Fig. 1

Example of fiducial marker registration. a X-ray of patient abdomen with the tumor located in the right bladder wall. This patient had 6 gold markers implanted around the transurethral resection of the bladder tumor (TUR-BT) scar. b Arrangement of the fluoroscopic units with the direction of the X-ray beam (arrows). The images were acquired by the two units that are a part of the RTRT system. c The colored circles in the fluoroscopic image indicate the gold marker positions at the registration and the black dots represent the actual positions of the gold markers. Up to three markers could be displayed in this system. The red arrow indicates the direction of the required positional correction. d Fluoroscopic images after fiducial marker registration. The red circles indicate the fiducial markers placed at the planned position