IEC 60336:2020 applies to FOCAL SPOTS in medical diagnostic X-RAY TUBE ASSEMBLIES for medical use, operating at X-RAY TUBE VOLTAGES up to and including 150 kV.This document describes the test methods employing digital detectors for determining:a) FOCAL SPOT dimensions in terms of NOMINAL FOCAL SPOT VALUES, ranging from 0,1 to 3,0;b) LINE SPREAD FUNCTIONS;c) one-dimensional MODULATION TRANSFER FUNCTIONS;d) FOCAL SPOT PINHOLE RADIOGRAMS,and the means for indicating compliance.In informative annexes, STAR PATTERN imaging and BLOOMING VALUE are described.IEC 60336:2020 cancels and replaces the fourth edition published in 2005. This edition constitutes a technical revision.The significant changes of this fifth edition with respect to the previous edition are detailed in Clause E.6. These changes are:a) introduction of digital detectors and discretization errors;b) fewer normative requirements;c) support for both SLIT CAMERA and PINHOLE CAMERA;d) reintroduction of distorted (skewed) FOCAL SPOT;e) keeping of STAR PATTERNS and BLOOMING VALUE as informative.