Abstract Purpose: Despite widespread studying of the polarity effect of Roos parallel plate ion chamber in electron beams as mentioned in several protocols, no investigations have up till now studied this effect in photon beams in the build-up region. It is important to examine its polarity effect in the build-up region for photon beams, so this is the first work that focuses in to evaluate the polarity effect of the Roos chamber in the surface and build-up region and comparing its effect with other chambers. Methods: In this study, the Roos chamber was irradiated by a Theratron 780E 60Co beam to a known polarity effect. The Polarity effects of 5×5 up to 35×35 cm2 field sizes at positive and negative polarizing voltages were measured in the build-up region from surface to 0.7 cm in a solid water phantom. Results: The polarity ratios (PRs) were obtained at 1.020 ± 0.00 and 1.015 ± 0.00 for field sizes 5 × 5 up to 35 × 35 cm2, respectively. For the same fields, the percentage of polarity effects (%PEs) was obtained at 1.99% ± 0.00% and 1.47% ± 0.02%, respectively. The results found that the %PEs decrease with increased field sizes and depths. Moreover, the %PEs exhibited a decrease with an increased percentage surface dose (%SD). The uncertainty of %PE was estimated as 0.01% for all measurements in this study. Conclusions: As a result, the average %PE of the Roos chamber described here is equal to 0.756% ± 0.013% for all depths and field sizes for the 60Co γ-ray beam. It has introduced a less percentage of polarity effect than other chambers.
{"title":"Evaluation of the polarity effect of Roos parallel plate ionization chamber in build-up region","authors":"A. Al-Aghbari","doi":"10.2478/pjmpe-2022-0015","DOIUrl":"https://doi.org/10.2478/pjmpe-2022-0015","url":null,"abstract":"Abstract Purpose: Despite widespread studying of the polarity effect of Roos parallel plate ion chamber in electron beams as mentioned in several protocols, no investigations have up till now studied this effect in photon beams in the build-up region. It is important to examine its polarity effect in the build-up region for photon beams, so this is the first work that focuses in to evaluate the polarity effect of the Roos chamber in the surface and build-up region and comparing its effect with other chambers. Methods: In this study, the Roos chamber was irradiated by a Theratron 780E 60Co beam to a known polarity effect. The Polarity effects of 5×5 up to 35×35 cm2 field sizes at positive and negative polarizing voltages were measured in the build-up region from surface to 0.7 cm in a solid water phantom. Results: The polarity ratios (PRs) were obtained at 1.020 ± 0.00 and 1.015 ± 0.00 for field sizes 5 × 5 up to 35 × 35 cm2, respectively. For the same fields, the percentage of polarity effects (%PEs) was obtained at 1.99% ± 0.00% and 1.47% ± 0.02%, respectively. The results found that the %PEs decrease with increased field sizes and depths. Moreover, the %PEs exhibited a decrease with an increased percentage surface dose (%SD). The uncertainty of %PE was estimated as 0.01% for all measurements in this study. Conclusions: As a result, the average %PE of the Roos chamber described here is equal to 0.756% ± 0.013% for all depths and field sizes for the 60Co γ-ray beam. It has introduced a less percentage of polarity effect than other chambers.","PeriodicalId":53955,"journal":{"name":"Polish Journal of Medical Physics and Engineering","volume":"29 1","pages":"127 - 132"},"PeriodicalIF":0.4,"publicationDate":"2022-08-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83083556","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}
Abstract This review paper summarizes the possibilities of the use of therapeutic linear electron accelerators for the production of radioisotopes for nuclear medicine. This work is based on our published results and the thematically similar papers by other authors, directly related to five medical radioisotopes as 99Mo/99mTc, 198Au, 186Re, 188Re, 117mSn, produced using therapeutic linacs. Our unpublished data relating to the issues discussed have also been used here. In the experiments, two types of radiation were included in the analysis of the radioisotope production process, i.e. the therapeutic twenty-megavolt (20 MV) X-rays generated by Varian linacs and neutron radiation contaminating the therapeutic beam. Thus, the debated radioisotopes are produced in the photonuclear reactions and in the neutron ones. Linear therapeutic accelerators do not allow the production of radioisotopes with high specific activities, but the massive targets can be used instead. Thus, the amount of the produced radioisotopes may be increased. Apart from linear accelerators, more and more often, the production of radioisotopes is carried out in small medical cyclotrons. More such cyclotrons are developed, built, and sold commercially than for scientific research. The radioisotopes produced with the use of therapeutic linacs or cyclotrons can be successfully applied in various laboratory tests and in research.
