  Computerized tomography (CT) has been used for decades by medical
professionals to detect and diagnose injuries and ailments. CT scanners are
based on interesting physics, but due to their bulk, cost, and safety, hands on
experience with a medical CT scanner is unrealistic for undergraduate students.
Therefore, operationally similar, yet small, safe, and inexpensive CT scanners
are desirable teaching tools. This project details the development of a novel
model CT scanning apparatus. The experimental setup presented utilizes visible
light, has short data acquisition time, and operates on the same physics as its
X-ray counterpart. The apparatus employs a laser and a photodiode to image a
transparent material, while avoiding loss of transmitted intensity through
index of refraction matching. A simple back-projection algorithm results in a
2D cross section of the scan object. We found we could collect data and
reliably image samples in 15 min.
