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1.
J Low Temp Phys ; 209(5-6): 766-778, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36467121

RESUMO

We present a feasibility study for the high-redshift galaxy part of the Science Verification Campaign with the 220-440 GHz deshima 2.0 integrated superconducting spectrometer on the ASTE telescope. The first version of the deshima 2.0 chip has been recently manufactured and tested in the lab. Based on these realistic performance measurements, we evaluate potential target samples and prospects for detecting the [CII] and CO emission lines. The planned observations comprise two distinct, but complementary objectives: (1) acquiring spectroscopic redshifts for dusty galaxies selected in far-infrared/mm-wave surveys; (2) multi-line observations to infer physical conditions in dusty galaxies.

2.
Benef Microbes ; 13(1): 3-11, 2022 Feb 28.
Artigo em Inglês | MEDLINE | ID: mdl-35144525

RESUMO

Fructophilic lactic acid bacteria (FLAB) are heterofermentative and related to the genera Fructilactobacillus, Convivina, Leuconostoc, Oenococcus and Weissella. Although they generally prefer fructose above glucose, obligate heterofermentative species will ferment glucose in the presence of external electron acceptors such as pyruvate and fructose. Little is known about the presence of FLAB in the human gut, let alone probiotic properties. In this review we discuss the possible role FLAB may have in the human gastro-intestinal tract (GIT) and highlight the advantages and disadvantages these bacteria may have in individuals with a diet high in fructose.


Assuntos
Lactobacillales , Probióticos , Fermentação , Frutose , Glucose , Humanos
5.
Epidemiol Infect ; 148: e216, 2020 09 08.
Artigo em Inglês | MEDLINE | ID: mdl-32895088

RESUMO

The test-negative design (TND) has become a standard approach for vaccine effectiveness (VE) studies. However, previous studies suggested that it may be more vulnerable than other designs to misclassification of disease outcome caused by imperfect diagnostic tests. This could be a particular limitation in VE studies where simple tests (e.g. rapid influenza diagnostic tests) are used for logistical convenience. To address this issue, we derived a mathematical representation of the TND with imperfect tests, then developed a bias correction framework for possible misclassification. TND studies usually include multiple covariates other than vaccine history to adjust for potential confounders; our methods can also address multivariate analyses and be easily coupled with existing estimation tools. We validated the performance of these methods using simulations of common scenarios for vaccine efficacy and were able to obtain unbiased estimates in a variety of parameter settings.


Assuntos
Viés , Técnicas e Procedimentos Diagnósticos/normas , Vacinas/imunologia , Animais , Interpretação Estatística de Dados , Humanos , Análise Multivariada
6.
Math Biosci Eng ; 17(4): 4115-4126, 2020 06 09.
Artigo em Inglês | MEDLINE | ID: mdl-32987571

RESUMO

Intensive surveillance of Zika virus infection conducted on Yap Island has provided crucial information on the epidemiological characteristics of the virus, but the rate of infection and medical attendance stratified by age and geographical location of the epidemic have yet to be fully clarified. In the present study, we reanalyzed surveillance data reported in a previous study. Likelihood-based Bayesian inference was used to gauge the age and geographically dependent force of infection and age-dependent reporting rate, with unobservable variables imputed by the data augmentation method. The inferred age-dependent component of the force of infection was suggested to be up to 3-4 times higher among older adults than among children. The age-dependent reporting rate ranged from 0.7% (5-9 years old) to 3.3% (50-54 years old). The proportion of serologically confirmed cases among total probable or confirmed cases was estimated to be 44.9%. The cumulative incidence of infection varied by municipality: Median values were over 80% in multiple locations (Gagil, Tomil, and Weloy), but relatively low values (below 50%) were derived in other locations. However, the possibility of a comparably high incidence of infection was not excluded even in municipalities with the lowest estimates. The results suggested a high degree of heterogeneity in the Yap epidemic. The force of infection and reporting rate were higher among older age groups, and this discrepancy implied that the demographic patterns were remarkably different between all infected and medically attended individuals. A higher reporting rate may have reflected more severe clinical presentation among adults. The symptomatic ratio in dengue cases is known to correlate with age, and our findings presumably indicate a similar tendency in Zika virus disease.


