Pub Date : 2020-04-10DOI: 10.18869/ACADPUB.IJRR.18.2.201
J. B. Lee, J. Byun, J. Yun
Background: In gamma-ray spectrometry for the radioactivity analysis of bulk samples, self-attenuation correction is necessary when the attenuation rates in test sample differ from the one in the efficiency calibration source. Thus, the mass attenuation coefficient of test samples is an important factor in gamma-ray spectrometry. This study estimates the mass attenuation coefficients for seven kinds of environmental samples. Materials and Methods: An uncollimated transmission system with a high purity germanium detector system was used to measure the gamma-ray transmission rates with and without test samples. The system was calibrated using C (activated charcoal), H2O, MnO2, NaCl, Na2CO3, and (NH4)2SO4 as reference materials. Sea sediment, surface soil, fish, seaweed, Chinese cabbage, milk, and pine needles were selected, and ten identical samples for each sample type were tested using the system. Results: The calibration of the uncollimated transmission system was validated with good agreement within 4% between linear attenuation coefficients by experiment and calculation for K2CrO4 and SiO2. The standard deviation of the mass attenuation coefficients for each kind of sample was estimated as less than 5% above around 100 keV. Conclusion: Mass attenuation coefficient does not significantly depend on the sample type for gamma-ray energy higher than around 100 keV, but mass attenuation coefficient for the lower gamma-ray energy should be considered even with similar kinds of sample. The mass attenuation coefficients tabulated in this paper can be used as a reference or comparable value in gamma-ray spectrometry for environmental samples.
{"title":"Mass attenuation coefficients of environmental samples for gamma-ray energies from 46.5 keV to 1408 keV","authors":"J. B. Lee, J. Byun, J. Yun","doi":"10.18869/ACADPUB.IJRR.18.2.201","DOIUrl":"https://doi.org/10.18869/ACADPUB.IJRR.18.2.201","url":null,"abstract":"Background: In gamma-ray spectrometry for the radioactivity analysis of bulk samples, self-attenuation correction is necessary when the attenuation rates in test sample differ from the one in the efficiency calibration source. Thus, the mass attenuation coefficient of test samples is an important factor in gamma-ray spectrometry. This study estimates the mass attenuation coefficients for seven kinds of environmental samples. Materials and Methods: An uncollimated transmission system with a high purity germanium detector system was used to measure the gamma-ray transmission rates with and without test samples. The system was calibrated using C (activated charcoal), H2O, MnO2, NaCl, Na2CO3, and (NH4)2SO4 as reference materials. Sea sediment, surface soil, fish, seaweed, Chinese cabbage, milk, and pine needles were selected, and ten identical samples for each sample type were tested using the system. Results: The calibration of the uncollimated transmission system was validated with good agreement within 4% between linear attenuation coefficients by experiment and calculation for K2CrO4 and SiO2. The standard deviation of the mass attenuation coefficients for each kind of sample was estimated as less than 5% above around 100 keV. Conclusion: Mass attenuation coefficient does not significantly depend on the sample type for gamma-ray energy higher than around 100 keV, but mass attenuation coefficient for the lower gamma-ray energy should be considered even with similar kinds of sample. The mass attenuation coefficients tabulated in this paper can be used as a reference or comparable value in gamma-ray spectrometry for environmental samples.","PeriodicalId":14498,"journal":{"name":"Iranian Journal of Radiation Research","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48239083","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-04-10DOI: 10.18869/ACADPUB.IJRR.18.2.235
H. R. Tayeri, E. S. Khameneh, S. Zolghadri, S. Kakaei, D. Sardari
Background: Recently, several diagnostic radiopharmaceuticals including bleomycin (BLM) derivatives have been developed. Due to the suitable physical and chemical characteristics of Ga as a radionuclide for PET imaging, in this study, optimized production, quality control and preclinical evaluation of Ga-BLM as a new PET imaging agent is reported for the first time. Materials and Methods: Labeling of BLM with Ga was performed using Ge/Ga generator. Experiments were carried out by changing BLM concentration, temperature and pH of the reaction to determine the optimum parameters while the radiochemical purity was checked by radio thin layer chromatography at different times post labeling. Stability of the radiolabeled complex was studied at room temperature and in human serum at 37 °C. Biodistribution of the complex in BALB/c mice was assessed after intravenous injection and by counting the activity of each organ. Also, images were acquired up to 120 min by dual-head SPECT system. Results: The purity of this complex >96% (ITLC). At the optimized conditions for preparation of Ga-BLM (pH= 3.5-4, temperature = 90 oC, reaction time = 15 minutes and ligand concentration of 1 mg/ml) , the special activity of the labeled BLM reached to around 17.5 GBq/mmol. Biodistribution study showed significant accumulation of radioactivity in lung and bladder that was different pharmacokinetic compared to free Ga cation. Conclusion: Results show that Ga-BLM can be prepared in high radiochemical purity and high special activity only in 15 minutes and totally can be considered as a high potential agent for PET imaging.
