Accurate Respiration Measurement Using DC-Coupled Continuous-Wave Radar Sensor for Motion-Adaptive Cancer Radiotherapy

Abstract

Accurate respiration measurement is crucial in motion-adaptive cancer radiotherapy. Conventional methods for respiration measurement are undesirable because they are either invasive to the patient or do not have sufficient accuracy. In addition, measurement of external respiration signal based on conventional approaches requires close patient contact to the physical device which often causes patient discomfort and undesirable motion during radiation dose delivery. In this paper, a dc-coupled continuous-wave radar sensor was presented to provide a noncontact and noninvasive approach for respiration measurement. The radar sensor was designed with dc-coupled adaptive tuning architectures that include RF coarse-tuning and baseband fine-tuning, which allows the radar sensor to precisely measure movement with stationary moment and always work with the maximum dynamic range. The accuracy of respiration measurement with the proposed radar sensor was experimentally evaluated using a physical phantom, human subject, and moving plate in a radiotherapy environment. It was shown that respiration measurement with radar sensor while the radiation beam is on is feasible and the measurement has a submillimeter accuracy when compared with a commercial respiration monitoring system which requires patient contact. The proposed radar sensor provides accurate, noninvasive, and noncontact respiration measurement and therefore has a great potential in motion-adaptive radiotherapy.

Sensing Systems for Respiration Monitoring: A Technical Systematic Review

“…Most authors chose to detect chest wall movements (60%). For the environmental category, modulation of cardiac activity was also very common [ 5 , 7 , 50 , 52 , 54 , 163 , 164 , 168 , 174 , 175 , 177 , 178 , 189 , 190 , 196 , 197 , 198 , 199 , 205 , 206 , 207 , 213 , 214 , 219 , 221 , 223 , 224 , 225 , 226 , 229 , 232 , 233 ]. Meanwhile, air temperature and air humidity were the second [ 2 , 64 , 91 , 104 , 107 , 116 , 120 , 128 , 133 , 145 , 153 , 154 , 155 , 156 , 162 ] and third [ 66 , 74 , 75 , 80 ,…”

“…Regarding the tools for measurement processing, Figure 36 shows the distribution of use of the different tools for the wearable and environmental respiration monitoring systems. MATLAB was the preferred software for both types of systems, since it was adopted by half of the studies, while NI Labview was the second most used tool as it appeared in 20–30% of the works [ 2 , 3 , 19 , 63 , 71 , 85 , 86 , 87 , 88 , 127 , 129 , 131 , 138 , 142 , 146 , 153 , 163 , 201 , 218 , 219 , 220 , 223 , 225 ]. The rest of the tools relied heavily on the specific sensor used to capture the data.…”

“… 1 Note: The analysis for studies published before 2018 [ 5 , 6 , 7 , 9 , 10 , 19 , 48 , 50 , 51 , 52 , 53 , 54 , 183 , 184 , 185 , 186 , 187 , 188 , 189 , 190 , 191 , 192 , 193 , 194 , 195 , 196 , 197 , 198 , 199 , 200 , 201 , 202 , 203 , 204 , 205 , 206 , 207 , 208 , 209 , 210 , 211 , 212 , 213 , 214 , 215 , 216 , 217 , 218 , 219 , 220 , 221 , 222 , …”

Heartbeat Detection by Laser Doppler Vibrometry and Machine Learning

“…Those kinds of systems commonly find applications in heartbeat monitoring. In [ 6 , 7 ], a technology based on doppler radar is presented to non-contact heartbeat monitoring. This technology relies on the reflection properties of a body irradiated by high frequency radiowaves.…”

A non-contact method based on multiple signal classification algorithm to reduce the measurement time for accurately heart rate detection

“…[5][6][7] The CW Doppler radar will transmit an unmodulated carrier and will receive the reflected signal, which will be phase modulated. The periodic movement of the body due to respiration and heart rate will produce phase modulation of the reflected signal according to the Doppler principle.…”