Study on Motion Management of Lung Cancer Treated by CyberKnife: Based on Tumor Position

Purpose: We investigated the movement characteristics of lung cancers and the clinical accuracy of tracking lung tumors with Synchrony Respiratory Tracking System (SRTs) during the CyberKnife treatment. We also explored the influencing factors of accuracy. These data provided the appropriate expansion margins of patients with different respiratory characteristics, which was helpful to realize the personalized design of treatment plans of CyberKnife. Methods and Materials: 73 patients with lung cancer treated with CyberKnife SRTs were selected retrospectively for this study. The patient's age, gender, respiratory characteristics and tumor datas (tumor size, anatomical position and geometric position) were recorded. During treatment, the deviation was checked every 45 s and compensated by the synchronous respiratory tracking system.Results: The total mean motion amplitudes and standard deviations of lung tumors in superior-inferior (SI), left-right (LR), and anterior-posterior (AP) directions were 4.15 ± 3.47 mm, 3.98 ± 3.21 mm and 3.79 ± 2.73 mm, respectively. The overall mean correlation errors and standard deviations were 0.86 ± 0.45 mm, 1.04 ± 0.76 mm and 0.70 ± 0.47 mm, respectively. The overall mean prediction errors and standard deviations were 0.18 ± 0.17 mm, 0.35 ± 0.39 mm and 0.35 ± 0.42 mm, respectively. The correlation errors of LR direction were less correlated with the geometric position of the tumor (r = 0.38), and not correlated with the anatomical position of the tumor (r < 0.3). The prediction errors were moderately correlated with the respiratory amplitude (r = 0.588), and less correlated with the baseline drift and the motion amplitude of the tumor (r = 0.407 and 0.365, respectively).Conclusions: The patient’s respiratory amplitude, the tumor motion amplitude, the tumor baseline drift and geometric position were the main factors affecting the tracking accuracy. Tumors at different geometric positions should be treated differently to ensure sufficient dose coverage of the lung tumor target.

Change of psychophysiological indices in female students of creative occupations

Purpose: studying the dynamics of psychophysiological indices of creative occupation female students. Маterial: the study involved 120 female students. Reactive qualities, level of static and dynamic equilibrium, orientational qualities, speed of operative thinking, volume of rote memorization, attention distribution, level of accuracy, attention speed and switching, accuracy of task performance were assessed. Results: a decrease in the indices of the accuracy of reproducing motion amplitude and a given value of effort, those of response to vertically falling object and those of static and dynamic equilibrium was revealed. An improvement in the dynamics of nervous processes and the ability to constructive praxis was noted. The decrease in the level of development of motor qualities, professional skills, physical fitness, and health is observed already in the 1st year of study. The authors believe that the pedagogical influences should be started from the 1st course and continued until the end of the study. In the process of physical education classes, the physical exercises aimed at improving the professionally significant psychophysiological properties of students should be used. It is they that restrain the negative effect of increasing the intensity of educational classes simultaneously contributing to an increase in the development level of almost all motor qualities and health. Conclusions: uneven decrease of most psychophysiological indices negatively affects both the level of female student motor preparation and professional abilities of the future designers. The findings give ground for the development of the methods for improving motor qualities and psychophysiological properties professionally significant for students-designers. Taking into account the future profession specifics and the health indices will allow more precise planning of the content of physical education classes.

Stimulation efficiency of an actuator driven piston at the biological interface to the inner ear

Direct acoustic cochlear stimulation uses piston motion to substitute for stapes footplate (SFP) motion. The ratio of piston to stapes footplate motion amplitude, to generate the same loudness percept, is an indicator of stimulation efficiency. We determined the relationship between piston displacement to perceived loudness, the achieved maximum power output and investigated stapes fixation and obliteration as confounding factors. The electro-mechanical transfer function of the actuator was determined preoperatively on the bench and intraoperatively by laser Doppler vibrometry. Clinically, perceived loudness as a function of actuator input voltage was calculated from bone conduction thresholds and direct thresholds via the implant. The displacement of a 0.4 mm diameter piston required for a perception equivalent to 94 dB SPL at the tympanic membrane compared to normal SFP piston displacement was 27.6–35.9 dB larger, consistent with the hypothesis that the ratio between areas is responsible for stimulation efficiency. Actuator output was 110 ± 10 eq dB SPLFF @1Vrms ≤ 3 kHz and decreased to 100 eq dB SPLFF at 10 kHz. Output was significantly higher for mobile SFPs but independent from obliteration. Our findings from clinical data strongly support the assumption of a geometrical dependency on piston diameter at the biological interface to the cochlea.

