On A Vison-based Swallowing Detection Method In Radiotherapy Environment

During the radiotherapy of laryngeal tumor,patients' swallowing movement can affect the treatment effect.Therefore,detecting patients' swallowing movement can provide an objective basis for the subsequent supplement of radiation dose,which is conducive to achieving more accurate radiotherapy.In the medical field,VF(Video Fluorography)is usually used for the detection and evaluation of swallowing,but this method is accompanied by radiation,and will affect the patients' health.Although there are many non-radioactive swallowing detection methods,most of them are expensive and not suitable for the radiotherapy environment.Therefore,this paper attempts to study a vision-based non-contact swallowing detection method,which can be used to detect patients' swallowing movement in the radiotherapy environment and assist doctors to determine patients' swallowing status during treatment.According to the characteristics of physiological signals produced in the process of swallowing,a technical route for swallowing detection is proposed.In this paper,a marker is paste on the skin of human neck,and the movement of the marker is monitored by a camera to obtain the swallowing signal.Then swallowing parameters can be obtained from the signal.In order to extract swallowing signals from captured images,this paper proposes an improved image processing algorithm combining ellipse detection with traditional template matching to process images,and uses a target-based fast calibration method to convert the extracted pixel displacement into physical displacement.According to the characteristics of the extracted swallowing signal,this paper firstly preprocesses the signal,and then identifies the swallowing movement and detects the movement time and displacement through the peak characteristics of the signal.In addition,this paper carries out experiments on the vision-based swallowing detection method.Firstly,the displacement platform is used to verify the feasibility of this method and the accuracy is analyzed.The results show that the maximum error between the displacement measured by this method and the actual value is less than 0.5mm,and the average time to process a frame of image is less than 30 ms,which can meet the accuracy and real-time requirements proposed by doctors.At the same time,the experimental results in the positioning room show that there is a good correlation between the displacement of swallowing movement measured by this method and that measured by VF.In order to verify the practical effect of this method,swallowing movement detection experiments are performed on 18 healthy subjects and 9 laryngeal cancer patients.The experimental results show that this method can accurately detect the number of swallowing movements,time and displacement of the swallowing movement,and is applicable to the radiotherapy environment.