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A K - One of the best experts on this subject based on the ideXlab platform.
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Effective Dose to staff members in a positron emission tomography ct facility using zirconium 89
British Journal of Radiology, 2013Co-Authors: K S Alzimami, A KAbstract:Objective:Positron emission tomography (PET) using zirconium-89 (89Zr) is complicated by its complex decay scheme. In this study, we quantified the Effective Dose from 89Zr and compared it with fluorine-18 fludeoxyglucose (18F-FDG).Methods:Effective Dose distribution in a PET/CT facility in Riyadh was calculated by Monte Carlo simulations using MCNPX. The positron bremsstrahlung, the annihilation photons, the delayed gammas from 89Zr and those emissions from 18F-FDG were modelled in the simulations but low-energy characteristic X-rays were ignored.Results:On the basis of injected activity, the Dose from 89Zr was higher than that of 18F-FDG. However, the Dose per scan from 89Zr became less than that from 18F-FDG near the patient, owing to the difference in injected activities. In the corridor and control rooms, the 89Zr Dose was much higher than 18F-FDG, owing to the difference in attenuation by the shielding materials.Conclusion:The presence of the high-energy photons from 89Zr-labelled immuno-PET radioph...
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Effective Dose to staff members in a positron emission tomography/CT facility using zirconium-89
British Journal of Radiology, 2013Co-Authors: K S Alzimami, A KAbstract:Objective:Positron emission tomography (PET) using zirconium-89 (89Zr) is complicated by its complex decay scheme. In this study, we quantified the Effective Dose from 89Zr and compared it with fluorine-18 fludeoxyglucose (18F-FDG).Methods:Effective Dose distribution in a PET/CT facility in Riyadh was calculated by Monte Carlo simulations using MCNPX. The positron bremsstrahlung, the annihilation photons, the delayed gammas from 89Zr and those emissions from 18F-FDG were modelled in the simulations but low-energy characteristic X-rays were ignored.Results:On the basis of injected activity, the Dose from 89Zr was higher than that of 18F-FDG. However, the Dose per scan from 89Zr became less than that from 18F-FDG near the patient, owing to the difference in injected activities. In the corridor and control rooms, the 89Zr Dose was much higher than 18F-FDG, owing to the difference in attenuation by the shielding materials.Conclusion:The presence of the high-energy photons from 89Zr-labelled immuno-PET radioph...
Willi A Kalender - One of the best experts on this subject based on the ideXlab platform.
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estimates of Effective Dose for ct scans of the lower extremities
Radiology, 2014Co-Authors: Natalia Saltybaeva, Mary Ellen Jafari, Martin Hupfer, Willi A KalenderAbstract:The presented study provides Dose-length product–Effective Dose (ED) conversion coefficients for ED estimation specific for CT of the lower extremities to ensure compliance with regulatory and accrediting body recommendations for patient Dose tracking and for comparison and optimization of Dose for different CT protocols.
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multisection ct protocols sex and age specific conversion factors used to determine Effective Dose from Dose length product
Radiology, 2010Co-Authors: Paul Deak, Yulia Smal, Willi A KalenderAbstract:The conversion factors used to compute the Effective Dose from the Dose-length product may have to be updated with respect to modern cone-beam CT scanners and have to reflect the new International Commission on Radiological Protection recommendations.
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a pc program for estimating organ Dose and Effective Dose values in computed tomography
European Radiology, 1999Co-Authors: Willi A Kalender, Bernhard Schmidt, Maria Zankl, M SchmidtAbstract:Dose values in CT are specified by the manufacturers for all CT systems and operating conditions in phantoms. It is not trivial, however, to derive Dose values in patients from this information. Therefore, we have developed a PC-based program which calculates organ Dose and Effective Dose values for arbitrary scan parameters and anatomical ranges. Values for primary radiation are derived from measurements or manufacturer specifications; values for scattered radiation are derived from Monte Carlo calculations tabulated for standard anthropomorphic phantoms. Based on these values, organ Doses can be computed by the program for arbitrary scan protocols in conventional and in spiral CT. Effective Dose values are also provided, both with ICRP 26 and ICRP 60 tissue-weighting coefficients. Results for several standard CT protocols are presented in tabular form in this paper. In addition, potential for Dose reduction is demonstrated, for example, in spiral CT and in quantitative CT. Providing realistic patient Dose estimates for arbitrary CT protocols is relevant both for the physician and the patient, and it is particularly useful for educational and training purposes. The program, called WinDose, is now in use at the Erlangen University hospitals (Germany) as an information tool for radiologists and patients. Further extensions are planned.
