Hybrid Feedforward-Feedback Noise Control Using Virtual Sensors

Science.gov (United States)

Bean, Jacob; Fuller, Chris; Schiller, Noah

2016-01-01

Several approaches to active noise control using virtual sensors are evaluated for eventual use in an active headrest. Specifically, adaptive feedforward, feedback, and hybrid control structures are compared. Each controller incorporates the traditional filtered-x least mean squares algorithm. The feedback controller is arranged in an internal model configuration to draw comparisons with standard feedforward control theory results. Simulation and experimental results are presented that illustrate each controllers ability to minimize the pressure at both physical and virtual microphone locations. The remote microphone technique is used to obtain pressure estimates at the virtual locations. It is shown that a hybrid controller offers performance benefits over the traditional feedforward and feedback controllers. Stability issues associated with feedback and hybrid controllers are also addressed. Experimental results show that 15-20 dB reduction in broadband disturbances can be achieved by minimizing the measured pressure, whereas 10-15 dB reduction is obtained when minimizing the estimated pressure at a virtual location.

Baseline knowledge on vehicle safety and head restraints among Fleet Managers in British Columbia Canada: a pilot study.

Science.gov (United States)

Desapriya, Ediriweera; Hewapathirane, D Sesath; Peiris, Dinithi; Romilly, Doug; White, Marc

2011-09-01

Whiplash is the most common injury type arising from motor vehicle collisions, often leading to long-term suffering and disability. Prevention of such injuries is possible through the use of appropriate, correctly positioned, vehicular head restraints. To survey the awareness and knowledge level of vehicle fleet managers in the province of British Columbia, Canada, on the topics of vehicle safety, whiplash injury, and prevention; and to better understand whether these factors influence vehicle purchase/lease decisions. A survey was administered to municipal vehicle fleet managers at a professional meeting (n = 27). Although many respondents understood the effectiveness of vehicle head restraints in the prevention of whiplash injury, the majority rarely adjusted their own headrests. Fleet managers lacked knowledge about the seriousness of whiplash injuries, their associated costs for Canada's healthcare system, and appropriate head restraint positions to mitigate such injuries. The majority of respondents indicated that fleet vehicle purchase/lease decisions within their organization did not factor whiplash prevention as an explicit safety priority. There is relatively little awareness and enforcement of whiplash prevention strategies among municipal vehicle fleet managers.

Great auricular neuropraxia with beach chair position

Directory of Open Access Journals (Sweden)

Joshi M

2017-07-01

Full Text Available Minal Joshi,1 Ruth Cheng,2 Hattiyangadi Kamath,1 Joel Yarmush1 1Department of Anesthesiology, New York Methodist Hospital, New York, NY, USA; 2School of Medicine, St. George’s University, Grenada, West Indies Abstract: Shoulder arthroscopy has been shown to be the procedure of choice for many diagnostic and therapeutic interventions. Neuropraxia of the great auricular nerve (GAN is an uncommon complication of shoulder surgery, with the patient in the beach chair position. We report a case of great auricular neuropraxia associated with direct compression by a horseshoe headrest, used in routine positioning for uncomplicated shoulder surgery. In this case, an arthroscopic approach was taken, under regional anesthesia with sedation in the beach chair position. The GAN, a superficial branch of the cervical plexus, is vulnerable to neuropraxia due to its superficial anatomical location. We recommend that for the procedures of the beach chair position, the auricle be protected and covered with cotton and gauze to avoid direct compression and the position of the head and neck be checked and corrected frequently. Keywords: neuropraxia, anesthesia, arthroscopy, great auricular nerve

Active euthanasia in pre-modern society, 1500-1800: learned debates and popular practices.

Science.gov (United States)

Stolberg, Michael

2007-08-01

Historians of medical ethics have found that active euthanasia, in the sense of intentionally hastening the death of terminally-ill patients, was considered unacceptable in the Christian West before the 1870s. This paper presents a range of early modern texts on the issue which reflect a learned awareness of practices designed to shorten the lives of dying patients which were widely accepted among the lay public. Depriving the dying abruptly of their head-rest or placing them flat on the cold floor may strike us as merely symbolic today, but early moderns associated such measures with very concrete and immediate effects. In this sense, the intentional hastening of death in agonising patients had an accepted place in pre-modern popular culture. These practices must, however, be put into their proper context. Death was perceived more as a transition to the after-life and contemporary notions of dying could make even outright suffocation appear as an act of compassion which merely helped the soul depart from the body at the divinely ordained hour of death. The paper concludes with a brief comparison of early modern arguments with those of today.

Factors associated with rear seating of children in motor vehicles: a study in two low-income, predominantly Hispanic communities.

