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Search Results: 1 - 10 of 462049 matches for " A. Rajabi "
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Applying Activity Based Costing (ABC) Method to Calculate Cost Price in Hospital and Remedy Services
A Rajabi,A Dabiri
Iranian Journal of Public Health , 2012,
Abstract: Background: Activity Based Costing (ABC) is one of the new methods began appearing as a costing methodology in the 1990. It calculates cost price by determining the usage of resources. In this study, ABC method was used for calculating cost price of remedial services in hospitals.Methods: To apply ABC method, Shahid Faghihi Hospital was selected. First, hospital units were divided into three main departments: administrative, diagnostic, and hospitalized. Second, activity centers were defined by the activity analysis method. Third, costs of administrative activity centers were allocated into diagnostic and operational departments based on the cost driver. Finally, with regard to the usage of cost objectives from services of activity centers, the cost price of medical services was calculated.Results: The cost price from ABC method significantly differs from tariff method. In addition, high amount of indirect costs in the hospital indicates that capacities of resources are not used properly.Conclusion: Cost price of remedial services with tariff method is not properly calculated when compared with ABC method. ABC calculates cost price by applying suitable mechanisms but tariff method is based on the fixed price. In addition, ABC represents useful information about the amount and combination of cost price services.
Spectrum of mesons and hyperfine dependence potentials
A. A. Rajabi
Iranian Journal of Physics Research , 2006,
Abstract: In most models, mesons consist of quark -antiquark pairs moving in a confining potential. However, it would be interesting to consider the effect of an extra residual interaction by introducing the quark particles which contain a dependent spin and isospin. In the Chiral constituent quark model, the hyperfine part of the potential is provided by the interaction of the Goldstone bosons, which give rise to a spin- and isospin-dependent part that is crucial for the description of the spectrum for energies lower than 1.7 Gev. In this model we have, not only included the confinement potential at large separations but also the color charge as well as hyperfine interaction potentials. This combination of potentials yields meson spectra which are very close to the ones obtained in experiments.
A three-body force model for the harmonic and anharmonic oscillator
A. A. Rajabi
Iranian Journal of Physics Research , 2005,
Abstract: We present a mathematical method to describe motion of a system based on 3 identical body forces. The 3-body forces are more easily introduced and treated within the hyperspherical harmonics. We have obtained an exact solution of the radial Schr dinger equation for a 3- body system in three dimensions. The interact potential V is assumed to depend on the hyperradius X only where X is a function of the Jacobi relative coordinates ρ and λ which are functions of the three identical particles, relative positions r12 , r23 and r31 . This method has been extensively used in nuclear and molecular physics. This work is interesting to those who are studying hadronic and bosonics physics and problems consisting three - body systems.
Mesons states and their dependence on spin and isospin
A A Rajabi,N Salehi
Iranian Journal of Physics Research , 2008,
Abstract: Meson is composed of one quark and one antiquark moving under the effect of confinement, oscillating and color potentials. Since quarks are particles with spin , there is a spin-spin interaction potential. Also we have isospins for u and d quarks and we can consider related potentials on isospin-isospin and spin-isospin effects. By comparing the given meson spectrum with the amount calculated in this model, it can be inferred that mesons quark-antiquark are in a state of singlet or triplet regarding spin and isospin. By using this model, the states of configuration spin-isospin of each meson can be calculated
Spin and Pseudospin Symmetries with Trigonometric P schl-Teller Potential including Tensor Coupling
M. Hamzavi,A. A. Rajabi
Advances in High Energy Physics , 2013, DOI: 10.1155/2013/196986
Generalized Nuclear Woods-Saxon Potential under Relativistic Spin Symmetry Limit
M. Hamzavi,A. A. Rajabi
ISRN High Energy Physics , 2013, DOI: 10.1155/2013/987632
Calculation of 99mTc-DTPA transit times in normal kidney
Rajabi H,Shalchian B,Yaghoubi N,Bitarafan Rajabi A
Iranian Journal of Nuclear Medicine , 2003,
Abstract: Introduction: Renal dynamic study is a well-established and popular test in routine practice of nuclear medicine. The test is non-invasive, rapid and unique in evaluation of the kidney function. In despite of its clinical values, the parameters derived from renogram are physiologically meaningless. That is due to the fact that renogram is not the true kidney function. From mathematical points of view, renogram is the convolution of kidney function and kidney input function. The real kidney function, which is usually called Impulse Retention Function, could be derived using deconvolution technique. The main parameters that can be derived from IRF are transit times. Methods and Materials: The data collected from 30 normal healthy individual volunteers were used for calculation of transit times. Due to sensitivity of the deconvolution technique to the error and to minimize the error in the raw data, an investigation was launched to determine the most suitable method of noise reduction, background subtraction and numerical method of deconvolution. Based on our finding, a software package was developed on the system and evaluated using software phantom. Results: Our results shows that among different transit time parameters for different parts of the kidney, mean transit time of the parenchymal is statistically the most valuable parameter. Assuming a Gaussian distribution for the parameter and accepting a 95% confidence interval, the normal rage of mean parenchymal transit time was calculated to be “205±70 Sec”. Using the same logic, the abnormal rage of mean parenchymal transit time was calculated to be more than 300 sec. Discussion: During the last decade, skeptical questions have raised about the suitability of renogram for deconvolution and validity of transit time parameters. Our experiences have proved that kidney is approximately a linear and stationary system, therefore suitable for deconvolution. The validity of transit time parameters is extremely depended on the validity of software being used. Commercial software usually don’t have sufficient accuracy for calculation of transit times.
