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Papers by somayeh jahanfar
Iranian Journal of Physics Research, Dec 15, 2011
Arabian journal for science and engineering, Mar 23, 2022
Revista Mexicana De Fisica, Sep 2, 2019
Radiation therapy is a promising treatment for cancer patients. The highest dose of radiation mus... more Radiation therapy is a promising treatment for cancer patients. The highest dose of radiation must be deliver to tumor and the lowest to the healthy tissues. Since charged particles such as protons have high stopping-power at track-end, these particles can be used to treat tumors close to sensitive tissues. Formulas that commonly used for proton stopping-power in a soft tissue-equivalent (T.E.) material and each of its elements have 48 and 12 constants respectively. Due to the complexity of formulas, high number of constants, high occupancy of computer memory, and rounding error of computer, existing formulas reduces information processing speed. Because of the importance of proton therapy and its applications in dosimetry, microdosimetry, detectors, and computer simulations of these systems, it is necessary to use fast and accurate formulas for the stopping-power and range in the T.E., and its elements. We wrote a computer code in FORTRAN programming language, and used the fitting method and obtained simple and fairly accurate formulas for the proton range in these materials. Our range formulas in T.E. have 6 constants, and this formulas in elements of T.E. include carbon, nitrogen, and oxygen have 4 and hydrogen have 8 constants. So our formulas greatly reduce the above mentioned errors.
Iranian Journal of Medical Physics, Dec 1, 2018
Introduction: Proton therapy is a type of radiation treatment that it uses protons to treat cance... more Introduction: Proton therapy is a type of radiation treatment that it uses protons to treat cancer. Because of the protons’ unique ability to distribute the radiation dose more directly to the tumor, it minimizes the damage to nearby healthy tissues. The rate of energy loss by the ion in the target is called stopping power. The total stopping power is sum nuclear and electronic stopping power. Electronic stopping power refers to the slowing down of a projectile ion due to the inelastic collisions between bound electrons in the medium and the ion moving through it. Nuclear stopping power refers to the elastic collisions between the projectile ion and atoms in the target. Materials and Methods: It should be noted that soft tissue-equivalent material denotes a substance, with absorbing and scattering properties for a given radiation that sufficiently match those of a certain biological tissue. The soft tissue-equivalent material usually consists of four elements of hydrogen, oxygen, carbon and nitrogen. By using the SRIM code, we calculated the total stopping power in each element for 10-MeV proton beam. Then, using Bragg's rule, we got the total stopping power for these elements. Also, using the same code, we obtained the total stopping power for the compound. Also, we obtained the contribution of nuclear and electronic stopping power to the total stopping power in this material. Results: By comparing, we observed that the peak height of stopping power using Bragg's rule is more than 20% higher than the SRIM code. This is due to the core and bond (CAB) corrections at low energies in the SRIM code. Also, we observed that total stopping power is due to the electronic stopping power in high energies. By reducing energy, the electronic stopping power is slowly reduced, and the share of nuclear stopping power slowly increases, and the intersection of these is at 50eV energy. Then the contribution of the nuclear stopping power is greater. Conclusion: The proton therapy to treat cancerous tumors is a major technological advance. In low- energies CAB corrections must be taken into account for stopping power of the compound, and therefore, the peak height of the stopping power is reduced. In soft tissue equivalent material for proton beam the contribution of the nuclear stopping power at energies of less than 50 eV is greater than the electronic stopping power. In other energies, the electron- stopping power share is dominant.
Sains Malaysiana, Apr 30, 2022
In many experimental and simulation researches, water phantom is used instead of most body organs... more In many experimental and simulation researches, water phantom is used instead of most body organs. Therefore, in this study, we replaced the water phantom instead of some organs to calculate its effect on the proton stopping-power, and range and the consequence of deposited energy and microdosimetric spectra in small sites. Some organs such as the spleen, thyroid, pancreas, prostate, testis, and ovaries are considered. We calculated the proton stopping-power in these organs using the SRIM code. Then using these results, we wrote a program in the programming language of Fortran and computed the proton range and deposited energy in two sites of 1 and 100 micron. Also, using the Geant4-10-4 code, we simulated these sites and obtained microdosimetric spectra of protons at 1 and 5MeV energies. In order to compare different states, the frequency-mean lineal energy, dose-mean lineal energy, these statistical uncertainties and absorb dose in each case were calculated and reported. Also, we estimated the statistical uncertainty of quantities with a new formula. We observed that using water instead of the organs causes a significant error in the calculations of the range and the maximum relative difference percentage of 18% and 22% in deposited energy in 1 and 100 micron sites, respectively. These differences depend on the energy of the incident proton, organ, and size site. Also, this replacement changes microdosimetric spectra, the location, and intensity of the Bragg's peak. The percent difference of location and intensity of the Bragg's peak for water instead of the spleen is-8.66 and 13.42%, respectively. Therefore, using water instead of the body organs in microdosimetry calculations is not recommended.
