A tabletop Diffuse Optical Tomographic (DOT) experimental demonstration system

Abstract

Diffuse Optical Tomographic (DOT) experimental studies are performed in a dark environment, surrounded by dedicated instruments to acquire quality measurement data for the better image reconstruction. Hence, DOT experimental setups are bulky and educational experimental demonstration of DOT to the public in an open space is challenging. The International Year of Light (IYL 2015), motivated us to develop a DOT demonstration system to improve public understanding of the role of light in medical imaging. In this paper, we present a tabletop DOT system, that has four NIR light sources, six silicon-photodiode detectors, a control circuitry containing a 24-bit dual sigma-delta ADC with an ARM cortex-M3 processor and a MatLab based image reconstruction software. The control circuitry controls the light source and detector selections, measures diffused light and sends data to a laptop computer via USB for the low-resolution 2D DOT image reconstruction. The imaging domain was a tissue mimicking Intralipid and India ink solution in a circular tank, with a variable inhomogeneity location. We evaluated the system performance by demonstrating it on IISc Open Day an annual event opened for the general public in India. We performed interactive experimental demonstrations by allowing the audiences to place an optical inhomogeneity in the homogeneous phantom tank at their desired location. Our system was capable of localizing inhomogeneity in the reconstructed image from the experimental measurement data within a few seconds. The system was proven to be instrumental in demonstrating all of the basic principles and working principle of the DOT imaging in an interactive manner.