Science.gov (United States)

Greenberg-Seth, Jennifer; Hemenway, David; Gallagher, Susan S; Lissy, Karen S; Ross, Julie B

2004-07-01

This study examined child seating patterns in two predominantly low-income, Hispanic communities in Massachusetts. The purpose was to determine the factors associated with child rear seating in the community as a whole and for a subset of Hispanic motorists. Five hundred and five vehicles carrying child passengers and no adult other than the driver were observed in parking lots of fast food restaurants and grocery stores. Four hundred and thirty-two vehicle drivers agreed to be interviewed. A child was defined as a passenger younger than age 12 as determined by appearance and height (head below the vehicle headrest when seated). Variables under study included driver gender, age, ethnicity, and educational attainment; driver shoulder belt use; driver perception of passenger-side airbag presence; and the number and ages of children in the car. Overall, 51% of vehicles were observed with all children seated in the rear. In a bivariate analysis, child rear seating was strongly associated with female drivers ( P = 0.01), younger drivers ( P = 0.02) driver shoulder belt use ( P safety behavior (e.g. seat belt use). Messages should be culturally appropriate and should emphasize driver seat belt use in conjunction with rear seating and the importance of rear seating regardless of the presence of a passenger-side airbag.

Clinical outcome of stereotactic body radiotherapy of 54 Gy in nine fractions for patients with localized lung tumor using a custom-made immobilization system

International Nuclear Information System (INIS)

Aoki, Masahiko; Abe, Yoshinao; Kondo, Hidehiro

2007-01-01

The aim of this study was to investigate the clinical outcome of stereotactic body radiotherapy (SBRT) of 54 Gy in nine fractions for patients with localized lung tumor using a custom-made immobilization system. The subjects were 19 patients who had localized lung tumor (11 primaries, 8 metastases) between May 2003 and October 2005. Treatment was conducted on 19 lung tumors by fixed multiple noncoplanar conformal beams with a standard linear accelerator. The isocentric dose was 54 Gy in nine fractions. The median overall treatment time was 15 days (range 11-22 days). All patients were immobilized by a thermo-shell and a custom-made headrest during the treatment. The crude local tumor control rate was 95% during the follow-up of 9.4-39.5 (median 17.7) months. In-field recurrence was noted in only one patient at the last follow-up. The Kaplan-Meier overall survival rate at 2 years was 89.5%. Grade 1 radiation pneumonia and grade 1 radiation fibrosis were observed in 12 of the 19 patients. Treatment-related severe early and late complications were not observed in this series. The stereotactic body radiotherapy of 54 Gy in nine fractions achieved acceptable tumor control without any severe complications. The results suggest that SBRT can be one of the alternatives for patients with localized lung tumors. (author)

Exploring the design of a lightweight, sustainable and comfortable aircraft seat.

Science.gov (United States)

Kokorikou, A; Vink, P; de Pauw, I C; Braca, A

2016-07-19

Making a lightweight seat that is also comfortable can be contradictory because usually comfort improvement means adding a feature (e.g. headrest, adjustable lumbar support, movable armrests, integrated massage systems, etc.), which makes seats heavier. This paper explores the design of an economy class aircraft seat that aims to be lightweight, comfortable and sustainable. Theory about comfort in seats, ergonomics, lightweight design, Biomimicry and Cradle to cradle was studied and resulted in a list of requirements that the new seat should satisfy. The design process resulted in a new seat that is 36% lighter than the reference seat, which showed that a significant weight reduction can be achieved. This was completed by re-designing the backrest and seat pan and integrating their functions into a reduced number of parts. Apart from the weight reduction that helps in reducing the airplane's environmental impact, the seat also satisfies most of the other sustainability requirements such as the use of recyclable materials, design for disassembly, easy to repair. A user test compared the new seat with a premium economy class aircraft seat and the level of comfort was similar. Strong points of the new design were identified such as the lumbar support and the cushioning material, as well as shortcomings on which the seat needs to be improved, like the seat pan length and the first impression. Long term comfort tests are still needed as the seat is meant for long-haul flights.

Slit lamps and lenses: a potential source of nosocomial infections?

