Pub Date : 2020-05-01DOI: 10.22038/IJMP.2019.36221.1460
Mohamad Reza Rezaie Rayeni Nejad, Reza Shahhedarypoor, S. Mohammadi, P. Parvaresh
Introduction: Radiation therapy is regarded as the mainstay treatment for head or neck cancer patients. In this method, the backscattered radiation of dental composites can damage the surrounding tissue. Material and Methods: The current study compared the effects of electron beam radiation on healthy teeth with the tooth filled with materials used in dentistry with FLUKA and MCNPX2.6 codes. The simulation was performed for a 512 mm3 cubic tooth composed of Amalgam and Ceramco materials. Results: The simulation results indicated that patients with dental caries who inevitably filled their teeth with artificial restorationreceived a more effective dose, as compared to others. Moreover, it was revealed that Ceramco increases the radiation risk more than Amalgam does. Therefore, Amalgam is the right choice for dental filling. Conclusion: Based on the obtained results, ceramic material poses patients to increased radiation risk more than Amalgam does; therefore, it is recommended that Amalgam be used to fill dental cavities.
{"title":"Effect of Dental Filling Materials on Electron Beam Radiotherapy Dose Distribution in Head Region: a Monte Carlo Study by FLUKA and MCNPX Codes","authors":"Mohamad Reza Rezaie Rayeni Nejad, Reza Shahhedarypoor, S. Mohammadi, P. Parvaresh","doi":"10.22038/IJMP.2019.36221.1460","DOIUrl":"https://doi.org/10.22038/IJMP.2019.36221.1460","url":null,"abstract":"Introduction: Radiation therapy is regarded as the mainstay treatment for head or neck cancer patients. In this method, the backscattered radiation of dental composites can damage the surrounding tissue. \u0000Material and Methods: The current study compared the effects of electron beam radiation on healthy teeth with the tooth filled with materials used in dentistry with FLUKA and MCNPX2.6 codes. The simulation was performed for a 512 mm3 cubic tooth composed of Amalgam and Ceramco materials. \u0000Results: The simulation results indicated that patients with dental caries who inevitably filled their teeth with artificial restorationreceived a more effective dose, as compared to others. Moreover, it was revealed that Ceramco increases the radiation risk more than Amalgam does. Therefore, Amalgam is the right choice for dental filling. \u0000Conclusion: Based on the obtained results, ceramic material poses patients to increased radiation risk more than Amalgam does; therefore, it is recommended that Amalgam be used to fill dental cavities.","PeriodicalId":14613,"journal":{"name":"Iranian Journal of Medical Physics","volume":"17 1","pages":"183-187"},"PeriodicalIF":0.0,"publicationDate":"2020-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49626651","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 : 2020-05-01DOI: 10.22038/IJMP.2019.41400.1598
A. Dehkordi
Introduction: Pharmacokinetic (PK) modeling of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) is widely applied in tumor diagnosis and treatment evaluation. Precision analysis of the estimated PK parameters is essential when they are used as a measure for therapy evaluation or treatment planning. In this study, the accuracy of PK parameters in brain DCE-MRI studies was quantified in relation to two major sources of error(including pre-contrast longitudinal-relaxation time, T1,0 and flip angle, α). Material and Methods: 3470 dynamic contrast-enhanced-curves were simulated using a wide variation of the PK parameters. The bias of contrast concentration due to the systematic biases in α and T1,0 was calculated and added to both contrast concentration and AIF profiles. Thereafter, the PK parameters were estimated for each simulated curve in the presence of different percentages of relative biases in α and T1,0. The mean percentage error (MPE) of PK parameters was then calculated for all simulated curves. Results: The results indicated that plasma volume(vp) was the most sensitive parameter to bias of contrast concentration, which may overestimate up to 700% in 10% coincidence relative bias in α and T1,0. The lowest MPE was related to the backward transfer constant (kep), which was ~2%-15% in 10% coincidence relative bias in each α and T1, 0. Conclusion: Utilization of a nested model selection technique, along with an accurate estimator, such as maximum-likelihood estimation, created a unique approach for investigating the effect of the bias in the concentration measurement to the estimated PK parameters without the addition of any extra biases to the parameters during the estimation.