Assuntos
Infecção por Zika virus , Zika virus , Idoso , Teorema de Bayes , Criança , Surtos de Doenças , Humanos , Lactente , Funções Verossimilhança , Infecção por Zika virus/epidemiologia
7.
Pharmazie ; 75(2): 82-89, 2020 03 20.
Artigo em Inglês | MEDLINE | ID: mdl-32213239

RESUMO

Background/aim: In the convalescent rehabilitation ward, many elderly patients undergo rehabilitation. Histamine-2 receptor antagonists (H2RA), which is a one of the acid secretion inhibitors, is frequently prescribed for the patients as a peptic ulcer prevention measure. At present, H2RA are reported as being associated with factors that reduce cognitive function. However, little is known about the relationship H2RA and rehabilitation outcome. Therefore, this study examined the relationship between H2RA use and Functional Independence Measure (FIM) gain, which determines rehabilitation outcomes for patients admitted to the convalescent rehabilitation ward. Patients and methods: We retrospectively investigated FIM gain on discharge by both the administration group (H2RA (+)) (n = 118) and non-administration group (H2RA (-)) (n = 118). Results: The FIM gain scores of Motor FIM total, Cognition FIM total, and Total FIM were significantly lower in H2RA (+) than in H2RA (-) (Motor FIM total: 8.0 [4.0-16.0] [Inter-Quartile Range] vs. 12.0 [5.0-19.2], p =0.0217, Cognition FIM total: 3.0 [1.0-6.0] vs. 5.0 [2.0-7.0], p =0.0120, Total FIM: 11.5 [4.8-20.2] vs. 17.0 [8.0-27.0], p =0.0089). Conclusion: The administration of H2RA to elderly patients undergoing rehabilitation may prevent cognitive function maintenance or recovery by rehabilitation.


Assuntos
Atividades Cotidianas/psicologia , Cognição/efeitos dos fármacos , Antagonistas dos Receptores H2 da Histamina/efeitos adversos , Recuperação de Função Fisiológica/efeitos dos fármacos , Idoso , Idoso de 80 Anos ou mais , Feminino , Hospitalização , Humanos , Tempo de Internação , Masculino , Pessoa de Meia-Idade , Alta do Paciente , Recuperação de Função Fisiológica/fisiologia , Estudos Retrospectivos , Reabilitação do Acidente Vascular Cerebral , Resultado do Tratamento
8.
Arch Microbiol ; 201(10): 1453-1457, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31338543

RESUMO

A total of 104 exopolysaccharide (gum)-producing bacteria were isolated from the juice screen and juice tank in a sugarcane processing factory at times of low- and high dextran concentrations in the produced sugar. Dextran is an indicator of cane deterioration and sucrose loss after harvesting of the cane. The isolates were identified as Bacillus amyloliquefaciens (96 isolates) and Bacillus subtilis (eight isolates) based on restriction enzyme banding patterns of amplified 16S rRNA genes and rpoB gene sequence analysis. Exopolysaccharide production in sugarcane is normally associated with dextran produced by Leuconostoc mesenteroides. B. amyloliquefaciens, and to a lesser extent B. subtilis, could, however, also be responsible for exopolysaccharide (slime or gum) production in cane processing factories.


