Title :
Fast methods for including attenuation in the EM algorithm
Author :
Hebert, Thomas J. ; Leahy, Richard
Author_Institution :
Dept. of Electr. Eng., Houston Univ., TX, USA
fDate :
4/1/1990 12:00:00 AM
Abstract :
A fast approach to including attenuation in iterative maximum-likelihood and least-squares algorithms for single-photon-emission computed tomography (SPECT) is presented. Ray-tracing and summing of attenuation coefficients are replaced by the use of two lookup tables, one to compute attenuated ray path integrals based on a set of polar grid points and one to perform polar-to-rectangular transformations. The resulting algorithm implements a spatial average which is comparable in accuracy to ray-tracing with rectangular pixels, yet requires less than one sixteenth the CPU time
Keywords :
computerised tomography; iterative methods; least squares approximations; radioisotope scanning and imaging; EM algorithm; SPECT; attenuated ray path integrals; attenuation; fast approach; iterative maximum-likelihood; least-squares algorithms; lookup tables; polar grid points; polar-to-rectangular transformations; ray-tracing; rectangular pixels; single-photon-emission computed tomography; spatial average; Attenuation; Cameras; Iterative algorithms; Least squares approximation; Light scattering; Maximum likelihood detection; Maximum likelihood estimation; Particle scattering; Ray tracing; Tomography;
Journal_Title :
Nuclear Science, IEEE Transactions on
