Iranian Journal of Medical Physics最新文献_第8页

Quality Assurance of LINAC by Analyzing the Profile of 6-MV and 10-MV Photon Beams Using Star Track Device 利用星形跟踪装置分析6 mv和10 mv光子光束轮廓，保证直线加速器的质量

Iranian Journal of Medical Physics Pub Date : 2020-07-01 DOI: 10.22038/IJMP.2019.39987.1543

Basma Sabr Lazim, Basim Rejah, H. Alabedi

{"title":"Quality Assurance of LINAC by Analyzing the Profile of 6-MV and 10-MV Photon Beams Using Star Track Device","authors":"Basma Sabr Lazim, Basim Rejah, H. Alabedi","doi":"10.22038/IJMP.2019.39987.1543","DOIUrl":"https://doi.org/10.22038/IJMP.2019.39987.1543","url":null,"abstract":"Introduction: According to the American Society of Radiation Oncology, all patients receive radiation therapy during their illness, where radiation is delivered by the medical linear accelerator (Linac). The aim of this study was to evaluate the quality assurance (QA) of the Linac in analyzing the used dose profile in the treatment of cancer tumors. \u0000Material and Methods: This experimental study was performed using Linac (synergy device type) at Baghdad Radiotherapy and Nuclear Medicine laboratories, Baghdad, Iraq. The Star Track device was used for the routine quality assurance of the Linac, using photon beam for the reference Dmax and source to surface distance of 100 cm. The Star Track consists of 453 vented parallel plate ionization chambers. \u0000Results: The flatness and symmetry of beams for the reference field size did not exceed from ±2%, as they were within the allowed range. Moreover, the penumbra region showed a change in value that did not exceed from ±0.2 cm. using the Star Track method; maximum differences in beam symmetry and beam flatness were measured at 0.76%±2% and 1.17%±2%, respectively. Moreover, the maximum difference in the penumbra region was estimated at 0.12±0.2 cm. \u0000Conclusion: The results indicated, the Star Track could successfully calculate the characteristics of dose profile during a time period of 2,500 ms, showing the superiority of this instrument over other verification devices.","PeriodicalId":14613,"journal":{"name":"Iranian Journal of Medical Physics","volume":"17 1","pages":"260-265"},"PeriodicalIF":0.0,"publicationDate":"2020-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49236788","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}

引用次数: 1

Measurement of Radon Concentrations and Surface Exhalation Rates using CR-39 detector in Soil Samples of Al-Diwaniyah Governorate, Iraq 使用CR-39探测器测量伊拉克Al-Diwaniyah省土壤样品中的氡浓度和表面渗出率

Iranian Journal of Medical Physics Pub Date : 2020-07-01 DOI: 10.22038/IJMP.2019.40303.1552

Majied G. Al-Gharabi, A. A. Al-Hamzawi

{"title":"Measurement of Radon Concentrations and Surface Exhalation Rates using CR-39 detector in Soil Samples of Al-Diwaniyah Governorate, Iraq","authors":"Majied G. Al-Gharabi, A. A. Al-Hamzawi","doi":"10.22038/IJMP.2019.40303.1552","DOIUrl":"https://doi.org/10.22038/IJMP.2019.40303.1552","url":null,"abstract":"Introduction: Natural radioactivity in the soil is considered a major indicator of radiological contamination. Primordial radionuclides are the main source of natural radioactivity. Natural radioactivity transfers radionuclides into the environment and poses radiation hazards to people's health. Therefore, the present study aimed to determine the radon concentration and surface exhalation rate in soil samples collected from different locations of industrial, agricultural, and residential of Al-Diwaniyah governorate, southern Iraq. \u0000Material and Methods: In the present study, five different depths of 0, 10, 20, 30, and 40 cm were taken from each location. The radon concentration and exhalation rate were measured using CR-39 detectors (Pershore Moulding Ltd, UK). The CR-39 detectors were left inside plastic cans with soil samples. The tracks of nuclear particles were recorded using an optical microscope. \u0000Results: Results of the present study showed that the radon concentrations in soil samples ranged from 163.58 to 689.89 Bq/m3 with a mean value of 350.64 Bq/m3, while surface exhalation rate was found to be ranged from 0.015 Bq/m2.h to 0.063 Bq/m2.h with an average value of 0.031 Bq/m2.h. The obtained results demonstrated that the radon concentration and exhalation rate decreased with increased depth of soil. Conclusion: Based on the current findings, it was found that radon concentrations in all the examined soil samples were within the acceptable value of 600 Bq/m3, according to the International Commission on Radiological Protection and International Atomic Energy Agency. However, the sample S13 from AL-Hamad village with a mean value of 642.51±22.95 Bq/m3 was an exception.","PeriodicalId":14613,"journal":{"name":"Iranian Journal of Medical Physics","volume":"17 1","pages":"220-224"},"PeriodicalIF":0.0,"publicationDate":"2020-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45228404","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}

