On the accuracy of implant dosimetry reconstructed from rotational stereoradiographs

Stereo-shift implant reconstruction produces displacement errors when the shifts (S) are small (H/S>) relative to the focal spot-film distances (H). The authors investigated the errors using two films at 50 (S/H = 7), 100 (S/H = 4), 150 (S/H = 2.5), and 200 (S/H = 2) from a simulator and a commercial stereo reconstruction algorithm. Seven seeds on faces of an 8-cm cube served as the test object. Angles of 100, 16%, and 200 yielded errors of < 1 mm in the (x,y) coordinates and < 2 mm in the (z) coordinate