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1.
Nurs Manage ; 51(3): 22-29, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-32101944

RESUMO

Results of the Patient Care and Tracking Increasing Electronics in Nurses' Use of Time (PATIENT) study.


Assuntos
Equipamentos e Provisões Elétricas/estatística & dados numéricos , Padrões de Prática em Enfermagem/estatística & dados numéricos , Tempo , Estudos Transversais , Humanos
2.
Nat Commun ; 11(1): 1002, 2020 02 21.
Artigo em Inglês | MEDLINE | ID: mdl-32081910

RESUMO

Innovations in soft material synthesis and fabrication technologies have led to the development of integrated soft electronic devices. Such soft devices offer opportunities to interact with biological cells, mimicking their soft environment. However, existing fabrication technologies cannot create the submicron-scale, soft transducers needed for healthcare and medical applications involving single cells. This work presents a nanofabrication strategy to create submicron-scale, all-soft electronic devices based on eutectic gallium-indium alloy (EGaIn) using a hybrid method utilizing electron-beam lithography and soft lithography. The hybrid lithography process is applied to a biphasic structure, comprising a metallic adhesion layer coated with EGaIn, to create soft nano/microstructures embedded in elastomeric materials. Submicron-scale EGaIn thin-film patterning with feature sizes as small as 180 nm and 1 µm line spacing was achieved, resulting in the highest resolution EGaIn patterning technique to date. The resulting soft and stretchable EGaIn patterns offer a currently unrivaled combination of resolution, electrical conductivity, and electronic/wiring density.


Assuntos
Equipamentos e Provisões Elétricas , Eletrônica/instrumentação , Metais , Nanotecnologia/métodos , Ligas , Elastômeros , Condutividade Elétrica , Desenho de Equipamento , Gálio , Índio , Indústria Manufatureira/métodos , Impressão , Propriedades de Superfície
3.
Nat Commun ; 11(1): 1107, 2020 02 27.
Artigo em Inglês | MEDLINE | ID: mdl-32107380

RESUMO

The bio-integrated electronics industry is booming and becoming more integrated with biological tissues. To successfully integrate with the soft tissues of the body (eg. skin), the material must possess many of the same properties including compliance, toughness, elasticity, and tear resistance. In this work, we prepare mechanically and biologically skin-like materials (PSeD-U elastomers) by designing a unique physical and covalent hybrid crosslinking structure. The introduction of an optimal amount of hydrogen bonds significantly strengthens the resultant elastomers with 11 times the toughness and 3 times the strength of covalent crosslinked PSeD elastomers, while maintaining a low modulus. Besides, the PSeD-U elastomers show nonlinear mechanical behavior similar to skins. Furthermore, PSeD-U elastomers demonstrate the cytocompatibility and biodegradability to achieve better integration with tissues. Finally, piezocapacitive pressure sensors are fabricated with high pressure sensitivity and rapid response to demonstrate the potential use of PSeD-U elastomers in bio-integrated electronics.


Assuntos
Materiais Biomiméticos/química , Elastômeros/química , Equipamentos e Provisões Elétricas , Biomimética/métodos , Reagentes para Ligações Cruzadas/química , Elasticidade , Isocianatos/química , Teste de Materiais , Espectroscopia de Prótons por Ressonância Magnética , Pirimidinonas/química , Fenômenos Fisiológicos da Pele
4.
PLoS One ; 15(2): e0228343, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32012180

RESUMO

Multiplication is a widely used arithmetic operation that is frequently encountered in micro-processing and digital signal processing. Multiplication is implemented using a multiplier, and recently, QDI asynchronous array multipliers were presented in the literature utilizing delay-insensitive double-rail data encoding and four-phase return-to-zero (RTZ) handshaking and four-phase return-to-one (RTO) handshaking. In this context, this article makes two contributions: (i) the design of a new asynchronous partial product generator, and (ii) the design of a new asynchronous half adder. We analyze the usefulness of the proposed partial product generator and the proposed half adder to efficiently realize QDI array multipliers. When the new partial product generator and half adder are used along with our indicating full adder, significant reductions are achieved in the design metrics compared to the optimum QDI array multiplier reported in the literature. The cycle time is reduced by 17%, the area is reduced by 16.1%, the power is reduced by 15.3%, and the product of power and cycle time is reduced by 29.6% with respect to RTZ handshaking. On the other hand, the cycle time is reduced by 13%, the area is reduced by 16.1%, the power is reduced by 15.2%, and the product of power and cycle time is reduced by 26.1% with respect to RTO handshaking. Further, the RTO handshaking is found to be preferable to RTZ handshaking to achieve slightly improved optimizations in the design metrics. The QDI array multipliers were realized using a 32/28nm complementary metal oxide semiconductor (CMOS) process technology.


