Construction of a laser transmission photo-scanner: pre-clinical investigation (report 2).

Abstract

A prototype high-speed laser transmission photo-scanner using a 1 mm He-Ne laser beam and corresponding detector was constructed. Signals obtained from the detector were digitalized and stored in floppy disks by a micro-computer and displayed as color-coded pictures on the CRT monitor. The data were analyzed and absorption in the tissue was shown in a histogram. Breast tissue was simulated using pork, ham, lard, and cheese in a pre-clinical investigation. Normal breasts of volunteers were also examined. When disks of varying sizes were inserted into ham and cheese of various thicknesses, it was found that disks closer to the beam's point of entrance produced the best images, while disks in the center and those closer to the exit were poorly detected. Disks close to the surface were better detected than central lesions. Laser transmission images of normal breasts of twelve volunteers were symmetrical but often nonhomogeneous because of the complexity of breast tissue.