[Development of a laser-optical tomograph for demonstration of CT imaging without ionizing radiation]

Computed X-ray tomography (CT) is one of the most powerful diagnostic procedures in medicine. In this study, we developed a laser-optical CT scanner for the use by students as part of their curriculum in biomedical engineering. Our CT set-up employs a linear-scan technique where the measurement objects (light absorbing phantoms embedded in immersion oil), the light emitter (modulated laserdiode), and the detector (photodiode) are moved by linear-step motors. The spatial resolution is limited by the width of the laser beam (2 mm) and the smallest achievable raster step size (0.02 mm). Optical tomographic images of various objects can be measured within a few minutes and allow the demonstration of imaging principles like extinction, scanning, projection, and reconstruction techniques.