Assuntos
Bacillus amyloliquefaciens/classificação , Bacillus amyloliquefaciens/genética , Bacillus subtilis/classificação , Bacillus subtilis/genética , Indústria de Processamento de Alimentos , RNA Polimerases Dirigidas por DNA/genética , RNA Ribossômico 16S/genética , Saccharum/microbiologia
9.
Radiat Prot Dosimetry ; 184(3-4): 518-522, 2019 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-31330027

RESUMO

Soil samples from the surface to a 5 cm depth were collected at a residential house in Koriyama City, Fukushima Prefecture using a scraper plate every three months from March 2014 to September 2014 to evaluate the vertical distribution profiles and inventories of 134Cs and 137Cs in soil. The vertical distribution profiles of radiocesium (134Cs and 137Cs) in soil showed that greater than 86% of the total radiocesium was absorbed in the upper 2 cm 3 years after the accident. Radiocesium in the surface layer seems to move to the lower layer over time. The migration of radiocesium in surface layer might be influenced by the ground surface runoff by rainfall. Radiocesium inventories in June increased significantly over the short period between March and June. In contrast, the radiocesium inventories in September did not increase significantly compared to the values in June. Radiocesium resuspension and deposition caused by decontamination work and meteorological events might be one possible reason for the increased radiocesium inventories observed in June.


Assuntos
Radioisótopos de Césio/análise , Acidente Nuclear de Fukushima , Exposição à Radiação/análise , Monitoramento de Radiação/métodos , Poluentes Radioativos do Solo/análise , Descontaminação , Habitação , Humanos , Centrais Nucleares
10.
Br J Surg ; 105(11): 1426-1434, 2018 10.
Artigo em Inglês | MEDLINE | ID: mdl-29999518

RESUMO

BACKGROUND: The benefits of high transfusion ratios (plasma to red blood cells and platelets to red blood cells) on survival in injured patients who receive massive transfusions remain uncertain. This study aimed to assess the association between transfusion ratios and adverse events and survival in patients undergoing massive transfusion for major trauma. METHODS: A retrospective observational study was conducted on patients who had major trauma using a Japanese national administrative database. The associations between transfusion ratios and outcomes (in-hospital mortality and incidence of adverse events) were analysed using a non-linear logistic generalized additive model (GAM). In a logistic generalized estimating equation model, adjusted for patient and hospital-level confounders, transfusion ratios were included as continuous or categorical variables (low, transfusion ratio 0·75 or less; intermediate, over 0·75 to 1·25; high, over 1·25). RESULTS: Some 1777 patients were included in the analysis, of whom 602 died in hospital. GAM plots of the transfusion ratios for in-hospital mortality demonstrated a downward convex unimodal curve. In-hospital mortality was similar with increasing transfusion ratios for plasma (adjusted odds ratio (OR) 1·13, 95 per cent c.i. 0·82 to 1·55; P = 0·446) and platelets (adjusted OR 0·84, 0·66 to 1·08; P = 0·171). Both plasma to red blood cell ratio (adjusted OR 1·77, 1·32 to 2·37; P < 0·001) and platelet to red blood cell ratio (adjusted OR 1·71, 1·35 to 2·15; P < 0·001) were significantly associated with a higher incidence of adverse events. No significant differences in in-hospital mortality were observed between the three transfusion categories (low, medium and high). CONCLUSION: In this study, transfusion strategies with high plasma to red blood cell and platelet to red blood cell ratios did not have survival benefits, but were associated with an increase in adverse events.


Assuntos
Transfusão de Sangue/métodos , Ferimentos e Lesões/terapia , Adulto , Idoso , Feminino , Seguimentos , Mortalidade Hospitalar/tendências , Humanos , Escala de Gravidade do Ferimento , Japão/epidemiologia , Masculino , Pessoa de Meia-Idade , Prognóstico , Estudos Retrospectivos , Taxa de Sobrevida/tendências , Ferimentos e Lesões/diagnóstico , Ferimentos e Lesões/mortalidade
11.
Radiat Prot Dosimetry ; 180(1-4): 10-16, 2018 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-29165634

RESUMO

Report Committee 26 of the ICRU proposes a set of operational quantities for radiation protection for external radiation, directly based on effective dose and for an extended range of particles and energies. It is accompanied by quantities for estimating deterministic effects to the eye lens and the local skin. The operational quantities are designed to overcome the conceptual and technical shortcomings of those presently in use. This paper describes the proposed operational quantities, and highlights the improvements with respect to the present, legal monitoring quantities.


