Pub Date : 2020-09-01DOI: 10.22038/IJMP.2019.42841.1642
F. Zarei, S. Chatterjee, Vani Vardhan Chatterjee, R. R. Haghighi
Introduction: In dual-energy computed tomography (DECT), the Hounsfield values of a substance measured at two different energies are the basic data for finding the chemical properties of a substance. The trends of Hounsfield unit (HU) alterations following the changes in energy are different between the materials with high and low Zeff. The present study aimed to analyze the basic principles related to the attenuation coefficient of x-ray photons and a quantitative explanation is given for the mentioned behavior or trend. Material and Methods: A mathematical expression was derived for the HU difference between two different scanner voltages. Attenuation coefficients of diverse substances, such as methanol, glycerol, acetic acid, the aqueous solution of potassium hydroxide, and water were calculated for x-ray scanners operating differently at distinct applied voltages and with diverse inherent or added filters. Results: Findings of the current study demonstrated that the negative or positive outcome of HU(V1) - HU(V2) equation is not determined by the electron density of a substance. However, it is affected by the effective atomic number (Zeff) of the material and machine parameters specified by the source spectrum. Conclusion: According to our results, the sign of HU difference [HU(V1) – HU(V2)] for the variable cases of V2 and V1 gives an indication of the effective atomic number of the material under study. The obtained results might be of diagnostic value in the DECT technique.
{"title":"Reversal Trend of Hounsfield Unit Values of Substances with High and Low Effective Atomic Numbers","authors":"F. Zarei, S. Chatterjee, Vani Vardhan Chatterjee, R. R. Haghighi","doi":"10.22038/IJMP.2019.42841.1642","DOIUrl":"https://doi.org/10.22038/IJMP.2019.42841.1642","url":null,"abstract":"Introduction: In dual-energy computed tomography (DECT), the Hounsfield values of a substance measured at two different energies are the basic data for finding the chemical properties of a substance. The trends of Hounsfield unit (HU) alterations following the changes in energy are different between the materials with high and low Zeff. The present study aimed to analyze the basic principles related to the attenuation coefficient of x-ray photons and a quantitative explanation is given for the mentioned behavior or trend. \u0000Material and Methods: A mathematical expression was derived for the HU difference between two different scanner voltages. Attenuation coefficients of diverse substances, such as methanol, glycerol, acetic acid, the aqueous solution of potassium hydroxide, and water were calculated for x-ray scanners operating differently at distinct applied voltages and with diverse inherent or added filters. \u0000Results: Findings of the current study demonstrated that the negative or positive outcome of HU(V1) - HU(V2) equation is not determined by the electron density of a substance. However, it is affected by the effective atomic number (Zeff) of the material and machine parameters specified by the source spectrum. \u0000Conclusion: According to our results, the sign of HU difference [HU(V1) – HU(V2)] for the variable cases of V2 and V1 gives an indication of the effective atomic number of the material under study. The obtained results might be of diagnostic value in the DECT technique.","PeriodicalId":14613,"journal":{"name":"Iranian Journal of Medical Physics","volume":"17 1","pages":"340-349"},"PeriodicalIF":0.0,"publicationDate":"2020-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48843116","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 : 2020-08-21DOI: 10.22038/IJMP.2020.49358.1795
M. Nezamzadeh, N. Schuff
Introduction: Diffusion tensor imaging (DTI) is conventionally performed using echo planar imaging (EPI) for human brain mapping. However, EPI suffers from susceptibility distortion, requiring elaborate image post processing. Besides, DTI alone is limited in assessing gray and white matter boundaries of the brain, which is important for accurately imaging brain atrophy. The goal of this study was to design and evaluate simultaneous diffusion and T1 weighting high resolution imaging for human brain mapping. Materials and Methods: Three dimensional Magnetization-prepared rapid gradient-echo (3D MPRAGE) with T1 weighting, which is generally the method of choice for mapping gray and white matter structures in the brain, was extended to incorporate diffusion encoding using simulation and experiment to develop high resolution DTI and T1-weighted human brain data. Results: It is shown that the incorporation of DTI contrast (i.e. fractional anisotropy (FA) and mean diffusivity (MD)) into T1 weighted 3D MPRAGE using simulations as well as experimental results from in-vivo human brain studies at 4 Tesla magnetic field strength improves the contrast between gray and white matter sub-structural boundaries. Moreover, incorporating diffusion encoding into 3D MPRAGE avoids the inherent image distortions typically seen in EPI based DTI.Conclusion: This study suggests DTI weighted 3D MPRAGE combined with T1w is feasible for human brain imaging and expected to benefit improved assessment of gray/white matter boundaries.