Dosimetric study of the interplay effect using three-dimensional motion phantom in proton pencil beam scanning treatment of moving thoracic tumours

Aim: The dosimetric and clinical advantages offered by implementation of pencil beam scanning (PBS) proton therapy for moving thoracic tumours is hindered by interplay effect. The purpose of this study is to evaluate the impact of large proton beam spot size along with adaptive aperture (AA) and various motion mitigation techniques on the interplay effect for a range of motion amplitudes in a three-dimensional (3D) respiratory motion phantom. Materials and Methods: Point doses using ionisation chamber (IC) and planner dose distributions with radiochromic film were compared against the corresponding treatment planning system (TPS) information. A 3D respiratory motion phantom was scanned either for static or 4D computed tomographic (CT) technique for 6-, 10- and 14-mm motion amplitudes in SI direction. For free breathing (FB) treatment, a tumour was contoured on maximum intensity projection scan and an average scan was used for treatment planning. Each FB treatment was delivered with one, three and five volumetric repaintings (VRs). Three phases (CT40–60%) were extracted from the 4D-CT scans of each motion amplitude for the respiratory-gated treatment and were used for the treatment planning and delivery. All treatment plans were made using AA and robustly optimised with 5-mm set-up and 3·5% density uncertainty. A total of 26 treatment plans were delivered to IC and film using static, dynamic and respiratory-gated treatments combinations. A percent dose difference between IC and TPS for the point dose and gamma indices for film–TPS planner dose comparison was used. Results: The dose profile of film and TPS for the static phantom matched well, and percent dose difference between IC and TPS was 0·4%. The percent dose difference for all the gated treatments were below 3·0% except 14-mm motion amplitude-gated treatment. The gamma passing rate was more than 95% for film–TPS comparison for all gated treatment for the investigated gamma acceptance criteria. For FB treatments, the percent dose difference for 6-, 10- and 14-mm motion amplitude was 1·4%, −2·7% and −4·1%, respectively. As the number of VR increased, the percent difference between measured and calculated values decreased. The gamma passing rate met the required tolerance for different acceptance criteria except for the 14-mm motion amplitude FB treatment. Conclusion: The PBS technique for the FB thoracic treatments up to 10-mm motion amplitude can be implemented with an acceptable accuracy using large proton beam spot size, AA and robust optimisation. The impact of the interplay effect can be reduced with VR and respiratory-gated treatment and extend the treatable tumour motion amplitude.

Risks and Benefits of Fiducial Marker Placement in Tumor Lesions for Robotic Radiosurgery: Technical Outcomes of 357 Implantations

Fiducial markers (FM) inserted into tumors increase the precision of irradiation during robotic radiosurgery (RRS). This retrospective study evaluated the clinical complications, marker migration, and motion amplitude of FM implantations by analyzing 288 cancer patients (58% men; 63.1 ± 13.0 years) who underwent 357 FM implantations prior to RRS with CyberKnife, between 2011 and 2019. Complications were classified according to the Society of Interventional Radiology (SIR) guidelines. The radial motion amplitude was calculated for tumors that moved with respiration. A total of 725 gold FM was inserted. SIR-rated complications occurred in 17.9% of all procedures. Most complications (32.0%, 62/194 implantations) were observed in Synchrony®-tracked lesions affected by respiratory motion, particularly in pulmonary lesions (46.9% 52/111 implantations). Concurrent biopsy sampling was associated with a higher complication rate (p = 0.001). FM migration occurred in 3.6% after CT-guided and clinical FM implantations. The largest motion amplitudes were observed in hepatic (20.5 ± 11.0 mm) and lower lung lobe (15.4 ± 10.5 mm) lesions. This study increases the awareness of the risks of FM placement, especially in thoracic lesions affected by respiratory motion. Considering the maximum motion amplitude, FM placement remains essential in hepatic and lower lung lobe lesions located >100.0 mm from the spine.