Assuntos
Cristalino/efeitos da radiação , Exposição à Radiação/efeitos adversos , Lesões por Radiação/prevenção & controle , Monitoramento de Radiação/normas , Proteção Radiológica/normas , Calibragem , Humanos , Agências Internacionais , Doses de Radiação , Lesões por Radiação/etiologia
12.
Nat Commun ; 8(1): 1715, 2017 11 23.
Artigo em Inglês | MEDLINE | ID: mdl-29167425

RESUMO

The quantum Rabi model describing the fundamental interaction between light and matter is a cornerstone of quantum physics. It predicts exotic phenomena like quantum phase transitions and ground-state entanglement in ultrastrong and deep-strong coupling regimes, where coupling strengths are comparable to or larger than subsystem energies. Demonstrating dynamics remains an outstanding challenge, the few experiments reaching these regimes being limited to spectroscopy. Here, we employ a circuit quantum electrodynamics chip with moderate coupling between a resonator and transmon qubit to realise accurate digital quantum simulation of deep-strong coupling dynamics. We advance the state of the art in solid-state digital quantum simulation by using up to 90 second-order Trotter steps and probing both subsystems in a combined Hilbert space dimension of ∼80, demonstrating characteristic Schrödinger-cat-like entanglement and large photon build-up. Our approach will enable exploration of extreme coupling regimes and quantum phase transitions, and demonstrates a clear first step towards larger complexities such as in the Dicke model.

13.
J Low Temp Phys ; 184: 412-417, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27340291

RESUMO

We show the first experimental results which prove that superconducting NbTiN coplanar-waveguide resonators can achieve a loaded Q factor in excess of 800 in the 350 GHz band. These resonators can be used as narrow band pass filters for on-chip filter bank spectrometers for astronomy. Moreover, the low-loss coplanar waveguide technology provides an interesting alternative to microstrip lines for constructing large scale submillimeter wave electronics in general.

14.
Opt Express ; 24(2): 1402-8, 2016 Jan 25.
Artigo em Inglês | MEDLINE | ID: mdl-26832521

RESUMO

This work reports on a liquid-nitrogen-cooled, SESAM mode-locked Yb:YGAG (Yb:Y(3)Ga(2)Al(3)O(12)) ceramic laser. The Yb:YGAG has a similar structure to Yb:YAG, but its emission spectrum at low temperature remains much broader, which is suitable for ultrashort pulse generation and amplification. A stable pulse train with 119-MHz repetition rate was obtained at a wavelength of 1026 nm. The measured pulse duration is 2.4 ps, which is more than four times shorter than that achieved with a cryogenically-cooled Yb:YAG. Furthermore, laser performance of the Yb:YGAG ceramics in continuous-wave operation and wavelength tunability at 80 K was investigated.

15.
Phys Chem Chem Phys ; 18(4): 2699-709, 2016 Jan 28.
Artigo em Inglês | MEDLINE | ID: mdl-26726006

RESUMO

The present study demonstrates for the first time, the development of mesoporous zirconium hydroxide with high CO2 capacity and sustainable adsorption-desorption performance within a broad range of pressures (100-3000 kPa). Mesoporous zirconium hydroxide with a high surface area of ∼400 m(2) g(-1) was prepared by a simple and easy-to-handle precipitation route. The prepared high surface area mesoporous zirconium hydroxide exhibited significantly higher CO2 adsorption uptake and working adsorption capacity on a volumetric basis within a wide range of operating pressures of 100-3000 kPa than commercially available zeolite 13X. Reversible CO2 desorption was easily achieved by a pressure swing at moderate temperatures (298.15 K). Additionally, the prepared mesoporous zirconium hydroxide was adequately stable and strong to effectuate CO2 capture over multiple adsorption-desorption cycles without major reductions in its CO2 adsorption capacity. Furthermore, the effect of co-adsorbed water on the CO2 adsorption properties of mesoporous zirconium hydroxide was investigated. In the presence of co-adsorbed water, mesoporous zirconium hydroxide displayed reversible CO2 adsorption-desorption behavior in contrast to zeolite 13X that exhibited negligible CO2 adsorption within the wide range of pressures examined. The present study demonstrates the potential of high surface area mesoporous zirconium hydroxide toward efficient CO2 capturing processes.

