Guiding curve based on the normal breathing as monitored by thermocouple for regular breathing

Abstract

Adapting radiation fields to a moving target requires information continuously on the location of internal target by detecting it directly or indirectly. The aim of this study is to make the breathing regular effectively with minimizing stress to the patient. A system for regulating patient's breath consists of a respiratory monitoring mask (ReMM), a thermocouple module, a screen, inner earphones, and a personal computer. A ReMM with thermocouple was developed previously to measure the patient's respiration. A software was written in LabView 7.0 (National Instruments, TX), which acquires respiration signal and displays its pattern. Two curves are displayed on the screen: One is a curve indicating the patient's current breathing pattern; the other is a guiding curve, which is iterated with one period of the patient's normal breathing curve. The guiding curves were acquired for each volunteer before they breathed with guidance. Ten volunteers participated in this study to evaluate this system. A cycle of the representative guiding curve was acquired by monitoring each volunteer's free breathing with ReMM and was then generated iteratively. The regularity was compared between a free breath curve and a guided breath curve by measuring standard deviations of amplitudes and periods of two groups of breathing. When the breathing was guided, the standard deviation of amplitudes and periods on average were reduced from 0.0029 to 0.00139 (arbitrary units) and from 0.359 s to 0.202 s, respectively. And the correlation coefficients between breathing curves and guiding curves were greater than 0.99 for all volunteers. The regularity was improved statistically when the guiding curve was used.

Impact of incorporating visual biofeedback in 4D MRI

“…Therefore, faster scan times were observed with VBF while also reducing breathing irregularities. Our results were consistent with the literature, where 40%–55% reductions in irregularity were observed when using visual and audiovisual biofeedback systems, 18 , 19 respectively.…”

“…However, because this 4D MRI algorithm is prospectively triggered based on amplitude, long acquisition times were reported due to recurring pauses arising from highly irregular breathing patterns 14 , 15 , 16 . It has been shown that incorporating audio coaching and visual biofeedback (VBF) into 4D CT acquisition and radiation therapy delivery improves breathing regularity, increases anatomic reproducibility, and reduces the overall time burden of these procedures 17 , 18 , 19 . Given long 4D MRI exam times, efforts to reduce breathing irregularities are advantageous.…”

The internal–external respiratory motion correlation is unaffected by audiovisual biofeedback

“…Previous studies have indicated that AV biofeedback can result in significant reductions in the variability of both the period and the amplitude of a subject's breathing pattern [2,6,9,15,16]. An average improvement of 38 % has been seen in the RMSE in displacement, 82 % in the RMSE in Period, and 44 % in the baseline drift for individual breathing traces [9].…”

Breathing guidance in radiation oncology and radiology: A systematic review of patient and healthy volunteer studies

“…Breathing session 1: 1.426 Breathing session 2: 0.926, a larger discrepancy between free breathing and breathing guidance regularity (p = 0.212) e Pollock: RMSE between breathing signal and predicted breathing position patient to match their own breathing to, 54 and combinations thereof. 58,64,65 In addition to the nature of guiding prompts utilized, study design has also factored into influencing patient acceptance and compliance with the breathing guidance intervention.…”