Pub Date : 2021-02-27DOI: 10.22038/IJMP.2021.53179.1876
Z. Mansouri, A. Mostaar, M. Shiri, M. Shahabi
Introduction: According to new developments in radiation therapy techniques, accurate dose verification in three-dimensions has become more critical. Polymer gel dosimeters (PGDs) are valuable tools to be used for this purpose. Nowadays, various imaging modalities are employed to read out the gels. This study was aimed to investigate the measured dose distribution recorded in MAGIC-f PGD with optical computed tomography (OCT) by comparison with MRI. Material and methods: We developed an in-house CCD based cone-beam OCT scanner. A phantom of MAGIC-f PGD was used to measure a four-field box dose distribution. MRI and OCT scanners were performed for gel readouts. Both measurement results were compared by gamma index analysis with various acceptance criteria. The temporal stability of the gel was also evaluated with the OCT readout system.Results: The percentage of isodose lines from two measured datasets agreed well together. The pass rates were 99.02%, 96.8%, and 89.8% with 5%/5mm, 4%/4mm, and 3%/3mm criteria, respectively, at the phantom's central axial slice. Conclusion: The results indicate that the performance of this OCT system is almost the same with acceptable discrepancies to the MRI as accepted standard readout modality, and it can be used for three-dimensional dose verifications.
{"title":"MAGIC-f gel dosimeter reading: a comparison between an in-house optical CT and MRI imaging","authors":"Z. Mansouri, A. Mostaar, M. Shiri, M. Shahabi","doi":"10.22038/IJMP.2021.53179.1876","DOIUrl":"https://doi.org/10.22038/IJMP.2021.53179.1876","url":null,"abstract":"Introduction: According to new developments in radiation therapy techniques, accurate dose verification in three-dimensions has become more critical. Polymer gel dosimeters (PGDs) are valuable tools to be used for this purpose. Nowadays, various imaging modalities are employed to read out the gels. This study was aimed to investigate the measured dose distribution recorded in MAGIC-f PGD with optical computed tomography (OCT) by comparison with MRI. Material and methods: We developed an in-house CCD based cone-beam OCT scanner. A phantom of MAGIC-f PGD was used to measure a four-field box dose distribution. MRI and OCT scanners were performed for gel readouts. Both measurement results were compared by gamma index analysis with various acceptance criteria. The temporal stability of the gel was also evaluated with the OCT readout system.Results: The percentage of isodose lines from two measured datasets agreed well together. The pass rates were 99.02%, 96.8%, and 89.8% with 5%/5mm, 4%/4mm, and 3%/3mm criteria, respectively, at the phantom's central axial slice. Conclusion: The results indicate that the performance of this OCT system is almost the same with acceptable discrepancies to the MRI as accepted standard readout modality, and it can be used for three-dimensional dose verifications.","PeriodicalId":14613,"journal":{"name":"Iranian Journal of Medical Physics","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44124135","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 : 2021-02-23DOI: 10.22038/IJMP.2021.53719.1884
M. Toossi, S. Khademi, H. Azimian
Introduction: The aim of the present study was to understand the effect of low-doses of ionizing radiation (LDIR) on repair genes expression in blood samples that were taken from healthy donors. The next purpose was to examine the time-effect on the modified gene expression caused by low-doses of ionizing radiation. Material and method: The RNA of peripheral blood lymphocytes (PBLs) taken from four healthy donors was isolated at different time points after exposure included 4, 24, 48, 72, and 168 hours and then cDNA was synthesized. Modification of XPA and RAD51 expression levels due to LDIR (2, 5, 10 cGy) were evaluated by relative quantitative reverse transcription-polymerase chain reaction.Results: Significant up-regulation of both repair genes was observed at the 4 and 168 h following to 10 cGy. Also, this dose could increase expression levels of RAD51 at 48 and 72 h after radiation. For lower doses at 5 cGy, only XPA levels were significantly up-regulated after 168 h. A significant regression was found between the XPA levels and the dose, at 168 h after irradiation to PBLs that can represent a new potential biomarker for biological dosimetry purposes.Conclusion: The results of this study could support the hypothetical role of the different DNA repair pathways in response to LDIR. This led us to propose a molecular biodosimetry method for ionizing radiation in the range of LDIR.
