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1.
Biomed Phys Eng Express ; 10(2)2024 Feb 14.
Artigo em Inglês | MEDLINE | ID: mdl-38320327

RESUMO

The inherent biological hazards associated with ionizing radiation necessitate the implementation of effective shielding measures, particularly in medical applications. Interventional radiology, in particular, poses a unique challenge as it often exposes medical personnel to prolonged periods of high x-ray doses. Historically, lead and lead-based compounds have been the primary materials employed for shielding against photons. However, the drawbacks of lead, including its substantial weight causing personnel's inflexibility and its toxicity, have raised concerns regarding its long-term impact on both human health and the environment. Barium tantalate has emerged as a promising alternative, due to its unique attenuation properties against low-energy x-rays, specifically targeting the weak absorption area of lead. In the present study, we employ the Geant4 Monte Carlo simulation tool to investigate various formulations of barium tantalate doped with rare earth elements. The aim is to identify the optimal composition for shielding x-rays in the context of interventional radiology. To achieve this, we employ a reference x-ray spectrum typical of interventional radiology procedures, with energies extending up to 90 keV, within a carefully designed simulation setup. Our primary performance indicator is the reduction in air kerma transmission. Furthermore, we assess the absorbed doses to critical organs at risk within a standard human body phantom protected by the shield. Our results demonstrate that specific concentrations of the examined rare earth impurities can enhance the shielding performance of barium tantalate. To mitigate x-ray exposure in interventional radiology, our analysis reveals that the most effective shielding performance is achieved when using barium tantalate compositions containing 15% Erbium or 10% Samarium by weight. These findings suggest the possibility of developing lead-free shielding solutions or apron for interventional radiology personnel, offering a remarkable reduction in weight (exceeding 30%) while maintaining shielding performance at levels comparable to traditional lead-based materials.


Assuntos
Proteção Radiológica , Radiologia Intervencionista , Humanos , Bário , Radiometria , Proteção Radiológica/métodos , Radiografia
2.
Appl Radiat Isot ; 202: 111047, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37782983

RESUMO

Many minerals and compounds show thermoluminescence (TL) properties but only a few of them can meet the requirements of an ideal dosimeter. Several phosphate materials have been studied for low-dose dosimetryin recent times. Among the various phosphates, ABPO4-type material shows interesting TL properties. In this study, an ABPO4-type (A = Lithium, B=Calcium) phosphor is synthesized using a modified solid-state diffusion method. Temperature is maintained below 800 °C in every step of phosphor preparation to obtain the pure phase of Lithium calcium phosphate (LiCaPO4). The purpose of this work is to synthesize LiCaPO4 using a simple method, examine its structural and luminescence properties in order to gain a deeper understanding of its TL characteristics. The general TL properties, such as TL glow curve, dose linearity, sensitivity, and fading, are investigated. Additionally, this study aims to determine various kinetic parameters through Glow Curve Deconvolution (GCD) method using the Origin Lab software together with the Chen model. XRD analysis confirmed the phase purity of the phosphor with a rhombohedral structure. Lattice parameters, unit cell volume, grain size, dislocated density, and microstrain were also calculated from XRD data. Raman analysis and Fourier Transform Infrared analysis were used to collect information about molecular bonds, vibrations, identity, and structure of the phosphor. To investigate TL properties and associated kinetic parameters, the phosphor was irradiated with 6.0 MV (photon energy) and 6.0 MeV (electron energy) from a linear accelerator for doses ranging from 0.5 Gy to 6.0 Gy. For both photon and electron energy, TL glow curves have two identical peaks near 200 °C and 240 °C.The TL glow curves for 0.5 Gy-6 Gy are deconvoluted, then fitted with the appropriate model and then calculated the kinetic parameters. Kinetic parameters such as geometric factor (µg), order of kinetics, activation energy (E), and frequency factor (s) are obtained from Chen's peak shape method. The dose against the TL intensity curve shows that the response is almost linear in the investigated dose range. For photon and electron energy, the phosphor is found to be the most sensitive at 2.0 Gy and 4.0 Gy, respectively. The phosphor shows a low fading and after 28 days of exposure, it shows a signal loss of better than 3%. The studied TL properties suggest the suitability of LiCaPO4 in radiation dosimetry and associated fields.

