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Journal articles on the topic 'Respiratory motion simulation'

Author: Grafiati

Published: 5 June 2025

Last updated: 16 July 2025

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1

Ohsaki, Shuji, Ryosuke Mitani, Saki Fujiwara, Hideya Nakamura, and Satoru Watano. "Numerical Simulation of Particle Motions in Cascade Impactor and Human Respiratory System." MATEC Web of Conferences 333 (2021): 02013. http://dx.doi.org/10.1051/matecconf/202133302013.

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Dry powder inhalations (DPIs) have gathered attention as a treatment for respiratory diseases due to the large effective absorption area in a human lung. A cascade impactor is generally used to investigate the inhalation performance of DPIs. For the improvement of the efficiency of DPIs, understanding the particle motion and deposition behavior in the human lung and the cascade impactor is required. In the present study, computer simulations were conducted to calculate the particle motion and deposition behavior in the human lung and the cascade impactor. As simulation methods, a coupling model of a computational fluid dynamics and a discrete phase method (CFD−DPM) and a coupling model of a CFD and a discrete element method (CFD−DEM) were used. The CFD−DEM simulation could reproduce the experimental particle deposition behavior in the cascade impactor, although it was difficult by the CFD−DPM simulation. Furthermore, the calculation results using the CFD−DEM simulation quantitatively demonstrated the higher particle reachability into the simple lung model when smaller particles were used. It was found that the CFD−DEM simulation is a powerful tool to calculate the particle motion and deposition behavior in the cascade impactor and human lung.

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2

Ohsaki, Shuji, Ryosuke Mitani, Saki Fujiwara, Hideya Nakamura, and Satoru Watano. "Numerical Simulation of Particle Motions in Cascade Impactor and Human Respiratory System." MATEC Web of Conferences 333 (2021): 02013. http://dx.doi.org/10.1051/matecconf/202133302013.

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Dry powder inhalations (DPIs) have gathered attention as a treatment for respiratory diseases due to the large effective absorption area in a human lung. A cascade impactor is generally used to investigate the inhalation performance of DPIs. For the improvement of the efficiency of DPIs, understanding the particle motion and deposition behavior in the human lung and the cascade impactor is required. In the present study, computer simulations were conducted to calculate the particle motion and deposition behavior in the human lung and the cascade impactor. As simulation methods, a coupling model of a computational fluid dynamics and a discrete phase method (CFD−DPM) and a coupling model of a CFD and a discrete element method (CFD−DEM) were used. The CFD−DEM simulation could reproduce the experimental particle deposition behavior in the cascade impactor, although it was difficult by the CFD−DPM simulation. Furthermore, the calculation results using the CFD−DEM simulation quantitatively demonstrated the higher particle reachability into the simple lung model when smaller particles were used. It was found that the CFD−DEM simulation is a powerful tool to calculate the particle motion and deposition behavior in the cascade impactor and human lung.

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3

Mohn, Silje, and Ellen Wasbø. "Simulation of respiratory motion during IMRT dose delivery." Acta Oncologica 50, no. 6 (2011): 935–43. http://dx.doi.org/10.3109/0284186x.2011.580002.

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4

Werner, R., M. Blendowski, J. Ortmüller, H. Handels, and M. Wilms. "Simulation of Range Imaging-based Estimation of Respiratory Lung Motion." Methods of Information in Medicine 53, no. 04 (2014): 257–63. http://dx.doi.org/10.3414/me13-01-0137.

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SummaryObjectives: A major problem associated with the irradiation of thoracic and abdominal tumors is respiratory motion. In clinical practice, motion compensation approaches are frequently steered by low-dimensional breathing signals (e.g., spirometry) and patient-specific correspondence models, which are used to estimate the sought internal motion given a signal measurement. Recently, the use of multidimensional signals derived from range images of the moving skin surface has been proposed to better account for complex motion patterns. In this work, a simulation study is carried out to investigate the motion estimation accuracy of such multidimensional signals and the influence of noise, the signal dimensionality, and different sampling patterns (points, lines, regions).Methods: A diffeomorphic correspondence modeling framework is employed to relate multidimensional breathing signals derived from simulated range images to internal motion patterns represented by diffeomorphic non-linear transformations. Furthermore, an automatic approach for the selection of optimal signal combinations/patterns within this framework is presented.Results: This simulation study focuses on lung motion estimation and is based on 28 4D CT data sets. The results show that the use of multidimensional signals instead of one-dimensional signals significantly improves the motion estimation accuracy, which is, however, highly affected by noise. Only small differences exist between different multidimensional sampling patterns (lines and regions). Automatically determined optimal combinations of points and lines do not lead to accuracy improvements compared to results obtained by using all points or lines.Conclusions: Our results show the potential of multidimensional breathing signals derived from range images for the model-based estimation of respiratory motion in radiation therapy.

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5

Biederer, J., C. Plathow, M. Schoebinger, et al. "Reproducible Simulation of Respiratory Motion in Porcine Lung Explants." RöFo - Fortschritte auf dem Gebiet der Röntgenstrahlen und der bildgebenden Verfahren 178, no. 11 (2006): 1067–72. http://dx.doi.org/10.1055/s-2006-927149.

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6

Lee, Donghoon, Ellen Yorke, Masoud Zarepisheh, Saad Nadeem, and Yu-Chi Hu. "RMSim: Controlled respiratory motion simulation on static patient scans." Physics in Medicine & Biology 68, no. 4 (2023): 045009. https://doi.org/10.1088/1361-6560/acb484.