{"title":"Application of therapeutic linear accelerators for the production of radioisotopes used in nuclear medicine","authors":"A. Konefał, A. Orlef, M. Sokół","doi":"10.2478/pjmpe-2022-0013","DOIUrl":"https://doi.org/10.2478/pjmpe-2022-0013","url":null,"abstract":"Abstract This review paper summarizes the possibilities of the use of therapeutic linear electron accelerators for the production of radioisotopes for nuclear medicine. This work is based on our published results and the thematically similar papers by other authors, directly related to five medical radioisotopes as 99Mo/99mTc, 198Au, 186Re, 188Re, 117mSn, produced using therapeutic linacs. Our unpublished data relating to the issues discussed have also been used here. In the experiments, two types of radiation were included in the analysis of the radioisotope production process, i.e. the therapeutic twenty-megavolt (20 MV) X-rays generated by Varian linacs and neutron radiation contaminating the therapeutic beam. Thus, the debated radioisotopes are produced in the photonuclear reactions and in the neutron ones. Linear therapeutic accelerators do not allow the production of radioisotopes with high specific activities, but the massive targets can be used instead. Thus, the amount of the produced radioisotopes may be increased. Apart from linear accelerators, more and more often, the production of radioisotopes is carried out in small medical cyclotrons. More such cyclotrons are developed, built, and sold commercially than for scientific research. The radioisotopes produced with the use of therapeutic linacs or cyclotrons can be successfully applied in various laboratory tests and in research.","PeriodicalId":53955,"journal":{"name":"Polish Journal of Medical Physics and Engineering","volume":"10 1","pages":"107 - 116"},"PeriodicalIF":0.4,"publicationDate":"2022-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76282387","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}
Ahmad Shalbaf, P. Gifani, G. Mehri-Kakavand, Mohamad Pursamimi, M. Ghorbani, A. Davanloo, Majid Vafaeezadeh
Abstract Introduction: Quantification of lung involvement in COVID-19 using chest Computed tomography (CT) scan can help physicians to evaluate the progression of the disease or treatment response. This paper presents an automatic deep transfer learning ensemble based on pre-trained convolutional neural networks (CNNs) to determine the severity of COVID -19 as normal, mild, moderate, and severe based on the images of the lungs CT. Material and methods: In this study, two different deep transfer learning strategies were used. In the first procedure, features were extracted from fifteen pre-trained CNNs architectures and then fed into a support vector machine (SVM) classifier. In the second procedure, the pre-trained CNNs were fine-tuned using the chest CT images, and then features were extracted for the purpose of classification by the softmax layer. Finally, an ensemble method was developed based on majority voting of the deep learning outputs to increase the performance of the recognition on each of the two strategies. A dataset of CT scans was collected and then labeled as normal (314), mild (262), moderate (72), and severe (35) for COVID-19 by the consensus of two highly qualified radiologists. Results: The ensemble of five deep transfer learning outputs named EfficientNetB3, EfficientNetB4, InceptionV3, NasNetMobile, and ResNext50 in the second strategy has better results than the first strategy and also the individual deep transfer learning models in diagnosing the severity of COVID-19 with 85% accuracy. Conclusions: Our proposed study is well suited for quantifying lung involvement of COVID-19 and can help physicians to monitor the progression of the disease.
{"title":"Automatic diagnosis of severity of COVID-19 patients using an ensemble of transfer learning models with convolutional neural networks in CT images","authors":"Ahmad Shalbaf, P. Gifani, G. Mehri-Kakavand, Mohamad Pursamimi, M. Ghorbani, A. Davanloo, Majid Vafaeezadeh","doi":"10.2478/pjmpe-2022-0014","DOIUrl":"https://doi.org/10.2478/pjmpe-2022-0014","url":null,"abstract":"Abstract Introduction: Quantification of lung involvement in COVID-19 using chest Computed tomography (CT) scan can help physicians to evaluate the progression of the disease or treatment response. This paper presents an automatic deep transfer learning ensemble based on pre-trained convolutional neural networks (CNNs) to determine the severity of COVID -19 as normal, mild, moderate, and severe based on the images of the lungs CT. Material and methods: In this study, two different deep transfer learning strategies were used. In the first procedure, features were extracted from fifteen pre-trained CNNs architectures and then fed into a support vector machine (SVM) classifier. In the second procedure, the pre-trained CNNs were fine-tuned using the chest CT images, and then features were extracted for the purpose of classification by the softmax layer. Finally, an ensemble method was developed based on majority voting of the deep learning outputs to increase the performance of the recognition on each of the two strategies. A dataset of CT scans was collected and then labeled as normal (314), mild (262), moderate (72), and severe (35) for COVID-19 by the consensus of two highly qualified radiologists. Results: The ensemble of five deep transfer learning outputs named EfficientNetB3, EfficientNetB4, InceptionV3, NasNetMobile, and ResNext50 in the second strategy has better results than the first strategy and also the individual deep transfer learning models in diagnosing the severity of COVID-19 with 85% accuracy. Conclusions: Our proposed study is well suited for quantifying lung involvement of COVID-19 and can help physicians to monitor the progression of the disease.","PeriodicalId":53955,"journal":{"name":"Polish Journal of Medical Physics and Engineering","volume":"17 1","pages":"117 - 126"},"PeriodicalIF":0.4,"publicationDate":"2022-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86171545","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}
