keyword
MENU ▼
Read by QxMD icon Read
search

Head rotations in roll

keyword
https://www.readbyqxmd.com/read/28048280/su-f-t-639-use-of-a-6d-couch-for-real-time-motion-correction-during-frameless-stereotactic-radiosurgery
#1
X Liu, A H Belcher, R Wiersma
PURPOSE: High precision patient positioning is critical in stereotactic radiosurgery (SRS). A 6 Degree-of-freedom (6D) robotic serial couch has the potential to correct both translational and rotational target motion deviations during image-guided radiosurgery procedures. An inverse kinematics algorithm based on the structure of the couch is presented, and a feedback control algorithm is discussed. The feasibility of motion compensation with a 6D couch is demonstrated by simulation with prerecorded volunteer head motion data...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28047649/su-g-jep1-04-characterization-of-a-high-definition-optical-patient-surface-tracking-system-across-five-installations
#2
T Smith, A Ayan, E Cochran, J Woollard, N Gupta
PURPOSE: To assess the performance of Varian's real-time, Optical Surface Monitoring System (OSMS) by measuring relative regular and irregular surface detection accuracy in 6 degrees of motion (6DoM), across multiple installations. METHODS: Varian's Intracranial SRS Package includes OSMS, which utilizes 3 HD camera/projector pods to map a patient surface, track intra-fraction motion, and gate the treatment beam if motion exceeds a threshold. To evaluate motion-detection accuracy of OSMS, we recorded shifts of a cube-shaped phantom on a single Varian TrueBeam linear accelerator as known displacements were performed incrementally across 6DoM...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28047634/su-f-t-640-feasibility-of-using-a-commercially-available-surface-guided-radiotherapy-system-with-an-open-face-srs-immobilization-system
#3
B Chinsky, R Patel, J Roeske, M Surucu
PURPOSE: To evaluate the inherent accuracy of using a surface guided radiotherapy system (SGRT) in the setup and monitoring of patients receiving stereotactic radiosurgery with an open-face SRS immobilization system. METHODS: An anthropomorphic head phantom was set up using the Qfix Encompass SRS Immobilization System on a Varian Edge with OSMS and Varian TrueBeam with AlignRT. The phantom was positioned at 0° gantry and couch. A reference image was acquired using the SGRT system and an ROI was created over the mask opening...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28047444/mo-fg-campus-jep3-02-a-novel-setup-approach-to-improve-c-spine-curvature-reproducibility-for-head-and-neck-radiotherapy-using-optical-surface-imaging-with-two-regions-of-interest
#4
K Ryan, M Gil, C Della Biancia, G Li
PURPOSE: To develop a novel approach to improve cervical spine (c-spine) curvature reproducibility for head and neck (HN) patients using optical surface imaging (OSI) with two regions of interests (ROIs). METHODS: The OSI-guided, two-step setup procedure requires two ROIs: ROI-1 of the shoulders and ROI-2 of the face. The neck can be stretched or squeezed in superior-inferior (SI) direction using a specially-designed sliding head support. We hypothesize that when these two ROIs are aligned, the c-spine should fall into a naturally reproducible position under same setup conditions...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28047362/su-f-j-24-setup-uncertainty-and-margin-of-the-exactrac-6d-image-guide-system-for-patients-with-brain-tumors
#5
S Kim, S Oh, J Yea, J Park
PURPOSE: This study evaluated the setup uncertainties for brain sites when using BrainLAB's ExacTrac X-ray 6D system for daily pretreatment to determine the optimal planning target volume (PTV) margin. METHODS: Between August 2012 and April 2015, 28 patients with brain tumors were treated by daily image-guided radiotherapy using the BrainLAB ExacTrac 6D image guidance system of the Novalis-Tx linear accelerator. DUONTM (Orfit Industries, Wijnegem, Belgium) masks were used to fix the head...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28047337/su-f-j-42-comparison-of-varian-truebeam-cone-beam-ct-and-brainlab-exactrac-x-ray-for-cranial-radiotherapy