{"title":"Effect of Bias in Contrast Agent Concentration Measurement on Estimated Pharmacokinetic Parameters in Brain Dynamic Contrast-Enhanced Magnetic Resonance Imaging Studies","authors":"A. Dehkordi","doi":"10.22038/IJMP.2019.41400.1598","DOIUrl":"https://doi.org/10.22038/IJMP.2019.41400.1598","url":null,"abstract":"Introduction: Pharmacokinetic (PK) modeling of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) is widely applied in tumor diagnosis and treatment evaluation. Precision analysis of the estimated PK parameters is essential when they are used as a measure for therapy evaluation or treatment planning. In this study, the accuracy of PK parameters in brain DCE-MRI studies was quantified in relation to two major sources of error(including pre-contrast longitudinal-relaxation time, T1,0 and flip angle, α). \u0000Material and Methods: 3470 dynamic contrast-enhanced-curves were simulated using a wide variation of the PK parameters. The bias of contrast concentration due to the systematic biases in α and T1,0 was calculated and added to both contrast concentration and AIF profiles. Thereafter, the PK parameters were estimated for each simulated curve in the presence of different percentages of relative biases in α and T1,0. The mean percentage error (MPE) of PK parameters was then calculated for all simulated curves. \u0000Results: The results indicated that plasma volume(vp) was the most sensitive parameter to bias of contrast concentration, which may overestimate up to 700% in 10% coincidence relative bias in α and T1,0. The lowest MPE was related to the backward transfer constant (kep), which was ~2%-15% in 10% coincidence relative bias in each α and T1, 0. \u0000Conclusion: Utilization of a nested model selection technique, along with an accurate estimator, such as maximum-likelihood estimation, created a unique approach for investigating the effect of the bias in the concentration measurement to the estimated PK parameters without the addition of any extra biases to the parameters during the estimation.","PeriodicalId":14613,"journal":{"name":"Iranian Journal of Medical Physics","volume":"17 1","pages":"142-152"},"PeriodicalIF":0.0,"publicationDate":"2020-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47879123","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 : 2020-05-01DOI: 10.22038/IJMP.2019.39889.1539
F. Mubarak, H. Saleh
Introduction: The present study investigated the relatively high concentrations of natural radionuclides in raw material that used in ceramic manufacturing, and estimated the occupational exposure due to these activity concentrations. Material and Methods: A high-purity Germanium detector was used to determine naturally occurring radionuclides in raw materials that used in ceramic manufacturing. Activity concentrations of these materials lead to potential radiological hazards due to gamma and alpha radiation. These hazards were evaluated in the present study. Results: Maximum activity concentrations was5844, 1065 and 41 Bq/kg for 226Ra, 232Th and 235U in powdered quartz; however, maximum activity concentration for 40K was 1868 Bq/kg in colors. These activities were observed to be exceeding the exemption limit. Pancreasreceived the lowest dose (i.e., 0.02 mSv/y), while skin received the highest dose (i.e., 0.044mSv/y). Internal hazard index (Hin) was reported as 53.74, which exceed the recommended value (Hin≤1). Alpha index was 42.4 which led to over exposure. Representative level index and excess lifetime cancer risk were 0.00062 and 0.641 respectively. The total annual external dose was 2.62 m Gy/y which led to 1.83 mSv/y effective dose. Radiological hazard due to radon inhalation was 1.53E-06 mSv/y. Conclusion: Due to the high activity concentrations of raw materials (especially zirconium compounds) and consequently the associated high dose, specific regulations must be applied in the ceramic industry in Egypt.