Liza Indrayani, C. Anam, H. Sutanto, Rinarto Subroto, G. Dougherty
Abstract Introduction: The purpose of this study was to determine the best normal tissue objective (NTO) values based on the dose distribution from brain tumor radiation therapy. Material and methods: The NTO is a constraint provided by Eclipse to limit the dose to normal tissues by steepening the dose gradient. The multitude of NTO setting combinations necessitates optimal NTO settings. The Eclipse supports manual and automatic NTOs. Fifteen patients were re-planned using NTO priorities of 1, 50, 100, 150, 200, and 500 in combination with dose fall-offs of 0.05, 0.1, 0.2, 0.3, 0.5, 1 and 5 mm-1. NTO distance to planning target volume (PTV), start dose, and end dose were 1 mm, 105%, and 60%, respectively, for all plans. In addition, planning without the NTO was arranged to find out its effect on planning. The prescription dose covered 95% of the PTV. Planning was evaluated using several indices: conformity index (CI), homogeneity index (HI), gradient index (GI), modified gradient index (mGI), comprehensive quality index (CQI), and monitor unit (MU). Differences among automatic NTO, manual NTO, and without NTO were evaluated using the Wilcoxon signed-rank test. Results: Comparisons obtained without and with manual NTO were: CI of 0.77 vs. 0.96 (p = 0.002), GI of 4.52 vs. 4.69 (p = 0.233), mGI of 4.93 vs. 3.95 (p = 0.001), HI of 1.10 vs. 1.10 (p = 0.330), and MU/cGy of 3.44 vs. 3.42 (p = 0.460). Planning without NTO produced a poor conformity index. Comparisons of automatic and manual NTOs were: CI of 0.92 vs. 0.96 (p = 0.035), GI of 5.25 vs. 4.69 (p = 0.253), mGI of 4.46 vs. 3.95 (p = 0.001), HI of 1.09 vs. 1.10 (p = 0.004), MU/cGy of 3.31 vs. 3.42 (p = 0.041). Conclusions: Based on these results, manual NTO with a priority of 100 and dose fall-off 0.5 mm-1 was optimal, as indicated by the high dose reduction in normal tissue.
摘要:本研究的目的是根据脑肿瘤放射治疗的剂量分布确定最佳的正常组织目标值(NTO)。材料和方法:NTO是Eclipse提供的一种约束，通过增大剂量梯度来限制对正常组织的剂量。大量的NTO设置组合需要最佳的NTO设置。Eclipse支持手动和自动nto。15例患者采用NTO优先级1、50、100、150、200和500，并结合剂量降量0.05、0.1、0.2、0.3、0.5、1和5 mm-1重新计划。所有计划的NTO距离计划靶体积(PTV)、起始剂量和结束剂量分别为1mm、105%和60%。此外，安排了没有NTO的规划，以了解其对规划的影响。处方剂量覆盖了95%的PTV。采用符合性指数(CI)、均匀性指数(HI)、梯度指数(GI)、修正梯度指数(mGI)、综合质量指数(CQI)和监测单位(MU)等指标对规划进行评价。使用Wilcoxon符号秩检验评估自动NTO、手动NTO和无NTO之间的差异。结果:无人工NTO和人工NTO的比较结果为:CI为0.77 vs. 0.96 (p = 0.002)， GI为4.52 vs. 4.69 (p = 0.233)， mGI为4.93 vs. 3.95 (p = 0.001)， HI为1.10 vs. 1.10 (p = 0.330)， MU/cGy为3.44 vs. 3.42 (p = 0.460)。没有NTO的计划产生了较差的符合性指数。自动与手动NTOs的比较:CI为0.92 vs. 0.96 (p = 0.035)， GI为5.25 vs. 4.69 (p = 0.253)， mGI为4.46 vs. 3.95 (p = 0.001)， HI为1.09 vs. 1.10 (p = 0.004)， MU/cGy为3.31 vs. 3.42 (p = 0.041)。结论:根据上述结果，手动NTO的优先级为100，剂量下降0.5 mm-1是最佳的，因为正常组织的剂量降低很高。
{"title":"Normal tissue objective (NTO) tool in Eclipse treatment planning system for dose distribution optimization","authors":"Liza Indrayani, C. Anam, H. Sutanto, Rinarto Subroto, G. Dougherty","doi":"10.2478/pjmpe-2022-0012","DOIUrl":"https://doi.org/10.2478/pjmpe-2022-0012","url":null,"abstract":"Abstract Introduction: The purpose of this study was to determine the best normal tissue objective (NTO) values based on the dose distribution from brain tumor radiation therapy. Material and methods: The NTO is a constraint provided by Eclipse to limit the dose to normal tissues by steepening the dose gradient. The multitude of NTO setting combinations necessitates optimal NTO settings. The Eclipse supports manual and automatic NTOs. Fifteen patients were re-planned using NTO priorities of 1, 50, 100, 150, 200, and 500 in combination with dose fall-offs of 0.05, 0.1, 0.2, 0.3, 0.5, 1 and 5 mm-1. NTO distance to planning target volume (PTV), start dose, and end dose were 1 mm, 105%, and 60%, respectively, for all plans. In addition, planning without the NTO was arranged to find out its effect on planning. The prescription dose covered 95% of the PTV. Planning was evaluated using several indices: conformity index (CI), homogeneity index (HI), gradient index (GI), modified gradient index (mGI), comprehensive quality index (CQI), and monitor unit (MU). Differences among automatic NTO, manual NTO, and without NTO were evaluated using the Wilcoxon signed-rank test. Results: Comparisons obtained without and with manual NTO were: CI of 0.77 vs. 0.96 (p = 0.002), GI of 4.52 vs. 4.69 (p = 0.233), mGI of 4.93 vs. 3.95 (p = 0.001), HI of 1.10 vs. 1.10 (p = 0.330), and MU/cGy of 3.44 vs. 3.42 (p = 0.460). Planning without NTO produced a poor conformity index. Comparisons of automatic and manual NTOs were: CI of 0.92 vs. 0.96 (p = 0.035), GI of 5.25 vs. 4.69 (p = 0.253), mGI of 4.46 vs. 3.95 (p = 0.001), HI of 1.09 vs. 1.10 (p = 0.004), MU/cGy of 3.31 vs. 3.42 (p = 0.041). Conclusions: Based on these results, manual NTO with a priority of 100 and dose fall-off 0.5 mm-1 was optimal, as indicated by the high dose reduction in normal tissue.","PeriodicalId":53955,"journal":{"name":"Polish Journal of Medical Physics and Engineering","volume":"13 1","pages":"99 - 106"},"PeriodicalIF":0.4,"publicationDate":"2022-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87716719","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}