{"title":"Time-Dependent Induction of the Nucleotide Excision Repair Gene XPA and RAD51 in Homologous Recombination in Human Lymphocytes Exposed to Low Doses of Ionizing Radiation","authors":"M. Toossi, S. Khademi, H. Azimian","doi":"10.22038/IJMP.2021.53719.1884","DOIUrl":"https://doi.org/10.22038/IJMP.2021.53719.1884","url":null,"abstract":"Introduction: The aim of the present study was to understand the effect of low-doses of ionizing radiation (LDIR) on repair genes expression in blood samples that were taken from healthy donors. The next purpose was to examine the time-effect on the modified gene expression caused by low-doses of ionizing radiation. Material and method: The RNA of peripheral blood lymphocytes (PBLs) taken from four healthy donors was isolated at different time points after exposure included 4, 24, 48, 72, and 168 hours and then cDNA was synthesized. Modification of XPA and RAD51 expression levels due to LDIR (2, 5, 10 cGy) were evaluated by relative quantitative reverse transcription-polymerase chain reaction.Results: Significant up-regulation of both repair genes was observed at the 4 and 168 h following to 10 cGy. Also, this dose could increase expression levels of RAD51 at 48 and 72 h after radiation. For lower doses at 5 cGy, only XPA levels were significantly up-regulated after 168 h. A significant regression was found between the XPA levels and the dose, at 168 h after irradiation to PBLs that can represent a new potential biomarker for biological dosimetry purposes.Conclusion: The results of this study could support the hypothetical role of the different DNA repair pathways in response to LDIR. This led us to propose a molecular biodosimetry method for ionizing radiation in the range of LDIR.","PeriodicalId":14613,"journal":{"name":"Iranian Journal of Medical Physics","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-02-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47429986","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 : 2021-02-14DOI: 10.22038/IJMP.2021.51256.1837
D. Curto, F. Bonutti, Youssef Bouzekraoui, Hicham Asmi, F. Bentayeb
Introduction: In Yttrium-90 SPECT imaging, the energy window and collimator used during acquisition can have a major effect on image quality. In this work, we used a new and independent method to verify the prevoius results suggest different energy ranges, but all centered at 130 keV. Materials and method: We used Siemens Symbia SPECT-CT system fitted with High Energy General Purpose (HEGP), Medium Energy General Purpose (MEGP) and Low Energy High Resolution (LEHR) to acquire data from NEMA IEC PET Body Phantom with its 6 different spheres of 3.7, 2.8, 2.2, 1.7, 1.3, 1.0 cm diameter. Results:HEGP collimator is the most suitable for acquisitions of 90Y bremsstrahlung radiation from the point of view of the correct volume reproduction. For the bigger sphere’s study, the optimum ISO-counting curves is related to the energy range centred in 130 keV.Conclusion: The results obtained are consistent with previous studies. The Iso Counting Curves method can help to improve image quality.
{"title":"Energy window optimization for Bremsstrahlung Y90 SPECT-CT imaging : a phantom study","authors":"D. Curto, F. Bonutti, Youssef Bouzekraoui, Hicham Asmi, F. Bentayeb","doi":"10.22038/IJMP.2021.51256.1837","DOIUrl":"https://doi.org/10.22038/IJMP.2021.51256.1837","url":null,"abstract":"Introduction: In Yttrium-90 SPECT imaging, the energy window and collimator used during acquisition can have a major effect on image quality. In this work, we used a new and independent method to verify the prevoius results suggest different energy ranges, but all centered at 130 keV. Materials and method: We used Siemens Symbia SPECT-CT system fitted with High Energy General Purpose (HEGP), Medium Energy General Purpose (MEGP) and Low Energy High Resolution (LEHR) to acquire data from NEMA IEC PET Body Phantom with its 6 different spheres of 3.7, 2.8, 2.2, 1.7, 1.3, 1.0 cm diameter. Results:HEGP collimator is the most suitable for acquisitions of 90Y bremsstrahlung radiation from the point of view of the correct volume reproduction. For the bigger sphere’s study, the optimum ISO-counting curves is related to the energy range centred in 130 keV.Conclusion: The results obtained are consistent with previous studies. The Iso Counting Curves method can help to improve image quality.","PeriodicalId":14613,"journal":{"name":"Iranian Journal of Medical Physics","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-02-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48564460","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 : 2021-01-28DOI: 10.22038/IJMP.2021.51781.1849
A. Khumaeni, M. Alhamid, C. Anam, A. Budiono