Science.gov (United States)

Sobolewska, Bianka; Buhl, Michael; Liese, Jan; Ziemssen, Focke

2018-01-30

The aim of the study was to evaluate the bacterial contamination level of contact surfaces on slit lamps and the grip areas of lenses. Within unannounced audits, two regions of the slit lamps (headrest and joystick), indirect ophthalmoscopy devices, and ultrasound probes were obtained with rayon-tipped swab. Non-contact lenses used for indirect fundoscopy were pressed on RODAC (Replicate Organism Detection and Counting) plates. One hundred and eighty-one surfaces were sampled. The total number of colony-forming units was assessed and bacterial species were identified. Spa-typing and antimicrobial susceptibility testing were performed from Staphylococcus aureus isolates. Among the total bacterial isolates from ophthalmological equipment (lenses: 51 of 78, slit lamps: 43 of 88, ophthalmoscopy helmets: 3 of 8, ultrasound probes: 2 of 7), coagulase-negative staphylococci (CNS) was most frequently found, followed by Micrococcus spp. (lenses vs. slit lamps: P lenses (76%) was significantly higher than that of slit lamps (54%) (P lenses from residents vs. from consultants (78% vs. 35%, P = 0.01). A total of seven different spa-types of S. aureus were isolated. No correlation was found between S. aureus contamination of different ophthalmological equipments (Spearman's rank correlation coefficient, ρ = 0.04, P = 0.75). Methicillin-resistant S. aureus was not detected. Bacterial species of the normal skin flora were isolated from the ophthalmological equipment. The bacterial contamination of the portable devices was significantly higher than that of slit lamps. Therefore, proper hygiene of the mobile instruments should be monitored in order to prevent transmission of bacteria in residents and consultants.

Investigating Car Body Construction Influence on the Passive Safety in a Rear Impact

Directory of Open Access Journals (Sweden)

D. Yu. Solopov

2015-01-01

Full Text Available This article solves the task to assess how much a car body construction influences on the parameters of passive safety in a rear impact. The task concerns the impact and, as a result, is highly nonlinear with large values of deformations, stresses, and accelerations. A finite element method based on software systems LS-DYNA, ANSYS, FEMAP, and others solves this task.One of the most important stages of the work was to develop the finite element models (FEM of the car as a whole, as well as the car seat with a dummy mounted in the car. Body of the Chiseler Grand Caravan car, which parameters are close to average ones, was used as an object of research.The results of calculations and experiments allowed us to find that in assessing the passive safety of a car, taking into consideration the body design with a seat mounted in it, values of velocities, accelerations, and NIC criterion turned out to be lower than when calculating the seat with a dummy separately. The relative error (relative to the results of calculations in the "dangerous" impact of FEM seat of the highest level in accordance with EURO NCAP was 32% for full acceleration and was 33% for NIC criterion.It was found that in the calculations based on the FEM car, as a whole, the results are more accurate than when using the load operation conditions simulating energy absorption by the car body (20%.This leads to the conclusion that the calculations based on the FEM car with the seat mounted in it gives the possibility to design a seat (with passive or active headrest to ensure the best level of passive safety of this car.

SU-F-T-642: Sub Millimeter Accurate Setup of More Than Three Vertebrae in Spinal SBRT with 6D Couch

International Nuclear Information System (INIS)

Wang, X; Zhao, Z; Yang, J; Yang, J; McAleer, M; Brown, P; Li, J; Ghia, A

2016-01-01

Purpose: To assess the initial setup accuracy in treating more than 3 vertebral body levels in spinal SBRT using a 6D couch. Methods: We retrospectively analyzed last 20 spinal SBRT patients (4 cervical, 9 thoracic, 7 lumbar/sacrum) treated in our clinic. These patients in customized immobilization device were treated in 1 or 3 fractions. Initial setup used ExacTrac and Brainlab 6D couch to align target within 1 mm and 1 degree, following by a cone beam CT (CBCT) for verification. Our current standard practice allows treating a maximum of three continuous vertebrae. Here we assess the possibility to achieve sub millimeter setup accuracy for more than three vertebrae by examining the residual error in every slice of CBCT. The CBCT had a range of 17.5 cm, which covered 5 to 9 continuous vertebrae depending on the patient and target location. In the study, CBCT from the 1st fraction treatment was rigidly registered with the planning CT in Pinnacle. The residual setup error of a vertebra was determined by expanding the vertebra contour on the planning CT to be large enough to enclose the corresponding vertebra on CBCT. The margin of the expansion was considered as setup error. Results: Out of the 20 patients analyzed, initial setup accuracy can be achieved within 1 mm for a span of 5 or more vertebrae starting from T2 vertebra to inferior vertebra levels. 2 cervical and 2 upper thoracic patients showed the cervical spine was difficult to achieve sub millimeter accuracy for multi levels without a customized immobilization headrest. Conclusion: If the curvature of spinal columns can be reproduced in customized immobilization device during treatment as simulation, multiple continuous vertebrae can be setup within 1 mm with the use of a 6D couch.

