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Title: MO-FG-BRA-02: A Feasibility Study of Integrating Breathing Audio Signal with Surface Surrogates for Respiratory Motion Management

Abstract

Purpose: Tracking the surrogate placed on patient skin surface sometimes leads to problematic signals for certain patients, such as shallow breathers. This in turn impairs the 4D CT image quality and dosimetric accuracy. In this pilot study, we explored the feasibility of monitoring human breathing motion by integrating breathing sound signal with surface surrogates. Methods: The breathing sound signals were acquired though a microphone attached adjacently to volunteer’s nostrils, and breathing curve were analyzed using a low pass filter. Simultaneously, the Real-time Position Management™ (RPM) system from Varian were employed on a volunteer to monitor respiratory motion including both shallow and deep breath modes. The similar experiment was performed by using Calypso system, and three beacons taped on volunteer abdominal region to capture breath motion. The period of each breathing curves were calculated with autocorrelation functions. The coherence and consistency between breathing signals using different acquisition methods were examined. Results: Clear breathing patterns were revealed by the sound signal which was coherent with the signal obtained from both the RPM system and Calypso system. For shallow breathing, the periods of breathing cycle were 3.00±0.19 sec (sound) and 3.00±0.21 sec (RPM); For deep breathing, the periods were 3.49± 0.11 sec (sound)more » and 3.49±0.12 sec (RPM). Compared with 4.54±0.66 sec period recorded by the calypso system, the sound measured 4.64±0.54 sec. The additional signal from sound could be supplement to the surface monitoring, and provide new parameters to model the hysteresis lung motion. Conclusion: Our preliminary study shows that the breathing sound signal can provide a comparable way as the RPM system to evaluate the respiratory motion. It’s instantaneous and robust characteristics facilitate it possibly to be a either independently or as auxiliary methods to manage respiratory motion in radiotherapy.« less

Authors:
; ; ; ; ; ; ; ; ;  [1];  [2]
  1. University of Nebraska Medical Center, Omaha, NE (United States)
  2. Memorial Sloan Kettering Cancer Center, West Harrison, NY (United States)
Publication Date:
OSTI Identifier:
22653857
Resource Type:
Journal Article
Resource Relation:
Journal Name: Medical Physics; Journal Volume: 43; Journal Issue: 6; Other Information: (c) 2016 American Association of Physicists in Medicine; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
60 APPLIED LIFE SCIENCES; 61 RADIATION PROTECTION AND DOSIMETRY; BIOMEDICAL RADIOGRAPHY; COMPUTERIZED TOMOGRAPHY; FEASIBILITY STUDIES; IMAGE PROCESSING; SIGNALS