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<em>Objective.</em> This work aims to generate realistic anatomical deformations from static patient scans. Specifically, we present a method to generate these deformations/augmentations via deep learning driven respiratory motion simulation that provides the ground truth for validating deformable image registration (DIR) algorithms and driving more accurate deep learning based DIR. <em>Approach.</em> We present a novel 3D Seq2Seq deep learning respiratory motion simulator (RMSim) that learns from 4D-CT images and predicts future breathing phases given a static CT image. The predicted respiratory patterns, represented by time-varying displacement vector fields (DVFs) at different breathing phases, are modulated through auxiliary inputs of 1D breathing traces so that a larger amplitude in the trace results in more significant predicted deformation. Stacked 3D-ConvLSTMs are used to capture the spatial-temporal respiration patterns. Training loss includes a smoothness loss in the DVF and mean-squared error between the predicted and ground truth phase images. A spatial transformer deforms the static CT with the predicted DVF to generate the predicted phase image. 10-phase 4D-CTs of 140 internal patients were used to train and test RMSim. The trained RMSim was then used to augment a public DIR challenge dataset for training VoxelMorph to show the effectiveness of RMSim-generated deformation augmentation. <em>Main results.</em> We validated our RMSim output with both private and public benchmark datasets (healthy and cancer patients). The structure similarity index measure (SSIM) for predicted breathing phases and ground truth 4D CT images was 0.92 ± 0.04, demonstrating RMSim's potential to generate realistic respiratory motion. Moreover, the landmark registration error in a public DIR dataset was improved from 8.12 ± 5.78 mm to 6.58mm ± 6.38 mm using RMSim-augmented training data. <em>Significance.</em> The proposed approach can be used for validating DIR algorithms as well as for patient-specific augmentations to improve deep learning DIR algorithms. The code, pretrained models, and augmented DIR validation datasets will be released at https://github.com/nadeemlab/SeqX2Y.

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7

Bögel, Marco, Hannes G. Hofmann, Joachim Hornegger, Rebecca Fahrig, Stefan Britzen, and Andreas Maier. "Respiratory Motion Compensation Using Diaphragm Tracking for Cone-Beam C-Arm CT: A Simulation and a Phantom Study." International Journal of Biomedical Imaging 2013 (2013): 1–10. http://dx.doi.org/10.1155/2013/520540.

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Long acquisition times lead to image artifacts in thoracic C-arm CT. Motion blur caused by respiratory motion leads to decreased image quality in many clinical applications. We introduce an image-based method to estimate and compensate respiratory motion in C-arm CT based on diaphragm motion. In order to estimate respiratory motion, we track the contour of the diaphragm in the projection image sequence. Using a motion corrected triangulation approach on the diaphragm vertex, we are able to estimate a motion signal. The estimated motion signal is used to compensate for respiratory motion in the target region, for example, heart or lungs. First, we evaluated our approach in a simulation study using XCAT. As ground truth data was available, a quantitative evaluation was performed. We observed an improvement of about 14% using the structural similarity index. In a real phantom study, using the artiCHEST phantom, we investigated the visibility of bronchial tubes in a porcine lung. Compared to an uncompensated scan, the visibility of bronchial structures is improved drastically. Preliminary results indicate that this kind of motion compensation can deliver a first step in reconstruction image quality improvement. Compared to ground truth data, image quality is still considerably reduced.

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8

Yang, Dongrong, Yuhua Huang, Bing Li, Jing Cai, and Ge Ren. "Dynamic Chest Radiograph Simulation Technique with Deep Convolutional Neural Networks: A Proof-of-Concept Study." Cancers 15, no. 24 (2023): 5768. http://dx.doi.org/10.3390/cancers15245768.

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In this study, we present an innovative approach that harnesses deep neural networks to simulate respiratory lung motion and extract local functional information from single-phase chest X-rays, thus providing valuable auxiliary data for early diagnosis of lung cancer. A novel radiograph motion simulation (RMS) network was developed by combining a U-Net and a long short-term memory (LSTM) network for image generation and sequential prediction. By utilizing a spatial transformer network to deform input images, our proposed network ensures accurate image generation. We conducted both qualitative and quantitative assessments to evaluate the effectiveness and accuracy of our proposed network. The simulated respiratory motion closely aligns with pulmonary biomechanics and reveals enhanced details of pulmonary diseases. The proposed network demonstrates precise prediction of respiratory motion in the test cases, achieving remarkable average Dice scores exceeding 0.96 across all phases. The maximum variation in lung length prediction was observed during the end-exhale phase, with average deviation of 4.76 mm (±6.64) for the left lung and 4.77 mm (±7.00) for the right lung. This research validates the feasibility of generating patient-specific respiratory motion profiles from single-phase chest radiographs.

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9

PUNZALAN, Florencio Rusty, Tetsuo SATO, Tomohisa OKADA, Shigehide KUHARA, Kaori TOGASHI, and Kotaro MINATO. "Respiratory Motion and Correction Simulation Platform for Coronary MR Angiography." IEICE Transactions on Information and Systems E96.D, no. 1 (2013): 111–19. http://dx.doi.org/10.1587/transinf.e96.d.111.

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10

Schwenke, Michael, Joachim Georgii, and Tobias Preusser. "Fast Numerical Simulation of Focused Ultrasound Treatments During Respiratory Motion With Discontinuous Motion Boundaries." IEEE Transactions on Biomedical Engineering 64, no. 7 (2017): 1455–68. http://dx.doi.org/10.1109/tbme.2016.2619741.

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11

Zhu, Di, Ezanee Gires, Huizhen Dong, Aolin Chen, and Kamarul Arifin Ahmad. "Review of Motion Simulation of Particulate Matter in the Respiratory System and Further CFD Simulations on COVID-19." Processes 11, no. 4 (2023): 1281. http://dx.doi.org/10.3390/pr11041281.