本研究调查了陶瓷制造中使用的原料中相对高浓度的天然放射性核素，并估计了这些活性浓度引起的职业暴露。材料和方法:高纯度锗探测器用于测定陶瓷制造原料中天然存在的放射性核素。这些物质的活动浓度会导致由于γ和α辐射的潜在辐射危害。本研究对这些危害进行了评价。结果:粉末石英中226Ra、232Th和235U的最大活性浓度分别为5844、1065和41 Bq/kg;在40K条件下，颜色的最大活性浓度为1868 Bq/kg。据观察，这些活动超出了豁免限额。胰腺接受的剂量最低(即0.02 mSv/y)，而皮肤接受的剂量最高(即0.044mSv/y)。内部危害指数(Hin)为53.74，超过推荐值(Hin≤1)。Alpha指数为42.4，导致过度暴露。代表水平指数为0.00062，超额终生癌风险为0.641。年总外照射剂量为2.62 m Gy/y，有效剂量为1.83 mSv/y。吸入氡的辐射危害为1.53E-06 mSv/y。结论:由于原料(特别是锆化合物)的活性浓度很高，因此相应的剂量也很高，因此必须在埃及的陶瓷工业中实施具体的规定。
{"title":"Estimation of Occupational Exposure during Ceramic Manufacturing","authors":"F. Mubarak, H. Saleh","doi":"10.22038/IJMP.2019.39889.1539","DOIUrl":"https://doi.org/10.22038/IJMP.2019.39889.1539","url":null,"abstract":"Introduction: The present study investigated the relatively high concentrations of natural radionuclides in raw material that used in ceramic manufacturing, and estimated the occupational exposure due to these activity concentrations. \u0000Material and Methods: A high-purity Germanium detector was used to determine naturally occurring radionuclides in raw materials that used in ceramic manufacturing. Activity concentrations of these materials lead to potential radiological hazards due to gamma and alpha radiation. These hazards were evaluated in the present study. \u0000Results: Maximum activity concentrations was5844, 1065 and 41 Bq/kg for 226Ra, 232Th and 235U in powdered quartz; however, maximum activity concentration for 40K was 1868 Bq/kg in colors. These activities were observed to be exceeding the exemption limit. Pancreasreceived the lowest dose (i.e., 0.02 mSv/y), while skin received the highest dose (i.e., 0.044mSv/y). Internal hazard index (Hin) was reported as 53.74, which exceed the recommended value (Hin≤1). Alpha index was 42.4 which led to over exposure. Representative level index and excess lifetime cancer risk were 0.00062 and 0.641 respectively. The total annual external dose was 2.62 m Gy/y which led to 1.83 mSv/y effective dose. Radiological hazard due to radon inhalation was 1.53E-06 mSv/y. \u0000Conclusion: Due to the high activity concentrations of raw materials (especially zirconium compounds) and consequently the associated high dose, specific regulations must be applied in the ceramic industry in Egypt.","PeriodicalId":14613,"journal":{"name":"Iranian Journal of Medical Physics","volume":"17 1","pages":"175-182"},"PeriodicalIF":0.0,"publicationDate":"2020-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45208248","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 : 2020-05-01DOI: 10.22038/IJMP.2019.39054.1515
D. Saroj, Suresh Yadav, Gopa Ghosh, Shuchishree Shukla, G. Gupta, Suman Kumar Choudhary
Introduction: The present study evaluated the dosimetric comparison between 6MV flattened filter (FF) and flattening filter-free (FFF) photon beams in intensity-modulated radiation therapy (IMRT) technique for the treatment of glioblastoma (GBM) patients. Material and Methods: The present study was conducted on 10 patients with GBM previously planned and treated with 6MV FF photon beam by IMRT technique. Additional IMRT plans were retrospectively created using 6MV FFF photon beam for each patient plan. The dose prescription, beam parameters, and planning objective were kept same in both plans. The plans were evaluated using cumulative dose-volume histogram (c-DVH). Both types of plans were compared on the basis of homogeneity index (HI), conformity index (CI), beam-on time (BOT), monitor unit (MU), and doses to organs at risk (OARs). Results: Dose received by 95% (D95%) of planning target volume (PTV) coverage was observed significantly higher in 6MV_FF_IMRT plan than 6MV_FFF_IMRT plan (P<0.05). No significant dose differences were noticed for HI, CI, D98%, and D2% between both plans. Significantly lower Dmax for the brainstem, eyes, and eye lens was observed in 6MV_FFF_IMRT plan. For the brain, less than 2% mean dose was observed in 6MV_FFF_IMRT plan than 6MV_FF_IMRT plan (P=0.017). In 6MV_FFF_IMRT plan, mean BOT decreased by 39% in comparison to that in 6MV_FF_IMRT plans. Conclusion: The 6MV FFF beam provides a desirable and clinically acceptable IMRT plan for the treatment of GBM than 6MV FF beam. In addition, 6MV FFF beam provides higher MUs, better OARs sparing, lower scattered dose, and lower beam delivery time.