3.
Sci Rep ; 13(1): 11918, 2023 Jul 24.
Artigo em Inglês | MEDLINE | ID: mdl-37488183

RESUMO

We have developed a radioluminescence-based survey meter for use in industries in which there is involvement in naturally occurring radioactive material (NORM), also in support of those needing to detect other weak emitters of radiation. The functionality of the system confronts particular shortcomings of the handheld survey meters that are currently being made use of. The device couples a LYSO:Ce scintillator with a photodetector via a polymer optical fibre waveguide, allowing for "intrinsically safe" inspection within pipework, separators, valves and other such component pieces. The small-diameter optical fibre probe is electrically passive, immune to electromagnetic interference, and chemically inert. The readout circuit is entirely incorporated within a handheld casing housing a silicon photomultiplier (SiPM) detection circuit and a microprocessor circuit connected to an LCD display. A 15 m long flexible PMMA optical fibre waveguide is butt coupled to an ABS plastic probe that retains the LYSO:Ce scintillator. Initial tests have included the use of lab-based mixed gamma-ray sources, measurements being made in concert with a reference conventional GM survey-meter. Characterization, via NORM sources at a decontamination facility, has shown useful sensitivity, covering the dose-rate range 0.10- to 28 µSv h-1 (R-squared 0.966), extending to 80 µSv/h as demonstrated in use of a Cs-137 source. The system is shown to provide an effective tool for detection of radioactivity within hard to access locations, in particular for sources emitting at low radiation levels, down to values that approach background.

4.
Appl Radiat Isot ; 174: 109771, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34048992

RESUMO

Present study concerns the key thermoluminescence (TL) properties of photonic crystal fibres (PCFs), seeking development of alternatively structured TL materials that are able to offer a advantages over existing passive dosimeters. In terms of their internal structure and light guiding properties the PCFs, collapsed and structured, differ significantly from that of conventional optical fibres. To investigate the dosimetric parameters of the PCFs use was made of a linear accelerator producing a 6 MV photon beam, delivering doses ranging from 0.5 Gy to 8 Gy. The parameters studied included TL response, linearity index, glow curves, relative sensitivity and TL signal fading, the results being compared against those obtained using TLD-100 chips. At 4 Gy photon dose the Ge-doped collapsed PCFs were found to provide a response 27 × that of structured PCF, also giving a TL yield similar to that of standard TLD-100 chips. Over post-irradiation periods of 15 and 30 days collapsed PCF TL signal fading were 8% and 17% respectively, with corresponding values of 37% and 64% for the structured PCF. Trapping parameters including the order of kinetics (b), activation energy (E) and frequency factor (s-1) were assessed with Chen's peak shape method. Lifetime of trapping centre was found to be (2.36 E+03) s and (9.03 E +01) s regarding the collapsed and structured PCF respectively with 6 Gy of photon beam. For the Ge-doped collapsed PCF, the high TL yield, sensitivity and low fading provide the basis of a highly promising system of TLD for radiotherapy applications.


Assuntos
Fótons , Dosagem Radioterapêutica , Dosimetria Termoluminescente/instrumentação , Cristalização , Germânio/química
5.
Biomed Phys Eng Express ; 6(6)2020 11 05.
Artigo em Inglês | MEDLINE | ID: mdl-35042836

RESUMO

This work investigates the suitability of locally fabricated 6 mol% Ge-doped optical fibres as dosimeters for small-field output ratio measurements. Two fabrications of fibre, cylindrical (CF) and flat (FF) fibres, were used to measure doses in small photon fields, from 4 to 15 mm. The findings were compared to those of commercial Ge-doped fibre (COMM), EBT3 film and an IBA CC01 ionization chamber. Irradiations were carried out using a 6 MV SRS photon beam operating at a dose rate of 1000 cGy min-1, delivering a dose of 16 Gy. To minimise the possibility of the fibres failing to be exposed to the intended dose in small fields, the fibres were accommodated in a custom-made Perspex phantom. For the 4 mm cone the CF and FF measured output ratios were found to be smaller than obtained with EBT3 film by 32% and 13% respectively. Conversely, while for the 6 to 15 mm cone fields the FF output ratios were consistently greater than those obtained using EBT3 film, the CF output ratios differed from those of EBT3 film by at most 3.2%, at 6 mm, otherwise essentially agreeing with EBT3 values at the other field sizes. For the 4 to 7.5 mm cones, all output ratios obtained from Ge-doped optical fibre measurements were greater than those of IBA CC01 ionization chamber. The measured FF and CF output ratios for the 7.5 to 15 mm cones agreed with published MC estimates to within 15% and 13%, respectively. Down to 6 mm cone field, present measurements point to the potential of CF as a small-field dosimeter, its use recommended to be complemented by the use of EBT3 film for small-field dosimetry.