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Respirable particulate matter (RSP) is currently very harmful to the human body, potentially causing pulmonary silicosis, allergic rhinitis, acute bronchitis, and pulmonary heart disease. Therefore, the study of the deposition pattern of RSP in the human respiratory system is key in the prevention, treatment, and research of related diseases, whereby the main methods are computer simulation, in vitro solid models, and theoretical analysis. This paper summarizes and analyzes past deposition of RSP in the respiratory tract and also describes them in specific case studies such as COPD and COVID-19 patients, based on the review of the evidence, direction, and focus of future research focusing on simulation, experimentation, and related applications of RSP deposition in the respiratory tract.

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12

Loschak, Paul M., Alperen Degirmenci, Cory M. Tschabrunn, Elad Anter, and Robert D. Howe. "Automatically steering cardiac catheters in vivo with respiratory motion compensation." International Journal of Robotics Research 39, no. 5 (2020): 586–97. http://dx.doi.org/10.1177/0278364920903785.

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A robotic system for automatically navigating ultrasound (US) imaging catheters can provide real-time intra-cardiac imaging for diagnosis and treatment while reducing the need for clinicians to perform manual catheter steering. Clinical deployment of such a system requires accurate navigation despite the presence of disturbances including cyclical physiological motions (e.g., respiration). In this work, we report results from in vivo trials of automatic target tracking using our system, which is the first to navigate cardiac catheters with respiratory motion compensation. The effects of respiratory disturbances on the US catheter are modeled and then applied to four-degree-of-freedom steering kinematics with predictive filtering. This enables the system to accurately steer the US catheter and aim the US imager at a target despite respiratory motion disturbance. In vivo animal respiratory motion compensation results demonstrate automatic US catheter steering to image a target ablation catheter with 1.05 mm and 1.33° mean absolute error. Robotic US catheter steering with motion compensation can improve cardiac catheterization techniques while reducing clinician effort and X-ray exposure.

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13

Bolwin, Konstantin, Björn Czekalla, Lynn J. Frohwein, Florian Büther, and Klaus P. Schäfers. "Anthropomorphic thorax phantom for cardio-respiratory motion simulation in tomographic imaging." Physics in Medicine and Biology 63, no. 3 (2018): 035009. http://dx.doi.org/10.1088/1361-6560/aaa201.

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14

Ali, Azuwa, Noor Ashikin Mohd Razali, Mahmoud Albreem, Mohd Hafiz Arshad, and Khairuddin Khalid. "Matlab Simulink Simulation of Respiratory Effort Energy Harvester Using Electromagnetic Generator." Applied Mechanics and Materials 793 (September 2015): 417–21. http://dx.doi.org/10.4028/www.scientific.net/amm.793.417.

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Electromagnetic generator as respiratory effort energy harvester is designed as a renewable energy source to generate a low power and exploiting human motion to extract energy. By selecting respiratory effort as energy harvester it can be carried out 24 hours as long as the electromagnetic generator is wearing on the human chest. It is because the electromagnetic generator functions when there is a motion of the chest wall. The electromagnetic generator basically constructed with two miniature dc motor generator, pulley, belt, gear and chest belt. The generator operates when there is change in chest wall circumstance during exhalation breathing process. The low power that produces can be apply on low power devices such as sensor or microcontroller. Simulation is done using Matlab Simulink to verify that respiratory effort able to produce the minimum required power to power up low power devices. Result from the simulation showing good outcome with 2.5mW of output power.

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15

Kurniawandy, Alex, Muhammad Aminsyah, Belva Ulfah Cahyadi, and Zulfikar Djauhari. "Comparative study of the simulation ground motion by amplitude scale and spectral matching." E3S Web of Conferences 464 (2023): 02007. http://dx.doi.org/10.1051/e3sconf/202346402007.

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Dynamic analysis is more accurate than static analysis in determining a response of structure due to earthquake loads. The limitation of this analysis is the lack of recorded ground motion data of an earthquake for the entire territory of Indonesia. Therefore, according to the Indonesian Code, it is permitted to use seismic data from other locations that have similar seismic characteristics. In application, ground motions need to be modified to match the Indonesia design code. There are two modification methods, which are amplitude scaling and spectral matching. Thus, the purpose of this study is to determine the reliability of these two methods. As the result, the response spectra of the ground motion modified by the spectral matching method present a similar pattern to the target response spectra compared to the amplitude scaling method. Ground motions modified by the spectral matching method generate Peak Ground Acceleration (PGA) values almost the same as the target PGA values. In contrast, the modified motions with amplitude scaling provide diverse PGA values that are not the same as the target PGA. From this study, the utilization of the spectral matching method is recommended in modifying ground motion data for dynamic analysis.

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16

Zeng, Rongping, Jeffrey A. Fessler, and James M. Balter. "Respiratory motion estimation from slowly rotating x-ray projections: Theory and simulation." Medical Physics 32, no. 4 (2005): 984–91. http://dx.doi.org/10.1118/1.1879132.

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17

Bitarafan-Rajabi, Ahmad, Hossein Rajabi, Feridoon Rastgou, and Ali Akbar Sharafi. "Effect of respiratory motion on quantitative myocardial gated SPECT: a simulation study." Annals of Nuclear Medicine 23, no. 6 (2009): 587–93. http://dx.doi.org/10.1007/s12149-009-0277-x.

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18

He, Zhong Hai, Yi Hao Du, and Zhao Xia Wu. "Generation of Respiratory Flow Having Fractal Signal Feature." Advanced Materials Research 366 (October 2011): 211–14. http://dx.doi.org/10.4028/www.scientific.net/amr.366.211.

