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Pakravan D. Presentation of Organ Dose and Effective Dose Conversion Factors in Dual-Energy Computed Tomography: A Monte Carlo Simulation Study. J Biomed Phys Eng 2023; 13:333-344. [PMID: 37609513 PMCID: PMC10440407 DOI: 10.31661/jbpe.v0i0.2301-1586] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2023] [Accepted: 06/18/2023] [Indexed: 08/24/2023]
Abstract
Background The same conversion factors (k-factors) of Single CT (SECT) are applied to estimate the Effective Dose (ED) in Dual Energy Computed Tomography (DECT). However, k-factors for different organs need independently validating for DECT, due to the different conditions in DECT. Objective This study aimed to calculate organ dose and k-factors in different imaging protocols (liver, chest, cardiac, and abdomen) for male and female phantoms. Material and Methods This Monte Carlo Simulation study used Monte Carlo N-Particle (MCNP) code for modeling a Siemens Somatom Definition Flash dual-source CT scanner. The organ dose, dose length product, and k-factors were calculated for the Medical Internal Radiation Dose (MIRD) of male and female phantoms. Results For the male phantom, the k-factors for the liver, chest, cardiac, and abdomen-pelvis imaging protocols are equal to 0.020, 0.012, 0.016, and 0.014 mSv.mGy-1cm-1, respectively. For the female phantom, the corresponding values are equal to 0.026, 0.023, 0.036, and 0.018, respectively. These values for DECT are different from those corresponding values for SECT, especially for the female phantom. Conclusion The calculated k-factors for DECT can be used as reference values for the estimation of ED in DECT.
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Affiliation(s)
- Delaram Pakravan
- Department of Physics, Ahvaz Branch, Islamic Azad University, Ahvaz, Iran
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Mehri-Kakavand G, Pursamimi M, Parwaie W, Ghorbani M, Khosravi M, Hosseini SM, Soleimani Meigooni A. Assessment of Field-in-Field, 3-Field, and 4-Field Treatment Planning Methods for Radiotherapy of Gastro-Esophageal Junction Cancer. J Biomed Phys Eng 2022; 12:439-454. [PMID: 36313414 PMCID: PMC9589079 DOI: 10.31661/jbpe.v0i0.2206-1500] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Accepted: 08/17/2022] [Indexed: 11/06/2022]
Abstract
Background Gastro-esophageal (GE) junction cancer is the fastest-growing tumor, particularly in the United States (US). Objective This study aimed to compare dosimetric and radiobiological factors among field-in-field (FIF), three-field (3F), and four-field box (4FB) radiotherapy planning techniques for gastro-esophageal junction cancer. Material and Methods In this experimental study, thirty patients with GE junction cancer were evaluated, and three planning techniques (field-in-field (FIF), three-field (3F), and four-field box (4FB)) were performed for each patient for a 6-MV photon beam. Dose distribution in the target volume, the monitor units (MUs) required, and the dose delivered to organs at risk (OARs) were compared for these techniques using the paired-sample t-test. Results A significant difference was measured between the FIF and 3F techniques with respect to conformity index (CI), dose homogeneity index (HI), and tumor control probability (TCP) for the target organ, as well as the Dmean for the heart, kidneys, and liver. For the spinal cord, the FIF technique showed a slight reduction in the maximum dose compared to the other two techniques. In addition, the V20 Gy of the lungs and the normal tissue complication probability (NTCP) of all OARs were reduced with FIF method. Conclusion The FIF technique showed better performance for treating patients with gastro-esophageal junction tumors, in terms of dose homogeneity in the target, conformity of the radiation field with the target volume, TCP, less dose to healthy organs, and fewer MU.