Assuntos
Dosímetros de Radiação , Dióxido de Silício , Imagens de Fantasmas , Fótons , Radiometria
6.
Appl Radiat Isot ; 141: 176-181, 2018 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-29673719

RESUMO

In previous work we investigated the real-time radioluminescence (RL) yield of Ge-doped silica fibres and Al2O3 nanodot media, sensing electron- and x-ray energies and intensities at values familiarly obtained in external beam radiotherapy. The observation of an appreciable low-dose sensitivity has given rise to the realisation that there is strong potential for use of RL dosimetry in diagnostic radiology. Herein use has been made of P-doped silica optical fibre, 2 mm diameter, also including a 271 µm cylindrical doped core. With developing needs for versatile x-ray imaging dosimetry, preliminary investigations have been made covering the range of diagnostic x-ray tube potentials 30 kVp to 120 kVp, demonstrating linearity of RL with kVp as well as in terms of the current-time (mAs) product. RL yields also accord with the inverse-square law. Given typical radiographic-examination exposure durations from tens- to a few hundred milliseconds, particular value is found in the ability to record the influence of x-ray generator performance on the growth and decay of beam intensity, from initiation to termination.


Assuntos
Exposição Ocupacional/análise , Exposição à Radiação/análise , Dosimetria Termoluminescente/métodos , Humanos , Exposição Ocupacional/efeitos adversos , Fibras Ópticas , Exposição à Radiação/efeitos adversos , Radiografia/efeitos adversos , Dióxido de Silício , Dosimetria Termoluminescente/instrumentação , Dosimetria Termoluminescente/estatística & dados numéricos
7.
Appl Radiat Isot ; 138: 65-72, 2018 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-28427834

RESUMO

Using tailor-made sub-mm dimension doped-silica fibres, thermoluminescent dosimetric studies have been performed for α-emitting sources of 223RaCl2 (the basis of the Bayer Healthcare product Xofigo®). The use of 223RaCl2 in the palliative treatment of bone metastases resulting from late-stage castration-resistant prostate cancer focuses on its favourable uptake in metabolically active bone metastases. Such treatment benefits from the high linear energy transfer (LET) and associated short path length (<100µm) of the α-particles emitted by 223Ra and its decay progeny. In seeking to provide for in vitro dosimetry of the α-particles originating from the 223Ra decay series, investigation has been made of the TL yield of various forms of Ge-doped SiO2 fibres, including photonic crystal fibre (PCF) collapsed, PCF uncollapsed, flat and single-mode fibres. Irradiations of the fibres were performed at the UK National Physical Laboratory (NPL). Notable features are the considerable sensitivity of the dosimeters and an effective atomic number Zeff approaching that of bone, the glass fibres offering the added advantage of being able to be placed directly into liquid. The outcome of present research is expected to inform development of doped fibre dosimeters of versatile utility, including for applications as detailed herein.

8.
Appl Radiat Isot ; 117: 128-134, 2016 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-26778762

RESUMO

Using irradiated doped-silica preforms from which fibres for thermoluminescence dosimetry applications can be fabricated we have carried out a range of luminescence studies, the TL yield of the fibre systems offering many advantages over conventional passive dosimetry types. In this paper we investigate such media, showing emission spectra for irradiated preforms and the TL response of glass beads following irradiation to an 241Am-Be neutron source located in a tank of water, the glass fibres and beads offering the advantage of being able to be placed directly into liquid. The outcomes from these and other lines of research are intended to inform development of doped silica radiation dosimeters of versatile utility, extending from environmental evaluations through to clinical and industrial applications.