16.
Ann ICRP ; 45(2): 5-73, 2016 11.
Artigo em Inglês | MEDLINE | ID: mdl-29749258

RESUMO

Abstract ­: Dose coefficients for assessment of internal exposures to radionuclides are radiological protection quantities giving either the organ equivalent dose or effective dose per intake of radionuclide following ingestion or inhalation. In the International Commission on Radiological Protection's (ICRP) Occupational Intakes of Radionuclides (OIR) publication series, new biokinetic models for distribution of internalised radionuclides in the human body are presented as needed for establishing time-integrated activity within organs of deposition (source regions). This series of publications replaces Publications 30 and 68 (ICRP, 1979, 1980, 1981, 1988, 1994b). In addition, other fundamental data needed for computation of the dose coefficients are radionuclide decay data (energies and yields of emitted radiations), which are given in Publication 107 (ICRP, 2008), and specific absorbed fraction (SAF) values ­ defined as the fraction of the particle energy emitted in a source tissue region that is deposited in a target tissue region per mass of target tissue. This publication provides the technical basis for SAFs relevant to internalised radionuclide activity in the organs of Reference Adult Male and Reference Adult Female as defined in Publications 89 and 110 (ICRP, 2002, 2009). SAFs are given for uniform distributions of mono-energetic photons, electrons, alpha particles, and fission-spectrum neutrons over a range of relevant energies. Electron SAFs include both collision and radiative components of energy deposition. SAF data are matched to source and target organs of the biokinetic models of the OIR publication series, as well as the Publication 100 (ICRP, 2006) Human Alimentary Tract Model and the Publication 66 (ICRP, 1994a) Human Respiratory Tract Model, the latter as revised within Publication 130 (ICRP, 2015). This publication further outlines the computational methodology and nomenclature for assessment of internal dose in a manner consistent with that used for nuclear medicine applications. Numerical data for particle-specific and energy-dependent SAFs are given in electronic format for numerical coupling to the respiratory tract, alimentary tract, and systemic biokinetic models of the OIR publication series.

17.
Clin Exp Allergy ; 44(9): 1154-69, 2014 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-25048599

RESUMO

BACKGROUND: Regulatory T cells (T(regs)) are activated during anergy in response to T cell receptor (TCR) activation and functional immune suppression. Anergy of paediatric T(regs) is partially dependent on intracellular calcium mobility; following TCR activation, T(regs) do not exhibit increased intracellular Ca(2+) concentration ([Ca(2+) ](i)). OBJECTIVE: We determined whether [Ca(2+) ](i) in adult T(regs) defined their anergy, if intracellular Ca(2+) movement was linked to regulatory functions, whether [Ca(2+)](i) was indicative of asthma pathology, and the potential molecular mechanism responsible for Ca(2+) movement in T(regs). METHODS: T(regs) were purified by the magnetic bead method, and their regulatory functions were assessed by monitoring carboxyfluorescein succinimidyl ester-labelled responder T cell proliferation. The Ca(2+) response of Fura-2-labelled cells was measured using a video image analysis system. To analyse the functions of T(regs) at the molecular level, we generated Jurkat Tet-On(®) clones with doxycycline (Dox)-induced forkhead box P3 (FOXP3) protein expression. RESULTS: CD4(+) CD25(+) CD127(-/low) T(regs) from participants without asthma did not elicit Ca(2+) influx in response to TCR activation, exhibited little proliferation and suppressed proliferation of CD4(+) CD25(-) T cells. In contrast, under similar conditions, T(regs) from patients with asthma exhibited increased [Ca(2+)](i) and robust proliferation with partial loss of regulatory functions. FOXP3 protein levels in Tet-On(®) clones were high after both 2- and 5-day Dox treatment; however, 5-day cells were comparable with T(regs) from patients with asthma, whereas 2-day cells were similar to T(regs) from participants without asthma. Increasing [Ca(2+)](i) induced a high level of receptor for activated C kinase 1 (RACK1) expression in 5-day cells. CONCLUSIONS AND CLINICAL RELEVANCE: We confirmed that T(regs) in patients with asthma are functionally impaired and that the abnormal regulatory functions of these cells can be analysed by [Ca(2+)](i) following TCR engagement. Furthermore, the impaired functioning of T(regs) evident in patients with asthma may be due to a high level of RACK1.