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Affiliation(s)
- Ghazal Mehri-Kakavand
- MSc, Cancer Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Mohamad Pursamimi
- MSc, Cancer Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Wrya Parwaie
- PhD, Department of Medical Physics, Faculty of Paramedical Sciences, Ilam University of Medical Sciences, Ilam, Iran
| | - Mahdi Ghorbani
- PhD, Cancer Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Mehdi Khosravi
- MSc, Vali-e-Asr Radiotherapy and Oncology Center, Qom University of Medical Sciences, Qom, Iran
| | - Seyyed Mohammad Hosseini
- PhD Candidate, Department of Medical Physics and Biomedical Engineering, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
- PhD Candidate, Research Center for Molecular and Cellular Imaging, Tehran University of Medical Sciences, Tehran, Iran
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Zabihzadeh M, Rahimi A, Shahbazian H, Razmjoo S, Mahdavi SR. Accuracy Evaluation of EPL and ETAR Algorithms in the Treatment Planning Systems using CIRS Thorax Phantom. J Biomed Phys Eng 2021; 11:483-496. [PMID: 34458196 PMCID: PMC8385216 DOI: 10.31661/jbpe.v0i0.1097] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2019] [Accepted: 04/15/2019] [Indexed: 12/03/2022]
Abstract
Background: It is recommended for each set of radiation data and algorithm that subtle deliberation is done regarding dose calculation accuracy. Knowing the errors in dose calculation
for each treatment plan will result in an accurate estimate of the actual dose achieved by the tumor. Objective: This study aims to evaluate the equivalent path length (EPL) and equivalent tissue air ratio (ETAR) algorithms in radiation dose calculation. Material and Methods: In this experimental study, the TEC-DOC 1583 guideline was used. Measurements and calculations were obtained for each algorithm at specific points in thorax CIRS phantom
for 6 and 18 MVs and results were compared. Results: In the EPL, calculations were in agreement with measurements for 27 points and differences between them ranged from 0.1% to 10.4% at 6 MV. The calculations were
in agreement with measurements for 21 points and differences between them ranged from 0.4% to 13% at 18 MV. In ETAR, calculations were also in consistent with measurements
for 21 points, and differences between them ranged from 0.1% to 9% at 6 MV. Moreover, for 18 MV, the calculations were in agreement with measurements for 17 points
and differences between them ranged from 0% to 11%. Conclusion: For the EPL algorithm, more dose points were in consistent with acceptance criteria. The errors in the ETAR were 1% to 2% less than the EPL. The greatest calculation
error occurs in low-density lung tissue with inhomogeneities or in high-density bone. Errors were larger in shallow depths. The error in higher energy was more than low energy beam.
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Affiliation(s)
- Mansour Zabihzadeh
- PhD, Department of Medical Physics, Faculty of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
- PhD, Department of Clinical Oncology, Faculty of Medicine, Golestan Hospital, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
| | - Azizollah Rahimi
- PhD, Department of Medical Physics, Faculty of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
- PhD, Department of Radiology, Paramedical school, Hamadan University of Medical Sciences, Hamadan, Iran
| | - Hodjatollah Shahbazian
- MD, Department of Clinical Oncology, Faculty of Medicine, Golestan Hospital, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
| | - Sasan Razmjoo
- MD, Department of Clinical Oncology, Faculty of Medicine, Golestan Hospital, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
| | - Seyyed Rabie Mahdavi
- PhD, Department of Medical Physics, Faculty of Medicine, Iran University of Medical Sciences, Tehran, Iran
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Arefpour AM, Bahrami M, Haghparast A, Khoshgard K, Aryaei Tabar H, Farshchian N. Evaluating Dose-response of Cataract Induction in Radiotherapy of Head and Neck Cancers Patients. J Biomed Phys Eng 2021; 11:9-16. [PMID: 33564635 PMCID: PMC7859376 DOI: 10.31661/jbpe.v0i0.834] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2017] [Accepted: 11/16/2017] [Indexed: 12/15/2022]
Abstract
BACKGROUND Head and neck cancers are currently the most common types of cancers. 3D-conformal radiation therapy is the most common dose delivery technique for head and neck cancers. Eye Lens is a radio sensitive structure and cataract formation as a visual disorder associated with exposure to ionizing radiation which is documented. OBJECTIVE Determining the radiation dose to eye lens during head and neck radiography and estimating the probability of cataract induction are essential. MATERIAL AND METHODS This experimental study was performed on 14 patients with head and neck cancers through experimental study analysis. The maximum opacity of the eyes lens were measured by pentacamTM before radiation therapy. CT data of patients were transmitted to Isogray treatment planning Software, and dose calculations for each patient was performed. At the end of radiation treatment, 3 and 6 months after radiotherapy, the eye lens opacity of the patients was assessed. RESULTS Overall, 28 lenses were studied. Statistical one sample K- S test proved normality of obtained data. Using repeated measures test, the relation before and 3 months after radiotherapy, as well as the relationship before and 6 months after radiotherapy proved a significant relationship. CONCLUSION The opacity caused by radiation in eyes is a non-statistical and linear-quadratic response curve with no threshold. This opacity can also appear within 3 months after completion of radiation therapy.