Citation Formats

Lei, Y, Zhu, X, Zheng, D, Li, S, Ma, R, Zhang, M, Fan, Q, Wang, X, Verma, V, Zhou, S, and Tang, X. MO-FG-BRA-02: A Feasibility Study of Integrating Breathing Audio Signal with Surface Surrogates for Respiratory Motion Management. United States: N. p., 2016. Web. doi:10.1118/1.4957285.
Lei, Y, Zhu, X, Zheng, D, Li, S, Ma, R, Zhang, M, Fan, Q, Wang, X, Verma, V, Zhou, S, & Tang, X. MO-FG-BRA-02: A Feasibility Study of Integrating Breathing Audio Signal with Surface Surrogates for Respiratory Motion Management. United States. doi:10.1118/1.4957285.
Lei, Y, Zhu, X, Zheng, D, Li, S, Ma, R, Zhang, M, Fan, Q, Wang, X, Verma, V, Zhou, S, and Tang, X. 2016. "MO-FG-BRA-02: A Feasibility Study of Integrating Breathing Audio Signal with Surface Surrogates for Respiratory Motion Management". United States. doi:10.1118/1.4957285.
@article{osti_22653857,
title = {MO-FG-BRA-02: A Feasibility Study of Integrating Breathing Audio Signal with Surface Surrogates for Respiratory Motion Management},
author = {Lei, Y and Zhu, X and Zheng, D and Li, S and Ma, R and Zhang, M and Fan, Q and Wang, X and Verma, V and Zhou, S and Tang, X},
abstractNote = {Purpose: Tracking the surrogate placed on patient skin surface sometimes leads to problematic signals for certain patients, such as shallow breathers. This in turn impairs the 4D CT image quality and dosimetric accuracy. In this pilot study, we explored the feasibility of monitoring human breathing motion by integrating breathing sound signal with surface surrogates. Methods: The breathing sound signals were acquired though a microphone attached adjacently to volunteer’s nostrils, and breathing curve were analyzed using a low pass filter. Simultaneously, the Real-time Position Management™ (RPM) system from Varian were employed on a volunteer to monitor respiratory motion including both shallow and deep breath modes. The similar experiment was performed by using Calypso system, and three beacons taped on volunteer abdominal region to capture breath motion. The period of each breathing curves were calculated with autocorrelation functions. The coherence and consistency between breathing signals using different acquisition methods were examined. Results: Clear breathing patterns were revealed by the sound signal which was coherent with the signal obtained from both the RPM system and Calypso system. For shallow breathing, the periods of breathing cycle were 3.00±0.19 sec (sound) and 3.00±0.21 sec (RPM); For deep breathing, the periods were 3.49± 0.11 sec (sound) and 3.49±0.12 sec (RPM). Compared with 4.54±0.66 sec period recorded by the calypso system, the sound measured 4.64±0.54 sec. The additional signal from sound could be supplement to the surface monitoring, and provide new parameters to model the hysteresis lung motion. Conclusion: Our preliminary study shows that the breathing sound signal can provide a comparable way as the RPM system to evaluate the respiratory motion. It’s instantaneous and robust characteristics facilitate it possibly to be a either independently or as auxiliary methods to manage respiratory motion in radiotherapy.},
doi = {10.1118/1.4957285},
journal = {Medical Physics},
number = 6,
volume = 43,
place = {United States},
year = 2016,
month = 6
}
  • Purpose: To efficiently deliver respiratory-gated radiation during synchrotron-based pulsed heavy-ion radiotherapy, a novel respiratory guidance method combining a personalized audio-visual biofeedback (BFB) system, breath hold (BH), and synchrotron-based gating was designed to help patients synchronize their respiratory patterns with synchrotron pulses and to overcome typical limitations such as low efficiency, residual motion, and discomfort. Methods: In-house software was developed to acquire body surface marker positions and display BFB, gating signals, and real-time beam profiles on a LED screen. Patients were prompted to perform short BHs or short deep breath holds (SDBH) with the aid of BFB following a personalized standardmore » BH/SDBH (stBH/stSDBH) guiding curve or their own representative BH/SDBH (reBH/reSDBH) guiding curve. A practical simulation was performed for a group of 15 volunteers to evaluate the feasibility and effectiveness of this method. Effective dose rates (EDRs), mean absolute errors between the guiding curves and the measured curves, and mean absolute deviations of the measured curves were obtained within 10%–50% duty cycles (DCs) that were synchronized with the synchrotron’s flat-top phase. Results: All maneuvers for an individual volunteer took approximately half an hour, and no one experienced discomfort during the maneuvers. Using the respiratory guidance methods, the magnitude of residual motion was almost ten times less than during nongated irradiation, and increases in the average effective dose rate by factors of 2.39–4.65, 2.39–4.59, 1.73–3.50, and 1.73–3.55 for the stBH, reBH, stSDBH, and reSDBH guiding maneuvers, respectively, were observed in contrast with conventional free breathing-based gated irradiation, depending on the respiratory-gated duty cycle settings. Conclusions: The proposed respiratory guidance method with personalized BFB was confirmed to be feasible in a group of volunteers. Increased effective dose rate and improved overall treatment precision were observed compared to conventional free breathing-based, respiratory-gated irradiation. Because breathing guidance curves could be established based on the respective average respiratory period and amplitude for each patient, it may be easier for patients to cooperate using this technique.« less
  • Purpose: Respiratory correlated computed tomography has been shown to be effective for evaluation of breathing-induced motion of pulmonary tumors. This study investigated whether a single four-dimensional CT study (4D-CT) is representative and sufficient for treatment planning in stereotactic body radiotherapy (SBRT). Methods and Materials: Four repeated helical 4D-CT studies were acquired every 10 min for 10 patients with 14 pulmonary metastases. Patients remained immobilized in a stereotactic body frame (SBF) for 30 min; abdominal compression was applied to seven patients. Using amplitude based sorting, eight phases equally distributed over the breathing cycle were reconstructed for each 4D-CT study. Tumor positionmore » was defined in a total of 406 CT series and variability of breathing motion and mean tumor position were evaluated. Results: Peak-to-peak tumor motion was 9.9 mm {+-} 6.8 mm (mean {+-} standard deviation) and 9.0 mm {+-} 7.4 mm at time point 0 min (t{sub 0}) and t{sub 30}, respectively. In one patient with poor pulmonary function, continuous increase of breathing motion from 17.4 mm at t{sub 0} to 28.3 mm at t{sub 30} was seen. In five and two lesions, respectively, a drift of the mean tumor position greater than 3 mm and 5 mm was observed. A borderline significance was calculated for larger tumor position variability in midventilation phases compared with peak-ventilation phases of the breathing cycle (p = 0.08). Conclusion: Treatment planning based on a single 4D-CT study is reliable for the majority of patients. Increased intrafractional uncertainties were seen for patients with poor pulmonary function and with tumors located in the lower lobe.« less