{"title":"Optimized production, quality control and biological assessment of 68-Ga-bleomycin as a possible PET imaging agent","authors":"H. R. Tayeri, E. S. Khameneh, S. Zolghadri, S. Kakaei, D. Sardari","doi":"10.18869/ACADPUB.IJRR.18.2.235","DOIUrl":"https://doi.org/10.18869/ACADPUB.IJRR.18.2.235","url":null,"abstract":"Background: Recently, several diagnostic radiopharmaceuticals including bleomycin (BLM) derivatives have been developed. Due to the suitable physical and chemical characteristics of Ga as a radionuclide for PET imaging, in this study, optimized production, quality control and preclinical evaluation of Ga-BLM as a new PET imaging agent is reported for the first time. Materials and Methods: Labeling of BLM with Ga was performed using Ge/Ga generator. Experiments were carried out by changing BLM concentration, temperature and pH of the reaction to determine the optimum parameters while the radiochemical purity was checked by radio thin layer chromatography at different times post labeling. Stability of the radiolabeled complex was studied at room temperature and in human serum at 37 °C. Biodistribution of the complex in BALB/c mice was assessed after intravenous injection and by counting the activity of each organ. Also, images were acquired up to 120 min by dual-head SPECT system. Results: The purity of this complex >96% (ITLC). At the optimized conditions for preparation of Ga-BLM (pH= 3.5-4, temperature = 90 oC, reaction time = 15 minutes and ligand concentration of 1 mg/ml) , the special activity of the labeled BLM reached to around 17.5 GBq/mmol. Biodistribution study showed significant accumulation of radioactivity in lung and bladder that was different pharmacokinetic compared to free Ga cation. Conclusion: Results show that Ga-BLM can be prepared in high radiochemical purity and high special activity only in 15 minutes and totally can be considered as a high potential agent for PET imaging.","PeriodicalId":14498,"journal":{"name":"Iranian Journal of Radiation Research","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46444348","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-04-10DOI: 10.18869/ACADPUB.IJRR.18.2.209
T. Bijina, K. Ganesh, B. Subbulakshmi, A. Pichandi
Purpose: This study was conducted to evaluate single collimator (SC) and double collimator (DC) plans with respect to dosimetric analysis, calculated dose delivery to OAR and treatment time in carcinoma prostate patients treated with cyberknife. Materials and Methods: A retrospective study was conducted among twenty low and intermediate risk carcinoma prostate previously treated with Cyberknife. PTV was created and OARs were delineated. The prescribed dose was set as 37.5 Gy in 5 fractions and a base plan (BP), followed by three reduction plans (time, beam and node) were generated for both single and double collimators with sequential optimization module. The SC and DC plans were compared for the above-said variables. The mean differences were compared using paired t-test. A p-value of <0.05 was taken as statistically significant. Results: The median age of the patients was 63 years. DC plans had tighter isodose lines. The means of minimum doses did not vary significantly across the plans but the mean and maximum doses, PTV D2 and V95 means were significantly higher in single collimator plan. The mean CI and HI values were better in DC plans. The doses to OAR were comparable in both single and double collimator plans in terms of maximum doses. The mean doses received by OAR’s were significantly lesser in DC plans.SC plans resulted in lesser beams, nodes, MU and treatment time. Conclusion: Double collimator plans were better in producing good dosimetric results and reduced OAR doses with lesser estimated treatment efficiency.