#6
J Li, W Shi, D Andrews, M Werner-Wasik, B Lu, Y Yu, A Dicker, H Liu
PURPOSE: To compare online image registrations of TrueBeam cone-beam CT (CBCT) and BrainLab ExacTrac x-ray imaging systems for cranial radiotherapy. METHOD: Phantom and patient studies were performed on a Varian TrueBeam STx linear accelerator (Version 2.5), which is integrated with a BrainLab ExacTrac imaging system (Version 6.1.1). The phantom study was based on a Rando head phantom, which was designed to evaluate isocenter-location dependence of the image registrations...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/27911755/transformation-of-vestibular-signals-for-the-control-of-standing-in-humans
#7
Patrick A Forbes, Billy L Luu, H F Machiel Van der Loos, Elizabeth A Croft, J Timothy Inglis, Jean-Sébastien Blouin
: During standing balance, vestibular signals encode head movement and are transformed into coordinates that are relevant to maintaining upright posture of the whole body. This transformation must account for head-on-body orientation as well as the muscle actions generating the postural response. Here, we investigate whether this transformation is dependent upon a muscle's ability to stabilize the body along the direction of a vestibular disturbance. Subjects were braced on top of a robotic balance system that simulated the mechanics of standing while being exposed to an electrical vestibular stimulus that evoked a craniocentric vestibular error of head roll...
November 9, 2016: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
https://www.readbyqxmd.com/read/27814310/asymmetries-and-three-dimensional-features-of-vestibular-cross-coupled-stimuli-illuminated-through-modeling
#8
Jan E Holly, M Arjumand Masood, Chiran S Bhandari
Head movements during sustained rotation can cause angular cross-coupling which leads to tumbling illusions. Even though angular vectors predict equal magnitude illusions for head movements in opposite directions, the magnitudes of the illusions are often surprisingly asymmetric, such as during leftward versus rightward yaw while horizontal in a centrifuge. This paper presents a comprehensive investigation of the angular-linear stimulus combinations from eight different published papers in which asymmetries were found...
November 3, 2016: Journal of Vestibular Research: Equilibrium & Orientation
https://www.readbyqxmd.com/read/27741377/comparison-of-set-up-accuracy-among-three-common-immobilisation-systems-for-intensity-modulated-radiotherapy-of-nasopharyngeal-carcinoma-patients
#9
Cheng-Guang Lin, Sen-Kui Xu, Wen-Yan Yao, Yu-Qi Wu, Jian-Lan Fang, Vincent W C Wu
INTRODUCTION: In intensity modulated radiotherapy (IMRT) of nasopharyngeal carcinoma (NPC) patients, an effective immobilisation system is important to minimise set up deviation. This study evaluated the effectiveness of three immobilisation systems by assessing their set up deviations. METHODS: Patients were randomly assigned to one of the three immobilisation systems: (1) supine on head rest and base plate (HB); (2) supine with alpha cradle supporting the head and shoulder (AC); (3) supine with vacuum bag supporting the head and shoulder (VB)...
September 1, 2016: Journal of Medical Radiation Sciences
https://www.readbyqxmd.com/read/27586110/quantitative-evaluation-of-the-occupant-kinematic-response-of-the-thums-50th-percentile-male-model-relative-to-pmhs-laboratory-rollover-tests
#10
David Poulard, Qi Zhang, Jack Ryan Cochran, Bronislaw Gepner, Jason Kerrigan
OBJECTIVE: The objective of the current study was to evaluate the whole-body kinematic response of the Total Human Model for Safety (THUMS) occupant model in controlled laboratory rollover tests by comparing the model response to postmortem human surrogate (PMHS) kinematic response targets published in 2014. METHODS: A computational model of the parametric vehicle buck environment was developed and the AM50 THUMS occupant model (Ver 4.01) was subjected to a pure dynamic roll at 360°/s in trailing-side front-row seating position...