Introduction : Over the last seven years, the development of nanoparticles as computed tomography (CT) contrast agents has increased significantly. In this present work, syntheses of colloidal silver nanoparticles (Ag NPs), platinum nanoparticles (Pt NPs), and silver-platinum nanoparticles (Ag-Pt NPs) have been successfully performed using pulsed laser ablation method in deionized water media.Materials and Methods : Experimentally, an neodymium-doped yttrium aluminum garnet (Nd:YAG) laser (1064 nm, 45 mJ, 10 Hz) was focused on a high-purity metal plate including Ag and Pt plates, which are placed in deionized water medium. Colloidal Ag NPs has been succesfully produced with a dark brownish-yellow color with an averaged diameter of 24 nm. For colloidal Pt NPs, the liquid has transparent color with an averaged diameter of 20 nm. Both colloidal nanoparticles of Ag and Pt were then mixed to obtain a mixture composition of Ag and Pt with ratios of Ag:Pt of 75:25%, 50:50%, 25:75%, respectively, with a concentration of each of 10 part per million (ppm). The Ag NPs, Pt NPs, and Ag-Pt NPs mixture were then examined as contrast agents in computed tomography (CT) scan. The CT Scan was set at 80 kV and 100 mAs. Results: The imaging results of these agents were measured in Hounsfield Unit (HU), showing 13.5, 12.8, 13.3, 14.1, and 17.3 HUs for colloidal Ag NPs only, colloidal Ag and Pt NPs with ratios of Ag:Pt of 75:25%, 50:50%, 25:75%, and colloidal Pt NPs only, respectively.Conclusion: These findings confirmed that for colloidal solution containing high concentration of platinum (Pt NPs only and colloidal Ag and Pt NPs with ratio of 25:75%) has higher HU values compared to the case of Pt NPs. The higher HU value for platinium can be attributed to its higher density.
{"title":"Synthesis of colloidal silver, platinum, and mixture of silver-platinum nanoparticles using pulsed laser ablation as contrast agent in computed tomography","authors":"A. Khumaeni, M. Alhamid, C. Anam, A. Budiono","doi":"10.22038/IJMP.2021.51781.1849","DOIUrl":"https://doi.org/10.22038/IJMP.2021.51781.1849","url":null,"abstract":"Introduction : Over the last seven years, the development of nanoparticles as computed tomography (CT) contrast agents has increased significantly. In this present work, syntheses of colloidal silver nanoparticles (Ag NPs), platinum nanoparticles (Pt NPs), and silver-platinum nanoparticles (Ag-Pt NPs) have been successfully performed using pulsed laser ablation method in deionized water media.Materials and Methods : Experimentally, an neodymium-doped yttrium aluminum garnet (Nd:YAG) laser (1064 nm, 45 mJ, 10 Hz) was focused on a high-purity metal plate including Ag and Pt plates, which are placed in deionized water medium. Colloidal Ag NPs has been succesfully produced with a dark brownish-yellow color with an averaged diameter of 24 nm. For colloidal Pt NPs, the liquid has transparent color with an averaged diameter of 20 nm. Both colloidal nanoparticles of Ag and Pt were then mixed to obtain a mixture composition of Ag and Pt with ratios of Ag:Pt of 75:25%, 50:50%, 25:75%, respectively, with a concentration of each of 10 part per million (ppm). The Ag NPs, Pt NPs, and Ag-Pt NPs mixture were then examined as contrast agents in computed tomography (CT) scan. The CT Scan was set at 80 kV and 100 mAs. Results: The imaging results of these agents were measured in Hounsfield Unit (HU), showing 13.5, 12.8, 13.3, 14.1, and 17.3 HUs for colloidal Ag NPs only, colloidal Ag and Pt NPs with ratios of Ag:Pt of 75:25%, 50:50%, 25:75%, and colloidal Pt NPs only, respectively.Conclusion: These findings confirmed that for colloidal solution containing high concentration of platinum (Pt NPs only and colloidal Ag and Pt NPs with ratio of 25:75%) has higher HU values compared to the case of Pt NPs. The higher HU value for platinium can be attributed to its higher density.","PeriodicalId":14613,"journal":{"name":"Iranian Journal of Medical Physics","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41365111","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 : 2021-01-05DOI: 10.22038/IJMP.2021.50066.1814
Kheibar Bayati, S. Sina, R. Faghihi, Vahed Moharram Zadeh, M. Papie
Introduction: Treatment planning systems use TG-43 dose calculation protocol for brachytherapy sources. Dose calculations based on TG-43 formalism do not correct the perturbations due to the presence of tissue inhomogeneity, applicators, and inter-seed effects. Inter-seed attenuation has an important effect on dosimetry in permanent implant brachytherapy. The aim of this study is to evaluate the inter-seed attenuation effect for I-125 permanent implants. Then, a software was developed to find the real dose distribution for different combinations of sources. Materials and methods: In the first step, a hypothetical generic source model was designed based on the configurations of different commercial source types. MCNP5 Monte Carlo code was utilized to simulate the single active generic source at the center of the phantom, and an inactive placed at various positions inside the phantom. An algorithm was introduced using artificial neural network models that can estimate the dose distribution in presence of inactive sources. Results: The Monte Carlo calculation results showed that the dose distribution is clearly affected by the inter-seed attenuation effect. Comparison of the artificial neural network results with the Monte Carlo simulation results show that the artificial neural networks can predict the inter-seed attenuation with acceptable accuracy, and with not much greater than 3% deviation.Discussion and conclusions: Inter-seed effect is dependent on the distance between the seeds. Decreasing distances would cause more effect. According to the results, it seems that the artificial neural network can be used as a tool for correction of inter-seed attenuation effect in treatment planning systems.
