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Performance Evaluation of the Twist-Correction System for Head and Neck Radiotherapy Driven by Remote Control

H Shimizu1,2*, K Sasaki2, T Aoyama1, T Kitagawa1, T Iwata1, H Fukuma3, H Tachibana1, T Kodaira1, (1) Aichi Cancer Center, Nagoya, Aichi, JP, (2) Gunma Prefectural College of Health Sciences, Maebashi, Gunma, JP, (3) Nagoya City University Hospital, Nagoya, Aichi, JP


(Sunday, 7/12/2020)   [Eastern Time (GMT-4)]

Room: AAPM ePoster Library

Purpose: Our prototype device for correcting the twist of the patient's neck in radiotherapy could adjust the rotation angles in two independent (head and body) plates connected by a joint (fulcrum); however, only manual operation was allowed. In order to use the device in clinical practice, a system for remote control of each plate has been developed. The purpose of this study was to evaluate the performance of the new prototype system driven by the remote control.
Methods: The remote control system consists of motor units to operate each plate, a control panel, and an operation pendant (touch panel). When an arbitrary rotation angle is inputted on the touch panel, the angle is transmitted to the motor unit, and the plate tilts. For the performance of the new prototype system, the reproducibility of the origin return (zero position) and the rotation error for the ±1.5 degrees input was evaluated for each plate. In addition, the deflection under uniform loads of 100 and 200 N were simulated for the head and body plate, respectively.
Results: The pitch, roll, and yaw angles (average ± 1 standard deviation) of zero position for the head plate were 0.02 ± 0.01 degrees, -0.03 ± 0.00 degrees, -0.00 ± 0.01 degrees, respectively. For the body plate, they were -0.04 ± 0.00 degrees, -0.05 ± 0.00 degrees, and -0.01 ± 0.00 degrees, respectively. The rotation errors of the head and neck plates to the ± 1.5 degrees input were less than 0.02 degrees in all rotational axes. The maximum deflection under uniform loads was 0.36 mm at the corner of each plate.
Conclusion: The operation accuracy of the new prototype system showed excellent performance. This new system would make it easier to correct the twist of the patient's neck in radiotherapy.


Immobilization, Target Localization, Distortion


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