September 2016: Traffic Injury Prevention
https://www.readbyqxmd.com/read/27477714/an-evaluation-of-3d-head-pose-estimation-using-the-microsoft-kinect-v2
#11
John Darby, María B Sánchez, Penelope B Butler, Ian D Loram
The Kinect v2 sensor supports real-time non-invasive 3D head pose estimation. Because the sensor is small, widely available and relatively cheap it has great potential as a tool for groups interested in measuring head posture. In this paper we compare the Kinect's head pose estimates with a marker-based record of ground truth in order to establish its accuracy. During movement of the head and neck alone (with static torso), we find average errors in absolute yaw, pitch and roll angles of 2.0±1.2°, 7.3±3...
July 2016: Gait & Posture
https://www.readbyqxmd.com/read/27339731/head-movement-during-walking-in-the-cat
#12
Humza N Zubair, Irina N Beloozerova, Hai Sun, Vladimir Marlinski
Knowledge of how the head moves during locomotion is essential for understanding how locomotion is controlled by sensory systems of the head. We have analyzed head movements of the cat walking along a straight flat pathway in the darkness and light. We found that cats' head left-right translations, and roll and yaw rotations oscillated once per stride, while fore-aft and vertical translations, and pitch rotations oscillated twice. The head reached its highest vertical positions during second half of each forelimb swing, following maxima of the shoulder/trunk by 20-90°...
September 22, 2016: Neuroscience
https://www.readbyqxmd.com/read/27167275/improved-setup-and-positioning-accuracy-using-a-three-point-customized-cushion-mask-bite-block-immobilization-system-for-stereotactic-reirradiation-of-head-and-neck-cancer
#13
He Wang, Congjun Wang, Samuel Tung, Andrew Wilson Dimmitt, Pei Fong Wong, Mark A Edson, Adam S Garden, David I Rosenthal, Clifton D Fuller, Gary B Gunn, Vinita Takiar, Xin A Wang, Dershan Luo, James N Yang, Jennifer Wong, Jack Phan
The purpose of this study was to investigate the setup and positioning uncertainty of a custom cushion/mask/bite-block (CMB) immobilization system and determine PTV margin for image-guided head and neck stereotactic ablative radiotherapy (HN-SABR). We analyzed 105 treatment sessions among 21 patients treated with HN-SABR for recurrent head and neck cancers using a custom CMB immobilization system. Initial patient setup was performed using the ExacTrac infrared (IR) tracking system and initial setup errors were based on comparison of ExacTrac IR tracking system to corrected online ExacTrac X-rays images registered to treatment plans...
May 8, 2016: Journal of Applied Clinical Medical Physics
https://www.readbyqxmd.com/read/27167267/quantitative-evaluation-of-patient-setup-uncertainty-of-stereotactic-radiotherapy-with-the-frameless-6d-exactrac-system-using-statistical-modeling
#14
Vance Keeling, Sabbir Hossain, Hosang Jin, Ozer Algan, Salahuddin Ahmad, Imad Ali
The purpose of this study is to evaluate patient setup accuracy and quantify indi-vidual and cumulative positioning uncertainties associated with different hardware and software components of the stereotactic radiotherapy (SRS/SRT) with the frameless 6D ExacTrac system. A statistical model is used to evaluate positioning uncertainties of the different components of SRS/SRT treatment with the Brainlab 6D ExacTrac system using the positioning shifts of 35 patients having cranial lesions. All these patients are immobilized with rigid head-and-neck masks, simu-lated with Brainlab localizer and planned with iPlan treatment planning system...
May 8, 2016: Journal of Applied Clinical Medical Physics
https://www.readbyqxmd.com/read/27019082/analysis-of-the-setup-uncertainty-and-margin-of-the-daily-exactrac-6d-image-guide-system-for-patients-with-brain-tumors
#15
Se An Oh, Ji Woon Yea, Min Kyu Kang, Jae Won Park, Sung Kyu Kim
This study evaluated the setup uncertainties for brain sites when using BrainLAB's ExacTrac X-ray 6D system for daily pretreatment to determine the optimal planning target volume (PTV) margin. Between August 2012 and April 2015, 28 patients with brain tumors were treated by daily image-guided radiotherapy using the BrainLAB ExacTrac 6D image guidance system of the Novalis-Tx linear accelerator. DUONTM (Orfit Industries, Wijnegem, Belgium) masks were used to fix the head. The radiotherapy was fractionated into 27-33 treatments...
