The Experts below are selected from a list of 231 Experts worldwide ranked by ideXlab platform
Gyuseong Cho - One of the best experts on this subject based on the ideXlab platform.
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Study on the Influence of the Scattered Radiation in the Industrial Transmission Gamma Tomography
Journal of Nuclear Science and Technology, 2008Co-Authors: Jong-bum Kim, Sung-hee Jung, Jin-seop Kim, Na-young Lee, Gyuseong ChoAbstract:The effect of Scattered Radiation on the transmitted gamma ray signal should be carefully taken into account because it certainly affects the quality of reconstructed tomography images. Therefore this effect was evaluated with different counting modes and gamma energies. For less dense objects such as wood and plastics, the build-up effect can be ignored and 137Cs can yield the better result than 60Co. On the contrary, for the relatively heavy material such as oil and metal the Scattered Radiation effect of 137Cs source should be considered because the build-up effect is more serious than 60Co. It was also found that the image quality gets better when the count data of photo-peak were used rather than the total counts from the full spectrum. The image improvement technique using precise weight matrix calculation method was suggested to remove the influence of the Scattered Radiation on the reconstructed image quality. From the experiment, it was concluded that the effect of Scattered Radiation on the imag...
David R. Dance - One of the best experts on this subject based on the ideXlab platform.
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Simple method for computing Scattered Radiation in breast tomosynthesis
Medical physics, 2019Co-Authors: Oliver Diaz, Kenneth C. Young, Premkumar Elangovan, Kevin Wells, David R. DanceAbstract:Purpose Virtual clinical trials (VCT) are a powerful imaging tool that can be used to investigate digital breast tomosynthesis (DBT) technology. In this work, a fast and simple method is proposed to estimate the two‐dimensional distribution of Scattered Radiation which is needed when simulating DBT geometries in VCTs. Methods Monte Carlo simulations are used to precalculate scatter‐to‐primary ratio (SPR) for a range of low‐resolution homogeneous phantoms. The resulting values can be used to estimate the two‐dimensional (2D) distribution of Scattered Radiation arising from inhomogeneous anthropomorphic phantoms used in VCTs. The method has been validated by comparing the values of the scatter thus obtained against the results of direct Monte Carlo simulation for three different types of inhomogeneous anthropomorphic phantoms. Results Differences between the proposed scatter field estimation method and the ground truth data for the OPTIMAM phantom had an average modulus and standard deviation of over the projected breast area of 2.4 ± 0.9% (minimum −17.0%, maximum 27.7%). The corresponding values for the University of Pennsylvania and Duke University breast phantoms were 1.8 ± 0.1% (minimum −8.7%, maximum 8.0%) and 5.1 ± 0.1% (minimum −16.2%, maximum 7.4%), respectively. Conclusions The proposed method, which has been validated using three of the most common breast models, is a useful tool for accurately estimating Scattered Radiation in VCT schemes used to study current designs of DBT system.
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Can breast models be simplified to estimate Scattered Radiation in breast tomosythesis
Medical Imaging 2019: Physics of Medical Imaging, 2019Co-Authors: Oliver Diaz, David R. Dance, Kevin Wells, Prekumar Elangovan, Kenneth C. YoungAbstract:Scattered Radiation can represent a large portion of the total signal recorded at the image receptor in certain x-ray breast imaging systems, such as digital breast tomosynthesis (DBT). For many years, Monte Carlo (MC) simulations have represented the golden approach to estimate the scatter field, initially with simple models and more recently with anthropomorphic phantoms. However, it is unclear how the Scattered Radiation varies between such models. Further knowledge of the scatter behaviour can help to develop faster and simpler scatter field estimation approaches, which are highly demanded in virtual clinical trial (VCT) strategies. In this work, the Scattered Radiation estimated for several homogeneous breast models is compared against that from textured breast phantoms. By means of MC simulations, scatter fields are investigated under the same DBT scenario. Results for a quasi-realistic breast model suggest that homogeneous models with same shape and glandularity can approximate the Scattered Radiation produced by a heterogeneous phantom with a median error of 2%. Simpler models with semi-circular shapes, which reduces the complexity in the scatter field estimation and decrease the computational time, show good approximation in the central region of the breast although larger discrepancies are observed in the peripheral region of the breast image.
