Study of Respiration Simulating Phantom using Thermocouple-based Respiration Monitoring Mask

Lim, Sangwook; Ahn, Seung Do; Park, Sung Ho; Yi, Byong Yong; Lee, Sang Hoon; Cho, Sam Ju; Huh, Hyun Do; Shin, Seong Soo; Kim, Jong Hoon; Lee, Sang wook; Kwon, Soo Il; Choi, Eun Kyung

Abstract

PURPOSE: To develop the respiration simulating phantom with thermocouple for evaluating 4D radiotherapy such as gated radiotherapy, breathing control radiotherapy and dynamic tumor tracking radiotherapy.
MATERIALS AND METHODS
The respiration monitoring mask (ReMM) with thermocouple was developed to monitor the patient's irregular respiration. The signal from ReMM controls the simulating phantom as organ motion of patients in real-time. The organ and the phantom motion were compared with its respiratory curves to evaluate the simulating phantom. ReMM was used to measure patients' respiration, and the movement of simulating phantom was measured by using RPM(R). The fluoroscope was used to monitor the patient's diaphragm motion.
RESULTS
Comparing with the curves of respiration measured by thermocouple and those of the organ motion measured by fluoroscope and RPM, the standard deviations between the curves were 9.68% and 8.53% relative to the organ motion, respectively. The standard deviation of discrepancy between the respiratory curve and the organ motion was 8.52% of motion range.
CONCLUSION
Patients felt comfortable with ReMM. The relationship between the signal from ReMM and the organ motion shows strong correlation. The phantom simulates the organ motion in real-time according to the respiratory signal from the ReMM. It is expected that the simulating phantom with ReMM could be used to verify the 4D radiotherapy.