{"title":"Dosimetric Comparison between 6MV Flattened Filter and Flattening Filter Free Photon Beams in the Treatment of Glioblastoma with IMRT Technique: A Treatment Planning Study","authors":"D. Saroj, Suresh Yadav, Gopa Ghosh, Shuchishree Shukla, G. Gupta, Suman Kumar Choudhary","doi":"10.22038/IJMP.2019.39054.1515","DOIUrl":"https://doi.org/10.22038/IJMP.2019.39054.1515","url":null,"abstract":"Introduction: The present study evaluated the dosimetric comparison between 6MV flattened filter (FF) and flattening filter-free (FFF) photon beams in intensity-modulated radiation therapy (IMRT) technique for the treatment of glioblastoma (GBM) patients. \u0000Material and Methods: The present study was conducted on 10 patients with GBM previously planned and treated with 6MV FF photon beam by IMRT technique. Additional IMRT plans were retrospectively created using 6MV FFF photon beam for each patient plan. The dose prescription, beam parameters, and planning objective were kept same in both plans. The plans were evaluated using cumulative dose-volume histogram (c-DVH). Both types of plans were compared on the basis of homogeneity index (HI), conformity index (CI), beam-on time (BOT), monitor unit (MU), and doses to organs at risk (OARs). \u0000Results: Dose received by 95% (D95%) of planning target volume (PTV) coverage was observed significantly higher in 6MV_FF_IMRT plan than 6MV_FFF_IMRT plan (P<0.05). No significant dose differences were noticed for HI, CI, D98%, and D2% between both plans. Significantly lower Dmax for the brainstem, eyes, and eye lens was observed in 6MV_FFF_IMRT plan. For the brain, less than 2% mean dose was observed in 6MV_FFF_IMRT plan than 6MV_FF_IMRT plan (P=0.017). In 6MV_FFF_IMRT plan, mean BOT decreased by 39% in comparison to that in 6MV_FF_IMRT plans. \u0000Conclusion: The 6MV FFF beam provides a desirable and clinically acceptable IMRT plan for the treatment of GBM than 6MV FF beam. In addition, 6MV FFF beam provides higher MUs, better OARs sparing, lower scattered dose, and lower beam delivery time.","PeriodicalId":14613,"journal":{"name":"Iranian Journal of Medical Physics","volume":"17 1","pages":"188-196"},"PeriodicalIF":0.0,"publicationDate":"2020-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42553663","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 : 2020-05-01DOI: 10.22038/IJMP.2019.41861.1612
Vajiheh Vejdani Noghreiyan, S. Naseri, M. Momennezhad
Introduction: Radiation therapy involves a multistep procedure; therefore, the error in patient set up is an inherent part of the treatment. Main purpose of this study was to determine the clinical target volume (CTV) to planning target volume (PTV) in head and neck cancer patients. Material and Methods: A total of 15 patients who had daily portal images during the treatment courses were randomly selected in the present study. Systematic (Σ) and random (σ) errors were evaluated in three directions. The Isogray treatment planning system and Elekta linear accelerator were used in this study. Moreover, we had used MOSIAQ software as arecord and Verify system. Setup margins were calculated using three published margin recipes, including the International Commission on Radiation Units and Measurements (ICRU) report 62, as well as Stroom’s and van Herk’s formulae. Results: Average magnitude of the translational errors was reported between 0.7 and 10 mm. The systematic and random errors for head and neck cancer patients were 3.55 (2.58-4.52) and 1.83 (1.56-2.10) mm, respectively. According to the ICRU report 62, as well as Stoorm’s and van Herk’s formulas, the required margins to cover the target were obtained within the ranges of 3.1-4.9, 6.4-10.5, and 7.7-12.7 mm, respectively. Conclusion: According to the results of the present study, 6.5-10.5 mm extension in CTV to PTV margin can ensure that 90% of the head and neck cancer patients will receive a minimum cumulative CTV dose higher than or equal to 95% of the prescribed dose.
{"title":"Utilization of Electronic Portal Imaging Device (EPID) For Setup Verification and Determination of Setup Margin in Head and Neck Radiation Therapy","authors":"Vajiheh Vejdani Noghreiyan, S. Naseri, M. Momennezhad","doi":"10.22038/IJMP.2019.41861.1612","DOIUrl":"https://doi.org/10.22038/IJMP.2019.41861.1612","url":null,"abstract":"Introduction: Radiation therapy involves a multistep procedure; therefore, the error in patient set up is an inherent part of the treatment. Main purpose of this study was to determine the clinical target volume (CTV) to planning target volume (PTV) in head and neck cancer patients. \u0000Material and Methods: A total of 15 patients who had daily portal images during the treatment courses were randomly selected in the present study. Systematic (Σ) and random (σ) errors were evaluated in three directions. The Isogray treatment planning system and Elekta linear accelerator were used in this study. Moreover, we had used MOSIAQ software as arecord and Verify system. Setup margins were calculated using three published margin recipes, including the International Commission on Radiation Units and Measurements (ICRU) report 62, as well as Stroom’s and van Herk’s formulae. \u0000Results: Average magnitude of the translational errors was reported between 0.7 and 10 mm. The systematic and random errors for head and neck cancer patients were 3.55 (2.58-4.52) and 1.83 (1.56-2.10) mm, respectively. According to the ICRU report 62, as well as Stoorm’s and van Herk’s formulas, the required margins to cover the target were obtained within the ranges of 3.1-4.9, 6.4-10.5, and 7.7-12.7 mm, respectively. \u0000Conclusion: According to the results of the present study, 6.5-10.5 mm extension in CTV to PTV margin can ensure that 90% of the head and neck cancer patients will receive a minimum cumulative CTV dose higher than or equal to 95% of the prescribed dose.","PeriodicalId":14613,"journal":{"name":"Iranian Journal of Medical Physics","volume":"17 1","pages":"197-204"},"PeriodicalIF":0.0,"publicationDate":"2020-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43406186","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 : 2020-05-01DOI: 10.22038/IJMP.2019.37851.1482
