Jokic, Vesna Spasic

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  • Jokic, Vesna Spasic (3)
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Author's Bibliography

Absorbed Dose Uncertainty Estimation for Proton Therapy

Jokic, Vesna Spasic; Dobrosavljević, Aleksandar S.; Beličev, Petar

(2012)

TY  - JOUR
AU  - Jokic, Vesna Spasic
AU  - Dobrosavljević, Aleksandar S.
AU  - Beličev, Petar
PY  - 2012
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/5070
AB  - Successful radiotherapy treatment depends on the absorbed dose evaluation and the possibility to define metrological characteristics of the therapy beam. Radiotherapy requires tumor dose delivery with expanded uncertainty less than +/- 5 %. It is particularly important to reduce uncertainty during therapy beam calibration as well as to apply all necessary ionization chamber correction factors. Absorbed dose to water was determined using ionometric method. Calibration was performed in reference cobalt beam. Combined standard uncertainty of the calculated absorbed dose to water in 65 MeV proton beam was +/- 1.97% while the obtained expanded uncertainty of absorbed dose for the same beam quality was +/- 5.02%. The uncertainty estimation method has been developed within the project TESLA.
T2  - Nuclear technology and radiation protection
T1  - Absorbed Dose Uncertainty Estimation for Proton Therapy
VL  - 27
IS  - 3
SP  - 297
EP  - 304
DO  - 10.2298/NTRP1203297S
ER  - 
@article{
author = "Jokic, Vesna Spasic and Dobrosavljević, Aleksandar S. and Beličev, Petar",
year = "2012",
abstract = "Successful radiotherapy treatment depends on the absorbed dose evaluation and the possibility to define metrological characteristics of the therapy beam. Radiotherapy requires tumor dose delivery with expanded uncertainty less than +/- 5 %. It is particularly important to reduce uncertainty during therapy beam calibration as well as to apply all necessary ionization chamber correction factors. Absorbed dose to water was determined using ionometric method. Calibration was performed in reference cobalt beam. Combined standard uncertainty of the calculated absorbed dose to water in 65 MeV proton beam was +/- 1.97% while the obtained expanded uncertainty of absorbed dose for the same beam quality was +/- 5.02%. The uncertainty estimation method has been developed within the project TESLA.",
journal = "Nuclear technology and radiation protection",
title = "Absorbed Dose Uncertainty Estimation for Proton Therapy",
volume = "27",
number = "3",
pages = "297-304",
doi = "10.2298/NTRP1203297S"
}
Jokic, V. S., Dobrosavljević, A. S.,& Beličev, P.. (2012). Absorbed Dose Uncertainty Estimation for Proton Therapy. in Nuclear technology and radiation protection, 27(3), 297-304.
https://doi.org/10.2298/NTRP1203297S
Jokic VS, Dobrosavljević AS, Beličev P. Absorbed Dose Uncertainty Estimation for Proton Therapy. in Nuclear technology and radiation protection. 2012;27(3):297-304.
doi:10.2298/NTRP1203297S .
Jokic, Vesna Spasic, Dobrosavljević, Aleksandar S., Beličev, Petar, "Absorbed Dose Uncertainty Estimation for Proton Therapy" in Nuclear technology and radiation protection, 27, no. 3 (2012):297-304,
https://doi.org/10.2298/NTRP1203297S . .

Concentration of trace elements in blood and feed of homebred animals in Southern Serbia

Popovic, Dragana; Bozic, Tatjana; Stevanović, Jelka; Frontasyeva, Marina; Todorović, Dragana; Ajtic, Jelena V.; Jokic, Vesna Spasic

(2010)