Assuntos
Equipamentos e Provisões Elétricas , Matemática , Desenho de Equipamento
5.
PLoS One ; 15(1): e0226708, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31940372

RESUMO

The end of deep reading is a commonplace in public debates, whenever societies talk about youth, books, and the digital age. In contrast to this, we show for the first time and in detail, how intensively young readers write and comment literary texts at an unprecedented scale. We present several analyses of how fiction is transmitted through the social reading platform Wattpad, one of the largest platforms for user-generated stories, including novels, fanfiction, humour, classics, and poetry. By mixed quantitative and qualitative methods and scalable reading we scrutinise texts and comments on Wattpad, what themes are preferred in 13 languages, what role does genre play for readers behaviour, and what kind of emotional engagement is prevalent when young readers share stories. Our results point out the rise of a global reading culture in youth reading besides national preferences for certain topics and genres, patterns of reading engagement, aesthetic values and social interaction. When reading Teen Fiction social-bonding (affective interaction) is prevalent, when reading Classics social-cognitive interaction (collective intelligence) is prevalent. An educational outcome suggests that readers who engage in Teen Fiction learn to read Classics and to judge books not only in direct emotional response to character's behaviour, but focusing more on contextualised interpretation of the text.


Assuntos
Equipamentos e Provisões Elétricas , Internet , Relações Interpessoais , Leitura , Emoções , Humanos
6.
Anesth Analg ; 130(4): 845-853, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-31453870

RESUMO

BACKGROUND: District-level hospitals (DLHs) are the main providers of surgical services for rural populations in Sub-Saharan Africa (SSA). Skilled teams are essential for surgical care, and gaps in anesthesia impact negatively on surgical capacity and outcomes. This study, from a baseline of a project scaling-up access to safe surgical and anesthesia care in Malawi, Tanzania, and Zambia, illustrates the deficit of anesthesia care in DLHs. METHODS: We undertook an in-depth investigation of anesthesia capacity in 76 DLHs across the 3 countries, July to November 2017, using a mixed-methods approach. The quantitative component assessed district-level anesthesia capacity using a standardized scoring system based on an adapted and extended Personnel, Infrastructure, Procedures, Equipment and Supplies (PIPES) Index. The qualitative component involved semistructured interviews with providers from 33 DLHs, exploring how weaknesses in anesthesia impacted district surgical team practices and quality, volume, and scope of service provision. RESULTS: Anesthesia care at the district level in these countries is provided only by nonphysician anesthetists, some of whom have no formal training. Ketamine anesthesia is widely used in all hospitals, compensating for shortages of other forms of anesthesia. Pediatric size supplies/equipment were frequently missing. Anesthesia PIPES index scores in Malawi (M = 8.0), Zambia (M = 8.3), and Tanzania (M = 8.4) were similar (P = .59), but an analysis of individual PIPES components revealed important cross-country differences. Irregular availability of reliable equipment and supply is a particular priority in Malawi, where only 29% of facilities have uninterrupted access to electricity and 23% have constant access to water, among other challenges. Zambia is mostly affected by staffing shortages, with 30% of surveyed hospitals lacking an anesthesia provider. The challenge that stood out in Tanzania was nonavailability of functioning anesthesia machines among frequent shortages of staff and other equipment. CONCLUSIONS: Tanzania, Malawi, and Zambia are falling far short of ensuring universal access to safe and affordable surgical and anesthesia care for district and rural populations. Mixed-methods situation analyses, undertaken in collaboration with anesthesia specialists-measuring and understanding deficits in district hospital anesthetic staff, equipment, and supplies-are needed to address the critical neglect of anesthesia that is essential to providing surgical responses to the needs of rural populations in SSA.