L. A. Fitri, Y. Warty, F. Haryanto, U. Fauzi, F. Latief
Introduction: Micro-CT scanner with a resolution of about 5 micrometers is one of the modalities used to create three-dimensional/two-dimensional images of urinary stones. This study aimed to optimize imaging parameters in micro-computed tomography (CT) scanner based on the signal-to-noise ratio (SNR) of urinary stones for the analysis of stone composition. Material and Methods: In this study,eight micro-CT scanning protocols were applied to five urinary stones taken from different patients. Each scanning protocol had different voltage, current, and exposure parameters. The reconstructed images were then analyzed based on image brightness and SNR. The optimized imaging parameters which were chosen were that having high SNR because the high-quality image has high SNR. Results: The results showed that two groups of urinary stones had the same mean Hounsfield Units (HU) value in the third scanning protocols (i.e., 65 kV, 123 µA, and 850 ms). Mean HU values in group one (i.e., stones numbered 1, 3, and 4) were reported as 790, 760, and 720, respectively. The second group (i.e., stones numbered 2 and 5) had mean HU values of -514 and -343, respectively. The imaging parameters (i.e., 75 kV, 106 µA, and 600 ms) had high SNR (25-34) for the first group. The SNR (12.8-13.25) was for the second group at imaging parameters (i.e., 85 kV, 94 µA, and 500 ms). Conclusion: Based on the SNR, the two optimal imaging parameters for the first and second groups were reported as 75 kV, 106 µA, and 600 ms, as well as 85 kV, 94 µA, and 500 ms, respectively.
{"title":"Optimization of Imaging Parameters in Micro-CT Scanner Based On Signal-To-Noise Ratio for the Analysis of Urinary Stone Composition","authors":"L. A. Fitri, Y. Warty, F. Haryanto, U. Fauzi, F. Latief","doi":"10.22038/IJMP.2019.37851.1482","DOIUrl":"https://doi.org/10.22038/IJMP.2019.37851.1482","url":null,"abstract":"Introduction: Micro-CT scanner with a resolution of about 5 micrometers is one of the modalities used to create three-dimensional/two-dimensional images of urinary stones. This study aimed to optimize imaging parameters in micro-computed tomography (CT) scanner based on the signal-to-noise ratio (SNR) of urinary stones for the analysis of stone composition. Material and Methods: In this study,eight micro-CT scanning protocols were applied to five urinary stones taken from different patients. Each scanning protocol had different voltage, current, and exposure parameters. The reconstructed images were then analyzed based on image brightness and SNR. The optimized imaging parameters which were chosen were that having high SNR because the high-quality image has high SNR. Results: The results showed that two groups of urinary stones had the same mean Hounsfield Units (HU) value in the third scanning protocols (i.e., 65 kV, 123 µA, and 850 ms). Mean HU values in group one (i.e., stones numbered 1, 3, and 4) were reported as 790, 760, and 720, respectively. The second group (i.e., stones numbered 2 and 5) had mean HU values of -514 and -343, respectively. The imaging parameters (i.e., 75 kV, 106 µA, and 600 ms) had high SNR (25-34) for the first group. The SNR (12.8-13.25) was for the second group at imaging parameters (i.e., 85 kV, 94 µA, and 500 ms). Conclusion: Based on the SNR, the two optimal imaging parameters for the first and second groups were reported as 75 kV, 106 µA, and 600 ms, as well as 85 kV, 94 µA, and 500 ms, respectively.","PeriodicalId":14613,"journal":{"name":"Iranian Journal of Medical Physics","volume":"17 1","pages":"153-160"},"PeriodicalIF":0.0,"publicationDate":"2020-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49610777","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 : 2020-05-01DOI: 10.22038/IJMP.2019.40381.1556
Khatibeh Verdipoor, A. Mesbahi
Introduction: The present study aimed to evaluate the impact of PbO nano and micro-sized fillers on ordinary and heavy concretes for different photon energies. Material and Methods: The MCNPX Monte Carlo code (version 2.6.0) was used for all simulations in the present study. A model of narrow-beam geometry was validated and utilized to calculate the linear attenuation of samples. Three concentrations of PbO, including the weight of 23%, 37.5%, and 50% were simulated. The nano- and microparticle-loaded concretes were simulated using the Lattice and Universe properties of MCNPX code. Finally, the mass attenuation coefficients of studied concretes were analyzed and compared in this study. Results: Among all the studied concretes, the highest increase of 11% in attenuation coefficient was seen for concretes doped with PbO nanoparticles. The particle size effect was not observed for 18 MeV photon beam, and maximum difference between nano-fillers and micro-fillers was observed for photon energies around 1 MeV. Conclusion: The difference between nano-fillers and micro-fillers was not significant for heavy concretes in comparison to that for ordinary concrete. It is recommended to apply PbO nanoparticles as effective filler in the ordinary concrete composition for providing higher shielding performance.
