An improved FORTRAN program for calculating modulation transfer functions.
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Biomedical subjects
Publications and source records attributed to R K Tyson.
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In the Siemens star image, exact determination of the first disappearance frequency, which is used to measure the focal spot size, is difficult since the disappearance band has a finite width and the image also has other artifacts. The origin of these artifacts and their appearance was studied by Siemens star image simulation on a digital computer. The simulated images were manipulated by using many different modulation and phase transfer functions. It is shown that the bending of spokes is not related to zero contrast; exact triplet splitting can occur only at the disappearance frequency, and therefore splitting is a valuable indicator of that frequency.
In recent years the modulation transfer function (MTF) has played an important role in the quantitation of imaging performance of gamma cameras. The most common method of MTF determination requires line spread function (LSF) measurement. This paper reviews methods used for LSF measurements with special consideration given to the practical aspects of LSF measurement and MTF calculation. An analysis of errors in LSF measurements is made and means to reduce or to avoid these errors are discussed. Recommendations regarding practical considerations for LSF measurement and MTF calculation are presented in tabular form for convenience.