Coating processes are carried out in many areas of industry to improve the surface properties of materials such as wear and corrosion resistance or appearance. One of these coating processes is ceramic-based surface coatings. In order to obtain harder, denser and more uniform coatings, the substrate material is coated with a ceramic-based material at the desired thickness. In this study, 7075 series aluminum was coated with nano Ti powder and non-additive micro arc oxidation (MAO) method in a solution consisting of KOH, NaAlO2 and Na3PO4, and the effects of process parameters on coating thickness and wear behavior were experimentally investigated and the results were analyzed. According to the results obtained, it was observed that as the coating voltage, frequency and coating time increased, the wear rate decreased and a harder structure against wear is obtained. In addition, it was determined that the samples with nano titanium powder were less worn than the non-additive samples. According to SEM, EDX and XRD analyses, Al2O3 phase was observed in the coatings made without adding titanium particles; It has been observed that in addition to the Al2O3 main phase, TiO2 and SiO phases are also formed in titanium doped coatings.
{"title":"The Effect of the Parameters on Al 7075 Coated with MAO Method by Adding Nano Ti-Powder","authors":"M. Özcan, Latif Özler","doi":"10.54287/gujsa.1148417","DOIUrl":"https://doi.org/10.54287/gujsa.1148417","url":null,"abstract":"Coating processes are carried out in many areas of industry to improve the surface properties of materials such as wear and corrosion resistance or appearance. One of these coating processes is ceramic-based surface coatings. In order to obtain harder, denser and more uniform coatings, the substrate material is coated with a ceramic-based material at the desired thickness. In this study, 7075 series aluminum was coated with nano Ti powder and non-additive micro arc oxidation (MAO) method in a solution consisting of KOH, NaAlO2 and Na3PO4, and the effects of process parameters on coating thickness and wear behavior were experimentally investigated and the results were analyzed. According to the results obtained, it was observed that as the coating voltage, frequency and coating time increased, the wear rate decreased and a harder structure against wear is obtained. In addition, it was determined that the samples with nano titanium powder were less worn than the non-additive samples. According to SEM, EDX and XRD analyses, Al2O3 phase was observed in the coatings made without adding titanium particles; It has been observed that in addition to the Al2O3 main phase, TiO2 and SiO phases are also formed in titanium doped coatings.","PeriodicalId":134301,"journal":{"name":"Gazi University Journal of Science Part A: Engineering and Innovation","volume":"32 4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132368503","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}
Ayınde MUHAMMED ABDULLAHI, A. James, Ajimoti Adam Ishaq, T. Oyedepo
{"title":"A New Numerical Approach Using Chebyshev Third Kind Polynomial for Solving Integrodifferential Equations of Higher Order","authors":"Ayınde MUHAMMED ABDULLAHI, A. James, Ajimoti Adam Ishaq, T. Oyedepo","doi":"10.54287/gujsa.1093536","DOIUrl":"https://doi.org/10.54287/gujsa.1093536","url":null,"abstract":"<jats:p xml:lang=\"tr\" />","PeriodicalId":134301,"journal":{"name":"Gazi University Journal of Science Part A: Engineering and Innovation","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122630907","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}
The amount and conformation of bovine serum albumin upon adsorption on titanium (Ti) surfaces containing nanotubes with different pore sizes were investigated. Nanotubes were created on the surfaces via anodization. Protein adsorption behavior on anodized surfaces were compared with the adsorption behavior on smooth and sanded Ti surfaces. The conformational changes in surface adsorbed proteins were evaluated using the second derivative and curve fitting methods applied to the Fourier transform infrared spectra of the surfaces. Results showed that the amount of protein adsorbed on the surfaces increased significantly with increasing surface roughness and a significant change in the conformation of the adsorbed protein occurred on every surface albeit in a different fashion. When anodized samples were considered, it was observed that the changes in the secondary structure seemed to be correlated with to the pore size of the nanotubes rather than the surface roughness.