{"title":"Radiation Shielding Features of Ordinary and High-Density Concretes Loaded With PbO Micro and Nanoparticles against High-Energy Photons","authors":"Khatibeh Verdipoor, A. Mesbahi","doi":"10.22038/IJMP.2019.40381.1556","DOIUrl":"https://doi.org/10.22038/IJMP.2019.40381.1556","url":null,"abstract":"Introduction: The present study aimed to evaluate the impact of PbO nano and micro-sized fillers on ordinary and heavy concretes for different photon energies. \u0000Material and Methods: The MCNPX Monte Carlo code (version 2.6.0) was used for all simulations in the present study. A model of narrow-beam geometry was validated and utilized to calculate the linear attenuation of samples. Three concentrations of PbO, including the weight of 23%, 37.5%, and 50% were simulated. The nano- and microparticle-loaded concretes were simulated using the Lattice and Universe properties of MCNPX code. Finally, the mass attenuation coefficients of studied concretes were analyzed and compared in this study. \u0000Results: Among all the studied concretes, the highest increase of 11% in attenuation coefficient was seen for concretes doped with PbO nanoparticles. The particle size effect was not observed for 18 MeV photon beam, and maximum difference between nano-fillers and micro-fillers was observed for photon energies around 1 MeV. \u0000Conclusion: The difference between nano-fillers and micro-fillers was not significant for heavy concretes in comparison to that for ordinary concrete. It is recommended to apply PbO nanoparticles as effective filler in the ordinary concrete composition for providing higher shielding performance.","PeriodicalId":14613,"journal":{"name":"Iranian Journal of Medical Physics","volume":"17 1","pages":"205-212"},"PeriodicalIF":0.0,"publicationDate":"2020-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45939607","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 : 2020-05-01DOI: 10.22038/IJMP.2019.39798.1537
A. P. Hariyanto, F. Mariyam, L. Almira, E. Endarko, S. Bambang
Introduction: This study aimed to evaluate the efficacy of a synthesized bolus in the reduction of damage to body tissues and the protection of the organ at risk (OAR) in radiotherapy application. Several properties of the synthesized bolus, including density, transmission factor, and effective mass attenuation coefficient, were investigated. Material and Methods: The materials used comprising of propylene glycol (PG), silicone rubber (SR), and aluminum (Al). The dimension of the synthesized bolus was measured using an acrylic case with a size of 11×11 cm² and thickness sizes of 0.5, 1, and 1.5 cm. Furthermore, the boluses were irradiated by linear accelerator with the photon beam energies of 6 and 10 MV, using linier accelerator (LINAC) Varian 2300ix. Results: In this research,the density of synthesized bolus was evaluated by mass per volume equation. The results showed that the density of bolus was similar to the density of tissue/water, fat, and air. . Furthermore the bolus with the composition of PG 24%, SR 8%, and Al 1.5% of all energies, transmission factors of 0.978 and 0.984, thickness of 1.5 cm, and effective mass attenuation coefficients of 0.0144 and 0.0107 cm²/g had the closest properties to the body tissues in terms of dosimetry characterization. Conclusion: The results revealed that the synthesized bolus could increase the percentage surface dose, reduce skin-sparing effect, and protect OAR. The findings indicated that the synthesized bolus had a potential application in clinical therapy.