The Burden and Determinants of Neck Pain in Whiplash-Associated Disorders After Traffic Collisions

Science.gov (United States)

Carroll, Linda J.; Cassidy, J. David; Hogg-Johnson, Sheilah; Côté, Pierre; Guzman, Jamie; Peloso, Paul; Nordin, Margareta; Hurwitz, Eric; van der Velde, Gabrielle; Carragee, Eugene; Haldeman, Scott

2008-01-01

Study Design Best evidence synthesis. Objective To undertake a best evidence synthesis on the burden and determinants of whiplash-associated disorders (WAD) after traffic collisions. Study Design Summary of Background Data. Previous best evidence synthesis on WAD has noted a lack of evidence regarding incidence of and risk factors for WAD. Therefore there was a warrant of a reanalyze of this body of research. Methods A systematic search of Medline was conducted. The reviewers looked for studies on neck pain and its associated disorders published 1980 –2006. Each relevant study was independently and critically reviewed by rotating pairs of reviewers. Data from studies judged to have acceptable internal validity (scientifically admissible) were abstracted into evidence tables, and provide the body of the best evidence synthesis. Results The authors found 32 scientifically admissible studies related to the burden and determinants of WAD. In the Western world, visits to emergency rooms due to WAD have increased over the past 30 years. The annual cumulative incidence of WAD differed substantially between countries. They found that occupant seat position and collision impact direction were associated with WAD in one study. Eliminating insurance payments for pain and suffering were associated with a lower incidence of WAD injury claims in one study. Younger ages and being a female were both associated with filing claims or seeking care for WAD, although the evidence is not consistent. Preliminary evidence suggested that headrests/car seats, aimed to limiting head extension during rear-end collisions had a preventive effect on reporting WAD, especially in females. Conclusion WAD after traffic collisions affects many people. Despite many years of research, the evidence regarding risk factors for WAD is sparse but seems to include personal, societal, and environmental factors. More research including, well-defined studies with accurate denominators for calculating risk

Course and Prognostic Factors for Neck Pain in Whiplash-Associated Disorders (WAD)

Science.gov (United States)

Holm, Lena W.; Hogg-Johnson, Sheilah; Côté, Pierre; Cassidy, J. David; Haldeman, Scott; Nordin, Margareta; Hurwitz, Eric L.; Carragee, Eugene J.; van der Velde, Gabrielle; Peloso, Paul M.; Guzman, Jaime

2008-01-01

Study Design Best evidence synthesis. Objective To perform a best evidence synthesis on the course and prognostic factors for neck pain and its associated disorders in Grades I–III whiplash-associated disorders (WAD). Summary of Background Data Knowledge of the course of recovery of WAD guides expectations for recovery. Identifying prognostic factors assists in planning management and intervention strategies and effective compensation policies to decrease the burden of WAD. Methods The Bone and Joint Decade 2000–2010 Task Force on Neck Pain and its Associated Disorders (Neck Pain Task Force) conducted a critical review of the literature published between 1980 and 2006 to assemble the best evidence on neck pain and its associated disorders. Studies meeting criteria for scientific validity were included in a best evidence synthesis. Results We found 226 articles related to course and prognostic factors in neck pain and its associated disorders. After a critical review, 70 (31%) were accepted on scientific merit; 47 of these studies related to course and prognostic factors in WAD. The evidence suggests that approximately 50% of those with WAD will report neck pain symptoms 1 year after their injuries. Greater initial pain, more symptoms, and greater initial disability predicted slower recovery. Few factors related to the collision itself (for example, direction of the collision, headrest type) were prognostic; however, postinjury psychological factors such as passive coping style, depressed mood, and fear of movement were prognostic for slower or less complete recovery. There is also preliminary evidence that the prevailing compensation system is prognostic for recovery in WAD. Conclusion The Neck Pain Task Force undertook a best evidence synthesis to establish a baseline of the current best evidence on the course and prognosis for WAD. Recovery of WAD seems to be multifactorial.

SU-F-T-642: Sub Millimeter Accurate Setup of More Than Three Vertebrae in Spinal SBRT with 6D Couch

Energy Technology Data Exchange (ETDEWEB)

Wang, X; Zhao, Z; Yang, J; Yang, J; McAleer, M; Brown, P; Li, J; Ghia, A [MD Anderson Cancer Center, Houston, TX (United States)