9.
Appl Radiat Isot ; 104: 197-202, 2015 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-26188687

RESUMO

In regard to thermoluminescence (TL) applied to dosimetry, in recent times a number of researchers have explored the role of optical fibers for radiation detection and measurement. Many of the studies have focused on the specific dopant concentration, the type of dopant and the fiber core diameter, all key dependencies in producing significant increase in the sensitivity of such fibers. At doses of less than 1 Gy none of these investigations have addressed the relationship between dose response and TL glow peak behavior of erbium (Er)-doped silica cylindrical fibers (CF). For x-rays obtained at accelerating potentials from 70 to 130 kVp, delivering doses of between 0.1 and 0.7 Gy, present study explores the issue of dose response, special attention being paid to determination of the kinetic parameters and dosimetric peak properties of Er-doped CF. The effect of dose response on the kinetic parameters of the glow peak has been compared against other fiber types, revealing previously misunderstood connections between kinetic parameters and radiation dose. Within the investigated dose range there was an absence of supralinearity of response of the Er-doped silica CF, instead sub-linear response being observed. Detailed examination of glow peak response and kinetic parameters has thus been shown to shed new light of the rarely acknowledged issue of the limitation of TL kinetic model and sub-linear dose response of Er-doped silica CF.


Assuntos
Érbio/química , Fibras Ópticas , Dióxido de Silício/química , Dosimetria Termoluminescente/instrumentação , Dosimetria Termoluminescente/métodos , Relação Dose-Resposta à Radiação , Desenho de Equipamento , Análise de Falha de Equipamento , Érbio/efeitos da radiação , Teste de Materiais , Doses de Radiação , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Dióxido de Silício/efeitos da radiação , Raios X
10.
Appl Radiat Isot ; 98: 80-6, 2015 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-25644081

RESUMO

The thermoluminescence (TL) glow curves and kinetics parameters of Thulium (Tm) doped silica cylindrical fibers (CF) are presented. A linear accelerator (LINAC) was used to deliver high-energy radiation of 21MeV electrons and 10MV photons. The CFs were irradiated in the dose range of 0.2-10Gy. The experimental glow curve data was reconstructed by using WinREMS. The WinGCF software was used for the kinetic parameters evaluation. The TL sensitivity of Tm-doped silica CF is about 2 times higher as compared to pure silica CF. Tm-doped silica CF seems to be more sensitive to 21MeV electrons than to 10MV photons. Surprisingly, no supralinearity was displayed and a sub-linear response of Tm-doped silica CF was observed within the analyzed dose range for both 21MeV electrons and 10MV photons. The Tm-doped silica CF glow curve consists of 5 individual glow peaks. The Ea of peak 4 and peak 5 was highly dependent on dose when irradiated with photons. We also noticed that the electron radiation (21MeV) caused a shift of glow peak by 7-13°C to the higher temperature region compared with photons radiation (10MV). Our Tm-doped fibers seem to give high TL response after 21MeV electrons, which gives around 2 times higher peak integral as compared with 10MV photon radiation. We concluded that peak 4 is the first-order kinetic peak and can be used as the main dosimetric peak of Tm-doped silica CF.

11.
Appl Radiat Isot ; 100: 79-83, 2015 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-25468288

RESUMO

Important thermoluminescence (TL) properties of five (5) different core sizes Ge-doped optical fibers have been studied to develop new TL material with better response. These are drawn from same preform applying different speed and tension during drawing phase to produce Ge-doped optical fibers with five (5) different core sizes. The results of the investigations are also compared with most commonly used standard TLD-100 chips (LiF:Mg,Ti) and commercial multimode Ge-doped optical fiber (Yangtze Optical Fiber, China). Scanning Electron Microscope (SEM) and EDX analysis of the fibers are also performed to map Ge distribution across the deposited region. Standard Gamma radiation source in Secondary Standard Dosimetry Lab (SSDL) was used for irradiation covering dose range from 1Gy to 10Gy. The essential dosimetric parameters that have been studied are TL linearity, reproducibility and fading. Prior to irradiation all samples ∼0.5cm length are annealed at temperature of 400°C for 1h period to standardize their sensitivities and background. Standard TLD-100 chips are also annealed for 1h at 400°C and subsequently 2h at 100°C to yield the highest sensitivity. TL responses of these fibers show linearity over a wide gamma radiation dose that is an important property for radiation dosimetry. Among all fibers used in this study, 100µm core diameter fiber provides highest response that is 2.6 times than that of smallest core (20µm core) optical fiber. These fiber-samples demonstrate better response than commercial multi-mode optical fiber and also provide low degree of fading about 20% over a period of fifteen days for gamma radiation. Effective atomic number (Zeff) is found in the range (13.25-13.69) which is higher than soft tissue (7.5) however within the range of human-bone (11.6-13.8). All the fibers can also be re-used several times as a detector after annealing. TL properties of the Ge-doped optical fibers indicate promising applications in ionizing radiation dosimetry.