{"title":"The Effect of Nanostructured Titanium Surface on Protein Adsorption","authors":"H. T. Şirin, E. Akdoğan","doi":"10.54287/gujsa.1134881","DOIUrl":"https://doi.org/10.54287/gujsa.1134881","url":null,"abstract":"The amount and conformation of bovine serum albumin upon adsorption on titanium (Ti) surfaces containing nanotubes with different pore sizes were investigated. Nanotubes were created on the surfaces via anodization. Protein adsorption behavior on anodized surfaces were compared with the adsorption behavior on smooth and sanded Ti surfaces. The conformational changes in surface adsorbed proteins were evaluated using the second derivative and curve fitting methods applied to the Fourier transform infrared spectra of the surfaces. Results showed that the amount of protein adsorbed on the surfaces increased significantly with increasing surface roughness and a significant change in the conformation of the adsorbed protein occurred on every surface albeit in a different fashion. When anodized samples were considered, it was observed that the changes in the secondary structure seemed to be correlated with to the pore size of the nanotubes rather than the surface roughness.","PeriodicalId":134301,"journal":{"name":"Gazi University Journal of Science Part A: Engineering and Innovation","volume":"69 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131591594","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}
{"title":"Optimal Cutting Conditions of Abrasive Waterjet Cutting for Ti-6Al-2Sn-2Mo Alpha-Beta Alloy Using EDAS and DFA Methods","authors":"Sunday Oke, Ugochukwu Sixtus Nwankiti","doi":"10.54287/gujsa.1135609","DOIUrl":"https://doi.org/10.54287/gujsa.1135609","url":null,"abstract":"<jats:p xml:lang=\"tr\" />","PeriodicalId":134301,"journal":{"name":"Gazi University Journal of Science Part A: Engineering and Innovation","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128604520","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}
Potato is an industrial plant that is produced and consumed globally due to its cheapness, high yield in the unit area, high nutritional values. It is used in many different fields. It has been stated that wild species with various characteristics can be used in studies to increase productivity because they have greater rate of genetic variation than their domesticated relatives. One of the wild species of potato found in nature is S. commersonii Dunal. It is more resistant to many stresses than cultivated potato S. tuberosum L. Also, its tuber has better quality due to the fact that it contains a higher proportion of dry matter. With the aim of determining the effects of miRNAs in tuber production and root characteristics relation we aimed to detect miRNAs in two transcriptome libraries of S. commersonii. In this study miRNAs were evaluated for the first time in the wild potato transcriptome data using in silico analysis. A number of miRNAs were identified, and their potential roles in tuber were discussed.
{"title":"In silico Analyzes of miRNAs Associated with Root and Tuber in S. commersonii","authors":"Aysel Özgül Koral, M. Türktaş","doi":"10.54287/gujsa.1142153","DOIUrl":"https://doi.org/10.54287/gujsa.1142153","url":null,"abstract":"Potato is an industrial plant that is produced and consumed globally due to its cheapness, high yield in the unit area, high nutritional values. It is used in many different fields. It has been stated that wild species with various characteristics can be used in studies to increase productivity because they have greater rate of genetic variation than their domesticated relatives. One of the wild species of potato found in nature is S. commersonii Dunal. It is more resistant to many stresses than cultivated potato S. tuberosum L. Also, its tuber has better quality due to the fact that it contains a higher proportion of dry matter. With the aim of determining the effects of miRNAs in tuber production and root characteristics relation we aimed to detect miRNAs in two transcriptome libraries of S. commersonii. In this study miRNAs were evaluated for the first time in the wild potato transcriptome data using in silico analysis. A number of miRNAs were identified, and their potential roles in tuber were discussed.","PeriodicalId":134301,"journal":{"name":"Gazi University Journal of Science Part A: Engineering and Innovation","volume":"41 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124107122","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}
Atrial fibrillation (AF) is a frequently encountered heart arrhythmia problem today. In the method followed in the detection of AF, the recording of the Electrocardiogram (ECG) signal for a long time (1-2 days) taken from people who are thought to be sick is analyzed by the clinician. However, this process is not an effective method for clinicians to make decisions. In this article, various artificial intelligence methods are tested for AF detection on long recorded ECG data. Since the ECG data is a time series, a hybrid model has been tried to be created with the Long Short Term Memory (LSTM) algorithm, which gives high results in time series classification and regression, and a hybrid method has been developed with the Extreme Gradient Boosting algorithm, which is derived from the Gradient Boosting algorithm. To improve the accuracy of the LSTM architecture, the architecture has been strengthened with an Attention-based block. To control the performance of the developed hybrid Attention-based LSTM-XGBoost algorithm, a public data set was used. Some preprocessing (filter, feature extraction) has been applied to this data set used. With the removal of these features, the accuracy rate has increased considerably. It has been proven to be a consistent study that can be used as a support system in decision-making by clinicians with an accuracy rate of 98.94%. It also provides a solution to the problem of long ECG record review by facilitating data tracking.