Revista Mexicana de Física, 2019
Radiation therapy is a promising treatment for cancer patients. The highest dose of radiation mus... more Radiation therapy is a promising treatment for cancer patients. The highest dose of radiation must deliver to tumor and the lowest to the healthy tissues. Since charged particles such as protons have high stopping-power at track-end, these particles can be used to treat tumors close to sensitive tissues. Formulas that commonly used for proton stopping-power in a soft tissue-equivalent material (T.E.) and each of its elements have respectively 48, and 12 constants. Due to the complexity of formulas, high number of constants, high occupancy of computer memory, and rounding error of computer, existing formulas reduces information processing speed. Because of the importance of proton therapy and its applications in dosimetry, microdosimetry, detectors, and computer simulations of these systems, it is necessary to use fast and accurate formulas for the stopping-power and range in the T.E., and its elements. We wrote a computer code in FORTRAN programming language, and used the fitting me...
Iranian Journal of Medical Physics, 2018
Introduction: Proton therapy is a type of radiation treatment that it uses protons to treat cance... more Introduction: Proton therapy is a type of radiation treatment that it uses protons to treat cancer. Because of the protons’ unique ability to distribute the radiation dose more directly to the tumor, it minimizes the damage to nearby healthy tissues. The rate of energy loss by the ion in the target is called stopping power. The total stopping power is sum nuclear and electronic stopping power. Electronic stopping power refers to the slowing down of a projectile ion due to the inelastic collisions between bound electrons in the medium and the ion moving through it. Nuclear stopping power refers to the elastic collisions between the projectile ion and atoms in the target. Materials and Methods: It should be noted that soft tissue-equivalent material denotes a substance, with absorbing and scattering properties for a given radiation that sufficiently match those of a certain biological tissue. The soft tissue-equivalent material usually consists of four elements of hydrogen, oxygen, ca...
Arabian Journal for Science and Engineering
Iranian Journal of Physics Research, Dec 15, 2011
Arabian journal for science and engineering, Mar 23, 2022
Revista Mexicana De Fisica, Sep 2, 2019
Radiation therapy is a promising treatment for cancer patients. The highest dose of radiation mus... more Radiation therapy is a promising treatment for cancer patients. The highest dose of radiation must be deliver to tumor and the lowest to the healthy tissues. Since charged particles such as protons have high stopping-power at track-end, these particles can be used to treat tumors close to sensitive tissues. Formulas that commonly used for proton stopping-power in a soft tissue-equivalent (T.E.) material and each of its elements have 48 and 12 constants respectively. Due to the complexity of formulas, high number of constants, high occupancy of computer memory, and rounding error of computer, existing formulas reduces information processing speed. Because of the importance of proton therapy and its applications in dosimetry, microdosimetry, detectors, and computer simulations of these systems, it is necessary to use fast and accurate formulas for the stopping-power and range in the T.E., and its elements. We wrote a computer code in FORTRAN programming language, and used the fitting method and obtained simple and fairly accurate formulas for the proton range in these materials. Our range formulas in T.E. have 6 constants, and this formulas in elements of T.E. include carbon, nitrogen, and oxygen have 4 and hydrogen have 8 constants. So our formulas greatly reduce the above mentioned errors.