Assuntos
Asma/imunologia , Asma/metabolismo , Cálcio/metabolismo , Receptores de Superfície Celular/metabolismo , Linfócitos T Reguladores/imunologia , Linfócitos T Reguladores/metabolismo , Corticosteroides/administração & dosagem , Corticosteroides/uso terapêutico , Adulto , Idoso , Antígenos de Superfície/metabolismo , Asma/diagnóstico , Asma/tratamento farmacológico , Asma/genética , Estudos de Casos e Controles , Linhagem Celular , Proliferação de Células , Feminino , Fatores de Transcrição Forkhead/genética , Fatores de Transcrição Forkhead/metabolismo , Expressão Gênica , Humanos , Imunofenotipagem , Espaço Intracelular/metabolismo , Ativação Linfocitária , Masculino , Pessoa de Meia-Idade , Fenótipo , Receptores de Quinase C Ativada , Receptores de Superfície Celular/genética , Fatores de Risco
18.
Nature ; 510(7504): 247-9, 2014 Jun 12.
Artigo em Inglês | MEDLINE | ID: mdl-24919918

RESUMO

Long-duration γ-ray bursts are associated with the explosions of massive stars and are accordingly expected to reside in star-forming regions with molecular gas (the fuel for star formation). Previous searches for carbon monoxide (CO), a tracer of molecular gas, in burst host galaxies did not detect any emission. Molecules have been detected as absorption in the spectra of γ-ray burst afterglows, and the molecular gas is similar to the translucent or diffuse molecular clouds of the Milky Way. Absorption lines probe the interstellar medium only along the line of sight, so it is not clear whether the molecular gas represents the general properties of the regions where the bursts occur. Here we report spatially resolved observations of CO line emission and millimetre-wavelength continuum emission in two galaxies hosting γ-ray bursts. The bursts happened in regions rich in dust, but not particularly rich in molecular gas. The ratio of molecular gas to dust (<9-14) is significantly lower than in star-forming regions of the Milky Way and nearby star-forming galaxies, suggesting that much of the dense gas where stars form has been dissipated by other massive stars.