{"title":"Developing A Method for Inter-Seed Effect Correction in 125I Interstitial Brachytherapy Using Artificial Neural Network","authors":"Kheibar Bayati, S. Sina, R. Faghihi, Vahed Moharram Zadeh, M. Papie","doi":"10.22038/IJMP.2021.50066.1814","DOIUrl":"https://doi.org/10.22038/IJMP.2021.50066.1814","url":null,"abstract":"Introduction: Treatment planning systems use TG-43 dose calculation protocol for brachytherapy sources. Dose calculations based on TG-43 formalism do not correct the perturbations due to the presence of tissue inhomogeneity, applicators, and inter-seed effects. Inter-seed attenuation has an important effect on dosimetry in permanent implant brachytherapy. The aim of this study is to evaluate the inter-seed attenuation effect for I-125 permanent implants. Then, a software was developed to find the real dose distribution for different combinations of sources. Materials and methods: In the first step, a hypothetical generic source model was designed based on the configurations of different commercial source types. MCNP5 Monte Carlo code was utilized to simulate the single active generic source at the center of the phantom, and an inactive placed at various positions inside the phantom. An algorithm was introduced using artificial neural network models that can estimate the dose distribution in presence of inactive sources. Results: The Monte Carlo calculation results showed that the dose distribution is clearly affected by the inter-seed attenuation effect. Comparison of the artificial neural network results with the Monte Carlo simulation results show that the artificial neural networks can predict the inter-seed attenuation with acceptable accuracy, and with not much greater than 3% deviation.Discussion and conclusions: Inter-seed effect is dependent on the distance between the seeds. Decreasing distances would cause more effect. According to the results, it seems that the artificial neural network can be used as a tool for correction of inter-seed attenuation effect in treatment planning systems.","PeriodicalId":14613,"journal":{"name":"Iranian Journal of Medical Physics","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45322657","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 : 2020-12-26DOI: 10.22038/IJMP.2020.48297.1845
Yasser Raoui, Yassine Herrassi, Khalid Elouardy, R. Sebihi, M. Ayad, V. P. Pandey
Linear accelerator multileaf collimator requires to be tested with best possible quality assurance tools and accordingly treatment planning system input with the data for appropriate modelling of MLC. Dose calculation is affected due to MLC modelling, especially when using the high standard techniques of treatment like IMRT or VMAT. An MLCI 2 multileaf collimator is verified by 2D detector matrix (IBA dosimetry, Germany) using the quality assurance kit Express QA test package & clinical cases verification. The standard plan in QA mode is made in TPS and delivered under medical linear accelerator like pre-treatment verification.The measured and calculated fluence is compared and accordingly the Gamma analysis done. Express QA tests & clinical cases fields showed a great agreement with TPS calculations with 3% DD and 3 mm DTA Gamma criteria. The open field 10 x 10 cm² and 20 x 20 cm² found to be passed with 100% results for 3% &3mm criteria. 3ABUT test helped in setting the leaf offset value from default 0.0mm to 0.15mm. FourL test provides adjustment in leaf transmission value and leaf groove width from 0.012 to 0.0073 and 1.0mm to 0.7mm respectively. The H&N and Prostate clinical cases passed with more than 95% for set criteria (3%DD&3mm).The absolute point dose measurement agreement was found to be more than 97%.This study confirmed that the appropriate MLC check before starting IMRT and VMAT in clinic and even after any repair is required thorough quality assurance check using Express QA and TG 119 package. Small changes in the MLC parameters like leaf offset, groove width and transmission n the TPS model can cause large changes in the calculated dose.At least annually Express QA test is recommended to be performed by every user to confirm the status of changed MLC parameters in due course of time.