Iranian Journal of Medical Physics, Dec 1, 2018
Introduction: Proton therapy is a type of radiation treatment that it uses protons to treat cance... more Introduction: Proton therapy is a type of radiation treatment that it uses protons to treat cancer. Because of the protons’ unique ability to distribute the radiation dose more directly to the tumor, it minimizes the damage to nearby healthy tissues. The rate of energy loss by the ion in the target is called stopping power. The total stopping power is sum nuclear and electronic stopping power. Electronic stopping power refers to the slowing down of a projectile ion due to the inelastic collisions between bound electrons in the medium and the ion moving through it. Nuclear stopping power refers to the elastic collisions between the projectile ion and atoms in the target. Materials and Methods: It should be noted that soft tissue-equivalent material denotes a substance, with absorbing and scattering properties for a given radiation that sufficiently match those of a certain biological tissue. The soft tissue-equivalent material usually consists of four elements of hydrogen, oxygen, carbon and nitrogen. By using the SRIM code, we calculated the total stopping power in each element for 10-MeV proton beam. Then, using Bragg's rule, we got the total stopping power for these elements. Also, using the same code, we obtained the total stopping power for the compound. Also, we obtained the contribution of nuclear and electronic stopping power to the total stopping power in this material. Results: By comparing, we observed that the peak height of stopping power using Bragg's rule is more than 20% higher than the SRIM code. This is due to the core and bond (CAB) corrections at low energies in the SRIM code. Also, we observed that total stopping power is due to the electronic stopping power in high energies. By reducing energy, the electronic stopping power is slowly reduced, and the share of nuclear stopping power slowly increases, and the intersection of these is at 50eV energy. Then the contribution of the nuclear stopping power is greater. Conclusion: The proton therapy to treat cancerous tumors is a major technological advance. In low- energies CAB corrections must be taken into account for stopping power of the compound, and therefore, the peak height of the stopping power is reduced. In soft tissue equivalent material for proton beam the contribution of the nuclear stopping power at energies of less than 50 eV is greater than the electronic stopping power. In other energies, the electron- stopping power share is dominant.
Sains Malaysiana, Apr 30, 2022
In many experimental and simulation researches, water phantom is used instead of most body organs... more In many experimental and simulation researches, water phantom is used instead of most body organs. Therefore, in this study, we replaced the water phantom instead of some organs to calculate its effect on the proton stopping-power, and range and the consequence of deposited energy and microdosimetric spectra in small sites. Some organs such as the spleen, thyroid, pancreas, prostate, testis, and ovaries are considered. We calculated the proton stopping-power in these organs using the SRIM code. Then using these results, we wrote a program in the programming language of Fortran and computed the proton range and deposited energy in two sites of 1 and 100 micron. Also, using the Geant4-10-4 code, we simulated these sites and obtained microdosimetric spectra of protons at 1 and 5MeV energies. In order to compare different states, the frequency-mean lineal energy, dose-mean lineal energy, these statistical uncertainties and absorb dose in each case were calculated and reported. Also, we estimated the statistical uncertainty of quantities with a new formula. We observed that using water instead of the organs causes a significant error in the calculations of the range and the maximum relative difference percentage of 18% and 22% in deposited energy in 1 and 100 micron sites, respectively. These differences depend on the energy of the incident proton, organ, and size site. Also, this replacement changes microdosimetric spectra, the location, and intensity of the Bragg's peak. The percent difference of location and intensity of the Bragg's peak for water instead of the spleen is-8.66 and 13.42%, respectively. Therefore, using water instead of the body organs in microdosimetry calculations is not recommended.
Revista Mexicana de Física, 2019
Radiation therapy is a promising treatment for cancer patients. The highest dose of radiation mus... more Radiation therapy is a promising treatment for cancer patients. The highest dose of radiation must deliver to tumor and the lowest to the healthy tissues. Since charged particles such as protons have high stopping-power at track-end, these particles can be used to treat tumors close to sensitive tissues. Formulas that commonly used for proton stopping-power in a soft tissue-equivalent material (T.E.) and each of its elements have respectively 48, and 12 constants. Due to the complexity of formulas, high number of constants, high occupancy of computer memory, and rounding error of computer, existing formulas reduces information processing speed. Because of the importance of proton therapy and its applications in dosimetry, microdosimetry, detectors, and computer simulations of these systems, it is necessary to use fast and accurate formulas for the stopping-power and range in the T.E., and its elements. We wrote a computer code in FORTRAN programming language, and used the fitting me...
Iranian Journal of Medical Physics, 2018
Introduction: Proton therapy is a type of radiation treatment that it uses protons to treat cance... more Introduction: Proton therapy is a type of radiation treatment that it uses protons to treat cancer. Because of the protons’ unique ability to distribute the radiation dose more directly to the tumor, it minimizes the damage to nearby healthy tissues. The rate of energy loss by the ion in the target is called stopping power. The total stopping power is sum nuclear and electronic stopping power. Electronic stopping power refers to the slowing down of a projectile ion due to the inelastic collisions between bound electrons in the medium and the ion moving through it. Nuclear stopping power refers to the elastic collisions between the projectile ion and atoms in the target. Materials and Methods: It should be noted that soft tissue-equivalent material denotes a substance, with absorbing and scattering properties for a given radiation that sufficiently match those of a certain biological tissue. The soft tissue-equivalent material usually consists of four elements of hydrogen, oxygen, ca...
Arabian Journal for Science and Engineering