引用次数: 6

An Evaluation of Effects of Black Grape and Ginger Extracts on Hematological Alteration and Lipid Peroxidation of Hepatocyte in Irradiated Albino Mice 黑葡萄和生姜提取物对白化小鼠血液学变化和肝细胞脂质过氧化作用的评价

Iranian Journal of Medical Physics Pub Date : 2020-07-01 DOI: 10.22038/IJMP.2019.40214.1553

A. Faiq, S. Amin, L. Mohammed, S. Salih, Zarean Y. Saeed, D. Rashid

{"title":"An Evaluation of Effects of Black Grape and Ginger Extracts on Hematological Alteration and Lipid Peroxidation of Hepatocyte in Irradiated Albino Mice","authors":"A. Faiq, S. Amin, L. Mohammed, S. Salih, Zarean Y. Saeed, D. Rashid","doi":"10.22038/IJMP.2019.40214.1553","DOIUrl":"https://doi.org/10.22038/IJMP.2019.40214.1553","url":null,"abstract":"Introduction: Exposure to ionizing radiation can trigger adverse biological effects on healthy tissues, such as causing hematological toxicity and potential injury to different organs. Ionizing radiation has sufficient energy to liberate electrons from atoms leaving them with unpaired electrons; hence ionizing them and producing free radicals. In the current study, the risk of exposing to 6 Gy x-irradiation on alteration of some hematological parameters and liver tissue lipid peroxidation activity in albino mice in the presence and absence of black grape and ginger extracts as antioxidants have been investigated. Material and Methods: Albino mice were exposed to 6 Gy wholebody xirradiation in the absence and presence of black grape and ginger extracts (10mL/Kg). Results: The results of the present study showed a significant decrease in mice red blood cell count, hemoglobin, hematocrit, mean corpuscular volume, and mean corpuscular hemoglobin, following the exposure to 6 Gy x-irradiation (P≤0.05), while all the mentioned parameters were relatively shifted toward the normal values in the mice that received black grape and ginger extracts as a treatment prior to the radiation. Accordingly, our results demonstrated a noticeable increase in the malondialdehyde analysis (MDA) level in the 6 Gy group, while a slight depletion in the MDA level was observed in the group of mice that received black grape and ginger extracts, compared to that of the control group. Conclusion: the administration of black grape and ginger extracts prior to irradiation may protect the mice from excess hepatocyte lipid peroxidation and alteration of hematological parameters.","PeriodicalId":14613,"journal":{"name":"Iranian Journal of Medical Physics","volume":"17 1","pages":"247-252"},"PeriodicalIF":0.0,"publicationDate":"2020-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47297451","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}

引用次数: 1

Out-Of-Field Dose Measurement and Second Cancer-Risk Estimation Following External Beam Radiotherapy and Brachytherapy for Cervical Cancer Treatment: A Phantom Study 外束放疗和近距离治疗宫颈癌后的场外剂量测量和第二次癌症风险评估:一项幻象研究

Iranian Journal of Medical Physics Pub Date : 2020-07-01 DOI: 10.22038/IJMP.2019.38166.1491