{"title":"A Hybrid Attention-based LSTM-XGBoost Model for Detection of ECG-based Atrial Fibrillation","authors":"Furkan Balci","doi":"10.54287/gujsa.1128006","DOIUrl":"https://doi.org/10.54287/gujsa.1128006","url":null,"abstract":"Atrial fibrillation (AF) is a frequently encountered heart arrhythmia problem today. In the method followed in the detection of AF, the recording of the Electrocardiogram (ECG) signal for a long time (1-2 days) taken from people who are thought to be sick is analyzed by the clinician. However, this process is not an effective method for clinicians to make decisions. In this article, various artificial intelligence methods are tested for AF detection on long recorded ECG data. Since the ECG data is a time series, a hybrid model has been tried to be created with the Long Short Term Memory (LSTM) algorithm, which gives high results in time series classification and regression, and a hybrid method has been developed with the Extreme Gradient Boosting algorithm, which is derived from the Gradient Boosting algorithm. To improve the accuracy of the LSTM architecture, the architecture has been strengthened with an Attention-based block. To control the performance of the developed hybrid Attention-based LSTM-XGBoost algorithm, a public data set was used. Some preprocessing (filter, feature extraction) has been applied to this data set used. With the removal of these features, the accuracy rate has increased considerably. It has been proven to be a consistent study that can be used as a support system in decision-making by clinicians with an accuracy rate of 98.94%. It also provides a solution to the problem of long ECG record review by facilitating data tracking.","PeriodicalId":134301,"journal":{"name":"Gazi University Journal of Science Part A: Engineering and Innovation","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131115265","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}
In this article, Stancu type Post-Widder operators are introduced, which are a modification of the Post-Widder operators that preserve the functions constant and e^2ax for fixed a>0. The uniform convergence of these modified operators for the function f on [0,∞) is examined and then the convergence rate is investigated with the help of the continuity module. The Voronovskaja type asymptotic formula is obtained to examine the asymptotic behavior of these operators. Finally, numerical examples and graphs are given to show the convergence of Stancu type Post- Widder operators and compared with Post Widder operators.
{"title":"On Approximation Properties of Stancu Type Post-Widder Operators Preserving Exponential Functions","authors":"Gülten Torun","doi":"10.54287/gujsa.1113567","DOIUrl":"https://doi.org/10.54287/gujsa.1113567","url":null,"abstract":"In this article, Stancu type Post-Widder operators are introduced, which are a modification of the Post-Widder operators that preserve the functions constant and e^2ax for fixed a>0. The uniform convergence of these modified operators for the function f on [0,∞) is examined and then the convergence rate is investigated with the help of the continuity module. The Voronovskaja type asymptotic formula is obtained to examine the asymptotic behavior of these operators. Finally, numerical examples and graphs are given to show the convergence of Stancu type Post- Widder operators and compared with Post Widder operators.","PeriodicalId":134301,"journal":{"name":"Gazi University Journal of Science Part A: Engineering and Innovation","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-06-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130389082","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}
The effective use of photonic-based integrated systems, whose optical properties can be tuned through light management engineering in optoelectronic devices, constitutes the backbone of today's technology. Especially in systems such as CdTe-based solar cells with well-known and high efficiency, one-dimensional photonic crystal designs emerge as an effective way to provide an electronic or optical improvement. With this intention, in this study, the optical spectra of the MgF2/MoO3 one-dimensional photonic crystal integrated into the CdTe solar cell to improve photon harvesting were investigated theoretically under both bottom and top illumination according to the incidence angle of the electromagnetic wave. The transfer matrix method was used to calculate the angle dependent optical spectra. Since the electromagnetic wave interacts directly with the photonic crystal, it has been observed that the optical properties are more dependent on the angle under the top illumination compared to the bottom one. For top illumination, up to 30°, there is no significant change in reflection in the photonic band gap, but reflection drops significantly at incidence angles greater than 30°. Also, increasing the angle indicates that the low wavelength tail of the photonic band gap shifts to shorter wavelengths and enters the visible region. In the photonic band gap, for angles greater than 45°, the probability of absorption increases significantly as more electromagnetic waves enter the structure. For the bottom illumination, there is no serious dependence on the angle of incidence. For 75°, there is an increase in reflection for all wavelengths and, therefore, a decrease in absorption.
