MTF, Nyquist & the frequency-domain description of resolution
A graph of modulation transfer function (MTF, the ratio of output to input modulation, from 0 to 1) against spatial frequency in line pairs per millimetre. Both curves start at MTF equal to 1 at zero frequency and fall towards 0 as frequency rises. The higher teal curve (a detail film–screen system) stays above the lower curve (computed radiography), crossing a 10 percent limiting-resolution guide at about 10 line pairs per mm, whereas computed radiography crosses at about 5 line pairs per mm. A higher curve retains more contrast for fine detail, meaning better resolution. Below, a line-pair test strip shows bar patterns getting finer towards the right.
Practice the Physics paper
FRCRX is a Part 1 Physics question bank: true/false items with explanations, timed mocks and topic analytics.