K S Alzimami - One of the best experts on this subject based on the ideXlab platform.
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Effective Dose to staff members in a positron emission tomography ct facility using zirconium 89
British Journal of Radiology, 2013Co-Authors: K S Alzimami, A KAbstract:Objective:Positron emission tomography (PET) using zirconium-89 (89Zr) is complicated by its complex decay scheme. In this study, we quantified the Effective Dose from 89Zr and compared it with fluorine-18 fludeoxyglucose (18F-FDG).Methods:Effective Dose distribution in a PET/CT facility in Riyadh was calculated by Monte Carlo simulations using MCNPX. The positron bremsstrahlung, the annihilation photons, the delayed gammas from 89Zr and those emissions from 18F-FDG were modelled in the simulations but low-energy characteristic X-rays were ignored.Results:On the basis of injected activity, the Dose from 89Zr was higher than that of 18F-FDG. However, the Dose per scan from 89Zr became less than that from 18F-FDG near the patient, owing to the difference in injected activities. In the corridor and control rooms, the 89Zr Dose was much higher than 18F-FDG, owing to the difference in attenuation by the shielding materials.Conclusion:The presence of the high-energy photons from 89Zr-labelled immuno-PET radioph...
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Effective Dose to staff members in a positron emission tomography/CT facility using zirconium-89
British Journal of Radiology, 2013Co-Authors: K S Alzimami, A KAbstract:Objective:Positron emission tomography (PET) using zirconium-89 (89Zr) is complicated by its complex decay scheme. In this study, we quantified the Effective Dose from 89Zr and compared it with fluorine-18 fludeoxyglucose (18F-FDG).Methods:Effective Dose distribution in a PET/CT facility in Riyadh was calculated by Monte Carlo simulations using MCNPX. The positron bremsstrahlung, the annihilation photons, the delayed gammas from 89Zr and those emissions from 18F-FDG were modelled in the simulations but low-energy characteristic X-rays were ignored.Results:On the basis of injected activity, the Dose from 89Zr was higher than that of 18F-FDG. However, the Dose per scan from 89Zr became less than that from 18F-FDG near the patient, owing to the difference in injected activities. In the corridor and control rooms, the 89Zr Dose was much higher than 18F-FDG, owing to the difference in attenuation by the shielding materials.Conclusion:The presence of the high-energy photons from 89Zr-labelled immuno-PET radioph...
Cynthia H Mccollough - One of the best experts on this subject based on the ideXlab platform.
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how Effective is Effective Dose as a predictor of radiation risk
American Journal of Roentgenology, 2010Co-Authors: Cynthia H Mccollough, Jodie A Christner, James M KoflerAbstract:OBJECTIVE. This article discusses the relatively recent adoption of Effective Dose in medicine that allows comparison between different imaging techniques, and describes the principles, pitfalls, and potential value of Effective Dose. The medical community must use this information wisely, realizing that Effective Dose represents a generic estimate of risk from a given procedure for a generic model of the human body.CONCLUSION. Effective Dose is not the risk for any one individual. Due to the inherent uncertainties and oversimplifications involved, Effective Dose should not be used for epidemiologic studies or for estimating population risks.
