To evaluate the feasibility and accuracy of using cone beam CT (CBCT) scans obtained in radiation studies using the small-animal radiation research platform to perform semi-automatic tumour segmentation of pre-clinical tumour volumes.
Volume measurements were evaluated for different anatomical tumour sites, the flank, thigh and dorsum of the hind foot, for a variety of tumour cell lines. The estimated tumour volumes from CBCT and manual calliper measurements using different volume equations were compared with the “gold standard”, measured by weighing the tumours following euthanasia and tumour resection. The correlation between tumour volumes estimated with the different methods, compared with the gold standard, was estimated by the Spearman’s rank correlation coefficient, root-mean-square deviation and the coefficient of determination.
The semi-automatic CBCT volume segmentation performed favourably compared with manual calliper measures for flank tumours ≤2 cm3 and thigh tumours ≤1 cm3. For tumours >2 cm3 or foot tumours, the CBCT method was not able to accurately segment the tumour volumes and manual calliper measures were superior.
We demonstrated that tumour volumes of flank and thigh tumours, obtained as a part of radiation studies using image-guided small-animal irradiators, can be estimated more efficiently and accurately using semi-automatic segmentation from CBCT scans.
N P Brodin, J Tang, K Skalina, TJ Quinn, I Basu, C Guha & W A Tomé.