Adaptive control of phase leading compensator parameters applied to respiratory motion compensation system

Article type: Research Article

Authors: Kuo, Chia-Chun^{b; f} | Chuang, Ho-Chiao^{a; *} | Yu, Hsiao-Wei^b | Huang, Jeng-Wei^a | Tien, Der-Chi^a | Jeng, Shiu-Chen^{b; c} | Chiou, Jeng-Fong^{b; d; e}

Affiliations: [a] Department of Mechanical Engineering National Taipei University of Technology, Taipei, Taiwan | [b] Department of Radiation Oncology, Taipei Medical University Hospital, Taipei, Taiwan | [c] School of Dentistry, College of Oral Medicine, Taipei Medical University, Taipei, Taiwan | [d] Department of Radiology, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan | [e] Taipei Cancer Center, Taipei Medical University, Taipei, Taiwan | [f] Department of Radiation Oncology, Wanfang Hospital, Taipei Medical University, Taipei, Taiwan

Correspondence: [*] Corresponding author: Prof. Ho-Chiao Chuang, Department of Mechanical Engineering, National Taipei University of Technology, No. 1, Sec. 3, Chung-Hsiao E. Rd., Taipei 10608, Taiwan. Tel.: +886-2-2771-2171 ext. 2076; Fax: +886-2-2731-7191; E-mail: hchuang@mail.ntut.edu.tw.

Abstract: PURPOSE:This study evaluates the feasibility of our previously developed Respiratory Motion Compensation System (RMCS) combined with the Phase Lead Compensator (PLC) to eliminate system delays during the compensation of respiration-induced tumor motion. The study objective is to improve the compensation effect of RMCS and the efficay of radiation therapy to reduce its side effects to the patients. MATERIAL AND METHODS:In this study, LabVIEW was used to develop the proposed software for calculating real-time adaptive control parameters, combined with PLC and RMCS for the compensation of total system delay time. Experiments of respiratory motion compensation were performed using 6 pre-recorded human respiration patterns and 7 sets of different sine waves. During the experiments, a respiratory simulation device, Respiratory Motion Simulation System (RMSS), was placed on the RMCS, and the detected target motion signals by the Ultrasound Image Tracking Algorithm (UITA) were transmitted to the RMCS, and the compensation of respiration induced motion was started. Finally, the tracking error of the system is obtained by comparing the encoder signals bwtween RMSS and RMCS. The compensation efficacy is verified by the root mean squared error (RMSE) and the system compensation rate (CR). RESULTS:The experimental results show that the calcuated CR with the simulated respiration patterns is between 42.85% ∼3.53% and 33.76% ∼2.62% in the Right-Left (RL) and Superior-Inferior (SI), respectively, after the RMCS compensation of using the adaptive control parameters in PLC. For the compensation results of human respiration patterns, the CR is between 58.95% ∼8.56% and 62.87% ∼9.05% in RL and SI, respectively. CONCLUSIONS:During the respiratory motion compensation, the influence of the delay time of the entire system (RMCS+RMSS+UITA) on the compensation effect was improved by adding an adaptive control PLC, which reduces compensation error and helps improve efficacy of radiation therapy.

Keywords: Real-time adaptive control parameters, respiratory motion compensation, ultrasound image tracking, organ motion correction

DOI: 10.3233/XST-190503

Journal: Journal of X-Ray Science and Technology, vol. 27, no. 4, pp. 715-729, 2019