# Calibration and volunteer testing of a prototype contactless respiratory motion detection system based on laser tracking

## TL;DR

Researchers tested a laser-based system for tracking breathing motion and found it to be accurate and promising for future clinical use.

## Contribution

A novel laser-based respiratory motion detection system was developed and validated against clinical standards.

## Key findings

- The laser system showed an average error of 1.17% during calibration tests.
- Volunteer tests showed strong correlation with clinical systems for breath-hold and free breathing.
- The system's performance suggests potential for clinical applications with further development.

## Abstract

The goal of this study was to assess the feasibility of a cost‐effective prototype of a laser‐based respiratory motion detection system utilizing a Leuze LDS for breath monitoring through calibration and volunteer tests.

This study was performed using the Anzai AZ‐773 V and computerized imaging reference systems (CIRS) motion phantoms for calibration tests. The calibration of the laser‐based respiratory motion detection system involved spatial accuracy testing, amplitude calibration, and temporal accuracy. Volunteer testing was conducted on eight volunteers at the inferior end of the sternum and the abdomen area. The accuracy of the data recorded by the laser‐based respiratory motion detection system was validated against established clinical reference tracking systems namely real‐time position management (RPM) and Anzai AZ‐733 V system.

Calibration with an Anzai AZ‐773 V and CIRS phantoms demonstrated an average error of 1.17% ± 0.64% and an average amplitude calibration correlation coefficient of 0.975 ± 0.004. Volunteer tests, compared to the Anzai AZ‐733 V clinical system and RPM system, revealed average correlation coefficients for deep inspiration breath‐hold are 0.931 ± 0.02 and 0.936 ± 0.03, respectively, and for free breathing are 0.85 ± 0.07 and 0.77 ± 0.1, respectively.

Overall, the data suggest that the in‐house laser‐based respiratory motion detection system performed well, with an error percentage below 10%. A reasonably good correlation coefficient was obtained, indicating that the readings obtained from the laser system are consistent with those set on the phantom and clinical respiratory motion detection systems. Although promising through the calibration process and volunteer tests, further studies are required to generate trigger data linked directly to computerized tomography and linear accelerator facilities, thereby advancing the clinical viability of this innovative laser‐based respiratory motion detection system.