Research On Continues Wave Non-contact Optical Tomography System

Diffuse optical tomography (DOT)/fluorescence diffuse optical tomography(FDOT) become a hot spot for medical imaging with the advantage of high sensitivity,non-invasiveness and dynamic monitoring. A non-contact measurement mode canprovide a large dataset and avoid the attenuation caused by the fiber-contact, whichhas very promising future for application.In this article, a non-contact DOT/FDOT system based on the laser scanningbeam and the Electron-Multiplying Charge-coupled Device (EMCCD) detector hasbeen build, which can provide a large measurement dataset in a relative short time.And the system is suit for the cylindrical and slab objects.The instrument controlsoftware, which is developed using Microsoft Visual C++6.0, enables the imagingsystem to acquire measurement data, display the real time measured images, and storethe result fully automated. Its functions also include hardware control (EMCCDpackage, filter wheel, laser source and translation stages for both target andinspiritment), as well as system parameter configuration through the friendly userinterface.To minimize the aberration and noise in measurement, the correspondingcalibration method has been proposed. And the performance and efficacy of thedesigned system are evaluated with a set of solid phantom experiment. The phantomsare fabricated by us and designed for the non-contact measurement.In the DOT measurements, several slab phantoms with different aanddifferent CCS are used and16×16measured images are collected and applied. It canbe found that the reconstructed images from the measurement data can reflect theactual target size and location correctly and the quantitativeness ratio is guaranteedover70%while the target contrast is2. Two targets with a CCS of12mm could bedistinguished through the DOT system. In the FDOT measurements, several cylinderphantoms with different fluorescence dye concentration are used and3×30measuredimages are collected and applied, It can be found that the reconstructed images fromthe measurement data are nearly in agreement with the actual target size and location,and the reconstructed fluorescence yield is sensitive to the concentration of the fluorescence dye. As a result, the non-contact DOT/FDOT system has the potentialvalue in small animal imaging.