{"title":"Fabrication and Characterization of Bolus Material Using Propylene Glycol for Radiation Therapy","authors":"A. P. Hariyanto, F. Mariyam, L. Almira, E. Endarko, S. Bambang","doi":"10.22038/IJMP.2019.39798.1537","DOIUrl":"https://doi.org/10.22038/IJMP.2019.39798.1537","url":null,"abstract":"Introduction: This study aimed to evaluate the efficacy of a synthesized bolus in the reduction of damage to body tissues and the protection of the organ at risk (OAR) in radiotherapy application. Several properties of the synthesized bolus, including density, transmission factor, and effective mass attenuation coefficient, were investigated. \u0000Material and Methods: The materials used comprising of propylene glycol (PG), silicone rubber (SR), and aluminum (Al). The dimension of the synthesized bolus was measured using an acrylic case with a size of 11×11 cm² and thickness sizes of 0.5, 1, and 1.5 cm. Furthermore, the boluses were irradiated by linear accelerator with the photon beam energies of 6 and 10 MV, using linier accelerator (LINAC) Varian 2300ix. \u0000Results: In this research,the density of synthesized bolus was evaluated by mass per volume equation. The results showed that the density of bolus was similar to the density of tissue/water, fat, and air. . Furthermore the bolus with the composition of PG 24%, SR 8%, and Al 1.5% of all energies, transmission factors of 0.978 and 0.984, thickness of 1.5 cm, and effective mass attenuation coefficients of 0.0144 and 0.0107 cm²/g had the closest properties to the body tissues in terms of dosimetry characterization. \u0000Conclusion: The results revealed that the synthesized bolus could increase the percentage surface dose, reduce skin-sparing effect, and protect OAR. The findings indicated that the synthesized bolus had a potential application in clinical therapy.","PeriodicalId":14613,"journal":{"name":"Iranian Journal of Medical Physics","volume":"17 1","pages":"161-169"},"PeriodicalIF":0.0,"publicationDate":"2020-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43380469","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 : 2020-05-01DOI: 10.22038/IJMP.2019.41275.1595
M. Zabihzadeh, Mahbube Fadaei, S. Hoseini, Sholeh Arvandi, Mohamad Tahmasebi
Introduction: Physical wedge by modify photon beam shape and intensity has been utilized in radiotherapy to obtain uniformly dose distribution in tumor site with reduced hot spots. Calculation of dosimetric parameters for both symmetric and asymmetric wedged fields is proved necessary during linear accelerator (Linac) commissioning. The present study aimed to achieve output factors and dose profiles for symmetric and asymmetric wedged fields of 6 MV beams. Material and Methods: The Siemens PRIMUS Linac head for 6 MV beam was simulated by BEAMnrc and all dose calculations were performed by DOSXYZnrc code. Percentage depth dose (PDD) and profiles for open and wedged (15° and 45°) fields were compared with corresponding measurements. Wedge factors for 10 x 10 cm2 field were obtained as a function of lateral distance as well for half beam wedged fields. Results: Based on the results of the present study, the calculated doses were in agreement with the measured data. The output factors on the central axis of symmetric wedged beams decreased to 0.693 and 0.307 for 15˚, and 45˚ wedges. The total photon fluence of 15˚ and 45˚ physical wedged fields reduced to 71.6% and 27.7% of open field, respectively. Conclusion: The output factor for asymmetric wedged fields was found to be lower than corresponding symmetric open and wedged fields, particularly at field edges. Lack of scattering photons near the half beam edges resulted in dose fall-off in these regions possible to be overestimated by treatment planning system and consequently caused cold spots at target volume.
通过改变光子束形状和强度的物理楔在放射治疗中得到均匀的剂量分布在肿瘤部位，减少了热点。在直线加速器调试过程中，计算对称和非对称楔形场的剂量学参数是必要的。本研究旨在获得对称和非对称6毫伏光束楔形场的输出因子和剂量分布。材料与方法:采用BEAMnrc软件模拟西门子PRIMUS直线磁头的6 MV束流，采用DOSXYZnrc程序进行剂量计算。对开放和楔形(15°和45°)场的百分比深度剂量(PDD)和剖面进行了比较。得到了10 x 10 cm2场的楔形因子作为侧向距离的函数，以及半束楔形场。结果:根据本研究的结果，计算出的剂量与实测数据基本一致。对称楔型梁在15°和45°楔型梁中轴线上的输出系数分别为0.693和0.307。15˚和45˚物理楔形场的总光子通量分别降低到开放场的71.6%和27.7%。结论:不对称楔形场的输出因子低于相应的对称开放和楔形场，特别是在场边缘。半束边缘附近缺乏散射光子导致这些区域的剂量衰减，可能被治疗计划系统高估，从而导致目标体积上的冷点。
{"title":"Characterization of Wedge Factors and Dose Distributions in Radiotherapy with Symmetric and Asymmetric Physical Wedged Beams of 6 MV Photon Beam","authors":"M. Zabihzadeh, Mahbube Fadaei, S. Hoseini, Sholeh Arvandi, Mohamad Tahmasebi","doi":"10.22038/IJMP.2019.41275.1595","DOIUrl":"https://doi.org/10.22038/IJMP.2019.41275.1595","url":null,"abstract":"Introduction: Physical wedge by modify photon beam shape and intensity has been utilized in radiotherapy to obtain uniformly dose distribution in tumor site with reduced hot spots. Calculation of dosimetric parameters for both symmetric and asymmetric wedged fields is proved necessary during linear accelerator (Linac) commissioning. The present study aimed to achieve output factors and dose profiles for symmetric and asymmetric wedged fields of 6 MV beams. \u0000Material and Methods: The Siemens PRIMUS