ICRU Report 41, Modulation Transfer Function of Screen- Film Systems


This Report reviews and describes various concepts used in the analysis of the physical aspects of radiographic image quality for the screen-film systems used in diagnostic radiology. Concepts are described generally, however, so that they can be applied to other radiographic imaging modalities. In treating radiographic image quality, the report covers resolution, noise, and contrast. The treatment of transfer function analysis encompasses linearity and shift in variance, point spread function, line spread function, convolution, modulation transfer function (MTF) and Fourier spectrum. Various methods for the measurement of MTFs of screen-film systems and factors affecting MTFs, such as crossover exposure and x-ray beam quality are also treated. Appendices to the Report provide mathematical derivations and a glossary.