A hybrid forecasting model for ageing breast deformation during yoga practice

In this work, the deformation of bilateral breasts was investigated with an established hybrid model to predict the nipple movement specifically for senior women during yoga exercise. A motion capture system was used to collect the displacement of 10 markers on the breasts from 11 senior women (average age of 62) during yoga practice and then the data were analyzed by integrating the absolute grey relation analysis (AGRA) and extreme learning machine (ELM). The right and left breasts had the maximum motion amplitude in the horizontal direction but they were respectively featured with contraction and extension during yoga practice. AGRA showed that the nipple motion was highly associated with the vertical region above the nipple for the left breast but the parallel region along with the nipple for the right breast. The ELM model is able to predict the nipple movement within tolerable error (∼0.0037). This study lays a foundation for a better understanding of ageing breast kinematics during yoga poses with limited practical experiments. Besides, the accurate and efficient results can be used not only for yoga pose instruction but also for ergonomic sports bra design.

SIMULATION OF THE RELATIONSHIP BETWEEN JOINT MOTION AMPLITUDE AND MOTION DAMAGE BASED ON ALGORITHM

ABSTRACT Introduction: With the continuous development of society and the continuous improvement of the economic level, the willingness of Chinese people to participate in sports is also showing an upward trend. However, how to reduce sports damage as much as possible during exercise should be a hot issue of particular concern to athletes in the sports world. Objective: It aimed to discuss the simulation of the relationship between joint motion amplitude (JMA) and motion damage (MD) via a rough set decision-making algorithm to avoid MD. Based on the rough set decision algorithm, JMA and MD models were constructed, and a motion data decision table was established. Methods: Joint change parameters and constraint conditions were set, and joint change parameters were analyzed. Moreover, the changing parameters, feature strength, and algorithm partition accuracy of the simulation model were analyzed. Results: The feature strength and the division accuracy of the rough set decision algorithm all showed good accuracy. The model constructed by such a method can well describe the relationship between JMA and MD. Conclusion: The proposed rough set decision algorithm can describe the relationship between JMA and MD scientifically and effectively, which provided reference value for sports. Level of evidence II; Therapeutic studies - investigation of treatment results.

3D Visual Motion Amplitude Tracking Simulation Method for Sports

Background: The character motion of 3D animation production is complex, and to solve this problem, motion-pose capture technology is very effective. The workload of character motion control is reduced by this technique, and the animation development is improved. It is used in virtual training grounds and real-time tracking of the motion. The complete contour features cannot be efficiently acquired by the 3D visual motion technique. The 3D visual motion amplitude tracking method in sports is studied in order to improve the training quality of athletes effectively. However, when the current method is used for motion amplitude tracking, the markers in the adjacent monocular sequence motion amplitude images cannot be calculated. Methodology: At this point, there is a problem of a large tracking error of 3D visual motion amplitude. To this end, a 3D amplitude tracking method in sports based on inverse kinematics is proposed. This method locates the marker points that appear in the adjacent monocular sequence motion range and merges it with the rotation angle method to predict the position of the motion range in the image. Results: Obtain the motion amplitude, and 3D visual motion amplitude is outside the optimization area and uses this as a basis to complete the tracking of the 3D visual motion amplitude in sports. Conclusion: Experimental simulation performed in MATLAB proves the high tracking accuracy of the proposed method.

Centrifuge Studies of Topographic Effects: Parametric Investigation

ABSTRACT This article presents the results of a comprehensive geotechnical centrifuge experimental program to investigate topographic effects across a series of single-sided slopes. The experimental campaign considered a range of governing factors, including slope inclination and ground-motion amplitude, frequency content, and duration. The testing program was nondestructive, allowing the centrifuge models to be subjected to over 140 different ground motions. Clear evidence of topographic effects, including amplification and deamplification of ground motion, were observed. Topography modified the frequency content and amplitude of the ground motion such that at the slope crest (1) peak ground accelerations ranged from 50% less than to 200% greater than the free-field, and (2) ground-motion mean square frequency shifted by as much as 55%. Higher topographic amplification levels lead to a larger topographic zone of influence, which, on average, spanned a distance equal to the slope height (H) behind and 2H in front of (toward slope) the slope crest. Physical modeling in the centrifuge proved to be a powerful experimental technique for generating empirical data to analyze topographic effects in a systematic and repeatable manner.