Assuntos
Anestesia/estatística & dados numéricos , Hospitais de Distrito/organização & administração , Adulto , Anestesia/normas , Anestésicos Dissociativos , Criança , Competência Clínica , Equipamentos e Provisões Elétricas , Hospitais de Distrito/normas , Hospitais de Distrito/estatística & dados numéricos , Humanos , Ketamina , Malaui , Enfermeiras Anestesistas , Equipe de Assistência ao Paciente , Assistência Perioperatória/normas , Tanzânia , Zâmbia
7.
Biomed Eng Online ; 18(1): 117, 2019 Dec 05.
Artigo em Inglês | MEDLINE | ID: mdl-31805942

RESUMO

BACKGROUND: One of the major concerns in implantable optoelectronics is the heat generated by emitters such as light emitting diodes (LEDs). Such devices typically produce more heat than light, whereas medical regulations state that the surface temperature change of medical implants must stay below + 2 °C. The LED's reverse current can be employed as a temperature-sensitive parameter to measure the temperature change at the implant's surface, and thus, monitor temperature rises. The main challenge in this approach is to bias the LED with a robust voltage since the reverse current is strongly and nonlinearly sensitive to the bias voltage. METHODS: To overcome this challenge, we have developed an area-efficient LED-based temperature sensor using the LED as its own sensor and a CMOS electronic circuit interface to ensure stable bias and current measurement. The circuit utilizes a second-generation current conveyor (CCII) configuration to achieve this and has been implemented in 0.35 µm CMOS technology. RESULTS: The developed circuits have been experimentally characterized, and the temperature-sensing functionality has been tested by interfacing different mini-LEDs in saline models of tissue prior to in vivo operation. The experimental results show the functionality of the CMOS electronics and the efficiency of the CCII-based technique with an operational frequency up to 130 kHz in achieving a resolution of 0.2 °C for the surface temperature up to + 45 °C. CONCLUSIONS: We developed a robust CMOS current-mode sensor interface which has a reliable CCII to accurately convey the LED's reverse current. It is low power and robust against power supply ripple and transistor mismatch which makes it reliable for sensor interface. The achieved results from the circuit characterization and in vivo experiments show the feasibility of the whole sensor interface in monitoring the tissue surface temperature in optogenetics.


Assuntos
Equipamentos e Provisões Elétricas/efeitos adversos , Luz , Próteses e Implantes , Temperatura , Animais , Condutividade Elétrica , Desenho de Equipamento , Humanos
8.
Artigo em Inglês | MEDLINE | ID: mdl-31877860

RESUMO

In implementing carbon emission trading schemes (ETSs), the cost of carbon embedded in raw materials further complicates supplier selection and order allocation. Firms have to make decisions by comprehensively considering the cost and the important intangible performance of suppliers. This paper uses an analytic network process-integer programming (ANP-IP) model based on a multiple-criteria decision-making (MCDM) approach to solve the above issues by first evaluating and then optimizing them. The carbon embedded in components, which can be used to reflect the carbon competitiveness of a supplier, is integrated into the ANP-IP model. In addition, an international large-scale electronic equipment manufacturer in China is used to validate the model. Different scenarios involving different carbon prices are designed to analyze whether China's current ETS drives firms to choose more low-carbon suppliers. The results show that current carbon constraints are not stringent enough to drive firms to select low-carbon suppliers. A more stringent ETS with a higher carbon price could facilitate the creation of a low-carbon supply chain. The analysis of the firm's total cost and of the total cost composition indicates that the impact of a more stringent ETS on the firm results mainly from indirect costs instead of direct costs. The indirect cost is caused by the suppliers' transfer of part of the low-carbon investment in the product, and arises from buying carbon permits with high carbon prices. Implications revealed by the model analysis are discussed to provide guidance to suppliers regarding the balance between soft competitiveness and low-carbon production capability and to provide guidance to the firm on how to cooperate with suppliers to achieve a mutually beneficial situation.


Assuntos
Carbono , Tomada de Decisões , China , Comércio , Custos e Análise de Custo , Equipamentos e Provisões Elétricas
9.
Dermatol Online J ; 25(9)2019 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-31738850

RESUMO

Allergic contact dermatitis (ACD) is a frequent problem, often caused from repeated exposure to an object or substance related to the patient's routine activities. We present a case of a well-demarcated, erythematous, scaly plaque on a finger caused from reading with an e-book device. Although metal from mobile devices can cause ACD, mobile device cases may cause irritation or contain additives that can also cause contact dermatitis. Similar presentations of contact dermatitis may become more common as technology use increases.