2016-06-15

Purpose: To assess the initial setup accuracy in treating more than 3 vertebral body levels in spinal SBRT using a 6D couch. Methods: We retrospectively analyzed last 20 spinal SBRT patients (4 cervical, 9 thoracic, 7 lumbar/sacrum) treated in our clinic. These patients in customized immobilization device were treated in 1 or 3 fractions. Initial setup used ExacTrac and Brainlab 6D couch to align target within 1 mm and 1 degree, following by a cone beam CT (CBCT) for verification. Our current standard practice allows treating a maximum of three continuous vertebrae. Here we assess the possibility to achieve sub millimeter setup accuracy for more than three vertebrae by examining the residual error in every slice of CBCT. The CBCT had a range of 17.5 cm, which covered 5 to 9 continuous vertebrae depending on the patient and target location. In the study, CBCT from the 1st fraction treatment was rigidly registered with the planning CT in Pinnacle. The residual setup error of a vertebra was determined by expanding the vertebra contour on the planning CT to be large enough to enclose the corresponding vertebra on CBCT. The margin of the expansion was considered as setup error. Results: Out of the 20 patients analyzed, initial setup accuracy can be achieved within 1 mm for a span of 5 or more vertebrae starting from T2 vertebra to inferior vertebra levels. 2 cervical and 2 upper thoracic patients showed the cervical spine was difficult to achieve sub millimeter accuracy for multi levels without a customized immobilization headrest. Conclusion: If the curvature of spinal columns can be reproduced in customized immobilization device during treatment as simulation, multiple continuous vertebrae can be setup within 1 mm with the use of a 6D couch.

SU-C-19A-06: A Robust and Affordable Table Indexing Approach for Total Lymphoid Irradiation Treatment

Energy Technology Data Exchange (ETDEWEB)

Yu, S; Fahimian, B; Kenyon, M; Hsu, A [Stanford University, Stanford, CA (United States)

2014-06-15

Purpose: Total lymphoid irradiation (TLI) is conventionally delivered through the dosimetric matching of mantle, spleen, and pelvis fields, necessitating multiple isocenters delivered through a combination of couch shifts and sliding of patients relative to the couch rendering the technique susceptible to shifting errors. To address this challenge, a novel technique for the couch indexing of TLI treatments is developed and evaluated through a multi-patient pilot trial. Methods: An immobilization device was designed consisting of a movable indexed slide board with an Exact Lok-Bar drilled into it. A Timo headrests were used fixate the head of the patient relative to the slide board. For the Varian Exact Couch™, the immobilization board was connected to the H3 notch to avoid the metal infrastructure of the couch for the delivery of the mantle and spleen fields. For tall patients the required shift for the pelvis isocenter reaches the shifting limit and the board was slid from H3 to H4 (a fixed distance of 14 cm). A total 22 patients were stratified in two groups of 11, one consisting of the conventional setup, and one group with the proposed immobilization technique. Results: The standard deviations (SD) of the couch positions in lateral, longitudinal, and vertical directions for 10 fractions for each patient in both groups were calculated. In the non-indexed group, the positioning SD ranged from 0.9 to 4.7 cm. Using our device, the positioning SD was reduced to a range of 0.2 to 0.9 cm, with the longitudinal direction showing the largest improvement. Conclusion: Matched field TLI remains error prone to geometrical misses. The feasibility of full indexing TLI treatments was validated and shown to result in a significant reduction of positioning errors.

SU-F-J-17: Patient Localization Using MRI-Guided Soft Tissue for Head-And-Neck Radiotherapy: Indication for Margin Reduction and Its Feasibility

International Nuclear Information System (INIS)

Qi, X; Yang, Y; Jack, N; Santhanam, A; Yang, L; Chen, A; Low, D

2016-01-01

Purpose: On-board MRI provides superior soft-tissue contrast, allowing patient alignment using tumor or nearby critical structures. This study aims to study H&N MRI-guided IGRT to analyze inter-fraction patient setup variations using soft-tissue targets and design appropriate CTV-to-PTV margin and clinical implication. Methods: 282 MR images for 10 H&N IMRT patients treated on a ViewRay system were retrospectively analyzed. Patients were immobilized using a thermoplastic mask on a customized headrest fitted in a radiofrequency coil and positioned to soft-tissue targets. The inter-fraction patient displacements were recorded to compute the PTV margins using the recipe: 2.5∑+0.7σ. New IMRT plans optimized on the revised PTVs were generated to evaluate the delivered dose distributions. An in-house dose deformation registration tool was used to assess the resulting dosimetric consequences when margin adaption is performed based on weekly MR images. The cumulative doses were compared to the reduced margin plans for targets and critical structures. Results: The inter-fraction displacements (and standard deviations), ∑ and σ were tabulated for MRI and compared to kVCBCT. The computed CTV-to-PTV margin was 3.5mm for soft-tissue based registration. There were minimal differences between the planned and delivered doses when comparing clinical and the PTV reduced margin plans: the paired t-tests yielded p=0.38 and 0.66 between the planned and delivered doses for the adapted margin plans for the maximum cord and mean parotid dose, respectively. Target V95 received comparable doses as planned for the reduced margin plans. Conclusion: The 0.35T MRI offers acceptable soft-tissue contrast and good spatial resolution for patient alignment and target visualization. Better tumor conspicuity from MRI allows soft-tissue based alignments with potentially improved accuracy, suggesting a benefit of margin reduction for H&N radiotherapy. The reduced margin plans (i.e., 2 mm) resulted