{"title":"Dosimetric comparison of single and double collimator stereotactic body radiotherapy plans using Cyber Knife for carcinoma prostate","authors":"T. Bijina, K. Ganesh, B. Subbulakshmi, A. Pichandi","doi":"10.18869/ACADPUB.IJRR.18.2.209","DOIUrl":"https://doi.org/10.18869/ACADPUB.IJRR.18.2.209","url":null,"abstract":"Purpose: This study was conducted to evaluate single collimator (SC) and double collimator (DC) plans with respect to dosimetric analysis, calculated dose delivery to OAR and treatment time in carcinoma prostate patients treated with cyberknife. Materials and Methods: A retrospective study was conducted among twenty low and intermediate risk carcinoma prostate previously treated with Cyberknife. PTV was created and OARs were delineated. The prescribed dose was set as 37.5 Gy in 5 fractions and a base plan (BP), followed by three reduction plans (time, beam and node) were generated for both single and double collimators with sequential optimization module. The SC and DC plans were compared for the above-said variables. The mean differences were compared using paired t-test. A p-value of <0.05 was taken as statistically significant. Results: The median age of the patients was 63 years. DC plans had tighter isodose lines. The means of minimum doses did not vary significantly across the plans but the mean and maximum doses, PTV D2 and V95 means were significantly higher in single collimator plan. The mean CI and HI values were better in DC plans. The doses to OAR were comparable in both single and double collimator plans in terms of maximum doses. The mean doses received by OAR’s were significantly lesser in DC plans.SC plans resulted in lesser beams, nodes, MU and treatment time. Conclusion: Double collimator plans were better in producing good dosimetric results and reduced OAR doses with lesser estimated treatment efficiency.","PeriodicalId":14498,"journal":{"name":"Iranian Journal of Radiation Research","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43994807","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-04-10DOI: 10.18869/ACADPUB.IJRR.18.2.359
Sang-Tae Kim, J. Yoo
Background: Radon is a normally occurring radioactive material, which is designated as a class 1 human carcinogen. Therefore, it is important to control radon exposure in dwellings and workplaces. Methods: The radon guidelines of 32 countries across Europe, North America, and Asia were examined to determine rational radon exposure standards for minimizing radon risk in dwellings, offices, and workplaces. The exposure standards were classified as standards for people in dwellings and offices, where radon exposure can occur through construction materials, and standards for workers exposed to radon at industrial sites, where they directly handle products containing radioactive matter such as raw materials and by-products from processing. Results: The examination results showed that in South Korea, the advisory reference level (ARL) for dwellings is set to 148 Bq/m. Moreover, ARLs are set for subway stations, libraries, medical institutions, and indoor parking lots, but there are no radon exposure standards to protect workers in manufacturing sites, officers, and other workplaces. In other countries, the ARL or the mandatory reference level (MRL) are usually regulated between 148–400 Bq/m for dwellings and public-use facilities, and between 200–1,000 Bq/m for workplaces. Conclusion: It is recommended to use 148 Bq/m, which is the standard set by the U.S. Environmental Protection Agency, for dwellings and workplaces. For workplaces, it is recommended to set the exposure standard between 400 Bq/m, which is the level adopted in most European Union member countries, and 1,000 Bq/m3, which is the reference level recommended by the International Commission on Radiological Protection.
{"title":"Rational establishment of radon exposure standards for dwellings and workplaces","authors":"Sang-Tae Kim, J. Yoo","doi":"10.18869/ACADPUB.IJRR.18.2.359","DOIUrl":"https://doi.org/10.18869/ACADPUB.IJRR.18.2.359","url":null,"abstract":"Background: Radon is a normally occurring radioactive material, which is designated as a class 1 human carcinogen. Therefore, it is important to control radon exposure in dwellings and workplaces. Methods: The radon guidelines of 32 countries across Europe, North America, and Asia were examined to determine rational radon exposure standards for minimizing radon risk in dwellings, offices, and workplaces. The exposure standards were classified as standards for people in dwellings and offices, where radon exposure can occur through construction materials, and standards for workers exposed to radon at industrial sites, where they directly handle products containing radioactive matter such as raw materials and by-products from processing. Results: The examination results showed that in South Korea, the advisory reference level (ARL) for dwellings is set to 148 Bq/m. Moreover, ARLs are set for subway stations, libraries, medical institutions, and indoor parking lots, but there are no radon exposure standards to protect workers in manufacturing sites, officers, and other workplaces. In other countries, the ARL or the mandatory reference level (MRL) are usually regulated between 148–400 Bq/m for dwellings and public-use facilities, and between 200–1,000 Bq/m for workplaces. Conclusion: It is recommended to use 148 Bq/m, which is the standard set by the U.S. Environmental Protection Agency, for dwellings and workplaces. For workplaces, it is recommended to set the exposure standard between 400 Bq/m, which is the level adopted in most European Union member countries, and 1,000 Bq/m3, which is the reference level recommended by the International Commission on Radiological Protection.","PeriodicalId":14498,"journal":{"name":"Iranian Journal of Radiation Research","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45291984","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-04-10DOI: 10.18869/ACADPUB.IJRR.18.2.315