Coincidence gamma camera imaging; a comparison between the two modes of imaging
F. Abbaspour,A. Bitarafan-Rajabi,H. Rajabi,F. Rastgou
Iranian Journal of Nuclear Medicine , 2006,
Abstract: Objectives: Scintillation cameras with the options for the detection and localization of positron annihilation in the coincidence mode may be considered as an intermediate device between conventional nuclear medicine and modern PET systems. This relatively inexpensive option offers an opportunity for the impoverished centers to perform some epigonic PET studies at acceptable quality. Due to great difference between photon energy used in coincidence and conventional modes, optimizing the performance of the system in both modes is a big challenge. In this study we acquired similar images in both modes to investigate if the camera is really optimized for both acquisition modes. Methods: The dual detector gamma camera (Vertex Molecular Coincidence Detection, ADAC Laboratories, and Milpitas, CA) equipped with a 5/8-inch crystal detector was investigated. In coincidence mode all photopeak-to-photopeak events as well as the photopeak-to-Compton scatter events were used. The energy windows were set at 511 kev/30% for the18F photopeak and 310 kev/30% for the Compton events. The SPECT studies were performed with VXHR collimator and matrix size 128*128 using 99mTc. The images of two dimensional brain phantom, SPECT resolution phantom and NEMA line-spread phantom were acquired in both modes five times each. Each dataset was rebinned using single slice rebinning and reconstructed using filtered backprojection and also ordered subset exception maximization iterative algorithm. Attenuation correction (by calculated factors, μ=0.095 cm-1) and random correction techniques were used in this study. Results: We investigated the best reconstruction condition for all images based on the spatial resolution (minimum FWHM and FWTM), contrast (highest) and quality (visual inspection) of the images. For each phantom the supreme quality images were compared. Regarding the resolution, contrast and quality the images that were acquired in coincidence mode were significantly (p-value <0.001) better than the similar images in conventional mode. Conclusion: The high cost of a PET system has been a major constraint to the clinical use of it. Though not a real competitor, a coincidence gamma camera may be useful when a PET system is not available. However it should not be ignored that a gamma camera can not be optimized to work in a wide rang of photon energy. Since now the most emphasis has been the inferior quality of coincidence image compared to PET images. Nevertheless the quality of such system in conventional mode should also be considered.
Comparison of Acceptance Tests for SPECT Systems in Tehran
A. Bitarafan-Rajabi,H. Rajabi,H. Firouzabadi,F. Rastgou
Iranian Journal of Nuclear Medicine , 2005,
Abstract: Introduction: Acceptance test is a necessary procedure after SPECT system installation. The goal of this test is to reveal system's present condition, to compare it with manufacturer's specifications and also as a base for later tests. Methods: This study investigated four SPECT systems in Tehran. All of the quality control tests are performed on the basis of NEMA and IAEA recommendations and by a same group. These tests include intrinsic spatial resolution, intrinsic energy resolution, temporal resolution, intrinsic linearity, maximum count rate, pixel size, intrinsic and extrinsic uniformity, sensitivity, reconstruction spatial resolution with and without scatter and centre of rotation. Results: Results of this investigation show that three systems have minimum acceptance conditions, but the fourth one due to it's suboptimal energy resolution and spatial resolution lacked the required specifications for acceptance. It was shown during the next six months after installation that this system showed frequent impairments and even had been out of service for a while. However, other systems did not show any considerable problems. Conclusion: The acceptance test is an essential step after installation of any SPECT system. If there is no considerable deficits at the initial acceptance test of a SPECT system, it won't become troublesome for a long time.
Filter selection for 99mTc-Sestamibi myocardial perfusion SPECT imaging
Bitarafan Rajabi A,Rajabi H,Yaghoobi N,Rastgoo F
Iranian Journal of Nuclear Medicine , 2003,
Abstract: Myocardial perfusion SPECT imaging with Tc99m-sestamibi is the most accurate non-invasive means of detecting coronary artery disease and assessing the severity of perfusion abnormalities in the patients with coronary stenosis. Though simple and straight forward the results produced by the technique is very much affected by the details being used. One of the main problems with the test, which has created a lot of discrepancies, is the selection of proper filter and adjustment of filter parameters to individual cases. In this study we have analyzed and compared for widely used filters for myocardial Tc-99m sestamibi SPECT study i.e. Hanning, Butterworth, Metz and Wiener. The aim of the study was to find the most suitable filter for this type of study and to verify the theoretical peculiarity of the filters in practice. Patients with proven coronary artery abnormality were selected. We have investigated four conventional filters commonly used in nuclear medicine using quantitative and qualitative method. Filters were compared to each other and to the results of angiography. Our results show that the best filter in terms of contrast; smoothing and spatial resolution is the classical Metz filter with the FWHM of 4, order of 0.5. The best filter in the myocardial viability was Hanning filter with the cutoff of 0.5.
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