  • Purpose: AAPM TG-76 report advises lung patients experiencing tumor motion >5mm to use some form of motion management with even smaller limit for complex/special procedures like SBRT. Generally, either respiratory gating or abdominal compression is used for motion management. In this retrospective study, we are using an innovative index, Volumetric Indices (VI) = (GTVnn AND GTV{sub 50+}Xmm)/(GTVnn) to quantify how much of the tumor remains within 1, 2, and 3mm margins throughout the breathing cycle using GTV{sub 50+}Xmm margin on GTV{sub 50}[nn=0,10,20,…90]. Using appropriate limits, VI can provide tumor motion information and to check if RPM gates could have beenmore » used in conjunction with abdominal compression to better manage tumor motion. Methods: 64 SBRT patients with a total of 67 lung tumors were studied. 4DCT scans were taken, fully capturing tumor motion throughout the 10 phases of the breathing cycle. For each phase, Gross Tumor Volume (GTV) was segmented and appropriates structures were defined to determine VI values. For the 2mm margin, VI values less than 0.95 for peripheral lesions and 0.97 for central lesions indicate tumor movement greater than 4mm. VI values for 1mm and 3mm margins were also analyzed signifying tumor motion of 2mm & 6mm, respectively. Results: Of the 64 patients, 35 (55%) had motion greater than 4mm & could have benefited from respiratory gating. For 5/8 (63%) middle lobe lesions, 21/27 (78%) lower lobe lesions, and 10/32 (31%) upper lobe lesions, gating could have resulted in smaller ITV. 32/55 (58%) peripheral lesions and 4/12 (33%) central lesions could have had gating. Average ITV decreased by 1.25cc (11.43%) and average VI increased by 0.11. Conclusion: Out of 64 patients, 55% exhibited motion greater than 4mm even with abdominal compression. Even with abdominalcompression, lung tumors can move >4mm as the degree of pressure which a patient can tolerate, is patient specific.« less
  • Purpose: Respiratory gating is a commercially available technology for reducing the deleterious effects of motion during imaging and treatment. The efficacy of gating is dependent on the reproducibility within and between respiratory cycles during imaging and treatment. The aim of this study was to determine whether audio-visual biofeedback can improve respiratory reproducibility by decreasing residual motion and therefore increasing the accuracy of gated radiotherapy. Methods and Materials: A total of 331 respiratory traces were collected from 24 lung cancer patients. The protocol consisted of five breathing training sessions spaced about a week apart. Within each session the patients initially breathedmore » without any instruction (free breathing), with audio instructions and with audio-visual biofeedback. Residual motion was quantified by the standard deviation of the respiratory signal within the gating window. Results: Audio-visual biofeedback significantly reduced residual motion compared with free breathing and audio instruction. Displacement-based gating has lower residual motion than phase-based gating. Little reduction in residual motion was found for duty cycles less than 30%; for duty cycles above 50% there was a sharp increase in residual motion. Conclusions: The efficiency and reproducibility of gating can be improved by: incorporating audio-visual biofeedback, using a 30-50% duty cycle, gating during exhalation, and using displacement-based gating.« less
  • It has been noted that some lung tumors exhibit large periodic motion due to respiration. To limit the amount of dose to healthy lung tissues, many clinics have begun gating radiotherapy treatment using externally placed surrogates. It has been observed by several institutions that the end-of-exhale (EOE) tumor position is more reproducible than other phases of the breathing cycle, so the gating window is often set there. From a treatment planning perspective, end-of-inhale (EOI) phase might be preferred for gating because the expanded lungs will further decrease the healthy tissue within the treatment field. We simulate gated treatment at themore » EOI phase, using a set of recently measured internal/external anatomy patient data. This paper attempts to answer three questions: (1) How much is the tumor residual motion when we use an external surrogate gating window at EOI? (2) How could we reduce the residual motion in the EOI gating window? (3) Is there a preference for amplitude- versus phase-based gating at EOI? We found that under free breathing conditions the residual motion of the tumors is much larger for EOI phase than for EOE phase. The mean values of residual motion at EOI were found to be 2.2 and 2.7 mm for amplitude- and phase-based gating, respectively, and, at EOE, 1.0 and 1.2 mm for amplitude- and phase-based gating, respectively. However, we note that the residual motion in the EOI gating window is correlated well with the reproducibility of the external surface position in the EOI phase. Using the results of a published breath-coaching study, we deduce that the residual motion of a lung tumor at EOI would approach that at EOE, with the same duty cycle (30%), under breath-coaching conditions. Additionally, we found that under these same conditions, phase-based gating approaches the same residual motion as amplitude-based gating, going from a 28% difference to 11%, for the patient with the largest difference between the two gating modalities. We conclude that it is feasible to achieve the same reproducibility of tumor location at EOI as at EOE if breath coaching is implemented, enabling us to reap the benefits of the dosimetric advantage of EOI gating.« less