Potential for BioXmark liquid fiducial marker to improve identification of superficial component of canine oral tumors for computer-based radiation therapy planning.

The objective of this study was to evaluate a novel liquid fiducial marker, BioXmark, to improve identification of the superficial component of oral tumors in dogs with computed tomography imaging. Liquid fiducial marker was injected in 6 patients at the visible and palpable extent of each tumor. Gross tumor volumes with and without BioXmark were compared in terms of volume and conformity using a Paddick conformity index, Dice similarity coefficient, and gross tumor volumes mismatch analysis. All patients showed an increase in gross tumor volumes defined by BioXmark compared with the conventionally identified post-contrast gross tumor volumes contours. Volumetric conformity and gross tumor volumes mismatch analysis of the superficial component of gross tumor volumes resulted in a median conformity index of 0.61 and median Dice similarity coefficient of 0.76. The superficial gross tumor volumes showed a median increase of 47% when BioXmark was used. This study demonstrated a potential utility to combining liquid fiducial markers to post-contrast computed tomography images for improved oral tumor localization and gross tumor volumes contouring for radiation therapy planning.