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Estimation of Scattered Radiation in digital breast tomosynthesis
Physics in Medicine and Biology, 2014Co-Authors: Oliver Diaz, David R. Dance, Kenneth C. Young, Premkumar Elangovan, Predrag R. Bakic, Kevin WellsAbstract:Digital breast tomosynthesis (DBT) is a promising technique to overcome the tissue superposition limitations found in planar 2D x-ray mammography. However, as most DBT systems do not employ an anti-scatter grid, the levels of Scattered Radiation recorded within the image receptor are significantly higher than that observed in planar 2D x-ray mammography. Knowledge of this field is necessary as part of any correction scheme and for computer modelling and optimisation of this examination. Monte Carlo (MC) simulations are often used for this purpose, however they are computationally expensive and a more rapid method of calculation is desirable. This issue is addressed in this work by the development of a fast kernel-based methodology for scatter field estimation using a detailed realistic DBT geometry. Thickness-dependent scatter kernels, which were validated against the literature with a maximum discrepancy of 4% for an idealised geometry, have been calculated and a new physical parameter (air gap distance) was used to estimate more accurately the distribution of Scattered Radiation for a series of anthropomorphic breast phantom models. The proposed methodology considers, for the first time, the effects of Scattered Radiation from the compression paddle and breast support plate, which can represent more than 30% of the total Scattered Radiation recorded within the image receptor. The results show that the scatter field estimator can calculate Scattered Radiation images in an average of 80 min for projection angles up to 25° with equal to or less than a 10% error across most of the breast area when compared with direct MC simulations.
Kevin Wells - One of the best experts on this subject based on the ideXlab platform.
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Simple method for computing Scattered Radiation in breast tomosynthesis
Medical physics, 2019Co-Authors: Oliver Diaz, Kenneth C. Young, Premkumar Elangovan, Kevin Wells, David R. DanceAbstract:Purpose Virtual clinical trials (VCT) are a powerful imaging tool that can be used to investigate digital breast tomosynthesis (DBT) technology. In this work, a fast and simple method is proposed to estimate the two‐dimensional distribution of Scattered Radiation which is needed when simulating DBT geometries in VCTs. Methods Monte Carlo simulations are used to precalculate scatter‐to‐primary ratio (SPR) for a range of low‐resolution homogeneous phantoms. The resulting values can be used to estimate the two‐dimensional (2D) distribution of Scattered Radiation arising from inhomogeneous anthropomorphic phantoms used in VCTs. The method has been validated by comparing the values of the scatter thus obtained against the results of direct Monte Carlo simulation for three different types of inhomogeneous anthropomorphic phantoms. Results Differences between the proposed scatter field estimation method and the ground truth data for the OPTIMAM phantom had an average modulus and standard deviation of over the projected breast area of 2.4 ± 0.9% (minimum −17.0%, maximum 27.7%). The corresponding values for the University of Pennsylvania and Duke University breast phantoms were 1.8 ± 0.1% (minimum −8.7%, maximum 8.0%) and 5.1 ± 0.1% (minimum −16.2%, maximum 7.4%), respectively. Conclusions The proposed method, which has been validated using three of the most common breast models, is a useful tool for accurately estimating Scattered Radiation in VCT schemes used to study current designs of DBT system.