TY  - JOUR
AU  - Popovic, Dragana
AU  - Bozic, Tatjana
AU  - Stevanović, Jelka
AU  - Frontasyeva, Marina
AU  - Todorović, Dragana
AU  - Ajtic, Jelena V.
AU  - Jokic, Vesna Spasic
PY  - 2010
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/3945
AB  - Background, aim and scope The paper presents concentrations of trace elements in blood of homebred animals (cows and sheep) from Southern Serbia (Bujanovac) and the contents of natural and anthropogenic radionuclides and some heavy metals in feed. The region of Southern Serbia was exposed to contamination by depleted uranium ammunition during NATO attacks in 1999 and therefore, is of great concern to environmental pollution and human and animal health. Materials and methods Conventional instrumental and epithermal neutron activation analyses are used to measure trace elements in cow and sheep blood samples collected randomly at six locations in the region of Bujanovac (village of Borovac) in the spring of 2005. Samples of feed (grass and crops: corn, wheat and oats), collected on the same locations (households), are analysed for the contents of radionuclides on an HPGe detector (Ortec, relative efficiency 23%) by standard gamma spectrometry. The content of Hg, Pb and Cd in feed is determined by standard atomic absorption spectrometry on the VarianSpectra220/ThermoSolar GFS97 spectrometer. Results Concentrations of 29 elements (Na, Al (P), Cl, K, Sc, Cr, Mn, Ni, Fe, Co, Zn, Se, As, Br, Sr, Rb, Sb, In, I, Ba, Cs, La, Nd, Eu, Sm, Tb, Hf, Ta and Th) are determined in blood of the examined animals. In feeds, natural 40K is found in all of the samples, cosmogenic Be-7 and fission product Cs-137 are detected only in the grass samples, while heavy metals Hg, Cd and Pb are found in the range of 0.01-0.02, 0.84-1.15 and 0.74-7.34 mg/kg, respectively. Calculated soil-to-blood transfer factors are in a wide range of 8.10(-6) to 64, as a result of varying significance of the elements in animal metabolism and feeding habits. Discussion The results of trace elements concentrations in animal blood are in good agreement with available data for K, Ni, Zn, Se and Rb. Higher Br concentrations in animal blood are most probably caused by large biomass burning events during blood sampling. Very low concentration of Fe in cows and sheep confirms the results of previous biochemical studies on animal anaemia in the region. High concentration of As correlates with geochemical peculiarities of the Balkans and is also likely influenced by the use of pesticides in the agricultural production. For some of the elements (La, Nd, Eu, Sm, Tb, Sb, Hf, Ta, Th, In, Ba, Sr, Sc and Cs), there are few or no literature data. Therefore, some of the presented data are significant not only for the country and the region, but on a wider scale. Activities of natural radionuclides in feeds are within the average values reported for the region, while the activities of Pb-210 and U-235/238 are below the limit of detection. This is in accordance with previous investigations showing no widespread contamination by depleted uranium in the area. Contents of Hg and Pb in feeds are below the nationally permissible levels, unlike the content of Cd which exceeds it, probably caused by the use of phosphate fertilisers and fossil fuel combustion in the area. Conclusions In general, the concentrations of trace elements in blood of homebred cows and sheep are in good agreement with reference materials, available literature data and the results of previous studies in the area. The exceptions are Fe, As and Br. The contents of natural and anthropogenic radionuclides in feeds are within the expected levels, and there are no signs of contamination by depleted uranium or other fission products. Apart from Cd, there are no signs of pollution by heavy metals in feeds. The highly sensitive method of instrumental neutron activation analysis provides data on the concentration of some elements in animal blood not previously reported for the region and elsewhere. Recommendations and perspectives The presented study is a part of the long term ongoing project on the health risk assessment on animals and humans in the region. The collected data is intended to provide a base for the animal and human risk assessment as well as an estimate of the general pollution status of the environment in the region. Since some of the investigated elements are classified as important trace elements for livestock, the results could also be used to balance and improve the animal diet and thus, improve the growth and reproduction rate.
T2  - Environmental Science and Pollution Research
T1  - Concentration of trace elements in blood and feed of homebred animals in Southern Serbia
VL  - 17
IS  - 5
SP  - 1119
EP  - 1128
DO  - 10.1007/s11356-009-0274-6
ER  - 
@article{
author = "Popovic, Dragana and Bozic, Tatjana and Stevanović, Jelka and Frontasyeva, Marina and Todorović, Dragana and Ajtic, Jelena V. and Jokic, Vesna Spasic",
year = "2010",