SU-E-T-633: Preparation and Planning of a VMAT Multi - Arc Radiation Therapy Technique for Full Scalp Treatment

Energy Technology Data Exchange (ETDEWEB)

Araujo, C; Bardock, A; Berkelaar, S; Gillund, D; McGee, K; Mohamed, I; Lapointe, C [British Columbia Cancer Agency, Kelowna, BC (Canada)

2015-06-15

Purpose: The target volume for angiosarcoma of the scalp encompasses the entire scalp. Full scalp radiotherapy (FSRT) requires careful design of required bolus, immobilization and marking of the field before the patient CT is acquired. A VMAT multi-arc technique was designed to deliver FSRT for a patient with angiosarcoma of the scalp to a dose of 6000cGy in 25 fractions. Methods: A custom bolus helmet was fabricated from a 0.5 cm thick sheet of aquaplast material, which was molded to the patient’s head. With the bolus helmet in place the patient was then positioned supine on a H&N immobilization board. A custom vaclock bag positioned on a standard headrest and a thermoplastic mask were used to immobilize the patient. Additional bolus to cover the remaining treatment area was attached to the mask. We acquired two CT scans of the patient’s head, one in treatment position and an additional scan without the immobilization mask with wires marking the treatment area that the oncologist had delineated on the patient’s skin. The second scan was registered to the first and used to define the treatment CTV. A four-arc VMAT treatment planned using Varian-Eclipse was optimized to cover the skin with a PTV margin while sparing the brain and limiting the dose to the optic apparatus and lacrimal glands. Daily treatment setup was verified using anterior and lateral kV on-board-imaging. To verify the treated dose, TLDs were positioned on the patient’s scalp during one fraction. Results: With full dose coverage to the PTV, the mean dose to the brain was less than 24 Gy. The dose measured by the TLDs (mean difference 1%, standard deviation 4%)showed excellent agreement with the treatment planning calculation. Conclusion: FSRT delivered with a bolus helmet and a VMAT multi-arc technique can be accurately delivered with high dose uniformity and conformality.

SU-E-T-633: Preparation and Planning of a VMAT Multi - Arc Radiation Therapy Technique for Full Scalp Treatment

International Nuclear Information System (INIS)

Araujo, C; Bardock, A; Berkelaar, S; Gillund, D; McGee, K; Mohamed, I; Lapointe, C

2015-01-01

Purpose: The target volume for angiosarcoma of the scalp encompasses the entire scalp. Full scalp radiotherapy (FSRT) requires careful design of required bolus, immobilization and marking of the field before the patient CT is acquired. A VMAT multi-arc technique was designed to deliver FSRT for a patient with angiosarcoma of the scalp to a dose of 6000cGy in 25 fractions. Methods: A custom bolus helmet was fabricated from a 0.5 cm thick sheet of aquaplast material, which was molded to the patient’s head. With the bolus helmet in place the patient was then positioned supine on a H&N immobilization board. A custom vaclock bag positioned on a standard headrest and a thermoplastic mask were used to immobilize the patient. Additional bolus to cover the remaining treatment area was attached to the mask. We acquired two CT scans of the patient’s head, one in treatment position and an additional scan without the immobilization mask with wires marking the treatment area that the oncologist had delineated on the patient’s skin. The second scan was registered to the first and used to define the treatment CTV. A four-arc VMAT treatment planned using Varian-Eclipse was optimized to cover the skin with a PTV margin while sparing the brain and limiting the dose to the optic apparatus and lacrimal glands. Daily treatment setup was verified using anterior and lateral kV on-board-imaging. To verify the treated dose, TLDs were positioned on the patient’s scalp during one fraction. Results: With full dose coverage to the PTV, the mean dose to the brain was less than 24 Gy. The dose measured by the TLDs (mean difference 1%, standard deviation 4%)showed excellent agreement with the treatment planning calculation. Conclusion: FSRT delivered with a bolus helmet and a VMAT multi-arc technique can be accurately delivered with high dose uniformity and conformality

Red Mandela: Contests of auto-biography and Auto/biography in South Africa

Directory of Open Access Journals (Sweden)