12.
Appl Radiat Isot ; 100: 43-9, 2015 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-25533626

RESUMO

A method for improving the thermoluminescence (TL) yield of silica-based optical fibres is demonstrated. Using silica obtained from a single manufacturer, three forms of pure (undoped) fibre (capillary-, flat-, and photonic crystal fibre (PCF)) and two forms of Ge-doped fibre (capillary- and flat-fibre) were fabricated. The pure fibre samples were exposed to 6 and 21MeV electrons, the doped fibres to 6MV photons. The consistent observation of large TL yield enhancement is strongly suggestive of surface-strain defects generation. For 6MeV irradiations of flat-fibre and PCF, respective TL yields per unit mass of about 12.0 and 17.5 times that of the undoped capillary-fibre have been observed. Similarly, by making a Ge-doped capillary-fibre into flat-fibre, the TL response is found to increase by some 6.0 times. Thus, in addition to TL from the presence of a dopant, the increase in fused surface areas of flat-fibres and PCF is seen to be a further important source of TL. The glow-curves of the undoped fibres have been analysed by computational deconvolution. Trap centre energies have been estimated and compared for the various fibre samples. Two trap centre types observed in capillary-fibre are also observed in flat-fibre and PCF. An additional trap centre in flat-fibre and one further trap centre in PCF are observed when compared to capillary fibre. These elevated-energy trap centres are linked with strain-generated defects in the collapsed regions of the flat fibre and PCF.

13.
Opt Express ; 20(28): 29784-97, 2012 Dec 31.
Artigo em Inglês | MEDLINE | ID: mdl-23388806

RESUMO

A new approach for filtering an optical band-pass in optical amplifier is proposed using a macro bending. The proposed filter leverages the bending loss of higher order modes at shorter wavelengths. At longer wavelengths, the filter increases fiber's bending loss as the fundamental mode 'tail' is leak out from the cladding. The combination of wavelength dependent loss at longer and shorter wavelength gives rise to the optical band-pass filter characteristic inside the fiber. The simulated spectral response of the filter is found to be in good agreement with the experimental results. Subsequently, the proposed optical band-pass filter is applied in Thulium-doped fiber amplifiers (TDFA) system for gain and noise figure enhancements. The filter functions to suppress both the amplified spontaneous emission (ASE) at 800 nm and 1800 nm wavelength regions and thus improves both gain and noise figure performances in S-band region. By bending of the gain medium, gain and noise figure of the TDFA are improved by about 2 dB and 0.5 dB respectively, within a wavelength region from 1440 and 1500 nm when the 1050 nm pump power is fixed at 250 mW.

14.
Mymensingh Med J ; 18(2): 215-20, 2009 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-19623150

RESUMO

A prospective experimental study was conducted in a postgraduate institute in Dhaka, Bangladesh, from April '05 to September '05. A total of 214 doctors of a postgraduate medical institute were included in the study who was involved in research works. A written questionnaire was given to the respondents to assess their knowledge, attitude and practice about informed consent (IC). The data was analyzed statistically. Chi-Square test was done to see the level of significance. Regarding knowledge of IC, we found maximum participants were more or less knowledgeable about it. The attitude of the respondents was also in favour of taking IC. In practice, most of them had taken informed consent that was verbal (39.3%) and written (47.6%). But some of the researcher (13.1%) had not taken any informed consent. By the present study, it may be concluded that the researchers of the concerned institute were aware of IC.