A. Shanei, A. Amouheidari, I. Abedi, A. Kazemzadeh, A. Jaafari
Background: The current study aimed to compare the tumor control probability (TCP) and normal tissue complication probability (NTCP) of threedimensional conformal radiation therapy (3D-CRT) and intensity-modulated radiation therapy (IMRT) for left-sided breast cancer using radiobiological models. Methods: This study was conducted on 30 patients with left-sided breast cancer, who were planned for 3D-CRT and 6-9 fields IMRT treatments using the PROWESS treatment planning system. The planning target volume (PTV) dose of 50 Gy was administered for the 3D-CRT and IMRT plans, respectively. The Niemierko’s equivalent uniform dose (EUD) model was utilized for the estimation of tumor control probability (TCP) and normal tissue complication probability (NTCP). Results: According to the results, the mean TCP values for 3D-CRT, 6-fields IMRT, and 9-fields IMRT plans were 99.07 ±0.07, 99.24 ±0.05 and 99.28 ±0.04, respectively, showing no statistically significant difference. The NTCPs of the lung and heart were considerably lower in the IMRT plans, compared to those in the 3D-CRT plans. Conclusions: From the radiobiological point of view, our results indicated that 3D-CRT produces a lower NTCP for ipsilateral lung. In contrast, for TCP calculations, there was a higher gain with IMRT plans compared to 3D-CRT plans.
{"title":"Radiobiological comparison of 3D conformal and intensity modulated radiation therapy in the treatment of left-sided breast cancer","authors":"A. Shanei, A. Amouheidari, I. Abedi, A. Kazemzadeh, A. Jaafari","doi":"10.18869/ACADPUB.IJRR.18.2.315","DOIUrl":"https://doi.org/10.18869/ACADPUB.IJRR.18.2.315","url":null,"abstract":"Background: The current study aimed to compare the tumor control probability (TCP) and normal tissue complication probability (NTCP) of threedimensional conformal radiation therapy (3D-CRT) and intensity-modulated radiation therapy (IMRT) for left-sided breast cancer using radiobiological models. Methods: This study was conducted on 30 patients with left-sided breast cancer, who were planned for 3D-CRT and 6-9 fields IMRT treatments using the PROWESS treatment planning system. The planning target volume (PTV) dose of 50 Gy was administered for the 3D-CRT and IMRT plans, respectively. The Niemierko’s equivalent uniform dose (EUD) model was utilized for the estimation of tumor control probability (TCP) and normal tissue complication probability (NTCP). Results: According to the results, the mean TCP values for 3D-CRT, 6-fields IMRT, and 9-fields IMRT plans were 99.07 ±0.07, 99.24 ±0.05 and 99.28 ±0.04, respectively, showing no statistically significant difference. The NTCPs of the lung and heart were considerably lower in the IMRT plans, compared to those in the 3D-CRT plans. Conclusions: From the radiobiological point of view, our results indicated that 3D-CRT produces a lower NTCP for ipsilateral lung. In contrast, for TCP calculations, there was a higher gain with IMRT plans compared to 3D-CRT plans.","PeriodicalId":14498,"journal":{"name":"Iranian Journal of Radiation Research","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46363240","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-04-10DOI: 10.18869/ACADPUB.IJRR.18.2.191
İ. Aral, S. Arslan, A. Yurekli, G. Inan, S. Tekin, H. Bozdemir, S. Sunel, H. Karabuğa, S. Acikgoz
Background and Aim: The incidence of internal lymph node (IMN) involvement was 465% in breast cancer patients. Despite studies indicating the positive effects of IMNRT on the oncological results, most of the clinicians avoided IMNRT because of the toxicity related to the increased dose of organs at risk (OAR). We aimed to compare the dosimetric results of RT plans with and without IMN containing planning target volumes (PTVs) using helical tomotherapy (HT) in obese patients. Materials and Methods: The PMRT data of 23 obese patients were evaluated retrospectively / dosimetrically. Two PTVs with and without IMN were defined and two separate plans were made with HT. Dose received by IMN and OAR were compared. Results: The untargeted IMN V40 were calculated between 0% to 99%. When the plans are evaluated in terms of critical organs, the inclusion of the IMN into the target volume, the most significant adverse effect was observed in heart doses in the left chest wall (CW) irradiation. The significant increases in cardiac V5 (% 62.6 vs %48.6 p=0.007), V10 (%38.2 vs %23.2 p=0.011), V20 (%14.15 vs %9.06 p=0.045) and maximum heart dose (48.04 vs 43.2 p=0.043) were observed in the left-side CW irradiations that involving the IMN. In CW irradiation on the right side with IMN, only a significant increase in mean heart dose (5.44 vs 4.52 p=0.036) was observed. Lung V5 doses were increased by inclusion with IMN in both sides. There was no difference in the contralateral breast doses in both plans for both sides. Conclusions: If the IMN is not targeted, some of the patients are getting appropriate doses in obese patients.