Abstract Introduction: The current regulations in Poland in the field of interventional radiology only include diagnostic reference levels (DRL) for five procedures, containing only two for cardiological (hemodynamic) procedures, and only for adults. Given the insufficient number of DRLs, the need to introduce local levels based on the intervention procedures performed was identified. The purpose of this research was the evaluation of radiation doses (DRL, effective dose) received by patients in cardiological interventional procedures. Material and methods: The DRL level was defined as the 75th percentile of the distribution of dosimetric parameters KAP and Kair,ref for each type of cardiological procedure. Data include three different X-ray units and 27 interventional cardiologists, derived from February 2019 to June 2019 and from August 2021 to December 2021. In order to estimate the effective dose, the appropriate conversion factors for cardiological procedures were used. The total number of analyzed procedures was 3818. Results: The proposed local DRL levels were found to be mostly lower than data found in literature and in the current Polish national requirements (60%-70% lower for coronary angiography (CA) and percutaneous coronary angioplasty (PCI) procedures). Median equivalent doses for cardiological procedures were estimated at 2.66 mSv, 6.11 mSv and 7.22 mSv for CA, PCI and combined PCI with CA procedure, respectively. Conclusions: The proposed local/institutional DRLs seem to be suitable for use and could be utilized by other centers for comparison purposes.
{"title":"Local diagnostic reference levels and effective doses: single institution levels for interventional cardiology procedures for adult patients","authors":"Joanna Kidoń, K. Polaczek-Grelik, Leszek Wojciuch","doi":"10.2478/pjmpe-2022-0009","DOIUrl":"https://doi.org/10.2478/pjmpe-2022-0009","url":null,"abstract":"Abstract Introduction: The current regulations in Poland in the field of interventional radiology only include diagnostic reference levels (DRL) for five procedures, containing only two for cardiological (hemodynamic) procedures, and only for adults. Given the insufficient number of DRLs, the need to introduce local levels based on the intervention procedures performed was identified. The purpose of this research was the evaluation of radiation doses (DRL, effective dose) received by patients in cardiological interventional procedures. Material and methods: The DRL level was defined as the 75th percentile of the distribution of dosimetric parameters KAP and Kair,ref for each type of cardiological procedure. Data include three different X-ray units and 27 interventional cardiologists, derived from February 2019 to June 2019 and from August 2021 to December 2021. In order to estimate the effective dose, the appropriate conversion factors for cardiological procedures were used. The total number of analyzed procedures was 3818. Results: The proposed local DRL levels were found to be mostly lower than data found in literature and in the current Polish national requirements (60%-70% lower for coronary angiography (CA) and percutaneous coronary angioplasty (PCI) procedures). Median equivalent doses for cardiological procedures were estimated at 2.66 mSv, 6.11 mSv and 7.22 mSv for CA, PCI and combined PCI with CA procedure, respectively. Conclusions: The proposed local/institutional DRLs seem to be suitable for use and could be utilized by other centers for comparison purposes.","PeriodicalId":53955,"journal":{"name":"Polish Journal of Medical Physics and Engineering","volume":"17 1","pages":"77 - 83"},"PeriodicalIF":0.4,"publicationDate":"2022-05-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79570731","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}
C. Dumenya, F. Hasford, S. Tagoe, E. Sasu, M. Pokoo-Aikins, B. B. Asamanyuah, J. Amuasi
Abstract Introduction: In radiotherapy, a computerized treatment planning system (TPS) is used for performing treatment planning to estimate the dose distribution within a patient. To simplify the dose calculation, mathematical algorithms are employed. TG43 formalism is widely used for brachytherapy. Before the implementation of a particular dose calculation algorithm in clinical practice, it is imperative to acknowledge the limitations and uncertainties associated with the algorithm. Regarding this, outputs of the algorithm are compared to measurements or dose calculation approaches using simple source placement geometries. The manual dose calculation method has to be robust, straightforward, and devoid of complexities to reduce the likelihood of committing errors in the dose calculation process. A lot of manual dose calculation approaches have been proposed for Brachytherapy sources, but one needs to ascertain their reliability. Material and methods: Considering this, the output of an HDRplus treatment planning system dedicated to brachytherapy treatment planning and using the TG43 formalism to calculate the dose distribution around a BEBIG Co-60 source was validated with Sievert integral dose calculation approach. Simple source placement geometries were created with the TPS using the universal applicator, LLA1200-20, selected from the applicator library, and doses at various equidistant points from the applicator calculated with the TPS and the Sievert integral. Various steps to enhance the efficacy of the Sievert integral approach have been outlined. Results: The doses compared favourably well with deviations ranging from 0.03 – 10.51% (mean of 3.13%), and 0.03 – 5.63% (mean of 2.55%) for angles along the perpendicular bisector of the source, ranging from 0° < θ < 70° and 0° < θ < 48°, respectively. Conclusions: The Sievert integral breaks down at angles: θ ≥ 60°, and therefore, neglecting large angles, the Sievert integral would be an efficient, effective, and valid tool for quality control of the HDRplus TPS for the Co-60 source.
