Background Image‐guided brachytherapy (BT) robots can be used to assist urologists during seed implantation, thereby improving therapeutic effects. However, safety issues must be considered in the design of such robots, including their structure, mechanical movements, function, materials and actuators. Previous reviews focused on image‐guided prostate BT robot technology (e.g., imaging and robot navigation technology and robot system introduction); however, this review is the first time that safety issues have been investigated as part of a study on low‐dose‐rate (LDR) prostate BT robots. Methods Multiple electronic databases were searched for LDR prostate BT robot articles published during the last 24 years (1996–2020), with a particular focus on two aspects of robots: safety in design and use. Results We retrieved a total of 26 LDR prostate BT robots. BT robots were divided into ultrasound, computed tomography, magnetic resonance imaging and fusion‐guided systems. The conditions associated with each system were then analysed to develop a set of requirements for the safety of prostate BT robots. Recommendations are also provided for future BT robot development. Conclusions The transrectal approach for prostate seed implantation is safer than the traditional transperineal approach. Research into the control of a steerable needle by the urologists and robot, the needle deflection model, and robotic automated needle changing and seed injection equipment should be pursued in a future study.

Proton heavy ion radiotherapy is widely used and currently represents the most advanced radiotherapy technology. However, at present, proton heavy ion radiotherapy chairs in fixed beam radiotherapy rooms do not have a head and neck positioning function. This paper presents a novel design for a proton heavy ion radiotherapy chair with a head and neck positioning device. The design of the posture adjustment mechanism and the head and neck positioning device of the treatment chair is based on U-TRIZ theory and ergonomics, respectively. A positive kinematic analysis of the posture adjusting mechanism was carried out, as well as a workspace analysis of the head and neck positioning device. Finally, positioning error experiment and ergonomic evaluation were performed on a prototype of the head and neck positioning device. The proposed design of the treatment chair satisfies the requirements for posture adjustment and achieves the head and neck positioning function. The experimental results also provide a basis for further optimization of the design.

Background Transrectal prostate brachytherapy (BT) involves the permanent implantation of radioactive seeds through a needle, which must be inserted along a straight path to satisfy dose distribution requirements. However, this process is complicated by bevelled needle tips that can cause deflection during penetration. In clinical practice, physicians typically rotate the bevelled tip intermittently or apply manual correction forces near the insertion point, to reduce needle deflection. While assisted rotational insertion robots have made substantial progress in the past 20 years, tissue sticking can be caused by rotation of the bevelled tip and there are currently few studies on the use of corrective forces. As such, an auxiliary needle insertion guide for transrectal prostate BT, based on corrective forces, is investigated in this study for the first time. Methods The proposed BT guide is designed to reduce needle deflection and was experimentally verified by in vitro experiments. An energy‐based deflection model was developed to predict needle motion as corrective forces were applied during insertion. An experimental platform was constructed to perform corrective force‐assisted punctures, using the magnitude of the corrective force (A), the position of corrective force application (B) and the puncture speed (C) as test factors, with needle deflection as a test indicator. Design‐Expert 8.0.5b software was used for simulation, and a high‐definition camera acquired pictures of the needle tip as it pierced the tissue. A regression equation was also established for the test factors and test indicators, using Design‐Expert software. Optimal parameter combinations (A, B and C) were determined through optimization. Results Calculated needle deflection values were then compared with the measured position of the needle insertion point, producing an average error of 0.39 ± 0.28 mm. Deflection was as low as 0.8 mm using optimal puncture parameters Conclusions A needle‐tissue interaction model, considering tissue nonlinearity, which experimental results demonstrated to be highly accurate. Optimal puncture parameters effectively improved puncture accuracy.

No abstract

Background: In order to increase the accuracy of radiotherapy and to improve the patient's comfort, diverse structures of radiotherapy bed have been designed and improved constantly. Objective: To provide an overview of recent patents about radiotherapy bed and to introduce their characteristics and development. Methods: In this study, various representative patents related to the radiotherapy bed were reviewed. Additionally, the structural characteristics and applications of the typical radiotherapy bed were introduced. Results: The characteristics of different radiotherapy beds were analyzed and concluded. Moreover, the main problems concerning their development were analyzed, and the current and future developments of patents on radiotherapy bed were also discussed. Conclusion: Radiotherapy bed is an important part of radiotherapy system, which also determines the therapeutic outcomes of radiotherapy. Further improvements are required in the aspects of accuracy, comfort, flexibility and result stability of the radiotherapy bed. More invention should be laid on more patents on radiotherapy beds.

Abstract. Transrectal prostate brachytherapy (BT) can effectively treat prostate cancer. During the operation, doctors need to hold the ultrasound probe for repeated adjustments, which makes it difficult to ensure the efficiency, accuracy, and safety of the operation. We designed an 11 DOF (degrees of freedom) active and passive transrectal BT robot, based on the analysis of the transrectal prostate BT process. The posture adjustment module designed, based on the double parallelogram mechanism, realizes the centering function of the ultrasound probe and performs the kinematic analysis. Based on Simscape Multibody, the working posture and centering effect of the ultrasound probe's different feed distances are simulated. A physical prototype of the transrectal BT robot was developed and measured in experiments. The experimental results indicate that the angle rotation error of the joint is controlled to within 1∘. The rotation range of each joint meets the design requirements. The maximum error of the yaw angle's remote center point motion and pitch angle's remote center point motion are 0.5 and 0.4 mm, respectively, which are less than the deformation that can be endured in the anus by 6 mm. The simulation and experimental results and the analysis of measurement errors have verified the effectiveness and stability of the transrectal BT robot.

The reptile search algorithm (RSA) is a swarm-based metaheuristic algorithm inspired by the encirclement and hunt mechanisms of crocodiles. Compared with other algorithms, RSA is competitive but still suffers from low population diversity, unbalanced exploitation and exploration, and the tendency to fall into local optima. To overcome these shortcomings, a modified variant of RSA, named MRSA, is proposed in this paper. First, an adaptive chaotic reverse learning strategy is employed to enhance the population diversity. Second, an elite alternative pooling strategy is proposed to balance exploitation and exploration. Finally, a shifted distribution estimation strategy is used to correct the evolutionary direction and improve the algorithm performance. Subsequently, the superiority of MRSA is verified using 23 benchmark functions, IEEE CEC2017 benchmark functions, and robot path planning problems. The Friedman test, the Wilcoxon signed-rank test, and simulation results show that the proposed MRSA outperforms other comparative algorithms in terms of convergence accuracy, convergence speed, and stability.