The purpose of this study was to examine the potential of using scatter information to evaluate t... more The purpose of this study was to examine the potential of using scatter information to evaluate tissue density at selected sites. A method for non-invasively generating profiles of density distribution within an object using Compton scattered X-rays is presented. The Compton scatter method is modified to scan longitudinal sections of composite phantoms and samples of tissue substitute materials. Line scan data are used to describe how the detected count rate changes in response to localized density variations within an extended object. The physical limitations of quantification are discussed, including the effect of attenuation, multiple scatter, and limited spatial resolution. Further, the theory of the method, its performance and results of experimental phantom studies are described. The results presented indicate that the suggested method has the potential for measuring physical density distribution within an object with a spatial resolution of 2mm and an accuracy of approximately 4% under the circumstances in which attenuation correction is avoided.
ABSTRACT The specific activity, hazard index, and the annual effective dose of the terrestrial na... more ABSTRACT The specific activity, hazard index, and the annual effective dose of the terrestrial naturally occurring radionuclides (238U, 232Th, and 40K) were determined in soil samples obtained from 20 sites of phosphate hills in the Russaifa region using an HPGe-detector of 50% relative efficiency. The resolution is 2 keV for the 1.33 MeV 60Co. The soil activity ranged from 5.3 to 1201.1 Bq kg−1 for 238U, 2.2 to 31.2 Bq kg−1 for 232Th, and 19.4 to 288.4 Bq kg−1 for 40K. Annual effective dose was found in the range 0.03–0.69 mSv. The external hazard index ranged from 0.15 to 3.29 Bq kg−1, while the global value given in UNSCEAR, 2000 publications is 1 Bq kg−1. The average values of the radium equivalent activities were determined for all sites and they were found to be approximately 319 Bq kg−1. This value is below the limit of 370 Bq kg−1 recommended by . The average value of the radium equivalent activities for certain locations (sample numbers: 2, 3, 4, 9, 10, and 14) is above the same limit.
The shielding properties of three different construction styles, and building materials, commonly... more The shielding properties of three different construction styles, and building materials, commonly used in Jordan, were evaluated using parameters such as attenuation coefficients, equivalent atomic number, penetration depth and energy buildup factor. Geometric progression (GP) method was used to calculate gamma-ray energy buildup factors of limestone, concrete, bricks, cement plaster and air for the energy range 0.05–3 MeV, and penetration depths up to 40 mfp. It has been observed that among the examined building materials, limestone offers highest value for equivalent atomic number and linear attenuation coefficient and the lowest values for penetration depth and energy buildup factor. The obtained buildup factors were used as basic data to establish the total equivalent energy buildup factors for three different multilayer construction styles using an iterative method. The three styles were then compared in terms of fractional transmission of photons at different incident photon e...
Applied radiation and isotopes: including data, instrumentation and methods for use in agriculture, industry and medicine
The major objective of this study has been to investigate methods of radioactive point source loc... more The major objective of this study has been to investigate methods of radioactive point source localization within an object. Count rate ratios from two opposite detectors around an object are used for localization. Potentially useful mathematical non-linear equations are derived and solved by MATHEMATICA-based program to identify activity position in multidimensions.
Nuclear Analytical Methods in the Life Sciences 1994, 1994
Neutron-induced gamma-ray emission tomography for quantitative determination of concentration and... more Neutron-induced gamma-ray emission tomography for quantitative determination of concentration and distribution of elements in a selected plane through a biological specimen is briefly explained and applied by way of illustration to the analysis of gallstones. A system capable of carrying out studies of the binding site of 75Se is different matrices using time differential perturbed angular correlation spectroscopy is also briefly described. Developments in the detector technology of positron emission tomography have allowed small-diameter imaging devices to be built for in vivo preclinical evaluation of new tracers in small animals and are discussed in the context of a proposed experiment combining the techniques mentioned above.
... A prototype X-ray transmission CT scanner system was designed and constructed successfully at... more ... A prototype X-ray transmission CT scanner system was designed and constructed successfully at the X-ray Laboratory in the University of Jordan. ... X-ray beam, then scanned across a sample with a radiation detector positioned on the opposite side of the sample (Martz et al ...
ABSTRACT A Monte Carlo simulation study has been conducted of 60Co photons Compton scattered in c... more ABSTRACT A Monte Carlo simulation study has been conducted of 60Co photons Compton scattered in concrete, illustrating the degraded energy spectra of gamma-ray radiation. Results are produced representing a NaI(Tl) detector model. We were able to analyse energy distributions of photons that reach the detector system after suffering several successive Compton scatterings in the target. The predicted decrease in intensity of single- and multiple-scattering peaks with increase in thickness of the target medium are in good agreement with experimental observations and findings reported by others.
This study is undertaken to determine the activity concentration of (226)Ra, (232)Th and (40)K in... more This study is undertaken to determine the activity concentration of (226)Ra, (232)Th and (40)K in samples of commonly used building materials in Jordan. Samples of seven different materials were collected from construction sites and local agencies supplying raw construction materials and analyzed using a HPGe gamma-ray spectrometer, taking into account self-attenuation in bulk samples. The average specific activity concentrations of (226)Ra, (232)Th, and (40)K ranged from 2.84 to 41.52, 0.78 to 58.42. and 3.74 to 897 Bq/kg, respectively. All the samples had radium equivalent activities well below the limit of 370 Bq/kg set by the Organization for Economic Cooperation and Development (OECD, 1979). External and internal hazard indices, absorbed dose and annual effective dose rate associated with the radionuclides of interest were calculated and compared with the international legislation and guidance. In general, most of the activities did not exceed the recommended international limits, except for granite and ceramic samples which are usually used as secondary building materials in Jordan.