背景与目的：癌症患者的内淋巴结（IMN）受累率为465%。尽管研究表明IMNRT对肿瘤学结果有积极影响，但大多数临床医生避免使用IMNRT，因为其毒性与风险器官（OAR）剂量增加有关。我们的目的是比较在肥胖患者中使用螺旋断层治疗（HT）的带有和不带有IMN的计划靶体积（PTV）的RT计划的剂量测定结果。材料与方法：对23例肥胖患者的PMRT数据进行回顾性/剂量评估。定义了两个有IMN和没有IMN的PTV，并制定了两个单独的HT计划。比较了IMN和OAR接受的剂量。结果：非靶向IMN V40的计算结果在0%至99%之间。当根据关键器官对计划进行评估时，将IMN纳入目标体积，在左胸壁（CW）照射的心脏剂量中观察到最显著的不良影响。在涉及IMN的左侧CW照射中，观察到心脏V5（%62.6 vs%48.6 p=0.007）、V10（%38.2 vs%23.2 p=0.011）、V20（%14.15 vs%9.06 p=0.045）和最大心脏剂量（48.04 vs 43.2 p=0.043）的显著增加。在右侧连续波IMN照射中，仅观察到平均心脏剂量显著增加（5.44 vs 4.52 p=0.036）。肺V5剂量通过在两侧加入IMN而增加。在两种方案中，对侧乳腺的剂量对两侧均无差异。结论：如果IMN不是靶向性的，一些肥胖患者会得到适当的剂量。
{"title":"Internal mammarial lymph node radiotherapy in obese patients with breast cancer, at what expense?","authors":"İ. Aral, S. Arslan, A. Yurekli, G. Inan, S. Tekin, H. Bozdemir, S. Sunel, H. Karabuğa, S. Acikgoz","doi":"10.18869/ACADPUB.IJRR.18.2.191","DOIUrl":"https://doi.org/10.18869/ACADPUB.IJRR.18.2.191","url":null,"abstract":"Background and Aim: The incidence of internal lymph node (IMN) involvement was 465% in breast cancer patients. Despite studies indicating the positive effects of IMNRT on the oncological results, most of the clinicians avoided IMNRT because of the toxicity related to the increased dose of organs at risk (OAR). We aimed to compare the dosimetric results of RT plans with and without IMN containing planning target volumes (PTVs) using helical tomotherapy (HT) in obese patients. Materials and Methods: The PMRT data of 23 obese patients were evaluated retrospectively / dosimetrically. Two PTVs with and without IMN were defined and two separate plans were made with HT. Dose received by IMN and OAR were compared. Results: The untargeted IMN V40 were calculated between 0% to 99%. When the plans are evaluated in terms of critical organs, the inclusion of the IMN into the target volume, the most significant adverse effect was observed in heart doses in the left chest wall (CW) irradiation. The significant increases in cardiac V5 (% 62.6 vs %48.6 p=0.007), V10 (%38.2 vs %23.2 p=0.011), V20 (%14.15 vs %9.06 p=0.045) and maximum heart dose (48.04 vs 43.2 p=0.043) were observed in the left-side CW irradiations that involving the IMN. In CW irradiation on the right side with IMN, only a significant increase in mean heart dose (5.44 vs 4.52 p=0.036) was observed. Lung V5 doses were increased by inclusion with IMN in both sides. There was no difference in the contralateral breast doses in both plans for both sides. Conclusions: If the IMN is not targeted, some of the patients are getting appropriate doses in obese patients.","PeriodicalId":14498,"journal":{"name":"Iranian Journal of Radiation Research","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48805250","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-04-10DOI: 10.18869/ACADPUB.IJRR.18.2.263
M. Vagheian, D. Sardari, S. Saramad, D. R. Ochbelagh
Background: Among all of the radiations, X-ray has been always the center of attention due to the increasing availability of the X-ray tubes in industry, research institutes and medical centers. In this study, X-ray shielding properties of bulk and nanostructured thin lead films were investigated by means of Monte-Carlo computational and experimental methods, respectively. Materials and Methods: The lead samples were fabricated by the Physical Vapor Deposition technique (PVD) with different thickness of 10, 100 and 1000 nm. To investigate the radiation shielding properties of the nanostructured thin films, all of the prepared samples were subjected to the X-ray ranging from 8 to 14 keV. In order to consider the shielding properties of the bulk-structured thin films, the Monte-Carlo MCNPX code was employed. Results: The results indicated that, for low X-ray energies, the nanostructured thin lead films attenuate more than bulk-structured samples; however, the difference disappears as film thickness increases to 1000 nm or X-ray energy reaches 14 keV. Conclusion: Results imply that the nanostructured thin lead films attenuate more photons than the bulkstructured thin lead films with the same thicknesses.