Athiyaman Hemalatha, Athiyaman Mayilvaganan, M. Joan, A. Chougule, HS Kumar

{"title":"Out-Of-Field Dose Measurement and Second Cancer-Risk Estimation Following External Beam Radiotherapy and Brachytherapy for Cervical Cancer Treatment: A Phantom Study","authors":"Athiyaman Hemalatha, Athiyaman Mayilvaganan, M. Joan, A. Chougule, HS Kumar","doi":"10.22038/IJMP.2019.38166.1491","DOIUrl":"https://doi.org/10.22038/IJMP.2019.38166.1491","url":null,"abstract":"Introduction: The present study aimed to measure the scatter and leakage dose received by out-of-field organs while delivering Radiotherapy (RT) treatment of cervical cancer. Moreover, this study estimated the risk of second cancer (SC). The doses to out-of-field organs were measured using a lithium fluoride (TLD 100) dosimeter while delivering External Beam Radiotherapy (EBRT) by 6 MV photon beam with Brachytherapy Boost (BB) treatment in the humanoid phantom. Material and Methods: The excess absolute risk of SC for the stomach, colon, liver, lung, breast, and kidney, as well as excess relative risk for the thyroid, were estimated based on Biological Effects of Ionizing Radiation VII report. Results: The out-of-field organ doses varied with respect to distance between organs. The colon (3DCRT-282.13 cGy and IMRT-381.24 cGy in 25 fractions) and kidney (70.65 cGy in 3 fractions) received the highest doses with EBRT and BB, respectively. For most of the aforementioned organs, the calculated dose was 0.2 Gy/fraction according to the treatment planning system. With the age at exposure (i.e., 30 years) as a reference, the highest LARs were associated with the colon (0.74%) and breast (2.76%) in 3DCRT plus BB and IMRT plus BB, respectively. The lifetime attributable risk of SC was also shown to decrease with increasing the age at exposure for all the organs. Conclusion: Although all the evaluated out-of-field organs in this study showed some levels of risk, the risk was more frequently reported for the colon, stomach, and breast with IMRT technique than that in 3DCRT.","PeriodicalId":14613,"journal":{"name":"Iranian Journal of Medical Physics","volume":"17 1","pages":"253-259"},"PeriodicalIF":0.0,"publicationDate":"2020-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44279329","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}

引用次数: 2

Assessment of Maximum Entrance Skin Dose of Patients Undergoing Cardiac Interventional Procedures and Its Correlation with Other Dosimetric Parameters 心脏介入手术患者最大入射皮肤剂量的评估及其与其他剂量测定参数的相关性

Iranian Journal of Medical Physics Pub Date : 2020-07-01 DOI: 10.22038/IJMP.2019.33109.1403

M. Toossi, M. Khosroabadi, Mohammad Mehrpouyan, H. R. Moghaddam

{"title":"Assessment of Maximum Entrance Skin Dose of Patients Undergoing Cardiac Interventional Procedures and Its Correlation with Other Dosimetric Parameters","authors":"M. Toossi, M. Khosroabadi, Mohammad Mehrpouyan, H. R. Moghaddam","doi":"10.22038/IJMP.2019.33109.1403","DOIUrl":"https://doi.org/10.22038/IJMP.2019.33109.1403","url":null,"abstract":"Introduction: In recent years, the number of complex coronary angiography (CA) is increasing rapidly. These procedures have a significant contribution to medical exposure to the general population. Exposure of patients to high doses of x-rays could cause deterministic effects on the skin. Therefore, the assessment of radiation doses of patients is of great importance. This study aimed to assess maximum entrance skin dose (MESD) of patients who underwent interventional cardiology procedures. Moreover, it was attempted to determine the correlation between MESD and other relevant dosimetric parameters. Material and Methods: The MESDs of 32 patients who underwent CA procedures were measured by an array of thermoluminescence dosimeters (TLDs). In this study, a Perspex tray consisting of 5 rows and 6 columns was used to hold the TLDs. Its long axis was perpendicular to the long axis of the table, and the top edges of the tray were approximately equal to the patient’s shoulders. Results: The results revealed a linear relationship between dose area product (DAP) values and MESDs (R2=0.89; P=0.00). In addition, there was a significant association between MESD and fluoroscopy time (R2=0.89). Moreover, a weak correlation was observed between MESD and the number of frames per second (R2=0.23). Conclusion: According to the results, the recorded DAP values and fluoroscopy time can be used to estimate the MESDs of patients undergoing coronary fluoroscopy procedures.","PeriodicalId":14613,"journal":{"name":"Iranian Journal of Medical Physics","volume":"17 1","pages":"235-246"},"PeriodicalIF":0.0,"publicationDate":"2020-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45209345","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}