{"title":"Implementation of the Sievert integral for the calculation of dose distribution around the BEBIG Co-60 high dose rate brachytherapy source","authors":"C. Dumenya, F. Hasford, S. Tagoe, E. Sasu, M. Pokoo-Aikins, B. B. Asamanyuah, J. Amuasi","doi":"10.2478/pjmpe-2022-0011","DOIUrl":"https://doi.org/10.2478/pjmpe-2022-0011","url":null,"abstract":"Abstract Introduction: In radiotherapy, a computerized treatment planning system (TPS) is used for performing treatment planning to estimate the dose distribution within a patient. To simplify the dose calculation, mathematical algorithms are employed. TG43 formalism is widely used for brachytherapy. Before the implementation of a particular dose calculation algorithm in clinical practice, it is imperative to acknowledge the limitations and uncertainties associated with the algorithm. Regarding this, outputs of the algorithm are compared to measurements or dose calculation approaches using simple source placement geometries. The manual dose calculation method has to be robust, straightforward, and devoid of complexities to reduce the likelihood of committing errors in the dose calculation process. A lot of manual dose calculation approaches have been proposed for Brachytherapy sources, but one needs to ascertain their reliability. Material and methods: Considering this, the output of an HDRplus treatment planning system dedicated to brachytherapy treatment planning and using the TG43 formalism to calculate the dose distribution around a BEBIG Co-60 source was validated with Sievert integral dose calculation approach. Simple source placement geometries were created with the TPS using the universal applicator, LLA1200-20, selected from the applicator library, and doses at various equidistant points from the applicator calculated with the TPS and the Sievert integral. Various steps to enhance the efficacy of the Sievert integral approach have been outlined. Results: The doses compared favourably well with deviations ranging from 0.03 – 10.51% (mean of 3.13%), and 0.03 – 5.63% (mean of 2.55%) for angles along the perpendicular bisector of the source, ranging from 0° < θ < 70° and 0° < θ < 48°, respectively. Conclusions: The Sievert integral breaks down at angles: θ ≥ 60°, and therefore, neglecting large angles, the Sievert integral would be an efficient, effective, and valid tool for quality control of the HDRplus TPS for the Co-60 source.","PeriodicalId":53955,"journal":{"name":"Polish Journal of Medical Physics and Engineering","volume":"66 1","pages":"90 - 98"},"PeriodicalIF":0.4,"publicationDate":"2022-05-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87993265","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}
B. Sadowski, Marta Fillmann, Dariusz Szałkowski, P. Kukołowicz
Abstract Introduction: The aim of this study was to evaluate the new 2-Dimensional diode array SRS MapCHECK (SunNuclear, Melbourne, USA) with dedicated phantom StereoPHAN (SunNuclear, Melbourne, USA) for the pre-treatment verification of the stereotactic body radiotherapy (SBRT). Material and methods: For the system, the short and mid-long stability, dose linearity with MU, angular dependence, and field size dependence (ratio of relative output factor) were measured. The results of verification for 15 pre-treatment cancer patients (5 brains, 5 lungs, and 5 livers) performed with SRS MapCHECK and EBT3 Gafchromic films were compared. All the SBRT plans were optimized with the Eclipse (v. 15.6, Varian, Palo Alto, USA) treatment planning system (TPS) using the Acuros XB (Varian, Palo Alto, USA) dose calculation algorithm and were delivered to the Varian EDGE® (Varian, Palo Alto, USA) accelerator equipped with a high-definition multileaf collimator. The 6MV flattening-filter-free beam (FFF) was used. Results: Short and mid-long stability of SRS MapCHECK was very good (0.1%-0.2%), dose linearity with MU and dependence of the response of the detector on field size results were also acceptable (for dose linearity R2 = 1 and 6% difference between microDiamond and SRS MapCHECK response for the smallest field of 1 × 1 cm2). The angular dependence was very good except for the angles close to 90° and 270°. For pre-treatment plan verification, the gamma method was used with the criteria of 3% dose difference and 3 mm distance to agreement (3%/3 mm), and 2%/2 mm, 1%/1 mm, 3%/1 mm, and 2%/1 mm. The highest passing rate for all criteria was observed on the SRS MapCHECK system. Conclusions: It is concluded that SRS MapCHECK with StereoPHAN has sufficient potential for pre-treatment verification of the SBRT plans, so that verification of stereotactic plans can be significantly accelerated.