Linac head for 6 MV beam was simulated by BEAMnrc and all dose calculations were performed by DOSXYZnrc code. Percentage depth dose (PDD) and profiles for open and wedged (15° and 45°) fields were compared with corresponding measurements. Wedge factors for 10 x 10 cm2 field were obtained as a function of lateral distance as well for half beam wedged fields. \u0000Results: Based on the results of the present study, the calculated doses were in agreement with the measured data. The output factors on the central axis of symmetric wedged beams decreased to 0.693 and 0.307 for 15˚, and 45˚ wedges. The total photon fluence of 15˚ and 45˚ physical wedged fields reduced to 71.6% and 27.7% of open field, respectively. \u0000Conclusion: The output factor for asymmetric wedged fields was found to be lower than corresponding symmetric open and wedged fields, particularly at field edges. Lack of scattering photons near the half beam edges resulted in dose fall-off in these regions possible to be overestimated by treatment planning system and consequently caused cold spots at target volume.","PeriodicalId":14613,"journal":{"name":"Iranian Journal of Medical Physics","volume":"17 1","pages":"213-219"},"PeriodicalIF":0.0,"publicationDate":"2020-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42768714","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 : 2020-05-01DOI: 10.22038/IJMP.2019.35701.1451
L. A. Najam, Qusay Al-dulamey, Yasir A. Al-Jawwady
Introduction: The study aimed to find the low dose effect gamma ray on some hematological parameters in male albino rats obtained from the Mosul University, IRAQ, and also studied the radioprotective effect of black seed oil on the hematological parameters. Material and Methods: The system is made of 241Am as gamma source .The rats were exposed to gamma radiation for limit period .Hematological investigations in which the red blood cells (RBC) also white blood cells (WBC) were found by the result of Neubauer haemocytometer method hemoglobin(Hb) concentration obtained due to cyanomethaemoglobin test. The packed cell volume (PCV) was determined using the micro-centrifuge method. Platelets were achieved. Results: All hematological parameters found significantly decreased in all groups receiving daily dose of 6 mGy/h for 7h/day for 25, and 50 days compared with those in the control group. However group 2. Treated with 400 mg/kg wt /day for 25 days, showed a significant increase in the mentioned parameters. Groups 3 and 4 were exposed to gamma ray in two stages(at a daily dose 6 mGy/h for 7h /day for 25 and 50 days) .Group 4 showed a significant enhancement in hematological parameter when treated with black seed oil , compared with group3 which had a significant decrease in these parameters compared with the control group. Conclusion: The present work showed the function of black seed oil considered as an advanced material in decreasing the oxidant stress on hematological parameters againstgamma ray with limited dose.
{"title":"Effects of Low Dose Gamma Ray on Some Hematological Parameters in Adult Rats","authors":"L. A. Najam, Qusay Al-dulamey, Yasir A. Al-Jawwady","doi":"10.22038/IJMP.2019.35701.1451","DOIUrl":"https://doi.org/10.22038/IJMP.2019.35701.1451","url":null,"abstract":"Introduction: The study aimed to find the low dose effect gamma ray on some hematological parameters in male albino rats obtained from the Mosul University, IRAQ, and also studied the radioprotective effect of black seed oil on the hematological parameters. Material and Methods: The system is made of 241Am as gamma source .The rats were exposed to gamma radiation for limit period .Hematological investigations in which the red blood cells (RBC) also white blood cells (WBC) were found by the result of Neubauer haemocytometer method hemoglobin(Hb) concentration obtained due to cyanomethaemoglobin test. The packed cell volume (PCV) was determined using the micro-centrifuge method. Platelets were achieved. Results: All hematological parameters found significantly decreased in all groups receiving daily dose of 6 mGy/h for 7h/day for 25, and 50 days compared with those in the control group. However group 2. Treated with 400 mg/kg wt /day for 25 days, showed a significant increase in the mentioned parameters. Groups 3 and 4 were exposed to gamma ray in two stages(at a daily dose 6 mGy/h for 7h /day for 25 and 50 days) .Group 4 showed a significant enhancement in hematological parameter when treated with black seed oil , compared with group3 which had a significant decrease in these parameters compared with the control group. Conclusion: The present work showed the function of black seed oil considered as an advanced material in decreasing the oxidant stress on hematological parameters againstgamma ray with limited dose.","PeriodicalId":14613,"journal":{"name":"Iranian Journal of Medical Physics","volume":"17 1","pages":"137-141"},"PeriodicalIF":0.0,"publicationDate":"2020-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45867344","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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