{"title":"Theoretical Evaluation of Angle-Dependent Optical Properties of a Thin Film Solar Cell including One-Dimension Photonic Crystals","authors":"Ç. Çetinkaya","doi":"10.54287/gujsa.1129794","DOIUrl":"https://doi.org/10.54287/gujsa.1129794","url":null,"abstract":"The effective use of photonic-based integrated systems, whose optical properties can be tuned through light management engineering in optoelectronic devices, constitutes the backbone of today's technology. Especially in systems such as CdTe-based solar cells with well-known and high efficiency, one-dimensional photonic crystal designs emerge as an effective way to provide an electronic or optical improvement. With this intention, in this study, the optical spectra of the MgF2/MoO3 one-dimensional photonic crystal integrated into the CdTe solar cell to improve photon harvesting were investigated theoretically under both bottom and top illumination according to the incidence angle of the electromagnetic wave. The transfer matrix method was used to calculate the angle dependent optical spectra. Since the electromagnetic wave interacts directly with the photonic crystal, it has been observed that the optical properties are more dependent on the angle under the top illumination compared to the bottom one. For top illumination, up to 30°, there is no significant change in reflection in the photonic band gap, but reflection drops significantly at incidence angles greater than 30°. Also, increasing the angle indicates that the low wavelength tail of the photonic band gap shifts to shorter wavelengths and enters the visible region. In the photonic band gap, for angles greater than 45°, the probability of absorption increases significantly as more electromagnetic waves enter the structure. For the bottom illumination, there is no serious dependence on the angle of incidence. For 75°, there is an increase in reflection for all wavelengths and, therefore, a decrease in absorption.","PeriodicalId":134301,"journal":{"name":"Gazi University Journal of Science Part A: Engineering and Innovation","volume":"115 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131225332","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}
Coal liquefaction process gives very efficient results, especially for value-added chemicals production from low-quality coal. However, when the literature is examined, notably there is not enough scientific study for liquefaction mechanisms. Here, in this study, There are five different liquefaction mechanisms of Beypazarı coals. It includes four different UV light power and a catalyst environment using 180 watts of UV power. Created first-order linear discrete models were proposed and compared with the experimental results. Additionally, the reaction rate constants for each proposed kinetic model were calculated using the Kalman filter method. However, to evaluate the compatibility of the experimental results and the modeling results, the sum of the squared differences of the values calculated from the experimental data and the models was examined. Because of these studies, it has been observed that the rate constants of direct oil formation from coal at 120 and 180 watts of UV power are at least three times greater than the rate constants for the formation of asphaltene and pre-asphaltene from coal. Simultaneously, The results demonstrate that models with reversible and parallel steps are more compatible with experimental data. Experimental data and modeling results are much more compatible with the studies conducted on Beypazarı coals in a 180-watt UV-catalyzed environment compared to a 180-watt catalyst-free environment. In the presence of ZnO catalyst, the rate constants occurring in the conversion reaction from coal to oil were again three times faster than the conversion rate constants from coal to asphaltene and from coal to preasphaltene. In the modeling and experimental results conducted in the catalyst environment, the efficiency was higher than the catalyst-free environment. The best fit was obtained using model that has both reversible (between asphaltene: coal, asphaltene: oil, and asphaltene: preasphaltene) and irreversible (coal: oil, coal: preasphaltene and preasphaltene: oil) reaction steps. The model also evidenced that reversible reactions are critical on the liquefaction of Beypazarı coal.
{"title":"Experimental and Modelling Comparison of the Effects of UV Energy on Liquefaction Efficiency In Coal Liquefaction Mechanism","authors":"Y. Altinsoy, E. Simsek","doi":"10.54287/gujsa.1104126","DOIUrl":"https://doi.org/10.54287/gujsa.1104126","url":null,"abstract":"Coal liquefaction process gives very efficient results, especially for value-added chemicals production from low-quality coal. However, when the literature is examined, notably there is not enough scientific study for liquefaction mechanisms. Here, in this study, There are five different liquefaction mechanisms of Beypazarı coals. It includes four different UV light power and a catalyst environment using 180 watts of UV power. Created first-order linear discrete models were proposed and compared with the experimental results. Additionally, the reaction rate constants for each proposed kinetic model were calculated using the Kalman filter method. However, to evaluate the compatibility of the experimental results and the modeling results, the sum of the squared differences of the values calculated from the experimental data and the models was examined. Because of these studies, it has been observed that the rate constants of direct oil formation from coal at 120 and 180 watts of UV power are at least three times greater than the rate constants for the formation of asphaltene and pre-asphaltene from coal. Simultaneously, The