The purpose of this study was to examine the potential of using scatter information to evaluate t... more The purpose of this study was to examine the potential of using scatter information to evaluate tissue density at selected sites. A method for non-invasively generating profiles of density distribution within an object using Compton scattered X-rays is presented. The Compton scatter method is modified to scan longitudinal sections of composite phantoms and samples of tissue substitute materials. Line scan data are used to describe how the detected count rate changes in response to localized density variations within an extended object. The physical limitations of quantification are discussed, including the effect of attenuation, multiple scatter, and limited spatial resolution. Further, the theory of the method, its performance and results of experimental phantom studies are described. The results presented indicate that the suggested method has the potential for measuring physical density distribution within an object with a spatial resolution of 2mm and an accuracy of approximately 4% under the circumstances in which attenuation correction is avoided.
ABSTRACT The specific activity, hazard index, and the annual effective dose of the terrestrial na... more ABSTRACT The specific activity, hazard index, and the annual effective dose of the terrestrial naturally occurring radionuclides (238U, 232Th, and 40K) were determined in soil samples obtained from 20 sites of phosphate hills in the Russaifa region using an HPGe-detector of 50% relative efficiency. The resolution is 2 keV for the 1.33 MeV 60Co. The soil activity ranged from 5.3 to 1201.1 Bq kg−1 for 238U, 2.2 to 31.2 Bq kg−1 for 232Th, and 19.4 to 288.4 Bq kg−1 for 40K. Annual effective dose was found in the range 0.03–0.69 mSv. The external hazard index ranged from 0.15 to 3.29 Bq kg−1, while the global value given in UNSCEAR, 2000 publications is 1 Bq kg−1. The average values of the radium equivalent activities were determined for all sites and they were found to be approximately 319 Bq kg−1. This value is below the limit of 370 Bq kg−1 recommended by . The average value of the radium equivalent activities for certain locations (sample numbers: 2, 3, 4, 9, 10, and 14) is above the same limit.
The shielding properties of three different construction styles, and building materials, commonly... more The shielding properties of three different construction styles, and building materials, commonly used in Jordan, were evaluated using parameters such as attenuation coefficients, equivalent atomic number, penetration depth and energy buildup factor. Geometric progression (GP) method was used to calculate gamma-ray energy buildup factors of limestone, concrete, bricks, cement plaster and air for the energy range 0.05–3 MeV, and penetration depths up to 40 mfp. It has been observed that among the examined building materials, limestone offers highest value for equivalent atomic number and linear attenuation coefficient and the lowest values for penetration depth and energy buildup factor. The obtained buildup factors were used as basic data to establish the total equivalent energy buildup factors for three different multilayer construction styles using an iterative method. The three styles were then compared in terms of fractional transmission of photons at different incident photon e...
Applied radiation and isotopes: including data, instrumentation and methods for use in agriculture, industry and medicine
The major objective of this study has been to investigate methods of radioactive point source loc... more The major objective of this study has been to investigate methods of radioactive point source localization within an object. Count rate ratios from two opposite detectors around an object are used for localization. Potentially useful mathematical non-linear equations are derived and solved by MATHEMATICA-based program to identify activity position in multidimensions.
Nuclear Analytical Methods in the Life Sciences 1994, 1994
Neutron-induced gamma-ray emission tomography for quantitative determination of concentration and... more Neutron-induced gamma-ray emission tomography for quantitative determination of concentration and distribution of elements in a selected plane through a biological specimen is briefly explained and applied by way of illustration to the analysis of gallstones. A system capable of carrying out studies of the binding site of 75Se is different matrices using time differential perturbed angular correlation spectroscopy is also briefly described. Developments in the detector technology of positron emission tomography have allowed small-diameter imaging devices to be built for in vivo preclinical evaluation of new tracers in small animals and are discussed in the context of a proposed experiment combining the techniques mentioned above.
... A prototype X-ray transmission CT scanner system was designed and constructed successfully at... more ... A prototype X-ray transmission CT scanner system was designed and constructed successfully at the X-ray Laboratory in the University of Jordan. ... X-ray beam, then scanned across a sample with a radiation detector positioned on the opposite side of the sample (Martz et al ...
ABSTRACT A Monte Carlo simulation study has been conducted of 60Co photons Compton scattered in c... more ABSTRACT A Monte Carlo simulation study has been conducted of 60Co photons Compton scattered in concrete, illustrating the degraded energy spectra of gamma-ray radiation. Results are produced representing a NaI(Tl) detector model. We were able to analyse energy distributions of photons that reach the detector system after suffering several successive Compton scatterings in the target. The predicted decrease in intensity of single- and multiple-scattering peaks with increase in thickness of the target medium are in good agreement with experimental observations and findings reported by others.
This study is undertaken to determine the activity concentration of (226)Ra, (232)Th and (40)K in... more This study is undertaken to determine the activity concentration of (226)Ra, (232)Th and (40)K in samples of commonly used building materials in Jordan. Samples of seven different materials were collected from construction sites and local agencies supplying raw construction materials and analyzed using a HPGe gamma-ray spectrometer, taking into account self-attenuation in bulk samples. The average specific activity concentrations of (226)Ra, (232)Th, and (40)K ranged from 2.84 to 41.52, 0.78 to 58.42. and 3.74 to 897 Bq/kg, respectively. All the samples had radium equivalent activities well below the limit of 370 Bq/kg set by the Organization for Economic Cooperation and Development (OECD, 1979). External and internal hazard indices, absorbed dose and annual effective dose rate associated with the radionuclides of interest were calculated and compared with the international legislation and guidance. In general, most of the activities did not exceed the recommended international limits, except for granite and ceramic samples which are usually used as secondary building materials in Jordan.
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