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In this paper how to generate respiratory flow that has fractal signal feature is introduced. Physiological signal have fractal feature have been verified by many researchers, such as heart beat rate, interbreath interval. Mechanical ventilators are used to provide life support for patients with respiratory failure. But these machines can damage the lung, causing them to collapse. On the other hand, fractal feature can be used as an indication of health situation; as a result in patient simulation the physiological signal should also have fractal features. The fractal feature is generated by fractional Brownian motion simulation. The fractal dimension is decided by Hurst exponent in routine. The algorithm is realized by R language and result is input into LabVIEW which have friendly interface and easy for simulation control usage. The method can be used in design of mechanical ventilator and medical patient simulator.

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19

Kim, Seung-Chul, and Min-A. Kim. "Evaluation 4D-CT Simulation used of Motion Organ and Tumor for Respiratory Gated Radiation Therapy." Journal of the Korea Contents Association 15, no. 9 (2015): 395–402. http://dx.doi.org/10.5392/jkca.2015.15.09.395.

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20

Coolens, Catherine, John Bracken, Brandon Driscoll, Andrew Hope, and David Jaffray. "Dynamic volume vs respiratory correlated 4DCT for motion assessment in radiation therapy simulation." Medical Physics 39, no. 5 (2012): 2669–81. http://dx.doi.org/10.1118/1.4704498.

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21

He, J., G. O'Keefe, G. Jones, et al. "SU-FF-I-106: Simulation of Respiratory Motion Gating Using GATE and NCAT." Medical Physics 34, no. 6Part4 (2007): 2362. http://dx.doi.org/10.1118/1.2760483.

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22

Thorndyke, B., A. Koong, and L. Xing. "Reducing respiratory motion artifacts in radionuclide imaging through retrospective stacking: A simulation study." Linear Algebra and its Applications 428, no. 5-6 (2008): 1325–44. http://dx.doi.org/10.1016/j.laa.2007.06.019.

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23

Galayini, M., M. Hazem, A. Wallis, et al. "OC-109: Implementing a Pre-simulation Assessment Session for abdominal SABR: respiratory motion management." Radiotherapy and Oncology 141 (December 2019): S47. http://dx.doi.org/10.1016/s0167-8140(20)30462-x.

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24

Vidal, Franck P., and Pierre-Frédéric Villard. "Development and validation of real-time simulation of X-ray imaging with respiratory motion." Computerized Medical Imaging and Graphics 49 (April 2016): 1–15. http://dx.doi.org/10.1016/j.compmedimag.2015.12.002.

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25

Tesfamicael, B., and T. Lee. "SU-E-J-119: Development of Voxel-by-Voxel Respiratory Lung Motion Simulation Model." Medical Physics 38, no. 6Part9 (2011): 3470. http://dx.doi.org/10.1118/1.3611887.

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26

Mutaf, Y. D., C. J. Scicutella, D. Michalski, et al. "A simulation study of irregular respiratory motion and its dosimetric impact on lung tumors." Physics in Medicine and Biology 56, no. 3 (2011): 845–59. http://dx.doi.org/10.1088/0031-9155/56/3/019.

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27

Dasari, Paul K. R., Arda Könik, P. Hendrik Pretorius, et al. "Correction of hysteretic respiratory motion in SPECT myocardial perfusion imaging: Simulation and patient studies." Medical Physics 44, no. 2 (2017): 437–50. http://dx.doi.org/10.1002/mp.12072.

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28

Kuo, Chia-Chun, Ho-Chiao Chuang, Chan-Yang Kuo, et al. "Feasibility of Two-Dimensional Radiation Dose Distribution Simulation Through Ultrasound Tracking of Respiratory Motion." Journal of Medical and Biological Engineering 39, no. 4 (2018): 480–89. http://dx.doi.org/10.1007/s40846-018-0420-z.

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29

Alzimami, Khalid, Nouf Abuhadi, Abdulaziz Alanazi, et al. "Optimization of Accurate Quantification in Single-Photon Emission Computed Tomography Myocardial Imaging." Journal of Medical Imaging and Health Informatics 8, no. 9 (2018): 1763–68. http://dx.doi.org/10.1166/jmihi.2018.2517.

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Purpose: The wide availability and reputation for accuracy of the single-photon emission computed tomography (SPECT) of the myocardium has made it a top global choice for nuclear cardiology procedures. The goal of this research is to determine the effectiveness and measurable accuracy of 3D iterative reconstruction algorithms compared to filtered back projection techniques for cardiac SPECT images. Effectiveness is determined by the ability of the various techniques to produce accurate cardiac SPECT images. Materials and Methods: A Siemens Symbia T16 SPECT/CT scanner was used to acquire SPECT/CT images and the Monte Carlo simulations whilst a GATE package was used with the implementation of Infinia™ (GE) dual head SPECT gamma camera–simulated data. The recordings were acquired from point and linear sources and a cardiac insert was created along with a simulation of a computerized phantom XCAT. Result: The results of this study demonstrated an improvement in image quality and the use of a Flash 3D algorithm relative to FBP technique enhances its accuracy. The data presented in this article further show that the image quality of myocardium images and quantification accuracy, particularly for high-resolution studies reconstructed using the Flash 3D algorithm, can be greatly affected by a respiratory-induced motion. Conclusion: Image quality and quantification accuracy can be better improved with respiratory-gating techniques, utilization of ordered-subsets maximization (OSEM) algorithms with attenuation and scatter correction. A simulation of respiratory-induced motion resulted in a reconstructed SPECT recording of 73% reduction in the quantified image resolution for Flash 3D and 43% for FBP. It also caused the underestimation for the left ventricle volume by 18% using FBP and 41% for the Flash 3D. In conclusion, our physical phantom studies and Monte Carlo simulation studies agree with the main hypothesis of our investigation. They showed improvement in image quality with increased accuracy when using the Flash 3D algorithm relative to the FBP technique.