线性加速器多叶准直器需要使用尽可能好的质量保证工具进行测试，并相应地使用数据输入治疗计划系统，以进行MLC的适当建模。MLC建模会影响剂量计算，尤其是在使用IMRT或VMAT等高标准治疗技术时。MLCI 2多叶准直器通过2D检测器矩阵（IBA剂量测定，德国）使用质量保证试剂盒Express QA测试包和临床病例验证进行验证。QA模式下的标准计划是在TPS中制定的，并在类似医疗线性加速器的预处理验证下交付。将测量的通量和计算的通量进行比较，并相应地进行伽马分析。Express QA测试和临床病例字段显示与TPS计算非常一致，采用3%DD和3mm DTA伽玛标准。10 x 10 cm²和20 x 20 cm²的开阔场地通过了3%和3mm标准的100%结果。3ABUT测试有助于将叶片偏移值从默认值0.0mm设置为0.15mm。FourL测试可将叶片透射值和叶槽宽度分别从0.012调整为0.0073和从1.0mm调整为0.7mm。H＆N和前列腺临床病例通过了95%以上的设定标准（3%DD和3mm）。发现绝对点剂量测量一致性超过97%。本研究证实，在临床开始IMRT和VMAT之前，甚至在任何修复之后，都需要使用Express QA和TG 119包进行彻底的质量保证检查。在TPS模型中，MLC参数如叶片偏移、凹槽宽度和透射率的微小变化可能会导致计算剂量的巨大变化。建议每个用户至少每年进行一次快速QA测试，以在适当的时候确认更改的MLC参数的状态。
{"title":"Beam Modeling in Commercial Treatment Planning System for IMRT and VMAT performance with an Elekta MLCI2 Multileaf Collimator.","authors":"Yasser Raoui, Yassine Herrassi, Khalid Elouardy, R. Sebihi, M. Ayad, V. P. Pandey","doi":"10.22038/IJMP.2020.48297.1845","DOIUrl":"https://doi.org/10.22038/IJMP.2020.48297.1845","url":null,"abstract":"Linear accelerator multileaf collimator requires to be tested with best possible quality assurance tools and accordingly treatment planning system input with the data for appropriate modelling of MLC. Dose calculation is affected due to MLC modelling, especially when using the high standard techniques of treatment like IMRT or VMAT. An MLCI 2 multileaf collimator is verified by 2D detector matrix (IBA dosimetry, Germany) using the quality assurance kit Express QA test package & clinical cases verification. The standard plan in QA mode is made in TPS and delivered under medical linear accelerator like pre-treatment verification.The measured and calculated fluence is compared and accordingly the Gamma analysis done. Express QA tests & clinical cases fields showed a great agreement with TPS calculations with 3% DD and 3 mm DTA Gamma criteria. The open field 10 x 10 cm² and 20 x 20 cm² found to be passed with 100% results for 3% &3mm criteria. 3ABUT test helped in setting the leaf offset value from default 0.0mm to 0.15mm. FourL test provides adjustment in leaf transmission value and leaf groove width from 0.012 to 0.0073 and 1.0mm to 0.7mm respectively. The H&N and Prostate clinical cases passed with more than 95% for set criteria (3%DD&3mm).The absolute point dose measurement agreement was found to be more than 97%.This study confirmed that the appropriate MLC check before starting IMRT and VMAT in clinic and even after any repair is required thorough quality assurance check using Express QA and TG 119 package. Small changes in the MLC parameters like leaf offset, groove width and transmission n the TPS model can cause large changes in the calculated dose.At least annually Express QA test is recommended to be performed by every user to confirm the status of changed MLC parameters in due course of time.","PeriodicalId":14613,"journal":{"name":"Iranian Journal of Medical Physics","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-12-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46259794","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 : 2020-12-26DOI: 10.22038/IJMP.2020.52305.1860
Nadia Zarghi, S. H. Miri-Hakimabad, E. Hoseinian-Azghadi, N. Mohammadi