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Can breast models be simplified to estimate Scattered Radiation in breast tomosythesis
Medical Imaging 2019: Physics of Medical Imaging, 2019Co-Authors: Oliver Diaz, David R. Dance, Kevin Wells, Prekumar Elangovan, Kenneth C. YoungAbstract:Scattered Radiation can represent a large portion of the total signal recorded at the image receptor in certain x-ray breast imaging systems, such as digital breast tomosynthesis (DBT). For many years, Monte Carlo (MC) simulations have represented the golden approach to estimate the scatter field, initially with simple models and more recently with anthropomorphic phantoms. However, it is unclear how the Scattered Radiation varies between such models. Further knowledge of the scatter behaviour can help to develop faster and simpler scatter field estimation approaches, which are highly demanded in virtual clinical trial (VCT) strategies. In this work, the Scattered Radiation estimated for several homogeneous breast models is compared against that from textured breast phantoms. By means of MC simulations, scatter fields are investigated under the same DBT scenario. Results for a quasi-realistic breast model suggest that homogeneous models with same shape and glandularity can approximate the Scattered Radiation produced by a heterogeneous phantom with a median error of 2%. Simpler models with semi-circular shapes, which reduces the complexity in the scatter field estimation and decrease the computational time, show good approximation in the central region of the breast although larger discrepancies are observed in the peripheral region of the breast image.
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Estimation of Scattered Radiation in digital breast tomosynthesis
Physics in Medicine and Biology, 2014Co-Authors: Oliver Diaz, David R. Dance, Kenneth C. Young, Premkumar Elangovan, Predrag R. Bakic, Kevin WellsAbstract:Digital breast tomosynthesis (DBT) is a promising technique to overcome the tissue superposition limitations found in planar 2D x-ray mammography. However, as most DBT systems do not employ an anti-scatter grid, the levels of Scattered Radiation recorded within the image receptor are significantly higher than that observed in planar 2D x-ray mammography. Knowledge of this field is necessary as part of any correction scheme and for computer modelling and optimisation of this examination. Monte Carlo (MC) simulations are often used for this purpose, however they are computationally expensive and a more rapid method of calculation is desirable. This issue is addressed in this work by the development of a fast kernel-based methodology for scatter field estimation using a detailed realistic DBT geometry. Thickness-dependent scatter kernels, which were validated against the literature with a maximum discrepancy of 4% for an idealised geometry, have been calculated and a new physical parameter (air gap distance) was used to estimate more accurately the distribution of Scattered Radiation for a series of anthropomorphic breast phantom models. The proposed methodology considers, for the first time, the effects of Scattered Radiation from the compression paddle and breast support plate, which can represent more than 30% of the total Scattered Radiation recorded within the image receptor. The results show that the scatter field estimator can calculate Scattered Radiation images in an average of 80 min for projection angles up to 25° with equal to or less than a 10% error across most of the breast area when compared with direct MC simulations.
Young-ho Park - One of the best experts on this subject based on the ideXlab platform.
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Scattered Radiation DOSES TO THE PATIENTS AND MEDICAL PERSONNEL AT THE TIME OF EXTRACORPOREAL SHOCK WAVE LITHOTRIPSY
The Journal of Urology, 2008Co-Authors: Yoon Dong Kim, Won Jae Yang, Yoon Seob Song, Young-ho ParkAbstract:1271 Scattered Radiation DOSES TO THE PATIENTS AND MEDICAL PERSONNEL AT THE TIME OF EXTRACORPOREAL SHOCK WAVE LITHOTRIPSY Yoon Dong Kim*, Won Jae Yang, Yoon Seob Song, Young Ho Park. Seoul, Republic of Korea. INTRODUCTION AND OBJECTIVE: To estimate Scattered Radiation doses to the patients and medical personnel and to reveal risk factors associated with increasing Radiation doses during extracorporeal shock wave lithotripsy (ESWL).
Oliver Diaz - One of the best experts on this subject based on the ideXlab platform.
