In recent years, noninvasive thermal treatment by using high-intensity focused ultrasound (HIFU) has high potential in tumor treatment. disease are very important measures to avoid worsening. Except biochemical tests such as GOT/GOP or relative to the tank DRF frame (is determined from the ultrasound image. The position of the target point relative to 114629-86-8 IC50 the optical tracker frame can be expressed through either the tank DRF frame or the ultrasound probe frame as shown in at three or more positions, = 1, 2,, 3, into (1) and solved by optimization method such as the least square algorithm. After the transformation matrix represents the focal point of the HIFU transducer) is designed and mounted at the end effector of the robotic arm. A DRF is fixed on the robot base and used to define the world coordinate frame W in case the optical tracker is moved during the registration. The robot coordinate frame is defined as frame R. The transformation matrices (the end of the pin) to the three peak points of the template (as shown in Figure 8). The distance errors between the peak points and the pinpoint are listed in Table 2. The distance errors in depth of 3?cm, 7?cm, and 12?cm are 0.72??0.26?mm, 1.02??0.26?mm, and 1.31??0.23?mm, respectively. Figure 8 The pinpoint of the rod positions to the peak point of the calibration template. Table 2 The distance error of the robotic arm (unit: mm). 3.3. Accuracy Evaluation III: The Positioning Accuracy of the Ultrasound Imaging-Guided Robotic HIFU System with Ablating a Phantom The ultrasound imaging-guided robotic HIFU treatment experiment was conducted by commanding the robotic arm to move the HIFU focal point to ablate the four corner points of a phantom, which was detected by ultrasound 114629-86-8 IC50 images. Figure 9 shows that the HIFU focal point can be positioned to the target (corner) points for thermal ablation. The average distance error is 1.32??0.58?mm, and the distance error of each corner point is listed in Table 3. Figure 9 Positioning experiment of the HIFU thermal ablation. Table 3 The distance error of HIFU thermal ablation (unit: mm). 4. Conclusions This study proposes an ultrasound imaging-guided robotic HIFU experimental system for thermal ablation of tumors. By using this system, the positioning coordinates of targets (which are determined by the ultrasound Cd99 114629-86-8 IC50 imaging system) are transformed to the robot coordinate frames so that the robotic arm can move the HIFU transducer to ablate the target tumors. Instead of building the huge, solid, and costly system, this system tries to combine with the existing ultrasound imaging equipment to achieve HIFU ablation function. The positioning accuracy evaluation results in Section 3 show that the distance error of the ultrasound imaging-guided robotic HIFU system is 1.32??0.58?mm. However, for clinical use, this system still has many things needed to improve. So far, this study has built an experimental HIFU treatment system and confirmed its possibility and accuracy. The next step of this research is to consider the path planning issue and the respiration problem (respiration might cause tumor moving during the HIFU treatment ) in order to get more closer to deal with a real HIFU treatment situation. Acknowledgments The authors would like to thank the Ministry of Science and Technology, Taiwan, for the financial support, under the contract NSC 101-2221-E-008-020-MY3. Notes This paper was supported by the following grant(s): Ministry of.