Abstract:Introduction: Current reported values of fetal doses from 18F-FDG in pregnant women imaged with PET scan showed a large variation. This study aimed to evaluate fetal radiation doses using the last generation of computational pregnant phantoms and also to shed light on one of the uncertainty components of the fetal dose.Materials and Methods: In this respects, we used a BREP series of computational pregnant phantoms to evaluate radiation doses to the fetus. We also reviewed available data on fetal time-integrated activities and evaluated the confidence and prediction (95%) intervals for the existing data. By doing this, the uncertainty of fetal Biokinetic data was taken into account in fetal dose calculations.Results: The fetal doses of 2.30E-02, 1.53E-02, and 1.02E-02 mGy/MBq at 3, 6 and 9 month of gestation were estimated. The results also showed the contributions of source organs to the fetal doses. The maternal “urinary bladder contents” and “other organs and tissues” are the main source regions contributing to fetal dose. We also indicated that the Biokinetic variation caused a large uncertainty on fetal dose (with prediction interval from 1.73E-02 to 3.93E-02 mGy/MBq) at first trimester of pregnancy, while it is much lower at second and third trimesters. Furthermore, it is indicated that variations on fetal dose outside the determined intervals may be related to the geometrical differences of used computational phantoms.Conclusions: Since the fetal dose is much higher and the radiation exposure is more deterministic at first trimester of pregnancy, attempting to accurately evaluate the fetal dose is relevant at this stage.
{"title":"Fetal dosimetry for 18F-FDG PET Imaging during pregnancy: a comparative Monte Carlo study","authors":"Nadia Zarghi, S. H. Miri-Hakimabad, E. Hoseinian-Azghadi, N. Mohammadi","doi":"10.22038/IJMP.2020.52305.1860","DOIUrl":"https://doi.org/10.22038/IJMP.2020.52305.1860","url":null,"abstract":"Abstract:Introduction: Current reported values of fetal doses from 18F-FDG in pregnant women imaged with PET scan showed a large variation. This study aimed to evaluate fetal radiation doses using the last generation of computational pregnant phantoms and also to shed light on one of the uncertainty components of the fetal dose.Materials and Methods: In this respects, we used a BREP series of computational pregnant phantoms to evaluate radiation doses to the fetus. We also reviewed available data on fetal time-integrated activities and evaluated the confidence and prediction (95%) intervals for the existing data. By doing this, the uncertainty of fetal Biokinetic data was taken into account in fetal dose calculations.Results: The fetal doses of 2.30E-02, 1.53E-02, and 1.02E-02 mGy/MBq at 3, 6 and 9 month of gestation were estimated. The results also showed the contributions of source organs to the fetal doses. The maternal “urinary bladder contents” and “other organs and tissues” are the main source regions contributing to fetal dose. We also indicated that the Biokinetic variation caused a large uncertainty on fetal dose (with prediction interval from 1.73E-02 to 3.93E-02 mGy/MBq) at first trimester of pregnancy, while it is much lower at second and third trimesters. Furthermore, it is indicated that variations on fetal dose outside the determined intervals may be related to the geometrical differences of used computational phantoms.Conclusions: Since the fetal dose is much higher and the radiation exposure is more deterministic at first trimester of pregnancy, attempting to accurately evaluate the fetal dose is relevant at this stage.","PeriodicalId":14613,"journal":{"name":"Iranian Journal of Medical Physics","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-12-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48852289","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 : 2020-12-15DOI: 10.22038/IJMP.2020.51442.1841
Sri Krishna Gangarapu, Srinivas Vuppu
