A method of time resolved radiation assisted device alteration testing of a semiconductor circuit which includes performing spatially resolved radiation assisted circuit testing on the semiconductor circuit while applying a test pattern to determine a pass-fail modulation location, asynchronously scanning the semiconductor circuit with radiation while repeatedly applying the test pattern and providing pass-fail results, combining corresponding pass-fail results provided during the asynchronously scanning to determine a shifted pass-fail modulation indication, determining time shift information between the pass-fail modulation location and the shifted pass-fail modulation indication, and identifying at least one of the test vectors based on the time shift information. The radiation may be a continuous wave laser beam. The time shift information may be determined by scanning an image, incorporating graphics into the image indicating the pass-fail modulation location and the shifted pass-fail modulation indication, and measuring a pixel shift on the scanned image.