引用次数: 0

An Enumeration Survey on Diagnostic X-Ray Generators and Essential Safety Parameters in Mizoram, India 印度米佐拉姆邦诊断X射线发生器和基本安全参数的计数调查

Iranian Journal of Medical Physics Pub Date : 2020-07-01 DOI: 10.22038/IJMP.2019.39307.1519

R. Tiwari, J. Lalrinmawia, K. S. Pau

{"title":"An Enumeration Survey on Diagnostic X-Ray Generators and Essential Safety Parameters in Mizoram, India","authors":"R. Tiwari, J. Lalrinmawia, K. S. Pau","doi":"10.22038/IJMP.2019.39307.1519","DOIUrl":"https://doi.org/10.22038/IJMP.2019.39307.1519","url":null,"abstract":"Introduction: Best radiography practice involves operational optimal machine performance, delivering cost-effective healthcare services under appropriate safety conditions for workers and the public. The present study aimed to investigate the safety status of diagnostic X-ray installations in Mizoram, India. Material and Methods: Linearity of time (sec), linearity of current (mA), output reproducibility, table dose (μGy/mAs), peak voltage (kVp) accuracy, and 16 essential safety parameters of 135 X-ray machines were considered in this study. A battery-operated dosimeter and wide-range digital kVp meter were used to measure output radiation and effective peak potential of X-ray tube. Data analysis was performed using SPSS software to obtain the mean, standard deviation, and coefficient of variation. Results: Among different electronic parameters, 59.2% linearity of time, 82.6% linearity of current, 89.7% kVp accuracy, 35.1% output reproducibility, and 92.8% table dose were beyond the acceptable limits. Based on 16 essential safety parameters, it was observed that 98.7% of X-ray machines did not receive proper quality assurance test, 1.9% of the installations employed lead-line patient entrance doors, 46.8% of the machines were operated without any protective barriers and 83.1% of the units were operated without personnel monitoring service. Conclusion: The present study had concluded with more problems than the previous studies in different parts of the world in this regard. Due to the absence of proper quality control (QC) programs, many installations did not follow standard installation guidelines. The authors recommended that proper QC should be implemented by the frequent monitoring of each and every diagnostic X-ray installation.","PeriodicalId":14613,"journal":{"name":"Iranian Journal of Medical Physics","volume":"17 1","pages":"273-281"},"PeriodicalIF":0.0,"publicationDate":"2020-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49551807","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}

引用次数: 1

Radiobiological modeling of acute esophagitis following radiotherapy of thorax and head-neck tumors: A comparison of Lyman Kutcher Burman with equivalent uniform dose-based models 胸部和头颈部肿瘤放疗后急性食管炎的放射生物学模型：Lyman-Kutcher-Burman与等效均匀剂量模型的比较

Iranian Journal of Medical Physics Pub Date : 2020-07-01 DOI: 10.22038/IJMP.2019.40500.1566

Mostafa Alizade-harakiyan, A. Jangjoo, Behnam Nasiri, T. Jafari-Koshki, M. Okutan, A. Mesbahi

{"title":"Radiobiological modeling of acute esophagitis following radiotherapy of thorax and head-neck tumors: A comparison of Lyman Kutcher Burman with equivalent uniform dose-based models","authors":"Mostafa Alizade-harakiyan, A. Jangjoo, Behnam Nasiri, T. Jafari-Koshki, M. Okutan, A. Mesbahi","doi":"10.22038/IJMP.2019.40500.1566","DOIUrl":"https://doi.org/10.22038/IJMP.2019.40500.1566","url":null,"abstract":"Purpose: The current study aimed to compare performance of radiobiological models in predicting acute esophagitis (AE) complication after three-dimensional conformal radiation therapy (3D-CRT) with and without chemotherapy of thoracic, head and neck patients. Materials and methods: A total of 100 patients, 50 patients receiving with and 50 patients without concurrent chemotherapy were treated on the basis of five days a week for 3 months with different total doses and a daily dose range between 1.8 -2.4 Gy. Predictions of AE were based on Lyman–Kutcher–Burman (LKB) and Equivalent Uniform Dose (EUD)-based radiobiological models and 3 months of follow up were performed to monitor the complication incidence among the studied patients. ROC and univariable logistic regression analyses were performed and the effect of mean dose, volume percentage and weight loss percentage on the probability of AE grade  2 were studied.Results: EUD-based model showed better concordance with the clinical data for all patients (AUC=0.919) and the concurrent chemo-radiotherapy (CCRT) group (AUC=0.986). For radiation therapy group the LKB model had better performance than EUD-based model (AUC=0.921). The incidence of grade 2 esophagitis for chemoradiation and radiation therapy groups was observed 37.94 ± 4.0 and 68.39 ± 7.1 days after initiation of radiation therapy. Conclusions: The EUD-based model showed higher agreement with follow up data. The incidence time of grade  2 AE for CCRT was approximately two times shorter than non- CCRT group.","PeriodicalId":14613,"journal":{"name":"Iranian Journal of Medical Physics","volume":"17 1","pages":"225-234"},"PeriodicalIF":0.0,"publicationDate":"2020-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42402657","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}