Background: The aim of the present study was to compare intensity-modulated radiation therapy (IMRT) plan with Bone Marrow sparing (BM-IMRT) and plan without Bone Marrow Sparing (N-IMRT). Materials and Methods: Fifteen cases of cervical cancer cases were selected for retrospective analysis. All the cases were previously treated with normal IMRT. For this study, plans with BM-IMRT were created again for all patients following Radiation Therapy Oncology Group (RTOG) guidelines. The prescribed dose (PD) of 50Gy in 25 fractions was given. The plan having coverage of 95% of PTV receiving 95% of prescribed dose was accepted. The plans were compared on the basis of planning target volume (PTV) coverage (dose to 2%, 98% of target), Constraints of OAR (Organs at Risk) were volume of 40% < 40Gy for normal bladder and rectum, (volume receiving dose 5Gy) V5
{"title":"Comparison of IMRT plans with and without bone marrow sparing for the treatment of cervical cancer","authors":"Sri Krishna Gangarapu, Srinivas Vuppu","doi":"10.22038/IJMP.2020.51442.1841","DOIUrl":"https://doi.org/10.22038/IJMP.2020.51442.1841","url":null,"abstract":"Background: The aim of the present study was to compare intensity-modulated radiation therapy (IMRT) plan with Bone Marrow sparing (BM-IMRT) and plan without Bone Marrow Sparing (N-IMRT). Materials and Methods: Fifteen cases of cervical cancer cases were selected for retrospective analysis. All the cases were previously treated with normal IMRT. For this study, plans with BM-IMRT were created again for all patients following Radiation Therapy Oncology Group (RTOG) guidelines. The prescribed dose (PD) of 50Gy in 25 fractions was given. The plan having coverage of 95% of PTV receiving 95% of prescribed dose was accepted. The plans were compared on the basis of planning target volume (PTV) coverage (dose to 2%, 98% of target), Constraints of OAR (Organs at Risk) were volume of 40% < 40Gy for normal bladder and rectum, (volume receiving dose 5Gy) V5","PeriodicalId":14613,"journal":{"name":"Iranian Journal of Medical Physics","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42955929","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 : 2020-12-09DOI: 10.22038/IJMP.2020.50881.1831
S. Souri, M. Jadidi, H. Hasanzadeh, Tahereh Khani, V. Semnani
ABSTRACTIntroduction: According to high mortality rate due to cancer and side effects of invasive treatments, the noninvasive method such as sonodynamic therapy for breast adenocarcinoma is considerable. Encapsulation of sonosensitizer in nanoparticles can improve the accumulation of these agents in the tumor tissue and decrease in drug side effect. Hence, sonodynamic therapy (SDT) with 1MHz ultrasound (US), hematoporphyrin (HP) and hematoporphyrin encapsulated mesoporous silica nanoparticles (HP-MSN) in breast adenocarcinoma was carried out.Material and Methods: Female Inbred Balb/C mice with grafted breast adenocarcinoma were divided to 16 groups: control, sham, HP (2.5 and 5 mg/kg), HP-MSN (2.5 and 5 mg/kg), 1MHz US (1 and 2 W/cm2), SDT+HP (2.5 and 5 mg/kg) and SDT+HP-MSN (2.5 and 5 mg/kg). The relative volume, tumor growth inhibition ratio (TGI) and the time of tumor growth (T2 and T5-times) evaluated 30-days after treatment.Results: Analysis of data showed the groups of SDT (2 W/cm2)+HP-MSN (5 mg/kg) and SDT (1 W/cm2)+HP-MSN (5 mg/kg) indicated anti-tumor effects from days 18 to 27 after treatment. TGI% in these groups was 45 and 42% respectively and the time of T2 and T5 is greater than that in the control and sham. Kaplan-Meier analysis revealed that the 44-day survival was 95% for the group treated with SDT (2 W/cm2)+HP-MSN (5 mg/kg). All experimental groups had a poorly differentiated grading except of SDT (2 W/cm2)+HP-MSN (5 mg/kg) group which has a moderately differentiated degree based on Bloom-Richardson classification.Conclusion:Based on this study, sonodynamic therapy with 1MHz US (2 W/cm2)+HP-MSN (5 mg/kg) have an anti-tumor effect.