{"title":"Evaluation of SRS MapCHECK with StereoPHAN phantom as a new pre-treatment system verification for SBRT plans","authors":"B. Sadowski, Marta Fillmann, Dariusz Szałkowski, P. Kukołowicz","doi":"10.2478/pjmpe-2022-0010","DOIUrl":"https://doi.org/10.2478/pjmpe-2022-0010","url":null,"abstract":"Abstract Introduction: The aim of this study was to evaluate the new 2-Dimensional diode array SRS MapCHECK (SunNuclear, Melbourne, USA) with dedicated phantom StereoPHAN (SunNuclear, Melbourne, USA) for the pre-treatment verification of the stereotactic body radiotherapy (SBRT). Material and methods: For the system, the short and mid-long stability, dose linearity with MU, angular dependence, and field size dependence (ratio of relative output factor) were measured. The results of verification for 15 pre-treatment cancer patients (5 brains, 5 lungs, and 5 livers) performed with SRS MapCHECK and EBT3 Gafchromic films were compared. All the SBRT plans were optimized with the Eclipse (v. 15.6, Varian, Palo Alto, USA) treatment planning system (TPS) using the Acuros XB (Varian, Palo Alto, USA) dose calculation algorithm and were delivered to the Varian EDGE® (Varian, Palo Alto, USA) accelerator equipped with a high-definition multileaf collimator. The 6MV flattening-filter-free beam (FFF) was used. Results: Short and mid-long stability of SRS MapCHECK was very good (0.1%-0.2%), dose linearity with MU and dependence of the response of the detector on field size results were also acceptable (for dose linearity R2 = 1 and 6% difference between microDiamond and SRS MapCHECK response for the smallest field of 1 × 1 cm2). The angular dependence was very good except for the angles close to 90° and 270°. For pre-treatment plan verification, the gamma method was used with the criteria of 3% dose difference and 3 mm distance to agreement (3%/3 mm), and 2%/2 mm, 1%/1 mm, 3%/1 mm, and 2%/1 mm. The highest passing rate for all criteria was observed on the SRS MapCHECK system. Conclusions: It is concluded that SRS MapCHECK with StereoPHAN has sufficient potential for pre-treatment verification of the SBRT plans, so that verification of stereotactic plans can be significantly accelerated.","PeriodicalId":53955,"journal":{"name":"Polish Journal of Medical Physics and Engineering","volume":"64 1 1","pages":"84 - 89"},"PeriodicalIF":0.4,"publicationDate":"2022-05-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75276155","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}
Noor Nabilah Talik Sisin, Muhammad Afiq Khairil Anuar, N. Dollah, K. A. Razak, M. Algethami, M. Geso, W. N. Rahman
Abstract Introduction: Nanoparticles (NPs) have been proven to enhance radiotherapy doses as radiosensitizers. The introduction of coating materials such as polyethylene glycol (PEG) to NPs could impact the NPs’ biocompatibility and their effectiveness as radiosensitizers. Optimization of surface coating is a crucial element to ensure the successful application of NPs as a radiosensitizer in radiotherapy. This study aims to investigate the influence of bismuth oxide NPs (BiONPs) coated with PEG on reactive oxygen species (ROS) generation on HeLa cervical cancer cell line. Material and methods: Different PEG concentrations (0.05, 0.10, 0.15 and 0.20 mM) were used in the synthesis of the NPs. The treated cells were irradiated with 6 and 12 MeV electron beams with a delivered dose of 3 Gy. The reactive oxygen species (ROS) generation was measured immediately after and 3 hours after irradiation. Results: The intracellular ROS generation was found to be slightly influenced by electron beam energy and independent of the PEG concentrations. Linear increments of ROS percentages over the 3 hours of incubation time were observed. Conclusions: Finally, the PEG coating might not substantially affect the ROS generated and thus emphasizing the functionalized BiONPs application as the radiosensitizer for electron beam therapy.
