Target detection and characterization using a hybrid handheld diffuse optical tomography and photoacoustic tomography system

Abstract

A handheld photoacoustic tomography-guided diffuse optical tomography system for imaging deeply-seated targets in scattering media is presented. This hybrid imager consists of a probe with an ultrasound transducer in the center and straddled by two optical fibers for taking photoacoustic images. The diffuse optical tomography component comprises of 9 light-source fibers for delivering light to the imaged tissue, and 14 detector fibers for collecting the light. Single- and two-phantom targets of high and low optical contrasts were immersed in a scattering intralipid solution to depths of up to 3cm and imaged. The reconstructed absorption coefficients of the targets with guidance from photoacoustic tomography were compared to those obtained with a-priori depth-only information, and no a-priori information. The reconstructed absorption maps yielded as much as 2.6-fold improvement in the quantification accuracy compared to the cases with no guidance from photoacoustic tomography.