A comparative study of image reconstructions in SPECT and ultrasonic diffraction tomography

Single-photon emission computed tomography (SPECT) and ultrasonic diffraction tomography (UDT) are tomographic imaging modalities that are based upon entirely different physical processes. In SPECT, from the measured intensity of the electromagnetic wave (i.e., the gamma-ray), one seeks to determine the distribution of the gamma-ray emitter within an object. In UDT, from the measured scattered fields (i.e., the scattered ultrasonic wave), one determines the refractive index distribution. However, in this work, we demonstrate that the mathematics describing image reconstruction and the statistical analysis of image-noise properties are virtually identical for SPECT and UDT. We also conducted computer-simulation studies, which quantitatively corroborated our theoretical analysis