{"title":"Experimental and theoretical investigation into X-ray shielding properties of thin lead films","authors":"M. Vagheian, D. Sardari, S. Saramad, D. R. Ochbelagh","doi":"10.18869/ACADPUB.IJRR.18.2.263","DOIUrl":"https://doi.org/10.18869/ACADPUB.IJRR.18.2.263","url":null,"abstract":"Background: Among all of the radiations, X-ray has been always the center of attention due to the increasing availability of the X-ray tubes in industry, research institutes and medical centers. In this study, X-ray shielding properties of bulk and nanostructured thin lead films were investigated by means of Monte-Carlo computational and experimental methods, respectively. Materials and Methods: The lead samples were fabricated by the Physical Vapor Deposition technique (PVD) with different thickness of 10, 100 and 1000 nm. To investigate the radiation shielding properties of the nanostructured thin films, all of the prepared samples were subjected to the X-ray ranging from 8 to 14 keV. In order to consider the shielding properties of the bulk-structured thin films, the Monte-Carlo MCNPX code was employed. Results: The results indicated that, for low X-ray energies, the nanostructured thin lead films attenuate more than bulk-structured samples; however, the difference disappears as film thickness increases to 1000 nm or X-ray energy reaches 14 keV. Conclusion: Results imply that the nanostructured thin lead films attenuate more photons than the bulkstructured thin lead films with the same thicknesses.","PeriodicalId":14498,"journal":{"name":"Iranian Journal of Radiation Research","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42719281","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-04-10DOI: 10.18869/ACADPUB.IJRR.18.2.369
B. I. Chibane, F. Benrachi, M. Bali
Background: Patients with head-and-neck cancers receiving radiotherapy show significant anatomical and dosimetric changes, especially during the latter part of treatment. The aim of this study is to evaluate the dosimetric effects of an adaptive Volumetric Modulated Arc Therapy (VMAT) treatment protocol for patients with locally advanced nasopharyngeal cancer (NPC). Material and methods: Ten patients treated with VMAT have benefited from a second computed tomography scan (CT2) after 15 fractions in order to apply a new adapted plan. A hybrid plan has been generated applying the original treatment plan configuration beam to the second CT scan. The dose– volume histograms (DVHs) of hybrid and adapted plans have been compared. Results: At the end of the 3 week of treatment, CT2 shows a considerable shrinkage of GTV N70 volume (45.2%) and a diminution of the left and right parotid glands volume (21.1%, 20.6% respectively). Compared to the initial plans, hybrid plans reveal that the dose delivered to target volume GTV N70 decreased by 15.2%, and the V30 of the left and right parotid glands increased by 47.3% and 25.6% respectively. However, there is no significant difference for the D2 of the brainstem and spinal cord. Conclusion: Our adaptive VMAT protocol improves dosimetric results in terms of GTV N70 coverage and nontoxic doses to parotid glands.