Assuntos
Livros , Dermatite Alérgica de Contato/etiologia , Equipamentos e Provisões Elétricas/efeitos adversos , Dedos/patologia , Idoso de 80 Anos ou mais , Dermatite Alérgica de Contato/patologia , Humanos , Masculino
10.
Phys Med ; 68: 117-123, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31783221

RESUMO

PURPOSE: We investigated the highly multiplexed readout of SiPM signals that are useful in developing brain-dedicated PET detectors with DOI-capable crystal blocks and large-area SiPM arrays. METHODS: The PET detector module used in this study was equipped with a two-layer relative-offset DOI crystal block and a 2 × 2 array of 16-channel SiPMs. The lower crystal-layer consisted of a 14 × 14 array of 1.78 × 1.78 × 8 mm3 LSO crystals and the upper crystal-layer consisted of a 13 × 13 array of 1.78 × 1.78 × 12 mm3 LSO crystals. The energy and position information was obtained via signals from the 8 × 8 resistive charge division multiplexing circuit. The timing performance was evaluated with varying multiplexing ratios (i.e. 16:1, 32:1, and 64:1) via first-order analog high-pass filtering. RESULTS: For three different multiplexing schemes, all LSO crystals with two-layer DOI information were clearly resolved and yielded good energy resolutions of 10.5 ± 1.0% (upper) and 12.1 ± 1.7% (lower). The 16:1 multiplexing yielded an optimal timing performance with average CRT values of 325 ps FWHM (upper) and 342 ps FWHM (lower); however, the timing performances were maintained almost constant even for 64:1 multiplexing with average CRT values of 336 ps FWHM (upper) and 347 ps FWHM (lower). CONCLUSIONS: The highly multiplexed SiPM signal readout via the first-order analog high-pass filtering could be an attractive solution to develop brain-dedicated PET scanners, effectively decreasing the burden of DAQ systems with moderate compromise in terms of TOF and DOI performances.


Assuntos
Encéfalo/diagnóstico por imagem , Tomografia por Emissão de Pósitrons/instrumentação , Equipamentos e Provisões Elétricas
11.
J Manag Care Spec Pharm ; 25(11): 1244-1254, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31663462

RESUMO

BACKGROUND: U.S. specialty drug spend is expected to reach $400 billion by 2020, with significant growth in oncology. New oral oncology approvals have allowed for more convenient outpatient administration compared with physician-administered chemotherapies; however, patients may encounter challenges with adherence when taking medications at home. Emerging medication adherence technology (MAT) attempts to provide at-home adherence support, and while one such technology, smart pill bottles (SPB), claims to improve medication adherence, few studies have formally assessed their effects. OBJECTIVES: To assess the effect of an SPB with pharmacist intervention on medication adherence in adult patients with multiple myeloma (MM) new to lenalidomide therapy (≤ 5 cycle dispenses). Secondary objectives were to evaluate treatment cycles completed, evaluate the significance of real-time pharmacist engagement (intervention group only), determine the incremental cost-effectiveness ratio (ICER), and evaluate patient satisfaction and likelihood to use an SPB. METHODS: This prospective, random assignment, single-site, and single-blinded study recruited 40 adult patients diagnosed with MM new to lenalidomide at a specialty pharmacy. Recruitment was completed January-February 2016, and the length of study was 6 months. Participants were randomized 1:1 between the intervention and control groups. The intervention group received lenalidomide in activated SPBs with light, chimes, text message reminders, and pharmacist follow-up if weekly SPB adherence rates dropped below 80%. The control group received lenalidomide in identical SPBs with all alerts deactivated. SBPs contained cellular capabilities, enabling around-the-clock data transmission and captured data upon bottle-uncapping events. Patient adherence was calculated by dividing the number of bottle-uncapping events by the total number of doses supplied for each dosing cycle. Lenalidomide cycles completed and pharmacist outreach to the same patient were counted to determine pharmacist intervention. The ICER was calculated to determine SPB cost-effectiveness, and a Likert scale survey was given to the intervention group to evaluate patient satisfaction with the full-service SPB. RESULTS: Sixteen participants in each arm completed the study; 4 patients in each arm were lost to follow-up. Median adherence was improved for the intervention group compared with the control group (median = 100% vs. 87.4%; P = 0.001). The ICER per patient percentage adherence increase was found to be $96.03. Sixty percent of patients in the intervention group who responded to the post-satisfaction survey rated the full SPB service very positively. CONCLUSIONS: In this study, SPB interventions were associated with increased medication adherence and patient satisfaction. This pilot also provides empirical data on the cost-effectiveness of adherence technology used in a specialty pharmacy oncology setting. DISCLOSURES: This study was supported by Avella Specialty Pharmacy and AdhereTech. All authors are employees of Avella; Eric Sredzinski was an option holder of Avella; and none of the Avella authors had a financial interest in AdhereTech. AdhereTech provided the SPBs and data services for the duration of this study. The authors report no other potential conflicts of interest. Interim study data were presented at the 2016 Southwestern States Residency Conference (SSRC) on June 20, 2016, in Phoenix, AZ.