abstract = "Background, aim and scope The paper presents concentrations of trace elements in blood of homebred animals (cows and sheep) from Southern Serbia (Bujanovac) and the contents of natural and anthropogenic radionuclides and some heavy metals in feed. The region of Southern Serbia was exposed to contamination by depleted uranium ammunition during NATO attacks in 1999 and therefore, is of great concern to environmental pollution and human and animal health. Materials and methods Conventional instrumental and epithermal neutron activation analyses are used to measure trace elements in cow and sheep blood samples collected randomly at six locations in the region of Bujanovac (village of Borovac) in the spring of 2005. Samples of feed (grass and crops: corn, wheat and oats), collected on the same locations (households), are analysed for the contents of radionuclides on an HPGe detector (Ortec, relative efficiency 23%) by standard gamma spectrometry. The content of Hg, Pb and Cd in feed is determined by standard atomic absorption spectrometry on the VarianSpectra220/ThermoSolar GFS97 spectrometer. Results Concentrations of 29 elements (Na, Al (P), Cl, K, Sc, Cr, Mn, Ni, Fe, Co, Zn, Se, As, Br, Sr, Rb, Sb, In, I, Ba, Cs, La, Nd, Eu, Sm, Tb, Hf, Ta and Th) are determined in blood of the examined animals. In feeds, natural 40K is found in all of the samples, cosmogenic Be-7 and fission product Cs-137 are detected only in the grass samples, while heavy metals Hg, Cd and Pb are found in the range of 0.01-0.02, 0.84-1.15 and 0.74-7.34 mg/kg, respectively. Calculated soil-to-blood transfer factors are in a wide range of 8.10(-6) to 64, as a result of varying significance of the elements in animal metabolism and feeding habits. Discussion The results of trace elements concentrations in animal blood are in good agreement with available data for K, Ni, Zn, Se and Rb. Higher Br concentrations in animal blood are most probably caused by large biomass burning events during blood sampling. Very low concentration of Fe in cows and sheep confirms the results of previous biochemical studies on animal anaemia in the region. High concentration of As correlates with geochemical peculiarities of the Balkans and is also likely influenced by the use of pesticides in the agricultural production. For some of the elements (La, Nd, Eu, Sm, Tb, Sb, Hf, Ta, Th, In, Ba, Sr, Sc and Cs), there are few or no literature data. Therefore, some of the presented data are significant not only for the country and the region, but on a wider scale. Activities of natural radionuclides in feeds are within the average values reported for the region, while the activities of Pb-210 and U-235/238 are below the limit of detection. This is in accordance with previous investigations showing no widespread contamination by depleted uranium in the area. Contents of Hg and Pb in feeds are below the nationally permissible levels, unlike the content of Cd which exceeds it, probably caused by the use of phosphate fertilisers and fossil fuel combustion in the area. Conclusions In general, the concentrations of trace elements in blood of homebred cows and sheep are in good agreement with reference materials, available literature data and the results of previous studies in the area. The exceptions are Fe, As and Br. The contents of natural and anthropogenic radionuclides in feeds are within the expected levels, and there are no signs of contamination by depleted uranium or other fission products. Apart from Cd, there are no signs of pollution by heavy metals in feeds. The highly sensitive method of instrumental neutron activation analysis provides data on the concentration of some elements in animal blood not previously reported for the region and elsewhere. Recommendations and perspectives The presented study is a part of the long term ongoing project on the health risk assessment on animals and humans in the region. The collected data is intended to provide a base for the animal and human risk assessment as well as an estimate of the general pollution status of the environment in the region. Since some of the investigated elements are classified as important trace elements for livestock, the results could also be used to balance and improve the animal diet and thus, improve the growth and reproduction rate.",
journal = "Environmental Science and Pollution Research",
title = "Concentration of trace elements in blood and feed of homebred animals in Southern Serbia",
volume = "17",
number = "5",
pages = "1119-1128",
doi = "10.1007/s11356-009-0274-6"
}
Popovic, D., Bozic, T., Stevanović, J., Frontasyeva, M., Todorović, D., Ajtic, J. V.,& Jokic, V. S.. (2010). Concentration of trace elements in blood and feed of homebred animals in Southern Serbia. in Environmental Science and Pollution Research, 17(5), 1119-1128.
https://doi.org/10.1007/s11356-009-0274-6
Popovic D, Bozic T, Stevanović J, Frontasyeva M, Todorović D, Ajtic JV, Jokic VS. Concentration of trace elements in blood and feed of homebred animals in Southern Serbia. in Environmental Science and Pollution Research. 2010;17(5):1119-1128.
doi:10.1007/s11356-009-0274-6 .
Popovic, Dragana, Bozic, Tatjana, Stevanović, Jelka, Frontasyeva, Marina, Todorović, Dragana, Ajtic, Jelena V., Jokic, Vesna Spasic, "Concentration of trace elements in blood and feed of homebred animals in Southern Serbia" in Environmental Science and Pollution Research, 17, no. 5 (2010):1119-1128,
https://doi.org/10.1007/s11356-009-0274-6 . .
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Estimation of Patient Effective Dose from I-131 Using Monte Carlo Calculation