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Affiliation(s)
- A M Arefpour
- MD, Department of Radiation Oncology, Faculty of Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - M Bahrami
- MSc, Department of Medical Physics, Faculty of Medicine, Kermanshah University of Medical Sciences, Kermanshah, Iran
| | - A Haghparast
- PhD, Department of Medical Physics, Faculty of Medicine, Kermanshah University of Medical Sciences, Kermanshah, Iran
| | - K Khoshgard
- PhD, Department of Medical Physics, Faculty of Medicine, Kermanshah University of Medical Sciences, Kermanshah, Iran
| | - H Aryaei Tabar
- MD, Departments of Ophthalmology, Faculty of Medicine, Kermanshah University of Medical Sciences, Kermanshah, Iran
| | - N Farshchian
- MD, Department of Radiation Oncology, Faculty of Medicine, Kermanshah University of Medical Sciences, Kermanshah, Iran
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S J, K GS, M K, H K, R G, M P. Establishment of Diagnostic Reference Levels for Computed Tomography Scanning in Hamadan. J Biomed Phys Eng 2020; 10:792-800. [PMID: 33364217 PMCID: PMC7753261 DOI: 10.31661/jbpe.v0i0.2004-1099] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2020] [Accepted: 06/03/2020] [Indexed: 12/24/2022]
Abstract
Background: New advancements have increased the capabilities of computed tomography as a sectional medical imaging modality. An important note is assessing absorbed dose to patients and minimizing it when performing computed tomography examinations. One approach to control dose is to establish diagnostic reference levels. Objective: This study aimed to investigate diagnostic reference levels of computed tomography in Hamadan. Material and Methods: This work was conducted as an experimental study. Computed tomography dose index (CTDI) was measured using a Piranha quality
control kit, head and body CTDI phantoms for brain, lung, abdomen-pelvic and coronary CT angiography examinations. Volume Computed
Tomography Dose Index (CTDIvol) was calculated from obtained data and 3rd quartile of that was determined as diagnostic reference levels. Results: Diagnostic reference levels (DRLs) in terms of CTDIvol for brain, lung, abdomen-pelvic and coronary CT angiography were 50/25, 6/73, 22/01 and
32/06 mGy respectively in Hamadan. Difference between displayed CTDIvol and measured CTDIvol is not significance for all examinations (p>0.05). Conclusion: DRLs depend on to many dose affecting parameters in CT. DRL for brain CT is greater than other scan regions. Application of DRLs which
resulted from this study can help to optimize radiation dose to the patients while maintaining acceptable diagnostic images quality.
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Affiliation(s)
- Jafari S
- PhD, Department of Radiology Technology, School of Paramedicine, Hamadan University of Medical Sciences, Hamadan, Iran
| | - Ghazikhanlu Sani K
- PhD, Department of Radiology Technology, School of Paramedicine, Hamadan University of Medical Sciences, Hamadan, Iran
| | - Karimi M
- MSc, Department of Biomedical Physics and Engineering, School Of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Khosravi H
- PhD, Department of Radiology Technology, School of Paramedicine, Hamadan University of Medical Sciences, Hamadan, Iran
| | - Goodarzi R
- MSc, Department of Radiology Technology, School of Paramedicine, Hamadan University of Medical Sciences, Hamadan, Iran
| | - Pourkaveh M
- MSc, Department of Radiology Technology, School of Paramedicine, Hamadan University of Medical Sciences, Hamadan, Iran
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M P, A H, M T E, K GS. Optimization of Clarkson's Method for Calculating Absorbed Dose under Compensator Filters used in Intensity-modulated Radiation Therapy. J Biomed Phys Eng 2020; 10:575-582. [PMID: 33134216 PMCID: PMC7557464 DOI: 10.31661/jbpe.v0i0.858] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2017] [Accepted: 04/04/2018] [Indexed: 11/17/2022]
Abstract
Background: Intensity Modulated Radiation Therapy (IMRT) is extensively used in the treatment of malignancies. Clarkson’s method is one of the leading methods for dose calculation at open points present in irregular fields. Objective: The aim of this study is to generalize the Clarkson’s method for dose calculation at points under compensator filters in IMRT method and its application in IMRT quality control as well. Material and Methods:
In this experimental study, compensator filters were designed in two forms: flat filter and block piled-up compensator. The measurements for the compensator filters and open fields in 5 and10 cm depths at energy levels (6, 10 and 18 MV) and in fields with different dimensions were performed using “Mapcheck2” dosimeter. The aim of performing calculations is to derive the theoretical dose by the generalized Clarkson’s equation and comparing it with data resulted from the measurement for confirming the Clarkson’s equation presented.