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Simple method for computing Scattered Radiation in breast tomosynthesis
Medical physics, 2019Co-Authors: Oliver Diaz, Kenneth C. Young, Premkumar Elangovan, Kevin Wells, David R. DanceAbstract:Purpose Virtual clinical trials (VCT) are a powerful imaging tool that can be used to investigate digital breast tomosynthesis (DBT) technology. In this work, a fast and simple method is proposed to estimate the two‐dimensional distribution of Scattered Radiation which is needed when simulating DBT geometries in VCTs. Methods Monte Carlo simulations are used to precalculate scatter‐to‐primary ratio (SPR) for a range of low‐resolution homogeneous phantoms. The resulting values can be used to estimate the two‐dimensional (2D) distribution of Scattered Radiation arising from inhomogeneous anthropomorphic phantoms used in VCTs. The method has been validated by comparing the values of the scatter thus obtained against the results of direct Monte Carlo simulation for three different types of inhomogeneous anthropomorphic phantoms. Results Differences between the proposed scatter field estimation method and the ground truth data for the OPTIMAM phantom had an average modulus and standard deviation of over the projected breast area of 2.4 ± 0.9% (minimum −17.0%, maximum 27.7%). The corresponding values for the University of Pennsylvania and Duke University breast phantoms were 1.8 ± 0.1% (minimum −8.7%, maximum 8.0%) and 5.1 ± 0.1% (minimum −16.2%, maximum 7.4%), respectively. Conclusions The proposed method, which has been validated using three of the most common breast models, is a useful tool for accurately estimating Scattered Radiation in VCT schemes used to study current designs of DBT system.
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Can breast models be simplified to estimate Scattered Radiation in breast tomosythesis
Medical Imaging 2019: Physics of Medical Imaging, 2019Co-Authors: Oliver Diaz, David R. Dance, Kevin Wells, Prekumar Elangovan, Kenneth C. YoungAbstract:Scattered Radiation can represent a large portion of the total signal recorded at the image receptor in certain x-ray breast imaging systems, such as digital breast tomosynthesis (DBT). For many years, Monte Carlo (MC) simulations have represented the golden approach to estimate the scatter field, initially with simple models and more recently with anthropomorphic phantoms. However, it is unclear how the Scattered Radiation varies between such models. Further knowledge of the scatter behaviour can help to develop faster and simpler scatter field estimation approaches, which are highly demanded in virtual clinical trial (VCT) strategies. In this work, the Scattered Radiation estimated for several homogeneous breast models is compared against that from textured breast phantoms. By means of MC simulations, scatter fields are investigated under the same DBT scenario. Results for a quasi-realistic breast model suggest that homogeneous models with same shape and glandularity can approximate the Scattered Radiation produced by a heterogeneous phantom with a median error of 2%. Simpler models with semi-circular shapes, which reduces the complexity in the scatter field estimation and decrease the computational time, show good approximation in the central region of the breast although larger discrepancies are observed in the peripheral region of the breast image.
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Estimation of Scattered Radiation in digital breast tomosynthesis
Physics in Medicine and Biology, 2014Co-Authors: Oliver Diaz, David R. Dance, Kenneth C. Young, Premkumar Elangovan, Predrag R. Bakic, Kevin WellsAbstract:Digital breast tomosynthesis (DBT) is a promising technique to overcome the tissue superposition limitations found in planar 2D x-ray mammography. However, as most DBT systems do not employ an anti-scatter grid, the levels of Scattered Radiation recorded within the image receptor are significantly higher than that observed in planar 2D x-ray mammography. Knowledge of this field is necessary as part of any correction scheme and for computer modelling and optimisation of this examination. Monte Carlo (MC) simulations are often used for this purpose, however they are computationally expensive and a more rapid method of calculation is desirable. This issue is addressed in this work by the development of a fast kernel-based methodology for scatter field estimation using a detailed realistic DBT geometry. Thickness-dependent scatter kernels, which were validated against the literature with a maximum discrepancy of 4% for an idealised geometry, have been calculated and a new physical parameter (air gap distance) was used to estimate more accurately the distribution of Scattered Radiation for a series of anthropomorphic breast phantom models. The proposed methodology considers, for the first time, the effects of Scattered Radiation from the compression paddle and breast support plate, which can represent more than 30% of the total Scattered Radiation recorded within the image receptor. The results show that the scatter field estimator can calculate Scattered Radiation images in an average of 80 min for projection angles up to 25° with equal to or less than a 10% error across most of the breast area when compared with direct MC simulations.