Ciraj Rassool

Full Text Available This article examines the case of the red Mercedes-Benz built in 1990 by workers at the Mercedes-Benz plant in East London and presented to Nelson Mandela as a gift shortly after his release from prison. During the 1990s a biographic order marked by a discourse of heroic leaders was growing in South Africa, where biographic narration and self-narration played a noticeable and, at times, substantial part in political transformation and reconstruction. Nelson Mandela's 'long walk to freedom' became the key trope for South Africa's history, narrated as the triumph of reconciliation. The presentation of the car to Nelson Mandela in 1990 occurred at a time of transition in the life of his auto/biography, from the biography of desire for the absent revolutionary leader to the biography of a statesman and president. This partly explains the ambiguous, double-edged history of the gift, as a labour of love on the part of NUMSA workers and as donation by Mercedes-Benz South Africa (the corporate version of these events emphasised the 'friendship' that was 'sparked' between Nelson Mandela and Mercedes-Benz South Africa. Inspired by the East London autoworkers' commitment to produce the car for Mandela, as well as by the resilience some of them showed during their nine-week strike and sleep-in in the plant soon afterwards, Simon Gush's installation Red has intervened in how those events should be remembered. By choosing to exhibit the disassembled body panels of a replica car alongside reconstructed displays of sleep-in strike beds made of scaffolding, foam, upholstery and car headrests, with imagined uniforms of striking workers, Gush has chosen to appropriate the history of the events of 1990 from the celebratory frames of the Mandela biographic order. The installation turns into an inquiry into the labour process and the events of the strike that was critical of the reconciliatory and celebratory understanding of the gift as a product of a partnership

Automated recognition of rear seat occupants' head position using Kinect™ 3D point cloud.

Science.gov (United States)

Loeb, Helen; Kim, Jinyong; Arbogast, Kristy; Kuo, Jonny; Koppel, Sjaan; Cross, Suzanne; Charlton, Judith

2017-12-01

Child occupant safety in motor-vehicle crashes is evaluated using Anthropomorphic Test Devices (ATD) seated in optimal positions. However, child occupants often assume suboptimal positions during real-world driving trips. Head impact to the seat back has been identified as one important injury causation scenario for seat belt restrained, head-injured children (Bohman et al., 2011). There is therefore a need to understand the interaction of children with the Child Restraint System to optimize protection. Naturalistic driving studies (NDS) will improve understanding of out-of-position (OOP) trends. To quantify OOP positions, an NDS was conducted. Families used a study vehicle for two weeks during their everyday driving trips. The positions of rear-seated child occupants, representing 22 families, were evaluated. The study vehicle - instrumented with data acquisition systems, including Microsoft Kinect™ V1 - recorded rear seat occupants in 1120 driving 26 trips. Three novel analytical methods were used to analyze data. To assess skeletal tracking accuracy, analysts recorded occurrences where Kinect™ exhibited invalid head recognition among a randomly-selected subset (81 trips). Errors included incorrect target detection (e.g., vehicle headrest) or environmental interference (e.g., sunlight). When head data was present, Kinect™ was correct 41% of the time; two other algorithms - filtering for extreme motion, and background subtraction/head-based depth detection are described in this paper and preliminary results are presented. Accuracy estimates were not possible because of their experimental nature and the difficulty to use a ground truth for this large database. This NDS tested methods to quantify the frequency and magnitude of head positions for rear-seated child occupants utilizing Kinect™ motion-tracking. This study's results informed recent ATD sled tests that replicated observed positions (most common and most extreme), and assessed the validity of child

SU-E-J-231: Comparison of Delineation Variability of Soft Tissue Volume and Position in Head-And-Neck Between Two T1-Weighted Pulse Sequences Using An MR-Simulator with Immobilization

Energy Technology Data Exchange (ETDEWEB)

Wong, O; Lo, G; Yuan, J; Law, M; Ding, A; Cheng, K; Chan, K; Cheung, K; Yu, S [Hong Kong Sanatorium & Hospital, Hong Kong (Hong Kong)

2015-06-15

Purpose: There is growing interests in applying MR-simulator(MR-sim) in radiotherapy but MR images subject to hardware, patient and pulse sequence dependent geometric distortion that may potentially influence target definition. This study aimed to evaluate the influence on head-and-neck tissue delineation, in terms of positional and volumetric variability, of two T1-weighted(T1w) MR sequences on a 1.5T MR-sim Methods: Four healthy volunteers were scanned (4 scans for each on different days) using both spin-echo (3DCUBE, TR/TE=500/14ms, TA=183s) and gradient-echo sequences (3DFSPGR, TE/TR=7/4ms, TA=173s) with identical coverage, voxel-size(0.8×0.8×1.0mm3), receiver-bandwidth(62.5kHz/pix) and geometric correction on a 1.5T MR-sim immobilized with personalized thermoplastic cast and head-rest. Under this setting, similar T1w contrast and signal-to-noise ratio were obtained, and factors other than sequence that might bias image distortion and tissue delineation were minimized. VOIs of parotid gland(PGR, PGL), pituitary gland(PIT) and eyeballs(EyeL, EyeR) were carefully drawn, and inter-scan coefficient-of-variation(CV) of VOI centroid position and volume were calculated for each subject. Mean and standard deviation(SD) of the CVs for four subjects were compared between sequences using Wilcoxon ranksum test. Results: The mean positional(<4%) and volumetric(<7%) CVs varied between tissues, majorly dependent on tissue inherent properties like volume, location, mobility and deformability. Smaller mean volumetric CV was found in 3DCUBE, probably due to its less proneness to tissue susceptibility, but only PGL showed significant difference(P<0.05). Positional CVs had no significant differences for all VOIs(P>0.05) between sequences, suggesting volumetric variation might be more sensitive to sequence-dependent delineation difference. Conclusion: Although 3DCUBE is considered less prone to tissue susceptibility-induced artifact and distortion, our preliminary data showed