{"title":"Adaptive approach for nasopharyngeal carcinoma patients during Volumetric Modulated Arc Therapy treatment (VMAT)","authors":"B. I. Chibane, F. Benrachi, M. Bali","doi":"10.18869/ACADPUB.IJRR.18.2.369","DOIUrl":"https://doi.org/10.18869/ACADPUB.IJRR.18.2.369","url":null,"abstract":"Background: Patients with head-and-neck cancers receiving radiotherapy show significant anatomical and dosimetric changes, especially during the latter part of treatment. The aim of this study is to evaluate the dosimetric effects of an adaptive Volumetric Modulated Arc Therapy (VMAT) treatment protocol for patients with locally advanced nasopharyngeal cancer (NPC). Material and methods: Ten patients treated with VMAT have benefited from a second computed tomography scan (CT2) after 15 fractions in order to apply a new adapted plan. A hybrid plan has been generated applying the original treatment plan configuration beam to the second CT scan. The dose– volume histograms (DVHs) of hybrid and adapted plans have been compared. Results: At the end of the 3 week of treatment, CT2 shows a considerable shrinkage of GTV N70 volume (45.2%) and a diminution of the left and right parotid glands volume (21.1%, 20.6% respectively). Compared to the initial plans, hybrid plans reveal that the dose delivered to target volume GTV N70 decreased by 15.2%, and the V30 of the left and right parotid glands increased by 47.3% and 25.6% respectively. However, there is no significant difference for the D2 of the brainstem and spinal cord. Conclusion: Our adaptive VMAT protocol improves dosimetric results in terms of GTV N70 coverage and nontoxic doses to parotid glands.","PeriodicalId":14498,"journal":{"name":"Iranian Journal of Radiation Research","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49515931","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-04-10DOI: 10.18869/ACADPUB.IJRR.18.2.381
Z. A. Rahvar, M. Ghorbani, M. Khosroabadi, C. Knaup
Background: The present study aimed to determine half-value layers (HVL) of different materials with neutron, photon, and simultaneous neutron and photon emissions by a Cf source. MCNPX code was used for the simulation of the applicator tube (AT) Cf source and the attenuation materials. Materials and methods: The Cf source, a source collimator, a detector, a detector collimator, and HVL material were defined in the present study. HVL was determined for lead, concrete, water, polyethylene, and polyethylene mixtures with various concentrations of boric acid for separate neutron, separate photon, and simultaneous emissions of neutron and photon by the Cf source. Results: HVL values were tabulated for the aforementioned materials for separate neutron, separate photon, and for simultaneous neutron and photon emissions by the Cf source. Among the evaluated materials, polyethylene was the most adequate material for neutron shielding. Conclusion: The obtained HVL results for different materials could be used for shielding design around a Cf source. According to the comparison of lead with concrete, lead was a suitable material for shielding against the photons emission. On the other hand, concrete with a lower HVL value seemed to be superior for neutron shielding. The combination of several HVL layers of polyethylene and lead could result in proper shielding against neutron and photon. In simultaneous neutron and photon emissions, the emitted neutrons from the source generate secondary photons. The issue led to increase HVL, and could be considered in the protection and shielding
{"title":"Radiation Shielding Materials: Half-value layer determination for separate and simultaneous photon and neutron emissions by a 252-Cf source","authors":"Z. A. Rahvar, M. Ghorbani, M. Khosroabadi, C. Knaup","doi":"10.18869/ACADPUB.IJRR.18.2.381","DOIUrl":"https://doi.org/10.18869/ACADPUB.IJRR.18.2.381","url":null,"abstract":"Background: The present study aimed to determine half-value layers (HVL) of different materials with neutron, photon, and simultaneous neutron and photon emissions by a Cf source. MCNPX code was used for the simulation of the applicator tube (AT) Cf source and the attenuation materials. Materials and methods: The Cf source, a source collimator, a detector, a detector collimator, and HVL material were defined in the present study. HVL was determined for lead, concrete, water, polyethylene, and polyethylene mixtures with various concentrations of boric acid for separate neutron, separate photon, and simultaneous emissions of neutron and photon by the Cf source. Results: HVL values were tabulated for the aforementioned materials for separate neutron, separate photon, and for simultaneous neutron and photon emissions by the Cf source. Among the evaluated materials, polyethylene was the most adequate material for neutron