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estimating radiation Doses from multidetector ct using monte carlo simulations effects of different size voxelized patient models on magnitudes of organ and Effective Dose
Physics in Medicine and Biology, 2007Co-Authors: J Demarco, Cynthia H Mccollough, M Zankl, C Cagnon, Dianna D Cody, Donna M Stevens, Erin Angel, M McnittgrayAbstract:The purpose of this work is to examine the effects of patient size on radiation Dose from CT scans. To perform these investigations, we used Monte Carlo simulation methods with detailed models of both patients and multidetector computed tomography (MDCT) scanners. A family of three-dimensional, voxelized patient models previously developed and validated by the GSF was implemented as input files using the Monte Carlo code MCNPX. These patient models represent a range of patient sizes and ages (8 weeks to 48 years) and have all radiosensitive organs previously identified and segmented, allowing the estimation of Dose to any individual organ and calculation of patient Effective Dose. To estimate radiation Dose, every voxel in each patient model was assigned both a specific organ index number and an elemental composition and mass density. Simulated CT scans of each voxelized patient model were performed using a previously developed MDCT source model that includes scanner specific spectra, including bowtie filter, scanner geometry and helical source path. The scan simulations in this work include a whole-body scan protocol and a thoracic CT scan protocol, each performed with fixed tube current. The whole-body scan simulation yielded a predictable decrease in Effective Dose as a function of increasing patient weight. Results from analysis of individual organs demonstrated similar trends, but with some individual variations. A comparison with a conventional Dose estimation method using the ImPACT spreadsheet yielded an Effective Dose of 0.14 mSv mAs?1 for the whole-body scan. This result is lower than the simulations on the voxelized model designated 'Irene' (0.15 mSv mAs?1) and higher than the models 'Donna' and 'Golem' (0.12 mSv mAs?1). For the thoracic scan protocol, the ImPACT spreadsheet estimates an Effective Dose of 0.037 mSv mAs?1, which falls between the calculated values for Irene (0.042 mSv mAs?1) and Donna (0.031 mSv mAs?1) and is higher relative to Golem (0.025 mSv mAs?1). This work demonstrates the ability to estimate both individual organ and Effective Doses from any arbitrary CT scan protocol on individual patient-based models and to provide estimates of the effect of patient size on these Dose metrics.
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calculation of Effective Dose
Medical Physics, 2000Co-Authors: Cynthia H Mccollough, Beth A SchuelerAbstract:The concept of “Effective Dose” was introduced in 1975 to provide a mechanism for assessing the radiation detriment from partial body irradiations in terms of data derived from whole body irradiations. The Effective Dose is the mean absorbed Dose from a uniform whole-body irradiation that results in the same total radiation detriment as from the nonuniform, partial-body irradiation in question. The Effective Dose is calculated as the weighted average of the mean absorbed Dose to the various body organs and tissues, where the weighting factor is the radiation detriment for a given organ (from a whole-body irradiation) as a fraction of the total radiation detriment. In this review, Effective Dose equivalent and Effective Dose, as established by the International Commission on Radiological Protection in 1977 and 1990, respectively, are defined and various methods of calculating these quantities are presented for radionuclides, radiography, fluoroscopy, computed tomography and mammography. In order to calculate either quantity, it is first necessary to estimate the radiation Dose to individual organs. One common method of determining organ Doses is through Monte Carlo simulations of photon interactions within a simplified mathematical model of the human body. Several groups have performed these calculations and published their results in the form of data tables of organ Dose per unit activity or exposure. These data tables are specified according to particular examination parameters, such as radiopharmaceutical, x-ray projection, x-ray beam energy spectra or patient size. Sources of these organ Dose conversion coefficients are presented and differences between them are examined. The estimates of Effective Dose equivalent or Effective Dose calculated using these data, although not intended to describe the Dose to an individual, can be used as a relative measure of stochastic radiation detriment. The calculated values, in units of sievert (or rem), indicate the amount of whole-body irradiation that would yield the equivalent radiation detriment as the exam in question. In this manner, the detriment associated with partial or organ-specific irradiations, as are common in diagnostic radiology, can be assessed.
H Paganetti - One of the best experts on this subject based on the ideXlab platform.
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simulation of organ specific patient Effective Dose due to secondary neutrons in proton radiation treatment
Physics in Medicine and Biology, 2005Co-Authors: H Jiang, Brian Wang, Herman D Suit, H PaganettiAbstract:Cancer patients undergoing radiation treatment are exposed to high Doses to the target (tumour), intermediate Doses to adjacent tissues and low Doses from scattered radiation to all parts of the body. In the case of proton therapy, secondary neutrons generated in the accelerator head and inside the patient reach many areas in the patient body. Due to the improved efficacy of management of cancer patients, the number of long term survivors post-radiation treatment is increasing substantially. This results in concern about the risk of radiation-induced cancer appearing at late post-treatment times. This paper presents a case study to determine the Effective Dose from secondary neutrons in patients undergoing proton treatment. A whole-body patient model, VIP-Man, was employed as the patient model. The geometry dataset generated from studies made on VIP-Man was implemented into the GEANT4 Monte Carlo code. Two proton treatment plans for tumours in the lung and paranasal sinus were simulated. The organ Doses and ICRP-60 radiation and tissue weighting factors were used to calculate the Effective Dose. Results show whole body Effective Doses for the two proton plans of 0.162 Sv and 0.0266 Sv, respectively, to which the major contributor is due to neutrons from the proton treatment nozzle. There is a substantial difference among organs depending on the treatment site.