Assuntos
Embalagem de Medicamentos/instrumentação , Lenalidomida/uso terapêutico , Adesão à Medicação/estatística & dados numéricos , Mieloma Múltiplo/tratamento farmacológico , Assistência Farmacêutica/organização & administração , Sistemas de Alerta/instrumentação , Idoso , Idoso de 80 Anos ou mais , Análise Custo-Benefício , Embalagem de Medicamentos/economia , Equipamentos e Provisões Elétricas/economia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Satisfação do Paciente , Assistência Farmacêutica/economia , Farmacêuticos/organização & administração , Técnicos em Farmácia/organização & administração , Projetos Piloto , Papel Profissional , Estudos Prospectivos , Sistemas de Alerta/economia , Envio de Mensagens de Texto , Estados Unidos
12.
Med Phys ; 46(12): 5685-5689, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31580489

RESUMO

PURPOSE: Measurement of the modulation transfer function (MTF) is performed by evaluating the response of an imaging system to a predefined input. To obtain accurate results when using an edge phantom, the detector input signal must resemble an ideal step function. The MTF of megavoltage (MV) imagers used in radiotherapy has been measured with highly absorbing edge phantoms fabricated from thick metal blocks. This study investigates the influence of the edge phantom design on the accuracy of the resulting MTF. METHODS: The MTF of an electronic portal imaging device (EPID) was measured at 6 MV beam quality with four edge phantoms made of lead with 1.3, 3.3, 5.0, and 10.0 cm thickness. Monte Carlo simulations were carried out for these and a selection of tungsten phantoms to determine the photon fluence at the imaging plane and quantify the systematic error in the MTF introduced by the edge phantom design. RESULTS: The measured MTF depends on the design of the edge phantom. The detector input signal of a thin phantom is affected by secondary radiation from the phantom itself, causing an overestimation of the MTF. The amount of secondary radiation can be reduced by increasing the phantom thickness or introducing an air gap between the phantom and the detector. Both methods introduce geometric unsharpness, which can result in an underestimation of the true MTF. Edge phantoms made from 4.0 cm thick tungsten or 5.0 cm thick lead induce comparatively small systematic errors of below 3% or 5%, respectively. CONCLUSIONS: When MTF measurements are conducted at MV energies, even a highly absorbing edge phantom will introduce a systematic error of several percent. Direct comparison of MTFs obtained with different edge phantoms should therefore be treated with caution.


Assuntos
Processamento de Imagem Assistida por Computador/instrumentação , Imagens de Fantasmas , Equipamentos e Provisões Elétricas , Método de Monte Carlo , Raios X
13.
Hosp Pediatr ; 9(11): 874-879, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31591139

RESUMO

OBJECTIVES: To characterize the baseline level of emergency preparedness among families of technology-dependent children admitted to our PICU and to determine if an ICU-based planning intervention can sustainably improve families' disaster preparedness. METHODS: A single-arm, survey-based study used to assess participants' preparedness to handle a 72-hour home power outage on the basis of a novel 8-point checklist. Parents of patients in the study completed the survey questions when their child was admitted to the PICU, discharged, or transferred from the PICU, after at least 2 weeks at home, and after at least 6 months at home. This study included a cohort of 50 children younger than18 years old who required daily use of at least 1 piece of qualifying electronic medical equipment at home and their custodial parents. The checklist surveyed was designed with the goals of maximizing care capacity at home during a power outage and planning for evacuation. Counseling and other resources were provided on the basis of item completion at admission assessment. RESULTS: Patients' families completed a median of 3 items (range: 0-8; N = 50) at admission, 4 items (range: 1-8; n = 45) at discharge, and 7 items (range: 3-8; n = 37) at the 2-week follow-up and retained 7 items (range: 5-8; n = 29) at the 6-month follow-up. Completion rates were significantly higher at each follow-up time point compared with baseline (P < .001). CONCLUSIONS: Families of technology-dependent children admitted to our PICU have significant disaster-preparedness needs, which can be addressed with an inpatient intervention.