shielding. Conclusion: The obtained HVL results for different materials could be used for shielding design around a Cf source. According to the comparison of lead with concrete, lead was a suitable material for shielding against the photons emission. On the other hand, concrete with a lower HVL value seemed to be superior for neutron shielding. The combination of several HVL layers of polyethylene and lead could result in proper shielding against neutron and photon. In simultaneous neutron and photon emissions, the emitted neutrons from the source generate secondary photons. The issue led to increase HVL, and could be considered in the protection and shielding","PeriodicalId":14498,"journal":{"name":"Iranian Journal of Radiation Research","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47085588","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-04-10DOI: 10.18869/ACADPUB.IJRR.18.2.243
I. Khan, Zhuang Qin, Tianci Xie, Z. Bin, Haopeng Li, Weimin Sun, E. Lewis
Background: The aim & objective of this study is to evaluate the health hazards of the general public from the existence of the radioactive nuclides in soil of North Waziristan and to establish a reference line for future work on radioactivity concentration in this locality. Methods and Materials: A highly background radiation shielded HPGe system is used to measure radioactivity in the collected samples of the geographical study area. Results: The radioactivity concentration is found to be in the range 42.6–106.3 Bq/kg for Ra-226, 4.0–93.8 Bq/kg for Th-232, 49.9–645.5 Bq/kg for K-40, and 2.6–8.33 Bq/kg for Cs-137. The external and internal hazards indices (Hext & Hint), absorbed γdose rate (ADR) and average effective dose (AED) are estimated from the computed activities and determined the average Hext ~ 0.75 and Hint ~ 0.94. The mean absorbed dose rate was found to be 101 nGy/h. The Radium equivalent activity of Datta Khel (422.081 Bq/kg), Khaisur forest (407.938 Bq/kg), Jani Khel (379.213) specific regions and the corresponding outdoor annual effective dose rate was found to be 0.15 mSv/yr, which is higher than the world’s mean value of 0.07 mSv/yr. Conclusion: A strong possitive correlation amongst the radioactive nuclides and, corresponding radiological variables at P ≤ 0.01confirmed that Ra-226 and Th-232 were the significant contributors to γ-radiation emission. Radioactivity concentrations and corresponding radiometric parameters were found to be higher in the specific areas of North Waziristan compared to the world’s mean values poses possible radiological risks for the residents of those areas.
{"title":"Evaluation of health hazards from radionuclides in soil and rocks of North Waziristan, Pakistan","authors":"I. Khan, Zhuang Qin, Tianci Xie, Z. Bin, Haopeng Li, Weimin Sun, E. Lewis","doi":"10.18869/ACADPUB.IJRR.18.2.243","DOIUrl":"https://doi.org/10.18869/ACADPUB.IJRR.18.2.243","url":null,"abstract":"Background: The aim & objective of this study is to evaluate the health hazards of the general public from the existence of the radioactive nuclides in soil of North Waziristan and to establish a reference line for future work on radioactivity concentration in this locality. Methods and Materials: A highly background radiation shielded HPGe system is used to measure radioactivity in the collected samples of the geographical study area. Results: The radioactivity concentration is found to be in the range 42.6–106.3 Bq/kg for Ra-226, 4.0–93.8 Bq/kg for Th-232, 49.9–645.5 Bq/kg for K-40, and 2.6–8.33 Bq/kg for Cs-137. The external and internal hazards indices (Hext & Hint), absorbed γdose rate (ADR) and average effective dose (AED) are estimated from the computed activities and determined the average Hext ~ 0.75 and Hint ~ 0.94. The mean absorbed dose rate was found to be 101 nGy/h. The Radium equivalent activity of Datta Khel (422.081 Bq/kg), Khaisur forest (407.938 Bq/kg), Jani Khel (379.213) specific regions and the corresponding outdoor annual effective dose rate was found to be 0.15 mSv/yr, which is higher than the world’s mean value of 0.07 mSv/yr. Conclusion: A strong possitive correlation amongst the radioactive nuclides and, corresponding radiological variables at P ≤ 0.01confirmed that Ra-226 and Th-232 were the significant contributors to γ-radiation emission. Radioactivity concentrations and corresponding radiometric parameters were found to be higher in the specific areas of North Waziristan compared to the world’s mean values poses possible radiological risks for the residents of those areas.","PeriodicalId":14498,"journal":{"name":"Iranian Journal of Radiation Research","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42858007","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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