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30

Bilal, Muhammad, Jawad Ali Shah, Ijaz M. Qureshi, and Kushsairy Kadir. "Respiratory Motion Correction for Compressively Sampled Free Breathing Cardiac MRI Using Smooth l1-Norm Approximation." International Journal of Biomedical Imaging 2018 (2018): 1–12. http://dx.doi.org/10.1155/2018/7803067.

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Transformed domain sparsity of Magnetic Resonance Imaging (MRI) has recently been used to reduce the acquisition time in conjunction with compressed sensing (CS) theory. Respiratory motion during MR scan results in strong blurring and ghosting artifacts in recovered MR images. To improve the quality of the recovered images, motion needs to be estimated and corrected. In this article, a two-step approach is proposed for the recovery of cardiac MR images in the presence of free breathing motion. In the first step, compressively sampled MR images are recovered by solving an optimization problem using gradient descent algorithm. The L1-norm based regularizer, used in optimization problem, is approximated by a hyperbolic tangent function. In the second step, a block matching algorithm, known as Adaptive Rood Pattern Search (ARPS), is exploited to estimate and correct respiratory motion among the recovered images. The framework is tested for free breathing simulated and in vivo 2D cardiac cine MRI data. Simulation results show improved structural similarity index (SSIM), peak signal-to-noise ratio (PSNR), and mean square error (MSE) with different acceleration factors for the proposed method. Experimental results also provide a comparison between k-t FOCUSS with MEMC and the proposed method.

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31

Seppenwoolde, Yvette, Ross I. Berbeco, Seiko Nishioka, Hiroki Shirato, and Ben Heijmen. "Accuracy of tumor motion compensation algorithm from a robotic respiratory tracking system: A simulation study." Medical Physics 34, no. 7 (2007): 2774–84. http://dx.doi.org/10.1118/1.2739811.

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32

Yang, Yu-Wen, Jyh-Cheng Chen, Xin He, Shyh-Jen Wang, and Benjamin M. W. Tsui. "Evaluation of Respiratory Motion Effect on Defect Detection in Myocardial Perfusion SPECT: A Simulation Study." IEEE Transactions on Nuclear Science 56, no. 3 (2009): 671–76. http://dx.doi.org/10.1109/tns.2009.2015446.

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33

Katsuta, T., D. Kawahara, Y. Murakami, et al. "Novel Simulation for Dosimetry Impact of Diaphragm Respiratory Motion in 4D VMAT for Esophageal Cancer." International Journal of Radiation Oncology*Biology*Physics 114, no. 3 (2022): e535. http://dx.doi.org/10.1016/j.ijrobp.2022.07.2144.

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34

Medvedev, A. E., and P. S. Golysheva. "Simulation of Air Motion in Human Lungs during Breathing. Dynamics of Liquid Droplet Precipitation in the Case of Medicine Drug Aerosols." Mathematical Biology and Bioinformatics 16, no. 2 (2021): 422–38. http://dx.doi.org/10.17537/2021.16.422.

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The paper deals with numerical simulation of the air flow in the full human bronchial tree. In their previous studies, the authors developed an analytical model of the full human bronchial tree and a method of stage-by-stage computation of the respiratory tract. A possibility of using the proposed method for a wide range of problems of numerical simulations of the air flow in human lungs is analyzed. The following situations are considered: 1) steady inspiration (with different flow rates of air) for circular and “starry” cross sections of bronchi (“starry” cross sections models some lung pathology); 2) steady expiration; 3) unsteady inspiration; 4) precipitation of medical drug aerosol droplets in human bronchi. The results predicted by the proposed method are compared with results of other researchers and found to be in good agreement. In contrast to previous investigations, the air flow in the full (down to alveoli) bronchial tree is studied for the first time. It is shown that expiration requires a greater pressure difference (approximately by 30%) than inspiration. Numerical simulations of precipitation of medical drug aerosol droplets in the human respiratory tract show that aerosol droplets generated by a standard nebulizer do not reach the alveoli (the droplets settle down in the lower regions of the bronchi).

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35

Xu, Pengfei, Jichang Zhang, Zhen Nan, Thomas Meersmann, and Chengbo Wang. "Free-Breathing Phase-Resolved Oxygen-Enhanced Pulmonary MRI Based on 3D Stack-of-Stars UTE Sequence." Sensors 22, no. 9 (2022): 3270. http://dx.doi.org/10.3390/s22093270.

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Compared with hyperpolarized noble gas MRI, oxygen-enhanced lung imaging is a cost-effective approach to investigate lung function. In this study, we investigated the feasibility of free-breathing phase-resolved oxygen-enhanced pulmonary MRI based on a 3D stack-of-stars ultra-short echo time (UTE) sequence. We conducted both computer simulation and in vivo experiments and calculated percent signal enhancement maps of four different respiratory phases on four healthy volunteers from the end of expiration to the end of inspiration. The phantom experiment was implemented to verify simulation results. The respiratory phase was segmented based on the extracted respiratory signal and sliding window reconstruction, providing phase-resolved pulmonary MRI. Demons registration algorithm was applied to compensate for respiratory motion. The mean percent signal enhancement of the average phase increases from anterior to posterior region, matching previous literature. More details of pulmonary tissues were observed on post-oxygen inhalation images through the phase-resolved technique. Phase-resolved UTE pulmonary MRI shows the potential as a valuable method for oxygen-enhanced MRI that enables the investigation of lung ventilation on middle states of the respiratory cycle.

