How is the resolution of a radiographic system evaluated?

The correct approach to evaluating the resolution of a radiographic system is through modulation transfer function (MTF) analysis. MTF is a mathematical analysis that measures how well a system can reproduce (or transfer) detail from the object being imaged to the image itself. It evaluates the contrast and size of various spatial frequencies in an image, allowing for a quantitative assessment of resolution. By measuring how different spatial frequencies are represented in the image relative to those in the object, MTF provides a comprehensive view of a system's resolution capability.

In contrast, measuring film density focuses more on the overall darkness or opacity of an image rather than its ability to resolve fine detail. Comparing images to reference standards may assist in general evaluations of quality but does not specifically quantify resolution. Similarly, contrast detail analysis primarily examines the ability of a system to differentiate between different levels of contrast in the image, and while it may relate to perceived resolution, it does not measure resolution directly. MTF specifically targets the performance of a system in terms of imaging fine details, making it the most appropriate method for evaluating resolution.