Assuntos
Conhecimentos, Atitudes e Prática em Saúde , Consentimento Livre e Esclarecido , Pesquisadores , Academias e Institutos , Adulto , Bangladesh , Humanos
15.
Bangladesh Med Res Counc Bull ; 29(3): 78-85, 2003 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-15053269

RESUMO

The Bangladesh Medical Research Council is implementing a training program on research bioethics under International Bioethics Education and Career Development Award of Fogarty International Center of National Institutes of Health (NIH), USA. The ultimate goal of the program is to improve ethical practice in implementation of health research through capacity strengthening of the professionals involved in health research in Bangladesh. The duration of the program is 4 years and it has started from the year 2002. The first year (2002-2003) was assigned for curriculum development. Several workshops, focus group discussions and consultative meetings were organized during 2002-2003 and curriculum was developed. Under this training program every year 2 Certificate Courses on Research Bioethics (CCRB) with a duration of 10 weeks will be conducted for 40 participants (20 participants in each batch). Each year one Advance Course on Research Bioethics (ACRB) will be organized for 10 participants with a duration of 6 days. The courses are to be conducted during 2nd, 3rd and 4th year. The Certificate Course on Research Bioethics is intended for multidisciplinary participants having previous experience in research methodology while the Advance Course on Research Bioethics will target for training the members of Ethics Review Committees of the country. Through this program one hundred fifty Bangladeshi professionals will get adequate training on research bioethics. The training program will be implemented by national experts with technical assistance from distinguished international scientists in the field.


Assuntos
Temas Bioéticos , Educação Médica/economia , Apoio à Pesquisa como Assunto , Ensino , Bangladesh , Currículo , Educação Médica/organização & administração , Guias como Assunto , Humanos , National Institutes of Health (U.S.) , Desenvolvimento de Programas , Estados Unidos
16.
Bangladesh Med Res Counc Bull ; 28(2): 54-60, 2002 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-12825762

RESUMO

A case control study was conducted in Dhaka city to measure the energy intake and expenditure among 220 obese children of 4-10 years age group and 220 randomly selected age and sex matched controls. A 24 hour dietary recall was used to assess the energy intake. Data on energy expenditure was obtained by 24 hour physical activity recall. The mean energy intake of obese children (2056 +/- 751 kcal/d) was found to be significantly higher (P<0.001) compared to the non obese (1508 +/- 529 kcal/d). No sex difference was found in both obese and non obese groups. Mean energy expenditure of the obese children (1868 +/- 313 kcal/d vs 1495 +/- 200 kcal/d) was significantly higher than the non-obese (P<0.001). Of the obese, boys expended more energy than the girls (P=0.01). Furthermore, physical activity level (1.40 +/- 0.09 vs 1.35 +/- 0.14) was significantly higher among the non obese than their obese counterpart (P<0.001). However, energy balance was significantly higher among the obese (P<0.001). Dose response of energy balance shows the estimated relative risk of obesity increases with higher level of energy balance (P<0.001). The findings of this study revealed that energy balance as a result of higher energy intake and lower energy expenditure was one of the important risk factors for the development of obesity among the children of Dhaka city. Thus, appropriate interventions like behavioural change regarding food habits and physical activities are recommended.


Assuntos
Ingestão de Energia , Metabolismo Energético , Obesidade/metabolismo , Bangladesh , Estudos de Casos e Controles , Criança , Pré-Escolar , Feminino , Humanos , Masculino , População Urbana
17.
Bangladesh Med Res Counc Bull ; 28(3): 87-96, 2002 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-14509380

RESUMO

The quality of health care is the consequence of strong link between service providers and user of the services. Perceived quality is one of the principal determinant of utilisation and non-utilisation of health services, a major issue in developing countries. Considering this, the present study was aimed to assess the quality of care in in-patient and outpatient departments of rural and urban government hospitals in Bangladesh. A total of 2420 patients were interviewed. The patients were selected by using systematic random sampling technique. Results revealed that age, waiting time, time spent for patient examination, place of treatment, income, years of schooling and male sex appeared to be independent predictors of patient satisfaction (p<0.001). Age, waiting time and years of schooling were negatively related with level of satisfaction indicating younger patients, less waiting time and patients with less education were more satisfied, whereas time spent for examination, income were positively related with patient's satisfaction. Patients attending at the urban hospitals and male sex were also significantly associated with patient's satisfaction. The study recommends that both short and long-term policy action should be adopted for quality assurance of the existing health care facilities in Bangladesh.