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36

Lahboub, D., A. Bakak, M. Lotfi, R. Heyd, and A. Koumina. "Modeling and simulation of complex flows using Basset digital filters." E3S Web of Conferences 297 (2021): 01018. http://dx.doi.org/10.1051/e3sconf/202129701018.

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Taking into account the Basset force (memory term), in the balance of the forces exerted on a colloidal particle (CP) suspended in a fluid, results in an equation of motion of integrodifferential form. This type of equation allows for example to modeling a colloidal particle settling in an quiescent fluid or in a fluid flowing at low particle’s Reynolds number. It also allows to study the transport of pathogens via aerosols, thus giving access to important information on the airborne propagation of respiratory viruses, such as COVID-19 and its variants for example. Most studies of the PCs motion in a fluid are usually simplified by not taking into account the Basset memory force, as it considerably complicates the numerical solution of the equations of motion of these PCs. This simplification can lead to considerable errors in the evaluation of the trajectory and velocity of the PCs, which can subsequently lead to errors in the calculation of the physical and rheological properties of colloidal suspensions. The present study deals with the numerical solution of Basset’s integro-differential equation, by two significantly different approaches, namely : a piecewise linear approximation (PLA) and the method of Basset numerical filters (BNF). These methods are first exposed and compared on test cases, they are then applied to the study of the sedimentation of spherical PCs with micrometer radii. This study has shown that the usual dynamics of PCs, which does not take into account the Basset memory term, can be very different from the exact dynamics using the Basset force. The BNF approach is finally applied to the study of the motion of PCs driven by flows through complex geometries (pipes, porous media, …).

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37

Sadkovskaya, Nataliya, Igor Kartsan, Aleksandr Zhukov, et al. "Vertical motion robot in the mining industry." E3S Web of Conferences 417 (2023): 05012. http://dx.doi.org/10.1051/e3sconf/202341705012.

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The main directions in the design and programming of vertical motion robots for the mining industry have certain operational risks that underlie the reasons for the lack of consideration of all possible scenarios. The main problem of vertical motion robots is the identification of specific situations. The problem of identification of specific situations occurring during the operation of a vertical motion robot is considered. Some critical situations are proposed for consideration, the forces acting on the robot nodes are illustrated. A model of the robot in MATLAB Simulink environment is created and programmed in order to study the current indicators in the electric motors of the robot. The submodel of the electric motor, based on the data of the technical data sheet of the existing product, which behaves reliably under the conditions of the simulation, is described. The simulation of one of the critical scenarios is considered, and the motor current indicators are analyzed.

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Duncan, Sophie, Felicity Hudson, Michaela Beavan, Mark Lee, Andrew Wallis, and Sankar Arumugam. "Quantification of Motion Reduction using Pre-simulation Assessment Sessions (PASS) for Stereotactic Ablative Body Radiotherapy (SABR)." Journal of Medical and Radiation Oncology 4, no. 7 (2024): 33–44. http://dx.doi.org/10.53011/jmro.2024.01.05.

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Background:Pre-simulation Assessment Sessions (PASS) can be utilised to assess respiratory motion in patients receiving stereotactic ablative body radiotherapy (SABR). PASS is an assessment process that uses cine x-ray images to determine whether expiration breath-hold (EBH) or abdominal compression (AC) can be effectively utilised to manage diaphragm motion, prior to computed tomography (CT) simulation. This study aimed to determine the effectiveness of PASS for eligible patients based on diaphragm motion in free breathing (FB) compared to using MMSs. Material and Methods: Retrospective data on diaphragm motion in FB and elected MMS was collected for 73 patients. Eligible patients were treated between 2018-2022 using SABR for abdominal and lower lobe lung tumours. In the PASS process, the diaphragm motion seen on cine x-ray images was measured through three cycles of FB versus the elected MMS. Differences in FB and MMS diaphragm motion was found for each patient using Wilcoxon Matched Pairs Test. Results: Of the 73 patients, 28 were treated with EBH, 34 with AC, 2 with alternate strategies and 11 were treated using FB as they were not suitable for a MMS. There was a statistically significant difference between the mean of the amplitude of the diaphragm motion when comparing FB and EBH and FB and AC (p= 0.05). There were no associations found between the PASS success rate for any MMS and BMI or age. Conclusion: PASS is a useful tool which can be used to shape the future of radiotherapy by selecting the patient specific MMS for the reduction of tumour motion during SABR treatments. This study will be used to further investigate the dosimetric effects of MMS on internal margin reductions and normal tissue sparing.

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NAKAI, TERUMI, YOSHITO HIRATA, SHUNSUKE HORAI, MICHIO AKAGI, and KAZUYUKI AIHARA. "FIRM EVIDENCE OF CHAOS FOR HEARTBEATS IN DOGS UNDER CONSTANT FLOW VENTILATION." International Journal of Bifurcation and Chaos 20, no. 12 (2010): 4151–58. http://dx.doi.org/10.1142/s0218127410028264.

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We show that heartbeats can be chaotic under the influence of the central nerve systems only. By using constant flow ventilation, the heartbeats of dogs were separated from phasic respiratory motion and measured. By using techniques of nonlinear time series analysis, three pieces of evidence are presented for the existence of chaos.

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Bai, Erwei, Chenglin Wang, Ying Liu, and Ge Wang. "Controlled Cardiac Computed Tomography." International Journal of Biomedical Imaging 2006 (2006): 1–11. http://dx.doi.org/10.1155/ijbi/2006/12819.