Assuntos
Crianças com Deficiência , Planejamento em Desastres , Equipamentos e Provisões Elétricas , Eletricidade , Pais , Adolescente , Lista de Checagem , Criança , Pré-Escolar , Emergências , Humanos , Lactente , Inquéritos e Questionários
14.
PLoS One ; 14(10): e0224149, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31665166

RESUMO

Information barriers are trusted measurement systems to confirm the authenticity of nuclear warheads based on their radiation signatures. Traditional inspection systems rely on complex electronics both for data acquisition and processing. Several research efforts have produced prototype systems, but it has proven difficult to demonstrate that hidden switches and side channels do not exist. After almost thirty years of research and development, no viable and widely accepted system has emerged. We pursue a fundamentally different approach: Our prototype of an inspection system uses vintage hardware built around a 6502 processor. The processor uses 8-micron technology and has only about 4,200 transistors. Vintage electronics may have a number of important advantages for applications where two parties need to simultaneously establish trust in the hardware used. CPUs designed in the distant past, at a time when their use for sensitive measurements was never envisioned, drastically reduce concerns that the other party implemented backdoors or hidden switches on the hardware level. We demonstrate the performance of a prototype system using an Apple IIe and a custom-made open-source data-processing board connected to a standard sodium-iodide radiation detector for low-resolution gamma spectroscopy. Data processing and analysis is exclusively done on the Apple IIe hardware. We show that subtle differences in radiation signatures can be detected in 2-3 minutes based on the result of a simple chi-squared test. Vintage electronics may therefore offer a new path toward fieldable, trusted information barriers.


Assuntos
Equipamentos e Provisões Elétricas , Armas Nucleares , Monitoramento de Radiação/instrumentação , Algoritmos , Controle de Qualidade , Processamento de Sinais Assistido por Computador
15.
Phys Med ; 64: 204-209, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31515021

RESUMO

PURPOSE: We evaluated the feasibility of electronic portal imaging based 3D in-vivo dosimetry for stereotactic body radiation therapy (SBRT) technique in prostate cancer. METHODS AND MATERIALS: To investigate error detectability limitations of iViewDose™ v.1.0.1 (Elekta, Stockholm, Sweden) for prostate SBRT cases, ten prostate cancer patients were selected and in-vivo electronic portal imaging devices dosimetry was performed. Also possible error scenarios including dose calibration, setup, collimator, multi leaf collimator and patient anatomy related inaccuracies were created to investigate detectability of EPID. For this purpose, a SBRT treatment was planned on BrainLab pelvis phantom (BrainLab Medical Systems, Westchester, IL) and irradiated after proving setup with cone beam computer tomography. After that incorrect plans were irradiated and obtained results were compared with original in vivo measurements. RESULTS: Mean gamma analysis (γ% ≤ 1) passing rate of ten patients was found as 96.2%. Additionally, mean dose reference point difference between measurement and calculated in treatment planning system for clinical target volume, rectum, bladder, left and right femur heads were found as 1.4%, 8%, 20.8%, 2.3% and 4.5%, respectively. Phantom measurements showed that positional errors can be escape from detection. However, the incorrect treated plans including linac calibration, MLC positions and patient anatomy based errors could not have passed the in vivo dosimetry analysis. CONCLUSIONS: EPID-based 3D in vivo dosimetry software (iViewDose) provides an efficient safety check on the accuracy of dose delivery during prostate SBRT treatments. However, phantom results showed some limitation of the system.