2016: PloS One
https://www.readbyqxmd.com/read/26956976/abnormal-tilt-perception-during-centrifugation-in-patients-with-vestibular-migraine
#16
Joanne Wang, Richard F Lewis
Vestibular migraine (VM), defined as vestibular symptoms caused by migraine mechanisms, is very common but poorly understood. Because dizziness is often provoked in VM patients when the semicircular canals and otolith organs are stimulated concurrently (e.g., tilting the head relative to gravity), we measured tilt perception and eye movements in patients with VM and in migraine and normal control subjects during fixed-radius centrifugation, a paradigm that simultaneously modulates afferent signals from the semicircular canals and otoliths organs...
June 2016: Journal of the Association for Research in Otolaryngology: JARO
https://www.readbyqxmd.com/read/26925031/the-effect-of-age-on-improvements-in-vestibulo-ocular-reflexes-and-balance-control-after-acute-unilateral-peripheral-vestibular-loss
#17
Alja Scheltinga, Flurin Honegger, Dionne P H Timmermans, John H J Allum
BACKGROUND: An acute unilateral peripheral vestibular loss (aUVL) initially causes severe gaze and balance control problems. However, vestibulo-ocular reflexes (VOR) and balance control are nearly normal 3 months later as a result of peripheral recovery and/or central compensation. As pre-existing vestibular sensory loss is assumed to be greater in the healthy elderly, this study investigated whether improvements in VOR and balance function over time after aUVL are different for the elderly than for the young...
2016: Frontiers in Neurology
https://www.readbyqxmd.com/read/26730687/microinstability-of-the-hip-and-the-splits-radiograph
#18
Joshua D Harris, Brayden J Gerrie, David M Lintner, Kevin E Varner, Patrick C McCulloch
A normal hip has a natural tendency toward stability because of both osseous and soft tissue structures. Hip motion is primarily rotational around a center of rotation. When the femoral head and its center of rotation translate, with or without rotation, the inherent stability of the femoroacetabular articulation may be lost. The spectrum of hip instability ranges from subtle microinstability to traumatic dislocation. Microinstability may be the cause or the effect of several other hip pathologies. Soft tissue contributions to stability include the static capsule, dynamic musculotendinous units, and underlying generalized connective tissue (eg, Ehlers-Danlos)...
January 2016: Orthopedics
https://www.readbyqxmd.com/read/26699301/utilization-of-optical-tracking-to-assess-efficacy-of-intracranial-immobilization-techniques-in-proton-therapy
#19
Wen C Hsi, Andries N Schreuder, Omar Zeidan
We present a quantitative methodology to measure head interfraction movements within intracranial masks of commercial immobilization devices used for proton radiotherapy. A three-points tracking (3PtTrack) method was developed to measure the mask location for each treatment field over an average of 10 fractions for seven patients. Five patients were treated in supine with the Qfix Base-of-Skull (BoS) headframe, and two patients were treated in prone with the CIVCO Uni-frame baseplate. Patients were first localized by an in-room, image-guidance (IG) system, and then the mask location was measured using the 3PtTrack method...
September 8, 2015: Journal of Applied Clinical Medical Physics
https://www.readbyqxmd.com/read/26614577/effect-of-head-pitch-and-roll-orientations-on-magnetically-induced-vertigo
#20
Omar S Mian, Yan Li, Andre Antunes, Paul M Glover, Brian L Day
KEY POINTS: Lying supine in a strong magnetic field, such as in magnetic resonance imaging scanners, can induce a perception of whole-body rotation. The leading hypothesis to explain this invokes a Lorentz force mechanism acting on vestibular endolymph that acts to stimulate semicircular canals. The hypothesis predicts that the perception of whole-body rotation will depend on head orientation in the field. Results showed that the direction and magnitude of apparent whole-body rotation while stationary in a 7 T magnetic field is influenced by head orientation...
February 15, 2016: Journal of Physiology
keyword
keyword
99878
1
2
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read
×

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"