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Cardiac computed tomography (CT) has been a hot topic for years because of the clinical importance of cardiac diseases and the rapid evolution of CT systems. In this paper, we propose a novel strategy for controlled cardiac CT that may effectively reduce image artifacts due to cardiac and respiratory motions. Our approach is radically different from existing ones and is based on controlling the X-ray source rotation velocity and powering status in reference to the cardiac motion. We theoretically show that by such a control-based intervention the data acquisition process can be optimized for cardiac CT in the cases of periodic and quasiperiodic cardiac motions. Specifically, we formulate the corresponding coordination/control schemes for either exact or approximate matches between the ideal and actual source positions, and report representative simulation results that support our analytic findings.

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41

Ichiji, Kei, Noriyasu Homma, Masao Sakai, et al. "A Time-Varying Seasonal Autoregressive Model-Based Prediction of Respiratory Motion for Tumor following Radiotherapy." Computational and Mathematical Methods in Medicine 2013 (2013): 1–9. http://dx.doi.org/10.1155/2013/390325.

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To achieve a better therapeutic effect and suppress side effects for lung cancer treatments, latency involved in current radiotherapy devices is aimed to be compensated for improving accuracy of continuous (not gating) irradiation to a respiratory moving tumor. A novel prediction method of lung tumor motion is developed for compensating the latency. An essential core of the method is to extract information valuable for the prediction, that is, the periodic nature inherent in respiratory motion. A seasonal autoregressive model useful to represent periodic motion has been extended to take into account the fluctuation of periodic nature in respiratory motion. The extended model estimates the fluctuation by using a correlation-based analysis for adaptation. The prediction performance of the proposed method was evaluated by using data sets of actual tumor motion and compared with those of the state-of-the-art methods. The proposed method demonstrated a high performance within submillimeter accuracy. That is, the average error of 1.0 s ahead predictions was0.931±0.055 mm. The accuracy achieved by the proposed method was the best among those by the others. The results suggest that the method can compensate the latency with sufficient accuracy for clinical use and contribute to improve the irradiation accuracy to the moving tumor.

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Belka, Miloslav, Frantisek Lizal, Jakub Elcner, Ondrej Misik, and Miroslav Jicha. "Numerical study of fiber deposition in airway replica using CFD-DEM simulation." EPJ Web of Conferences 299 (2024): 01002. http://dx.doi.org/10.1051/epjconf/202429901002.

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Inhalation of fibers has been a health concern for several decades. Although the use of some fibers, such as asbestos, was banned altogether in many countries, global demand for other fibers, such as man-made vitreous or carbon fibers, increases every year. The health hazard of fibers is given by their ability to penetrate deep into human lungs and avoid defensive mechanisms. This is mainly given by their anisometric shape and complex behavior in fluid flow, e.g. drag force acting on a fiber depends significantly on fiber orientation. The objective of the present work was to numerically investigate fiber transport and deposition in the model of child respiratory airways including the upper respiratory tract and tracheobronchial tree down to 2nd generation of branching. Computational fluid dynamics–discrete element method was employed to model a fiber motion during which the drag force was calculated based on actual fiber orientation in a flow. This method was compared to a simpler approach in which a modified drag coefficient accounting for fiber non-spherical shape was used. The results of the employed methods were compared.

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Covington, Elizabeth L., and Richard A. Popple. "Technical and Quality Considerations for Stereotactic Radiation Treatment Techniques." Cancer Journal 30, no. 6 (2024): 372–76. http://dx.doi.org/10.1097/ppo.0000000000000756.

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Abstract Stereotactic radiosurgery (SRS) and stereotactic body radiation therapy (SBRT), collectively termed SRS-SBRT, are advanced treatment modalities delivering high doses of radiation in a single treatment or condensed treatment phase. Due to the small margins and steep dose gradient used in SRS-SBRT, the technical and safety considerations are more stringent than traditional radiation therapy and may include more advanced simulation, patient immobilization, treatment planning, and treatment delivery techniques. Respiratory motion management and intrafraction motion monitoring are often used during SRS-SBRT to ensure treatments are robust to both internal organ motion and patient movement during treatment. To ensure optimal treatment quality, SRS-SBRT programs should use multidisciplinary coordination of care to ensure patient-specific treatment strategies are used for optimal patient outcomes. Quality and safety considerations are presented, including peer review and external validation, for optimizing quality and adhering to national guidelines for stereotactic techniques.

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Buliev, I. G., C. T. Badea, Z. Kolitsi, and N. Pallikarakis. "Estimation of the heart respiratory motion with applications for cone beam computed tomography imaging: a simulation study." IEEE Transactions on Information Technology in Biomedicine 7, no. 4 (2003): 404–11. http://dx.doi.org/10.1109/titb.2003.821336.

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Fan, Shaocan, and Zhenmiao Deng. "Chest Wall Motion Model of Cardiac Activity for Radar-Based Vital-Sign-Detection System." Sensors 24, no. 7 (2024): 2058. http://dx.doi.org/10.3390/s24072058.

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An increasing number of studies on non-contact vital sign detection using radar are now beginning to turn to data-driven neural network approaches rather than traditional signal-processing methods. However, there are few radar datasets available for deep learning due to the difficulty of acquiring and labeling the data, which require specialized equipment and physician collaboration. This paper presents a new model of heartbeat-induced chest wall motion (CWM) with the goal of generating a large amount of simulation data to support deep learning methods. An in-depth analysis of published CWM data collected by the VICON Infrared (IR) motion capture system and continuous wave (CW) radar system during respiratory hold was used to summarize the motion characteristics of each stage within a cardiac cycle. In combination with the physiological properties of the heartbeat, appropriate mathematical functions were selected to describe these movement properties. The model produced simulation data that closely matched the measured data as evaluated by dynamic time warping (DTW) and the root-mean-squared error (RMSE). By adjusting the model parameters, the heartbeat signals of different individuals were simulated. This will accelerate the application of data-driven deep learning methods in radar-based non-contact vital sign detection research and further advance the field.

