Digital tomographic imaging with time-modulated pseudorandom coded aperture and Anger camera.

The properties of a time-modulated pseudorandom coded aperture with digital reconstruction are compared with those of conventional collimators used in gamma-ray imaging. The theory of this coded aperture is given and the signal-to-noise ratio in an element of the reconstructed image is shown to depend on the entire source distribution. Experimental results with a preliminary 4 X 4-cm pseudorandom coded aperture and an Anger camera are presented. These results include phantom and human thyroid images and tomographic images of a rat bone scan. The experimental realization of the theoretical advantages of the time-modulated coded aperture gives reason for continuing the clinical implementation and further development of the method.