Microsurgical resection of ventral foramen magnum meningiomas via a far-lateral suboccipital approach

Institute of Scientific and Technical Information of China (English)

Zhihua Cheng; Zhilin Guo; Meixiu Ding

2006-01-01

BACKGROUND: In recent years some reports have been published propagating microsurgical resection of ventral foramen magnum meningiomas (VFMMs). Operative approaches to these lesions have been studied by various authors, but remain controversial.OBJECTIVE: To discuss the operative technique and outcome in patients with VFMMs who had been treatedvia a far lateral suboccipital approach.DESIGN: Retrospectively clinic case investigation. SElrING: Department of Neurosurgery, the Ninth People's Hospital, Medical School of Shanghai Jiao Tong University.PARTICIPANTS: Between January 1997 and June 2003, 10 patients were treated surgically with VFMMs in Department of Neurosurgery, the Ninth People's Hospital, Medical School of Shanghai Jiao Tong University. In the series of 10 patients, ages ranged from 37 to 72 years, mean (53±10) years, were consisted of 6 males and 4 females. All the subjects were informed of the treatment plan and agreed to join the experiment. Early symptoms included headache and upper cervical pain. The time between the first occurrence of symptoms and the diagnosis ranged from 6 months to 17 months, mean (10.3±3.4) months. Main presenting symptoms were unilateral upper extremity sensory and motor deficits in 6 cases, swallowing difficulties in 2 and spastic quadriparesis in 2. VFMMs were demonstrated as round by the computed tomographic (CT) scan and magnetic resonance imaging (MRI) in all patients. The maximum diameter of tumors ranged from 2 to 4 cm,mean (2.55±0.57) cm, including 2 cm in one case, 2.0-3.0 cm in six and 3.0-4.0 cm in three.METHODS: ①All tumors were removed via the far lateral suboccipital approach. Resection of the posterior 5 mm of the condyle was necessary in one patient whose tumors' diameter were 2 cm. The patient was situated in the lateral decubitus position. The head was fixed in a Mayfield headrest. A C-shaped incision made behind the ear 2 cm medial to the mastoid process, turning vertically down to the level C4, to

Sistema Automático Para la Detección de Distracción y Somnolencia en Conductores por Medio de Características Visuales Robustas

Directory of Open Access Journals (Sweden)

Alberto Fernández Villán

2017-07-01

, pudiendo aumentar la precisión en la detección de la región facial de un 86.88% a un 96.46%. Las pruebas en entornos reales se realizaron durante varios días recogiendo condiciones lumínicas muy diferentes durante las horas diurnas involucrando a 16 conductores, los cuales realizaron diversas actividades para reproducir síntomas de distracción y somnolencia. Dependiendo del tipo de actividad y su duración, se obtuvieron diferentes resultados. De manera general y considerando de forma conjunta todas las actividades se obtiene una tasa media de detección del 93.11%. Abstract: According to the most recent studies published by the World Health Organization (WHO in 2013, it is estimated that 1.25 million people die as a result of traffic crashes. Many of them are caused by what it is known as inattention, whose main contributing factors are both distraction and drowsiness. Overall, it is estimated that inattention causes between 25% and 75% of the crashes and near-crashes. That is why this is a thoroughly studied field by the research community, where solutions to combat distraction and drowsiness, in particular, and inattention, in general, can be classified into three main categories, and, where computer vision has clearly become a non-obtrusive effective tool for the detection of both distraction and drowsiness. The aim of this paper is to propose, build and validate an architecture based on the analysis of visual characteristics by using computer vision techniques and machine learning to detect both distraction and drowsiness in drivers. Firstly, the modules have been tested with all its components independently using several datasets. More specifically, the presence/absence of the driver is detected with an accuracy of 100%, 90.56%, 88.96% by using a marker positioned onto the headrest, the LBP operator and the CS-LBP operator, respectively. Regarding the eye closeness validation with CEW dataset, an accuracy of 93.39% and 91.84% is obtained using a new method