Navigated non-contact fluorescence tomography.

Navigated non-contact fluorescence tomography. Phys Med Biol. 2019 Jul 05;64(13):135021 Authors: Daly MJ, Wilson BC, Irish JC, Jaffray DA Abstract A non-contact approach for diffuse optical tomography (DOT) has been developed for on-demand image updates using surgical navigation technology. A stereoscopic optical tracker provides real-time localization of reflective spheres mounted to a laser diode and near-infrared camera. Standard camera calibration is combined with tracking data to determine the intrinsic camera parameters (focal length, principal point and non-linear lens distortion) and the tracker-to-camera transform. Tracker-to-laser calibration is performed using images of laser beam intersection with a tracked calibration surface. Source and detector positions for a finite-element DOT implementation are projected onto the boundary elements of the tissue mesh by finding ray-triangle intersections. A multi-stage model converts camera counts to surface flux by accounting for lens aperture settings, fluorescence filter transmittance, photodetector quantum efficiency, photon energy, exposure time, readout offset and camera gain. The image-guidance framework was applied to an in-house optical tomography system configured for indocyanine green (ICG) fluorescence. Mean target registration errors for camera and laser calibration were less than 1 mm. Surface flux measurements of total reflectance and fluorescence in Intralipid-based...
Source: Physics in Medicine and Biology - Category: Physics Authors: Tags: Phys Med Biol Source Type: research