Results: These results demonstrate the data derived from the generalized Clarkson’s method are in good agreement with the data resulted from measurement; the highest error of the proposed equation was 3% for flat filter, and less than 5% for block-piled-up filter. Higher error in the block-piled-up filter compared with the flat filter was due to the presence of leakage between these blocks. Conclusion: The results of this study demonstrated that the presented equation is reliable and valid, and the proposed equation can be applied for dose calculation at all points under the compensator filter or the shielded areas.
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Affiliation(s)
- Pourkaveh M
- MSc, Medical Physics Department, Faculty of Medicine, Kermanshah University of Medical Sciences, Kermanshah, Iran
| | - Haghparast A
- PhD, Medical Physics Department, Faculty of Medicine, Kermanshah University of Medical Sciences, Kermanshah, Iran
| | - Eivazi M T
- PhD, Medical Physics Department, Faculty of Medicine, Kermanshah University of Medical Sciences, Kermanshah, Iran
| | - Ghazikhanlu Sani K
- PhD, Radiology Department, Paramedical School, Hamadan University of Medical Sciences, Hamadan, Iran
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I S, C A, H S, P T, T F. Comparisons of Hounsfield Unit Linearity between Images Reconstructed using an Adaptive Iterative Dose Reduction (AIDR) and a Filter Back-Projection (FBP) Techniques. J Biomed Phys Eng 2020; 10:215-224. [PMID: 32337189 PMCID: PMC7166214 DOI: 10.31661/jbpe.v0i0.1912-1013] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Accepted: 12/09/2019] [Indexed: 12/13/2022]
Abstract
Background: The HU linearity is an essential parameter in a quantitative imaging and the treatment planning systems of radiotherapy. Objective: This study aims to evaluate the linearity of Hounsfield unit (HU) in applying the adaptive iterative dose reduction (AIDR)
on CT scanner and its comparison to the filtered back-projection (FBP). Material and Methods: In this experimental phantom study, a TOS-phantom was scanned using a Toshiba Alexion 6 CT scanner. The images were reconstructed
using the FBP and AIDR. Measurements of HU and noise values were performed on images of the “HU linearity” module of the TOS-phantom.
The module had five embedded objects, i.e., air, polypropylene, nylon, acrylic, and Delrin. On each object, a circle area of 4.32
cm2 was drawn and used to measure HU and noise values. The R2 of the relation between mass densities vs. HU values was used to
measure HU linearities at four different tube voltages. The Mann-Whitney U test was used to compare unpaired data and p-value < 0.05 was considered statistically significant. Results: The AIDR method produced a significant smaller image noise than the FBP method (p-value < 0.05).
There were no significant differences in HU values of images reconstructed using FBP and AIDR methods (p-value > 0.05).
The HU values acquired by the methods showed the same linearity marked by coinciding linear lines with the same R2 value (> 0.999). Conclusion: AIDR methods produce the HU linearity as FBP methods with a smaller image noise level.
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Affiliation(s)
- Suyudi I
- BSc, Department of Physics, Faculty of Sciences and Mathematics, Diponegoro University, Indonesia
| | - Anam C
- PhD, Department of Physics, Faculty of Sciences and Mathematics, Diponegoro University, Indonesia
| | - Sutanto H
- PhD, Department of Physics, Faculty of Sciences and Mathematics, Diponegoro University, Indonesia
| | - Triadyaksa P
- PhD, Department of Physics, Faculty of Sciences and Mathematics, Diponegoro University, Indonesia
| | - Fujibuchi T
- PhD, Department of Health Sciences, Faculty of Medical Sciences, Kyushu University, Japan
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