Fig. 9

Visualization of a targeting beam focus based on segmented thermal strain imaging (TSI). Here, an extended low-dose exposure is used and visualized at (a through e): t = 4, 9, 14, 19, and 24 s. The Ix is located at position [0, 0, 0] mm and the imaging volume outlined by the blue-lined pyramid. The final, algorithm-determined approximation of the targeting beam (black line) and the therapy tile aperture centroid (black circle) are shown in (e)