{"title":"Influence of PEG-coated Bismuth Oxide Nanoparticles on ROS Generation by Electron Beam Radiotherapy","authors":"Noor Nabilah Talik Sisin, Muhammad Afiq Khairil Anuar, N. Dollah, K. A. Razak, M. Algethami, M. Geso, W. N. Rahman","doi":"10.2478/pjmpe-2022-0008","DOIUrl":"https://doi.org/10.2478/pjmpe-2022-0008","url":null,"abstract":"Abstract Introduction: Nanoparticles (NPs) have been proven to enhance radiotherapy doses as radiosensitizers. The introduction of coating materials such as polyethylene glycol (PEG) to NPs could impact the NPs’ biocompatibility and their effectiveness as radiosensitizers. Optimization of surface coating is a crucial element to ensure the successful application of NPs as a radiosensitizer in radiotherapy. This study aims to investigate the influence of bismuth oxide NPs (BiONPs) coated with PEG on reactive oxygen species (ROS) generation on HeLa cervical cancer cell line. Material and methods: Different PEG concentrations (0.05, 0.10, 0.15 and 0.20 mM) were used in the synthesis of the NPs. The treated cells were irradiated with 6 and 12 MeV electron beams with a delivered dose of 3 Gy. The reactive oxygen species (ROS) generation was measured immediately after and 3 hours after irradiation. Results: The intracellular ROS generation was found to be slightly influenced by electron beam energy and independent of the PEG concentrations. Linear increments of ROS percentages over the 3 hours of incubation time were observed. Conclusions: Finally, the PEG coating might not substantially affect the ROS generated and thus emphasizing the functionalized BiONPs application as the radiosensitizer for electron beam therapy.","PeriodicalId":53955,"journal":{"name":"Polish Journal of Medical Physics and Engineering","volume":"40 1","pages":"69 - 76"},"PeriodicalIF":0.4,"publicationDate":"2022-05-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86329764","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}
B. Bąk, A. Skrobała, A. Adamska, N. Józefacka, Sara Styś, J. Malicki
Abstract Introduction: The aim of this study was the evaluation of volume and dose differences in selected structures in patients with head and neck cancer during treatment on Helical TomoTherapy (HT) using a commercially available deformable image registration (DIR) tool. We attempted to identify anatomical and clinical predictive factors for significant volume changes probability. Material and methods: According to our institutional protocol, we retrospectively evaluated the group of 20 H&N cancer patients treated with HT who received Adaptive Radiotherapy (ART) due to soft tissue alterations spotted on daily MVCT. We compared volumes on initial computed tomography (iCT) and replanning computed tomography (rCT) for clinical target volumes (CTV) – CTV1 (the primary tumor) and CTV2 (metastatic lymph nodes), parotid glands (PG) and body contour (B-body). To estimate the planned and delivered dose discrepancy, the dose from the original plan was registered and deformed to create a simulation of dose distribution on rCT (DIR-rCT). Results: The decision to replan was made at the 4th week of RT (N = 6; 30%). The average volume reduction in parotid right PG[R] and left PG[L] was 4.37 cc (18.9%) (p < 0.001) and 3.77 cc (16.8%) (p = 0.004), respectively. In N = 13/20 cases, the delivered dose was greater than the planned dose for PG[R] of mean 3 Gy (p < 0.001), and in N = 6/20 patients for PG[L] the mean of 3.6 Gy (p = 0.031). Multivariate regression analysis showed a very strong predictor explaining 88% (R2 = 0.88) and 83% (R2 = 0.83) of the variance based on the mean dose of iPG[R] and iPG[L] (p < 0.001), respectively. No statistically significant correlation between volume changes and risk factors was found. Conclusions: Dosimetric changes to the target demonstrated the validity of replanning. A DIR tool can be successfully used for dose deformation and ART qualification, significantly reducing the workload of radiotherapy centers. In addition, the mean dose for PG was a significant predictor that may indicate the need for a replan.
{"title":"Evaluation and risk factors of volume and dose differences of selected structures in patients with head and neck cancer treated on Helical TomoTherapy by using Deformable Image Registration tool","authors":"B. Bąk, A. Skrobała, A. Adamska, N. Józefacka, Sara Styś, J. Malicki","doi":"10.2478/pjmpe-2022-0007","DOIUrl":"https://doi.org/10.2478/pjmpe-2022-0007","url":null,"abstract":"Abstract Introduction: The aim of this study was the evaluation of volume and dose differences in selected structures in patients with head and neck cancer during treatment on Helical TomoTherapy (HT) using a commercially available deformable image registration (DIR) tool. We attempted to identify anatomical and clinical predictive factors for significant volume changes probability. Material and methods: According to our institutional protocol, we retrospectively evaluated the group of 20 H&N cancer patients treated with HT who received Adaptive Radiotherapy (ART) due to soft tissue alterations spotted on daily MVCT. We compared volumes on initial computed tomography (iCT) and replanning computed tomography (rCT) for clinical target volumes (CTV) – CTV1 (the primary tumor) and CTV2 (metastatic lymph nodes), parotid glands (PG) and body contour (B-body). To estimate the planned and delivered dose discrepancy, the dose from the original plan was registered and deformed to create a simulation of dose distribution on rCT (DIR-rCT). Results: The decision to replan was made at the 4th week of RT (N = 6; 30%). The average volume reduction in parotid right PG[R] and left PG[L] was 4.37 cc (18.9%) (p < 0.001) and 3.77 cc (16.8%) (p = 0.004), respectively. In N = 13/20 cases, the delivered dose was greater than the planned dose for PG[R] of mean 3 Gy (p < 0.001), and in N = 6/20 patients for PG[L] the mean of 3.6 Gy (p = 0.031). Multivariate regression analysis showed a very strong predictor explaining 88% (R2 = 0.88) and 83% (R2 = 0.83) of the variance based on the mean dose of iPG[R] and iPG[L] (p < 0.001), respectively. No statistically significant correlation between volume changes and risk factors was found. Conclusions: Dosimetric changes to the target demonstrated the validity of replanning. A DIR tool can be successfully used for dose deformation and ART qualification, significantly reducing the workload of radiotherapy centers. In addition, the mean dose for PG was a significant predictor that may indicate the need for a replan.","PeriodicalId":53955,"journal":{"name":"Polish Journal of Medical Physics and Engineering","volume":"18 1","pages":"60 - 68"},"PeriodicalIF":0.4,"publicationDate":"2022-05-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73741203","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}
Abstract Introduction: The doping of high Z nanoparticles into the tumor tissue increases the therapeutic efficiency of radiotherapy called nanoparticle enhanced radiotherapy (NERT). In the present study, we are identifying the effective types of radiation and effective doping concentration of bismuth radiosensitizer for NERT application by analyzing effective atomic number (Zeff) and photon buildup factor (PBF) of bismuth (Bi) doped soft tissue for the photon, electron, proton, alpha particle, and carbon ion interactions. Material and methods: The direct method was used for the calculation of Zeff for photon and electron beams (10 keV-30 MeV). The phy-X/ZeXTRa software was utilized for the particle beams such as proton, alpha particle, and carbon ions (1-15 MeV). Bismuth doping concentrations of 5, 10, 15, 20, 25 and 30 mg/g were considered. The PBF was calculated over 15 keV-15 MeV energies using phy-X/PSD software. Results: The low energy photon (<100 keV) interaction with a higher concentration of Bi dopped tissue gives the higher values of Zeff. The Zeff increased with the doping concentration of bismuth for all types of radiation. The Zeff was dependent on the type of radiation, the energy of radiation, and the concentration of Bi doping. The particle beams such as electron, proton, alpha particle, and carbon ion interaction gives the less values of Zeff has compared to photon beam interaction. On the other hand, the photon buildup factor values were decreased while increasing the Bi doping concentration. Conclusions: According to Zeff and PBF, the low energy photon and higher concentration of radiosensitizer are the most effective for nanoparticle enhanced radiotherapy application. Based on the calculated values of Zeff, the particle beams such as electron, proton, alpha particle, and carbon ions were less effective for NERT application. The presented values of Zeff and PBF are useful for the radiation dosimetry in NERT.
{"title":"Effective atomic number and photon buildup factor of bismuth doped tissue for photon and particles beam interaction","authors":"Krishnamurthy Srinivasan, E. Samuel","doi":"10.2478/pjmpe-2022-0005","DOIUrl":"https://doi.org/10.2478/pjmpe-2022-0005","url":null,"abstract":"Abstract Introduction: The doping of high Z nanoparticles into the tumor tissue increases the therapeutic efficiency of radiotherapy called nanoparticle enhanced radiotherapy (NERT). In the present study, we are identifying the effective types of radiation and effective doping concentration of bismuth radiosensitizer for NERT application by analyzing effective atomic number (Zeff) and photon buildup factor (PBF) of bismuth (Bi) doped soft tissue for the photon, electron, proton, alpha particle, and carbon ion interactions. Material and methods: The direct method was used for the calculation of Zeff for photon and electron beams (10 keV-30 MeV). The phy-X/ZeXTRa software was utilized for the particle beams such as proton, alpha particle, and carbon ions (1-15 MeV). Bismuth doping concentrations of 5, 10, 15, 20, 25 and 30 mg/g were considered. The PBF was calculated over 15 keV-15 MeV energies using phy-X/PSD software. Results: The low energy photon (<100 keV) interaction with a higher concentration of Bi dopped tissue gives the higher values of Zeff. The Zeff increased with the doping concentration of bismuth for all types of radiation. The Zeff was dependent on the type of radiation, the energy of radiation, and the concentration of Bi doping. The particle beams such as electron, proton, alpha particle, and carbon ion interaction gives the less values of Zeff has compared to photon beam interaction. On the other hand, the photon buildup factor values were decreased while increasing the Bi doping concentration. Conclusions: According to Zeff and PBF, the low energy photon and higher concentration of radiosensitizer are the most effective for nanoparticle enhanced radiotherapy application. Based on the calculated values of Zeff, the particle beams such as electron, proton, alpha particle, and carbon ions were less effective for NERT application. The presented values of Zeff and PBF are useful for the radiation dosimetry in NERT.","PeriodicalId":53955,"journal":{"name":"Polish Journal of Medical Physics and Engineering","volume":"13 1","pages":"37 - 51"},"PeriodicalIF":0.4,"publicationDate":"2022-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81916559","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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