Design and Construction of A Laser-Based Respiratory Gating System For Implementation of Deep Inspiration Breathe Hold Technique in Radiotherapy Clinics

Deep inspiration breath‑hold (DIBH) is known as a radiotherapy method for thetreatment of patients with left‑sided breast cancer. In this method, patient is under exposureonly while he/she is at the end of a deep inspiration cycle and holds his/her breath. In thissituation, the volume of the lung tissue is enhanced and the heart tissue is pushed away from thetreating breast. Therefore, heart dose of these patients, using DIBH, experiences a considerabledecline compared to free breathing treatment. There are a few commercialized systems forimplementation of DIBH in invasive or noninvasive manners. We present a novelconstructed noninvasive DIBH device relied on a manufacturing near‑field laser distance meter.This in‑house constructed system is composed of a CD22‑100AM122 laser sensor combinedwith a data acquisition system for monitoring the breathing curve. Qt Creator (a cross‑platformJavaScript, QML, and C++‑integrated development environment that is part of the SDK fordevelopment of the Qt Graphical User Interface application framework) and Keil MDK‑ARM (aprogramming software where users can write in C and C++ and assemble for ARM‑basedmicrocontrollers) are used for composing computer and microcontroller programs, respectively. This system could be mounted in treatment or computed tomography (CT) roomat suitable cost; it is also easy to use and needs a little training for personnel and patients.The system can assess the location of chest wall or abdomen in real time with high precisionand frequency. The performance of CD22‑100AM122 demonstrates promise for respiratorymonitoring for its fast sampling rate as well as high precision. It can also deliver reasonablespatial and temporal accuracy. The patient observes his/her breathing waveform through a 7”1024 × 600 liquid crystal display and gets some instructions during treatment and CT sessionsby an exploited algorithm called “interaction scenario” in this study. The system is alsononinvasive and well sustainable for patients. The constructed system has truereal‑time operation and is rapid enough for delivering clear contiguous monitoring. In addition,in this system, we have provided an interaction scenario option between patient and CT or Linacoperator. In addition, the constructed system has the capability of sending triggers for turningon and off CT or Linac facilities. In this concern, the system has the superiority of combining aplenty of characteristics.