Sensitivity of hemoglobin concentration on optical probe positioning in image-guided near infrared spectroscopy.

Multi-modality image-guided near infrared spectroscopy provides volume-based quantification of total hemoglobin, oxygen saturation, water and scatter in various tissue types in-vivo. The accuracy of these parameters depends on the location of the imaging probe and its distance from the tumor. In a numerical study, we have performed simulation to analyze this effect in a breast-specific imaging domain. Results show that the accuracy of total hemoglobin decreases by 25% for every centimeter away from the tumor center, for a typical size of 35mm cancer in the breast. Image guidance is necessary for accurate positioning, and multi-plane acquisition can improve this accuracy.