19.
J Clin Pharm Ther ; 39(1): 97-101, 2014 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-24117862

RESUMO

WHAT IS KNOWN AND OBJECTIVES: Belimumab is a recombinant human monoclonal antibody that binds and antagonizes the biological activity of soluble B-lymphocyte stimulator (BLyS) protein. BLyS appears to play a role in the pathogenesis of systemic lupus erythematosus, and the biological profile of belimumab suggests that it may have a therapeutic benefit in the treatment for the disease. In this healthy Japanese subjects study, we investigated the pharmacokinetics and safety of a single subcutaneous and intravenous injection of belimumab administered as a 200 mg/mL liquid formulation. METHODS: This was an open-label, randomized, parallel-group, single-dose study in healthy Japanese subjects. Each subject received a single intravenous infusion or a subcutaneous injection of 200 mg belimumab. The pharmacokinetic parameters and safety parameters including local tolerance (injection site), biomarkers, immunogenicity and adverse events were evaluated up to 70 days post-dosing. RESULTS: After a single intravenous or a subcutaneous administration of 200 mg belimumab, all 16 subjects completed the study. There were no serious adverse events or adverse events related to injection site reactions. All seven adverse events were considered mild or moderate in intensity and deemed unrelated to belimumab except for cellulitis following intravenous administration. The bioavailability of the single subcutaneous dose of 200 mg belimumab in the subjects was estimated to be 77·5%. Time to the maximum serum concentration after subcutaneous injection was 6·5 days (median). The geometric mean terminal half-life was comparable between the two administration routes (17·7 days intravenous and 15·9 days subcutaneous). Serum immunoglobulin G level decreased slightly after each treatment. No subjects were found to produce antibelimumab antibodies. WHAT IS NEW AND CONCLUSIONS: A favourable absolute bioavailability in healthy Japanese subjects was seen following a subcutaneous injection of 200 mg belimumab. Considering the intersubject variability, exposures were consistent with those previously observed in healthy non-Japanese subjects. Safety and biomarker data were also consistent with previous non-Japanese clinical studies.


Assuntos
Anticorpos Monoclonais Humanizados/efeitos adversos , Anticorpos Monoclonais Humanizados/farmacocinética , Adulto , Anticorpos Monoclonais Humanizados/administração & dosagem , Área Sob a Curva , Povo Asiático , Humanos , Imunossupressores/administração & dosagem , Imunossupressores/efeitos adversos , Imunossupressores/farmacocinética , Infusões Intravenosas , Injeções Subcutâneas , Masculino , Pessoa de Meia-Idade , Adulto Jovem
20.
Dentomaxillofac Radiol ; 42(8): 20120445, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23956235

RESUMO

OBJECTIVES: The SEDENTEXCT Project proposed quality assurance (QA) methods and introduced a QA image quality phantom. A new prototype was recently introduced that may be improved according to previous reports. The purpose of this study is to evaluate image quality in various protocols of three cone beam CT (CBCT) machines using the proposed QA phantom. METHODS: Using three CBCT machines, nine image quality parameters, including image homogeneity (noise), uniformity, geometrical distortion, pixel intensity value, contrast resolution, spatial resolution [line pair (LP) chart, point spread function (PSF) and modulation transfer function (MTF)] and metal artefacts, were evaluated using a QA phantom proposed by SEDENTEXCT. Exposure parameters, slice thickness and field of view position changed variously, and the number of total protocols was 22. RESULTS: Many protocols showed a uniform gray value distribution except in the minimum slice thickness image acquired using 3D Accuitomo 80 (Morita, Kyoto, Japan) and Veraviewepocs 3Df (Morita). Noise levels differed among the protocols. There was no geometric distortion, and the pixel intensity values were correlated with the CT value. Low contrast resolution differed among the protocols, but high contrast resolution performed well in all. Many protocols showed that the maximum line pair was larger than 1 LP mm(-1) but smaller than 3 LP mm(-1). PSF and MTF did not correlate well with the pixel size. The measured metal artefact areas varied for each device. CONCLUSIONS: We studied the image quality of three CBCT machines using the SEDENTEXCT phantom. Image quality varied with exposure protocols and machines.


Assuntos
Tomografia Computadorizada de Feixe Cônico/instrumentação , Imagens de Fantasmas , Intensificação de Imagem Radiográfica/normas , Alumínio/química , Artefatos , Tomografia Computadorizada de Feixe Cônico/normas , Desenho de Equipamento , Humanos , Processamento de Imagem Assistida por Computador/normas , Imageamento Tridimensional/normas , Polietileno/química , Polimetil Metacrilato/química , Politetrafluoretileno/química , Garantia da Qualidade dos Cuidados de Saúde/normas , Doses de Radiação , Ampliação Radiográfica , Resinas Sintéticas/química , Titânio/química , Tomógrafos Computadorizados/normas
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