Assuntos
Países em Desenvolvimento , Satisfação do Paciente/estatística & dados numéricos , Qualidade da Assistência à Saúde/estatística & dados numéricos , Adulto , Bangladesh , Feminino , Relações Hospital-Paciente , Humanos , Modelos Logísticos , Masculino , Aceitação pelo Paciente de Cuidados de Saúde/estatística & dados numéricos , Serviços de Saúde Rural/estatística & dados numéricos , Serviços Urbanos de Saúde/estatística & dados numéricos
18.
Eur J Pharm Biopharm ; 51(3): 227-34, 2001 May.
Artigo em Inglês | MEDLINE | ID: mdl-11343887

RESUMO

Drug-layered pellets based on microcrystalline cellulose (MCC) beads as substrates were prepared using a laboratory-scale centrifugal granulator. The effect of three independent process parameters (rotor rotation speed, slit air flow rate, and spray air rate) on responses describing the amount of drug loss during the process, amount of agglomerates, bulk density, flowability, friability, shape, and surface roughness were studied using a 3(3) full factorial experimental design. The variables studied were found to have a significant influence on the responses evaluated. Rotor rotation speed and slit air flow rate had a significant positive influence on the amount of drug loss during the process and the amount of agglomerates, whereas rotor rotation speed and spray air rate had the same effect on the bulk density, flowability, and the roundness of the pellets. The amount of agglomerates and the roundness value of the pellets were negatively affected by the spray air rate while the slit air flow rate showed the same effect on the bulk density and flow rate of the pellets. In addition to the main effects, there were some significant paired interactions between slit air flow rate and spray air rate as well as rotor rotation speed and slit air flow rate. Based on the results, the significance of these three parameters should be considered carefully for quality pellet preparation by the centrifugal granulating technique using MCC beads as substrates.


Assuntos
Celulose/química , Química Farmacêutica , Implantes de Medicamento/química , Centrifugação/métodos
19.
Drug Dev Ind Pharm ; 25(5): 605-11, 1999 May.
Artigo em Inglês | MEDLINE | ID: mdl-10219529

RESUMO

Preparation of microcrystalline cellulose (MCC) beads with a laboratory-scale centrifugal granulating apparatus was studied, and the pharmaceutical quality of the beads was characterized with respect to the subsequent drug layering. Five process parameters of potential importance, including rotor rotation speed X1, slit air X2, spray air pressure X3, spray air rate X4, and height of nozzle setting X5, were evaluated using a fractional factorial design (FFD 2(5-2)) as the experimental design. The responses evaluated were expected yield, mean size, size distribution, shape characteristics (including roundness, circularity, elongation, rectangularity, and modelx), and friability. All five process parameters studied were found to have an influence on the selected properties of the beads, but the effects of rotor rotation speed, slit air flow rate, and spray air rate were statistically significant (p < .05). The effect of the rotor rotation speed was found to be the most potent on all the responses studied. The results also show some significant interactions between the parameters tested. The most significant interactions were between rotor rotation speed and slit air, rotor rotation speed and spray air, and slit air and spray air.


Assuntos
Celulose , Excipientes , Centrifugação
20.
Ind Health ; 37(1): 116-21, 1999 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-10052309

RESUMO

Bangladesh is a relatively young and developing country. At the present time, like in most developing countries, a clear demarcation between occupational health care and general medical care is difficult to be recognized in Bangladesh. Occupational health is a fairly new field, as the country is undergoing industrialization and occupational health activities are operated by several ministries, such as Labour, Health, Industry and Transport. Legal foundations of the occupational health-care system based on British India and Pakistani era, were adopted and amended by the Government of Bangladesh after the liberation of the country in 1971. Most of the Labour laws have been rectified by the Government of Bangladesh according to the ILO Conventions. Reconsideration of the occupational health service system avoiding duplication for the 'occupational health' component in several ministries might be helpful to achieve the successful provision of an occupational health service in the developing Bangladesh.


Assuntos
Atenção à Saúde/tendências , Países em Desenvolvimento , Saúde Ocupacional , Medicina do Trabalho , Bangladesh , Previsões , Governo , Humanos , Indústrias/legislação & jurisprudência , Medicina do Trabalho/economia , Medicina do Trabalho/educação , Medicina do Trabalho/organização & administração
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