Enhancing Clinical Accuracy in DIBH Pattern Detection with a Combined Ultrasonic and IR Sensor System

Abstract

This study aimed to develop a DIBH monitoring system using IR (Infrared- VL6180X Time of Flight) distance sensors and a microcontroller, and to demonstrate its functionality and performance in various irregular free and DIBH breathings from the left breast and lung patients. A total of ten patients who performed DIBH breathing for treatment planning and optimized treatment delivery were randomly selected for the study. The breathing motion of the system was tested using an RPM (Real-Time Positioning Management) phantom. The IR sensors were interfaced with an Arduino microcontroller, and a body phantom was used to mimic the DIBH pattern on a CT scan. The detector holder was mounted perpendicularly between the xiphoid and umbilicus, with the ability to compensate for various patient body habitus and adapt to clinical setups. The plastic devices were 3D printed, and the sensors were mounted approximately 100mm apart to receive directed echo signals and prevent unwanted signals from scattering. The IR sensor DIBH system was able to detect and record the patient's breathing pattern in real-time. The IR sensor showed better visualization of breathing rhythm with fewer fluctuations and reduced noise than the previous ultrasonic sensor system. The breathing amplitude and duration for the patients were compared to our treatment planning of Varian Eclipse and verified in TrueBeam's Breath-Hold Gating mode. The amplitude and duration from the primary study were measured to ±5mm, including 3mm sensor noise level and ±1.5 second. The IR sensor DIBH system demonstrated better performance compared to the ultrasonic sensor, with a better visualization of breathing rhythm and reduced fluctuations and noise. It provided a clinically acceptable DIBH pattern for monitoring chest and abdominal motion in patients with irregular breathing. The findings of this study have the potential to enhance clinical accuracy in radiation therapy treatment planning and delivery for patients undergoing DIBH.