{"title":"Sonodynamic therapy of mice breast adenocarcinoma: An in vivo study with hematoporphyrin encapsulated mesoporous silica nanoparticles","authors":"S. Souri, M. Jadidi, H. Hasanzadeh, Tahereh Khani, V. Semnani","doi":"10.22038/IJMP.2020.50881.1831","DOIUrl":"https://doi.org/10.22038/IJMP.2020.50881.1831","url":null,"abstract":"ABSTRACTIntroduction: According to high mortality rate due to cancer and side effects of invasive treatments, the noninvasive method such as sonodynamic therapy for breast adenocarcinoma is considerable. Encapsulation of sonosensitizer in nanoparticles can improve the accumulation of these agents in the tumor tissue and decrease in drug side effect. Hence, sonodynamic therapy (SDT) with 1MHz ultrasound (US), hematoporphyrin (HP) and hematoporphyrin encapsulated mesoporous silica nanoparticles (HP-MSN) in breast adenocarcinoma was carried out.Material and Methods: Female Inbred Balb/C mice with grafted breast adenocarcinoma were divided to 16 groups: control, sham, HP (2.5 and 5 mg/kg), HP-MSN (2.5 and 5 mg/kg), 1MHz US (1 and 2 W/cm2), SDT+HP (2.5 and 5 mg/kg) and SDT+HP-MSN (2.5 and 5 mg/kg). The relative volume, tumor growth inhibition ratio (TGI) and the time of tumor growth (T2 and T5-times) evaluated 30-days after treatment.Results: Analysis of data showed the groups of SDT (2 W/cm2)+HP-MSN (5 mg/kg) and SDT (1 W/cm2)+HP-MSN (5 mg/kg) indicated anti-tumor effects from days 18 to 27 after treatment. TGI% in these groups was 45 and 42% respectively and the time of T2 and T5 is greater than that in the control and sham. Kaplan-Meier analysis revealed that the 44-day survival was 95% for the group treated with SDT (2 W/cm2)+HP-MSN (5 mg/kg). All experimental groups had a poorly differentiated grading except of SDT (2 W/cm2)+HP-MSN (5 mg/kg) group which has a moderately differentiated degree based on Bloom-Richardson classification.Conclusion:Based on this study, sonodynamic therapy with 1MHz US (2 W/cm2)+HP-MSN (5 mg/kg) have an anti-tumor effect.","PeriodicalId":14613,"journal":{"name":"Iranian Journal of Medical Physics","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41530741","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 : 2020-12-09DOI: 10.22038/IJMP.2020.52418.1864
Kyungjin Kim, Jihun Choi, Joo-Wan Hong, Jaeouk Ahn
Introduction: The objective of this study was to evaluate the usefulness of Computed Tomography(CT) images acquired through repeated subtraction reconstruction algorithms to reduce metal artifacts in CT Treatment Planning System(TPS).Materials and methods: Origin images of Gammex phantom and Rando phantom and non orthopedic metal artifact reduction(O-MAR) images were obtained after high density implantation. O-MAR applied images were also obtained. For evaluation of images, regions of interest(ROI) were set at five tissue rods and three points directly affected by artifacts in Gammex phantom. CT number and noise were compared and analyzed. To investigate dose change according to CT number change of the surrounding artifact, a three virtual cylindrical target volume was formed on Rando phantom CT images. The average dose was then compared and analyzed.Results: CT number difference according to the application of O-MAR showed significant difference among lung and bone rod and 3 ROI directly affected. Noise difference according to O-MAR application was significantly different in rod except for bone rod. In the treatment plan using Rando phantom, non-O-MAR and O-MAR images showed -4.3 ~ 1.9% and -0.4 ~ 2.3% dose differences, respectively.Conclusion: Applying a metal artifact reduction reconstruction algorithm can reduce image distortion due to high density implantation, improve image quality, and correct CT number.
{"title":"Evaluation of radiation treatment planning by computed tomography metal artifact reduction algorithm","authors":"Kyungjin Kim, Jihun Choi, Joo-Wan Hong, Jaeouk Ahn","doi":"10.22038/IJMP.2020.52418.1864","DOIUrl":"https://doi.org/10.22038/IJMP.2020.52418.1864","url":null,"abstract":"Introduction: The objective of this study was to evaluate the usefulness of Computed Tomography(CT) images acquired through repeated subtraction reconstruction algorithms to reduce metal artifacts in CT Treatment Planning System(TPS).Materials and methods: Origin images of Gammex phantom and Rando phantom and non orthopedic metal artifact reduction(O-MAR) images were obtained after high density implantation. O-MAR applied images were also obtained. For evaluation of images, regions of interest(ROI) were set at five tissue rods and three points directly affected by artifacts in Gammex phantom. CT number and noise were compared and analyzed. To investigate dose change according to CT number change of the surrounding artifact, a three virtual cylindrical target volume was formed on Rando phantom CT images. The average dose was then compared and analyzed.Results: CT number difference according to the application of O-MAR showed significant difference among lung and bone rod and 3 ROI directly affected. Noise difference according to O-MAR application was significantly different in rod except for bone rod. In the treatment plan using Rando phantom, non-O-MAR and O-MAR images showed -4.3 ~ 1.9% and -0.4 ~ 2.3% dose differences, respectively.Conclusion: Applying a metal artifact reduction reconstruction algorithm can reduce image distortion due to high density implantation, improve image quality, and correct CT number.","PeriodicalId":14613,"journal":{"name":"Iranian Journal of Medical Physics","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45517133","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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