tumour growth model. Finally,
we propose an alternative method to callipers for estimating volume –
BioVolumeTM, a 3D scanning technique. BioVolume simultaneously captures
both stereo RGB (Red, Green and Blue) images from different light sources
and infrared thermal images of the tumour in under a second. It then
detects the tumour region automatically and estimates the tumour volume in
under a minute. Furthermore, images can be processed in parallel within
the cloud and so the time required to process multiple images is similar
to that required for a single image. We present data of a pre-production
unit test consisting of 297 scans from over 120 mice collected by four
different operators. This work demonstrates that it is possible to record
tumour measurements in a rapid minimally invasive, morphology-independent
way, and with less human-bias compared to callipers, whilst also improving
data traceability. Furthermore, the images collected by BioVolume may be
useful, for example, as a source of biomarkers for animal welfare and
secondary drug toxicity / efficacy.