引用次数: 0

Assessment of Radiation-Induced Secondary Cancer Risks In Breast Cancer Patients Treated with 3D Conformal Radiotherapy 三维适形放疗对乳腺癌患者放射诱导继发癌风险的评价

Iranian Journal of Medical Physics Pub Date : 2020-06-28 DOI: 10.22038/IJMP.2020.47561.1758

H. Nedaie, S. Mahmoudi, N. Kavousi, Mohssen Hassani, Mahbod Esfahani

{"title":"Assessment of Radiation-Induced Secondary Cancer Risks In Breast Cancer Patients Treated with 3D Conformal Radiotherapy","authors":"H. Nedaie, S. Mahmoudi, N. Kavousi, Mohssen Hassani, Mahbod Esfahani","doi":"10.22038/IJMP.2020.47561.1758","DOIUrl":"https://doi.org/10.22038/IJMP.2020.47561.1758","url":null,"abstract":"Introduction: In the current study, radiation-induced secondary cancers risks (SCRs) have been evaluated in irradiated organs following three-dimensional conformal radiation therapy (3D-CRT) of breast cancer using the BEIR (Biological Effects of Ionizing Radiation) VII models. Material and Methods: Sixty patients with left-sided breast cancer were chosen for this study and who were treated with a total breast dose of 50 Gy in 2 Gy fractions. Differential dose volume histograms (dDVHs) were retrieved and values of mean organs dose were computed. SCRs to the heart, ipsilateral lung, liver, thyroid, and contralateral were estimated using both excess relative risk (ERR) and excess absolute risks (EAR) models as proposed by BEIR VII committee of the U.S National Academy of Sciences.Average values of organ dose to these 60 patients were 6.8, 15.9, 3.7, 4.5 and 1.5 Gy in the thyroid, ipsilateral lung, contralateral breast, heart, and liver, respectively. Results: From the BEIR VII models, ERR incidence was estimated to be 21.2, 5.0, 1.6 and 1.4 Gy-1 for the ipsilateral lung, thyroid, heart, and liver, respectively. EAR for cancer incidence was calculated as 105, 45.8, 15.8 and 4.35 Gy-1 for these same organs. Conclusion: The study showed SCRs quantitatively to various organs for patients with breast cancer who received 3D-CRT. We found that 3D-CRT treatment is associated with a relatively high SCR in the lung.","PeriodicalId":14613,"journal":{"name":"Iranian Journal of Medical Physics","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44747067","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}

引用次数: 1

Study on the impact of TRS-483 recommended correction factors for the dosimetry of flattening filter free small fields used in TrueBeam linear accelerator. TRS-483推荐校正因子对TrueBeam线性加速器中平坦无滤波器小场剂量测定的影响研究。

Iranian Journal of Medical Physics Pub Date : 2020-06-23 DOI: 10.22038/IJMP.2020.46236.1722

Gopinath Mamballikalam, Senthil Kumar, C. C.O, Jaon Bos R.C., Ahamed Basith P.M.