results demonstrate that models with reversible and parallel steps are more compatible with experimental data. Experimental data and modeling results are much more compatible with the studies conducted on Beypazarı coals in a 180-watt UV-catalyzed environment compared to a 180-watt catalyst-free environment. In the presence of ZnO catalyst, the rate constants occurring in the conversion reaction from coal to oil were again three times faster than the conversion rate constants from coal to asphaltene and from coal to preasphaltene. In the modeling and experimental results conducted in the catalyst environment, the efficiency was higher than the catalyst-free environment. The best fit was obtained using model that has both reversible (between asphaltene: coal, asphaltene: oil, and asphaltene: preasphaltene) and irreversible (coal: oil, coal: preasphaltene and preasphaltene: oil) reaction steps. The model also evidenced that reversible reactions are critical on the liquefaction of Beypazarı coal.","PeriodicalId":134301,"journal":{"name":"Gazi University Journal of Science Part A: Engineering and Innovation","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122585456","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}
Accurate estimation of the surface dose in radiotherapy of patients with head and neck cancer is very important in terms of treatment. The aim of this study is to evaluate the surface dose for intensity-modulated radiotherapy (IMRT) of head and neck cancer using thermoluminescent dosimeters (TLDs). In addition, it is aimed to examine the surface dose estimates of the treatment planning system (TPS) for different grid sizes. Before the computed tomography (CT) images were taken for 15 head and neck cancer patients, 5 different points determined in the neck region were marked in a way that would not cause artifacts. IMRT plans are created for 1.5 and 2.5 mm grid sizes. Surface doses were obtained for TPS calculations and TLD measurements at 5 different points in the neck region. Surface doses obtained from TLD measurements and TPS calculations with different grid sizes were compared. All patients received 3-stage adaptive radiotherapy (ART) and the surface dose comparison was repeated for each plan. According to plan 0, the height of TLD measurements for the 1.5 and 2.5 mm grid size were 4.06% and 7.87%, respectively. In Plan 1, the difference between TPS and TLD doses was 4.00% and 8.15% for grid size 1.5mm and 2.5mm, respectively (p=0.00 and p=0.00). For dose measurements from Plan 2, the difference between TPS and TLD doses was 4.07% and 9.96% for grid size 1.5mm and 2.5mm, respectively (p=0.00 and p=0.00). Surface doses obtained in TLD measurements for all treatment plans were higher than in TPS dose calculations. Accurate estimation of the surface dose in head and neck cancer radiotherapy is very important for treatment. Surface doses calculated with TPS are usually lower than the prescribed dose. Therefore, during the evaluation of radiotherapy plans, it should be considered that TPS underestimates the surface dose. This ratio can be determined by dosimetric measurements. Thermoluminescent dosimeters are suitable equipment for this process.
{"title":"Evaluation of Surface Dose for Intensity Modulated Radiotherapy of Head and Neck Cancer Using Thermoluminescent Dosimeters","authors":"O. Gül, Nihal Büyükçi̇zmeci̇, H. Başaran","doi":"10.54287/gujsa.1109112","DOIUrl":"https://doi.org/10.54287/gujsa.1109112","url":null,"abstract":"Accurate estimation of the surface dose in radiotherapy of patients with head and neck cancer is very important in terms of treatment. The aim of this study is to evaluate the surface dose for intensity-modulated radiotherapy (IMRT) of head and neck cancer using thermoluminescent dosimeters (TLDs). In addition, it is aimed to examine the surface dose estimates of the treatment planning system (TPS) for different grid sizes. Before the computed tomography (CT) images were taken for 15 head and neck cancer patients, 5 different points determined in the neck region were marked in a way that would not cause artifacts. IMRT plans are created for 1.5 and 2.5 mm grid sizes. Surface doses were obtained for TPS calculations and TLD measurements at 5 different points in the neck region. Surface doses obtained from TLD measurements and TPS calculations with different grid sizes were compared. All patients received 3-stage adaptive radiotherapy (ART) and the surface dose comparison was repeated for each plan. According to plan 0, the height of TLD measurements for the 1.5 and 2.5 mm grid size were 4.06% and 7.87%, respectively. In Plan 1, the difference between TPS and TLD doses was 4.00% and 8.15% for grid size 1.5mm and 2.5mm, respectively (p=0.00 and p=0.00). For dose measurements from Plan 2, the difference between TPS and TLD doses was 4.07% and 9.96% for grid size 1.5mm and 2.5mm, respectively (p=0.00 and p=0.00). Surface doses obtained in TLD measurements for all treatment plans were higher than in TPS dose calculations. Accurate estimation of the surface dose in head and neck cancer radiotherapy is very important for treatment. Surface doses calculated with TPS are usually lower than the prescribed dose. Therefore, during the evaluation of radiotherapy plans, it should be considered that TPS underestimates the surface dose. This ratio can be determined by dosimetric measurements. Thermoluminescent dosimeters are suitable equipment for this process.","PeriodicalId":134301,"journal":{"name":"Gazi University Journal of Science Part A: Engineering and Innovation","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131697841","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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