Research On Flexible Wearable Radiotherapy Respiratory Motion Monitoring System

In radiation therapy,the position of chest and abdominal tumours(like lung and liver)in most patients will vary with their inherent respiratory movement.Nowadays,4D-CT is the most common method for radiotherapy to treat patients with respiratory movement.However,due to the deviation of those already located target areas as well as the off-target phenomenon caused by the inconsistent respiratory movement of most patients in the course of target location and radiotherapy,it is necessary to detect and intervene the respiratory movement of patients in the course of target location and radiotherapy and ensure a same breath detection sensor so that errors caused by different measuring instruments can be avoided.In this paper,a flexible wearable respiratory movement monitoring system with the sensing element of the melamine foam as the flexible base,and the high-molecular polymer PEDOT:PSS and nano-gold flower as the main conductive part.By comparing the mechanical and electrical proprieties of three kinds of conductive sponges with only nano golden flower(Au@MS),only PEDOT:PSS(PEDOT:PSS@MS),and adding nano-gold flower and PEDOT:PSS(Au/PEDOT:PSS@MS),the conductive sponges with best comprehensive properties were chosen as the sensing element of the wearable respiratory monitoring system,through which the obtained respiratory signal can be provided for the respiratory waveform exhibition,parameter extraction,storage,playback and alarm of Android smartphone via the wireless transmission of Bluetooth.The results showed that the compressive and conductive properties of Au/PEDOT:PSS@MS are significantly higher than those of other two kinds of conductive sponges under different compressive strain.It was then packaged and built into a peripheral hardware circuitry to form a respiratory monitoring system and wirelessly transmit respiratory data over Bluetooth.The software based on Android smartphone was also developed.On the one hand,the software can extract and judge the parameters of the real-time collected waveforms,and ring the alarm in time when the respiratory parameters are abnormal;on the other hand,the software has the playback function,which can play back the respiratory waveforms of the patients when the 4DCT target area is located,so as to guide the breathing of the patients in the radiotherapy.Therefore,the system can avoid the Miss target phenomenoncaused by the difference of breath movement during radiotherapy and target location to the greatest extent,and the system is comfortable to wear,which meets the needs of patients' breath detection.It has a high application value for solving the problem of breath movement in radiotherapy and helps to achieve accurate radiotherapy.