{"title":"Study on the impact of TRS-483 recommended correction factors for the dosimetry of flattening filter free small fields used in TrueBeam linear accelerator.","authors":"Gopinath Mamballikalam, Senthil Kumar, C. C.O, Jaon Bos R.C., Ahamed Basith P.M.","doi":"10.22038/IJMP.2020.46236.1722","DOIUrl":"https://doi.org/10.22038/IJMP.2020.46236.1722","url":null,"abstract":"Purpose: To study the impact of TRS-483 recommended beam quality correction factor for reference dosimetry and field output correction factor for relative dosimetry of 6MV flattening filter free (FFF) small fields used in Varian Truebeam® linear accelerator (LINAC). Materials and Methods: Beam quality and Field output correction of 6MV FFF beam were adopted from TRS-483. Monte Carlo (MC) simulation of output factor was performed using PRIMO (PENELOPE based program) and compared with TRS-483 corrected output factors. Two Analytical Anisotropic Algorithm (AAA) models in EclipseTM treatment planning system (TPS) were created, one with output factor taken as ratio of meter readings and another model with output factor obtained by multiplying TRS-483 correction factor to the ratio of meter readings. Box field and Dynamic Conformal Arc (DCA) plans were created for both AAA models for verification and validation. Patient specific plan quality assurance (QA) was performed and deviation in point dose between measured and TPS calculated for both the models was analyzed. Results and Discussion: Separate beam quality correction factors provided for FFF in TRS-483 resulted in only 0.1% improvements for the reference dosimetry.TRS-483 corrected output factor are in better agreement with MC calculated output factor (OF) values. For the patient specific QA of DCA plans, output factor corrected AAA dose algorithm gave better agreement between measured and simulated dose. There is 1.2% less deviation observed for the smallest target of 0.23cc; 8mm equivalent sphere diameter used in this study. Conclusion: Field output factors for the LINAC small beams can be improved by incorporating the correction factors provided by TRS-483. But the extent of improvement that can be expected depends on the source model of calculating algorithm and how well generalized recommended corrections suit for user beam and the detector.","PeriodicalId":14613,"journal":{"name":"Iranian Journal of Medical Physics","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48310185","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}

引用次数: 0

Evaluation of the Anisotropic Analytical dose calculation Algorithm in heterogeneous medium using in vivo dosimetry for high energy photon beams 异质介质中高能光子光束体内剂量学各向异性分析剂量计算算法的评价

Iranian Journal of Medical Physics Pub Date : 2020-06-19 DOI: 10.22038/IJMP.2020.46457.1739

Y. Berkani, R. Khelifi

{"title":"Evaluation of the Anisotropic Analytical dose calculation Algorithm in heterogeneous medium using in vivo dosimetry for high energy photon beams","authors":"Y. Berkani, R. Khelifi","doi":"10.22038/IJMP.2020.46457.1739","DOIUrl":"https://doi.org/10.22038/IJMP.2020.46457.1739","url":null,"abstract":"Introduction: This work was aimed to determine the dose at any depth in heterogeneous medium using diodes to evaluate a dose calculation algorithm. Usually the calibration is limited at the depth of the maximum of energy. The particularity of this work was based on the determination of calibration curves.Material and methods: Measurements at three depths (4cm, 8cm and 12cm) were made by ten QEDTM diodes from Sun Nuclear on heterogeneous phantoms composed of PMMA and expanded polystyrene roughly simulating the rib cage. These phantoms were irradiated under 6MV and 18MV photon beams from a Varian linear accelerator (2100C) by plans calculated from the treatment planning system (TPS) Eclipse equipped with the Anisotropic Analytical Algorithm (AAA) V13.6.The calibration curves were carried out by considering several measurement points in depth by a graphite ionization chamber in a heterogeneous medium composed of expanded polystyrene slabs and PMMA plates. The diode calibration factor is taken from these curves by interpolation.The measured and calculated data were compared to evaluate the AAA.Results: Ninety measurements were performed on three types of heterogeneous phantoms. Depending on the depth of the measurements, the deviations obtained between the measurement and the calculation predicted by the TPS remained less than 2%. Some were in the order of magnitude around 3%.An average of 1.13% is obtained over all the measurements with an average deviation of 0.66% and a standard deviation of 0.80%. The upper limit of the confidence interval is 1.41% for a confidence level of 99.9%.Conclusion: The deviations obtained remain within the standards recommended for the validation of a dose calculation algorithm in a heterogeneous medium.The calibration method based on the dose profiles allowed the completion of the knowledge of the dose in a heterogeneous medium based on a single reading of the diode.","PeriodicalId":14613,"journal":{"name":"Iranian Journal of Medical Physics","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-06-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46902609","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}

引用次数: 0