Assuntos
Equipamentos e Provisões Elétricas , Neoplasias da Próstata/radioterapia , Radiocirurgia/instrumentação , Radioterapia Guiada por Imagem/instrumentação , Estudos de Viabilidade , Humanos , Masculino , Aceleradores de Partículas , Dosagem Radioterapêutica , Planejamento da Radioterapia Assistida por Computador
16.
Phys Med Biol ; 64(20): 205007, 2019 10 10.
Artigo em Inglês | MEDLINE | ID: mdl-31519004

RESUMO

Diodes dosimeters present a complex response to pulsed beams, with diode sensitivity varying with dose-per-pulse, monitor unit rate (time between pulses) or number of integrated pulses. Such a response is caused by the complex kinetics of the interplay among charge carriers, recombination-generation centers, which capture excess minority charge carriers and facilitate recombination with a majority charge carrier, and traps with energy levels close to the conduction/valence band, which can trap and release charge carriers. This behavior has been well characterized experimentally, and modeled with phenomenological models. In this work we present a kinetic multi-compartment model of the response of diode detectors, which includes the interplay among charge carriers, recombination-generation centers, and traps. The model can qualitatively fit experimental data extracted from the literature on diode response versus dose-per-pulse, monitor unit rate (time between pulses), or number of integrated pulses. In this regard, our work provides further insight on the response of diode detectors, and a theoretical framework for the development of simple phenomenological models.


Assuntos
Equipamentos e Provisões Elétricas , Modelos Estatísticos , Aceleradores de Partículas/instrumentação , Radiometria/instrumentação , Radiometria/métodos , Cinética , Doses de Radiação
17.
J Appl Clin Med Phys ; 20(9): 133-142, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31520517

RESUMO

PURPOSE: Assessment of the accuracy of geometric tests of a linac used in external beam therapy is crucial for ensuring precise dose delivery. In this paper, a new simulation-based method for assessing accuracy of such geometric tests is proposed and evaluated on a set of testing procedures. METHODS: Linac geometry testing methods used in this study are based on an established design of a two-module phantom. Electronic portal imaging device (EPID) images of fiducial balls contained in these modules can be used to automatically reconstruct linac geometry. The projection of the phantom modules fiducial balls onto the EPID detector plane is simulated for assumed nominal geometry of a linac. Then, random errors are added to the coordinates of the projections of the centers of the fiducial balls and the linac geometry is reconstructed from these data. RESULTS: Reconstruction is performed for a set of geometric test designs and it is shown how the dispersion of the reconstructed values of geometric parameters depends on the design of a geometric test. Assuming realistic accuracy of EPID image analysis, it is shown that for selected testing plans the reconstruction accuracy of geometric parameters can be significantly better than commonly used action thresholds for these parameters. CONCLUSIONS: Proposed solution has the potential to improve geometric testing design and practice. It is an important part of a fully automated geometric testing solution.


Assuntos
Simulação por Computador , Aceleradores de Partículas/instrumentação , Aceleradores de Partículas/normas , Imagens de Fantasmas , Garantia da Qualidade dos Cuidados de Saúde/normas , Controle de Qualidade , Radioterapia de Intensidade Modulada/normas , Algoritmos , Equipamentos e Provisões Elétricas , Humanos
18.
Med Phys ; 46(11): 5350-5359, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31532831