Jokic, Vesna Spasic; Orlić, Milan P.

(2009)

TY  - CONF
AU  - Jokic, Vesna Spasic
AU  - Orlić, Milan P.
PY  - 2009
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/6859
AB  - During the oral application of radionuclide therapy it is from the vital importance to measure effective dose in stomach in which the (NaI)-I-131 therapeutic capsule stays during the 15 minutes which is long enough to make risky exposure. As it is not possible to determine it by direct measurements there is a strong recommendation to estimate the dose by calculation. The main goal is to calculate effective dose and risk as a result of I-131 capsules remaining in stomach before the absorption starts. Monte Carlo code MCNP4b was used to model the transport of gamma and beta particles emitted by radionuclide I-131 treated as a point source at the bottom of the stomach. Absorbed energy per unit transformation in stomach and surrounding organs has been calculated. The dose equivalents in these organs have been calculated in aim to determine the effective doses using appropriate tissue weighting factor values. The local doses in stomach wall reached the values in order of several hundreds of grays in a very short time. In such case the traditional concept of risk is not applicable, so it becomes necessary to create the very new concept which is able to cover higher risks under presented circumstances.
T1  - Estimation of Patient Effective Dose from I-131 Using Monte Carlo Calculation
SP  - 1669
EP  - 1673
ER  - 
@conference{
author = "Jokic, Vesna Spasic and Orlić, Milan P.",
year = "2009",
abstract = "During the oral application of radionuclide therapy it is from the vital importance to measure effective dose in stomach in which the (NaI)-I-131 therapeutic capsule stays during the 15 minutes which is long enough to make risky exposure. As it is not possible to determine it by direct measurements there is a strong recommendation to estimate the dose by calculation. The main goal is to calculate effective dose and risk as a result of I-131 capsules remaining in stomach before the absorption starts. Monte Carlo code MCNP4b was used to model the transport of gamma and beta particles emitted by radionuclide I-131 treated as a point source at the bottom of the stomach. Absorbed energy per unit transformation in stomach and surrounding organs has been calculated. The dose equivalents in these organs have been calculated in aim to determine the effective doses using appropriate tissue weighting factor values. The local doses in stomach wall reached the values in order of several hundreds of grays in a very short time. In such case the traditional concept of risk is not applicable, so it becomes necessary to create the very new concept which is able to cover higher risks under presented circumstances.",
title = "Estimation of Patient Effective Dose from I-131 Using Monte Carlo Calculation",
pages = "1669-1673"
}
Jokic, V. S.,& Orlić, M. P.. (2009). Estimation of Patient Effective Dose from I-131 Using Monte Carlo Calculation. , 1669-1673.
Jokic VS, Orlić MP. Estimation of Patient Effective Dose from I-131 Using Monte Carlo Calculation. 2009;:1669-1673..
Jokic, Vesna Spasic, Orlić, Milan P., "Estimation of Patient Effective Dose from I-131 Using Monte Carlo Calculation" (2009):1669-1673.