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46

Alisin, V. V. "Simulation of transient friction modes of fluoroplastic seals in hydraulic piston pumps." E3S Web of Conferences 460 (2023): 10005. http://dx.doi.org/10.1051/e3sconf/202346010005.

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The article considers the issues associated with the friction of radiation-hardened fluoroplastic on steel in a hydraulic fluid environment during the transition period at the beginning of movement. The friction coefficients are studied when starting from a standstill, at the beginning and in steady motion. Changes in the value of the friction coefficient and changes in the amplitude of oscillation of the friction moment are analyzed. Particular attention is paid to the influence of the restart of motion in a friction coupling. Quantitative relationships of tribological properties are established depending on the time of relative sliding of the samples. It is noted that the friction coefficients in different modes are differ a lot, however, the running-in process proceeds quickly and in the practice of operating hydraulic devices, the running-in process of fluoroplastic seals can be ignored

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Jiang, Chunmeng, Jinhua Lv, Xiang Wu, Shuangquan Chen, and Hongrui Zhang. "Fault diagnosis of AUV based on sliding-mode observer." E3S Web of Conferences 360 (2022): 01094. http://dx.doi.org/10.1051/e3sconf/202236001094.

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Designing of a sliding mode observer was finished based on the motion model of autonomous underwater vehicle (AUV). A Flutter decrease strategy for the sliding mode observer was discussed and the sliding mode observer was applied to the fault diagnosis of the AUV. Simulation experiment without faults was designed. Simulation experiment of sensor fault diagnosis and field trial of thruster fault diagnosis were undertaken. The validity and feasibility of this method were validated based on the analysis of the simulation and field trial results.

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Sedelnikov, Andrei, Denis Orlov, Valeria Serdakova, Alexandra Nikolaeva, Maria Bratkova, and Vera Ershova. "The importance of a three-dimensional formulation of the thermal conductivity problem in assessing the effect of a temperature shock on the rotational motion of a small spacecraft." E3S Web of Conferences 371 (2023): 03015. http://dx.doi.org/10.1051/e3sconf/202337103015.

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The paper analyzes the conditions under which a two-dimensional formulation of the thermal conductivity problem for a correct assessment of the large elastic elements temperature shock effect on the rotational motion of a small spacecraft is insufficient. Numerical simulation was carried out for a scheme of a small “Aist-2D” spacecraft. The results of this work can be used in modeling the rotational motion of a small spacecraft taking into account the temperature shock of large elastic elements.

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Savanovic, Milovan, Bojan Strbac, Drazan Jaros, and Jean-Noel Foulquier. "The assessment of consecutive 4D-CT scans during simulation for lung stereotactic body radiation therapy patients." Polish Journal of Medical Physics and Engineering 26, no. 4 (2020): 193–99. http://dx.doi.org/10.2478/pjmpe-2020-0023.

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Abstract Purpose: To evaluate the breathing amplitude, tumor motion, patient positioning, and treatment volumes among consecutive four-dimensional computed tomography (4D-CT) scans, during the simulation for lung stereotactic body radiation therapy (SBRT). Material and methods: The variation and shape of the breathing amplitude, patient positioning, and treatment volumes were evaluated for 55 lung cancer patients after consecutive 4D-CT acquisitions, scanned at one-week intervals. The impact of variation in the breathing amplitude on lung tumor motion was determined for 20 patients. The gross tumor volume (GTV) was contoured from a free-breathing CT scan and at ten phases of the respiratory cycle, for both 4D-CTs (440 phases in total). Results: Breathing amplitude decreased by 3.6 (3.4-4.9) mm, tumor motion by 3.2 (0.4-5.0) mm while breathing period increased by 4 (2-6) s, inter-scan for 20 patients. Intra-scan variation was 4 times greater for the breathing amplitude, 5 times for the breathing period, and 8 times for the breathing cycle, comparing irregular versus regular breathing patterns for 55 patients. Using coaching, the breathing amplitude increases 3 to 8 mm, and the breathing period 2 to 6 s. Differences in the contoured treatment volumes were less than 10% between consecutive scans. Patient positioning remained stable, with a small inter-scan difference of 1.1 (0.6-1.4) mm. Conclusion: Decreasing the inter-scan breathing amplitude decreases the tumor motion reciprocally. When the breathing amplitude decreases, the breathing period increases at inter- and intra-scan, especially during irregular breathing. Coaching improves respiration, keeping the initial shape of the breathing amplitude. Contoured treatment volumes and patient positioning were reproducible through successive scans.

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Nuval, Anthony, Thanh D. Nguyen, Richard Watts, and Yi Wang. "An improved real-time navigator gating algorithm for reducing motion effects in coronary magnetic resonance angiography." Journal of X-Ray Science and Technology: Clinical Applications of Diagnosis and Therapeutics 11, no. 3 (2003): 115–23. http://dx.doi.org/10.3233/xst-2003-00083.

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The phase ordering with automatic window selection (PAWS) algorithm for respiratory gating in magnetic resonance imaging is improved by further smoothing motion distribution in k-space. This is achieved by requiring that the displacement discontinuities in k-space and the range of displacement during the acquisition of the center 30% region of k-space are limited to a fraction (1/3 in this study) of the gating window. Simulation results and in vivo imaging experiments suggest that these modifications reduce the amount of artifacts at a reasonable cost of additional scan time as compared to the original PAWS algorithm.

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