RESUMO

PURPOSE: To investigate the applicability of output correction factors reported in TRS-483 on 6-MV small-field detector-reading ratios using four solid-state detectors. Also, to investigate variations in 6-MV small-field output factors (OF) among nominally matched linear accelerators (linacs). METHODS: The TRS-483 Code of Practice (CoP) introduced and provided output correction factors to be applied to measured detector-reading ratios to obtain OFs for several small-field detectors. Detector readings for 0.5 cm × 0.5 cm to 8 cm × 8 cm fields were measured and normalized to that of 10 cm × 10 cm field giving the detector-reading ratios. Three silicon diodes, IBA PFD, IBA EFD (IBA, Schwarzenbruck, Germany), PTW T60017, and one microdiamond, PTW T60019 (PTW, Freiburg, Germany), were used. Output correction factors from the CoP were applied to measured detector-reading ratios. Measurements were performed on six Clinac and six TrueBeam linacs (Varian Medical Systems, Palo Alto, USA). An investigation of the relationship between the size of small fields and corresponding detector-reading ratio among the linacs was performed by measuring lateral dose profiles for 0.5 cm × 0.5 cm fields to determine the full width half maximum (FWHM). The relationship between the linacs' focal spot size and the small-field detector-reading ratio was investigated by measuring 10 cm × 10 cm lateral dose profiles and determining the penumbra width reflecting the focal spot size. Measurement geometry was as follows: gantry angle = 0°, collimator angle = 0°, source-to surface distance (SSD) = 90 cm, and depth in water = 10 cm. RESULTS: For a given linac and 0.5 cm × 0.5 cm field, the deviations in detector-reading ratios among the detectors were 9%-15% for the Clinacs and 4%-5% for the TrueBeams. Use of output correction factors reduced these deviations to 6%-12% and 3%-4%, respectively. For field sizes equal to or larger than 0.8 cm × 0.8 cm, the deviations were corrected to 1% using output correction factors for both Clinacs and TrueBeams. For a given detector and 0.5 cm × 0.5 cm field, the deviations in detector-reading ratios among the linacs were 11%-17% for the Clinacs and 5-6% for the TrueBeams. For 1 cm × 1 cm the deviations were 1%-2% for Clinacs and 1% for TrueBeams. For field sizes larger than 1 cm × 1 cm the deviations were within 1% for both Clinacs and TrueBeams. No relationship between FWHMs and detector-reading ratios for 0.5 cm × 0.5 cm was observed. For Clinacs, larger 10 cm × 10 cm penumbra width yielded lower 0.5 cm × 0.5 cm detector-reading ratio indicating an effect of the focal spot size. For TrueBeams, the spread of penumbra widths was lower compared to Clinacs and no similar relationship was observed. CONCLUSIONS: Output correction factors from the TRS-483 CoP are not sufficient for accurate determination of OF for 0.5 cm × 0.5 cm fields but are applicable for 0.8 cm × 0.8 cm to 8 cm × 8 cm fields. Nominally matched Clinacs and TrueBeams show large differences in detector-reading ratios for fields smaller than 1 cm × 1 cm.


Assuntos
Aceleradores de Partículas , Radiometria/instrumentação , Equipamentos e Provisões Elétricas , Método de Monte Carlo , Fótons/uso terapêutico
19.
Adv Mater ; 31(39): e1903095, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31410882

RESUMO

Mimicking brain-like functionality with an electronic device is an essential step toward the design of future technologies including artificial visual and memory applications. Here, a proof-of-concept all-oxide-based (NiO/TiO2 ) highly transparent (54%) heterostructure is proposed and demonstrated, which mimics the primitive functions of the visual cortex. Specifically, orientation selectivity and spatiotemporal processing similar to that of the visual cortex are demonstrated using direct optical stimuli under the self-biased condition due to photovoltaic effect, illustrating an energy-efficient approach for neuromorphic computing. The photocurrent of the device can be modulated from zero to 80 µA by simply rotating the slit by 90°. The device shows fast rise and fall times of 3 and 6 ms, respectively. Based on Kelvin probe force measurements, the observed results are attributed to a lateral photovoltaic effect. This highly transparent, self-biased, photonic triggered device paves the way for the advancement of energy-efficient neuromorphic computation.


Assuntos
Biomimética/instrumentação , Equipamentos e Provisões Elétricas , Fenômenos Ópticos , Fótons , Córtex Visual/fisiologia , Nanofios/química , Níquel/química , Prata/química , Titânio/química
20.
Artigo em Inglês | MEDLINE | ID: mdl-31434201

RESUMO

The industrial development and the increase in the use of fossil fuels have been accelerating global warming and climate change, thereby causing more frequent and intense natural disasters than ever before. Since electrical facilities are generally installed outdoors, they are greatly affected by natural disasters, thus accidents related to electrical equipment has been on the rise. In this paper, we present the risk rating associated with climate change by analyzing the statistics of electrical fires, electric shock accidents and electrical equipment accidents caused by domestic climate change. Further, we present a risk rating analysis model for electrical fires on a monthly basis through the data analysis of electrical hazards associated with various regional (metropolitan city) climatic conditions (temperature, humidity), and analyze the accident risk rating for natural disasters related to low and high voltage equipment. Through this risk analysis model for each region and type of equipment, we presented a basic prediction model for electrical hazards. Therefore, it is possible to provide electrical safety services in the future by displaying a risk prediction map of electrical hazards for each region and type of electrical equipment through web sites or smart phone apps using the presented analysis data. Further, efforts should be made to increase the robustness or reliability of electrical equipment in order to prevent electrical accidents caused by natural disasters due to climate change in advance.


Assuntos
Acidentes , Equipamentos e Provisões Elétricas , Fogo , Aquecimento Global , Mudança Climática , Eletricidade , Previsões , Reprodutibilidade dos Testes , Medição de Risco , Temperatura
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