{"title":"Simultaneous Diffusion and T1 Weighted Contrast Imaging for Human Brain Mapping","authors":"M. Nezamzadeh, N. Schuff","doi":"10.22038/IJMP.2020.49358.1795","DOIUrl":"https://doi.org/10.22038/IJMP.2020.49358.1795","url":null,"abstract":"Introduction: Diffusion tensor imaging (DTI) is conventionally performed using echo planar imaging (EPI) for human brain mapping. However, EPI suffers from susceptibility distortion, requiring elaborate image post processing. Besides, DTI alone is limited in assessing gray and white matter boundaries of the brain, which is important for accurately imaging brain atrophy. The goal of this study was to design and evaluate simultaneous diffusion and T1 weighting high resolution imaging for human brain mapping. Materials and Methods: Three dimensional Magnetization-prepared rapid gradient-echo (3D MPRAGE) with T1 weighting, which is generally the method of choice for mapping gray and white matter structures in the brain, was extended to incorporate diffusion encoding using simulation and experiment to develop high resolution DTI and T1-weighted human brain data. Results: It is shown that the incorporation of DTI contrast (i.e. fractional anisotropy (FA) and mean diffusivity (MD)) into T1 weighted 3D MPRAGE using simulations as well as experimental results from in-vivo human brain studies at 4 Tesla magnetic field strength improves the contrast between gray and white matter sub-structural boundaries. Moreover, incorporating diffusion encoding into 3D MPRAGE avoids the inherent image distortions typically seen in EPI based DTI.Conclusion: This study suggests DTI weighted 3D MPRAGE combined with T1w is feasible for human brain imaging and expected to benefit improved assessment of gray/white matter boundaries.","PeriodicalId":14613,"journal":{"name":"Iranian Journal of Medical Physics","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-08-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48178045","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 : 2020-08-14DOI: 10.22038/IJMP.2020.50131.1820
M. Savanović, B. Štrbac, D. Jaroš, Dejan Ćazić, G. Kolarević, J. Foulquier
Purpose: To evaluate internal (lung, heart and diaphragm) and external (nine glass marbles) marker motion in correlation with lung tumor motion, to determine potential surrogate for respiratory gating radiation therapy (RGRT) depending on tumor localization, upper lobe (UL) vs lower lobe (LL).Methods: This study included 58 patients (34 male and 24 female) with small lung cancer (≤ 5cm), who underwent Stereotactic Body Radiation Therapy (SBRT). All patients were scanned and contoured in all ten phases (Varian Eclipse 13.7) after four-dimensional computed tomography simulation (4D-CT). The motion of internal markers and external markers were analyzed and correlated with tumor motion. The Pearson correlation coefficient (PCC) was used to evaluate the correlation between internal and external marker motion with tumor motion. Results: The median (range) values of tumor motion were 3.2 (0.6-11.0) vs 8.6 (4.0-24.0) mm in the UL vs LL. The median (range) values of organs motion and PCC comparing UL vs LL were: 2.0 (0.3-9.1) vs 6.0 (2.8-13.9) mm and 0.46 (0.30-0.95) vs 0.79 (0.50-0.94) to the lung; 11.9 (2.5-16.3) vs 12.5 (5.0-22.5) mm and 0.68 (0.11-0.93) vs 0.89 (0.30-0.99) to the diaphragm; and 3.9 (2.5-6.3) vs 7.6 (4.5-8.6) mm and 0.49 (0.20-0.70) vs 0.59 (0.36-0.83) to the heart. The external marker motion and correlation coefficient for UL and LL were 2.5 (0.9-7.4) vs 2.3 (1.0-5.9) mm and 0.54 (0.09-0.96) vs 0.73 (0.27-0.94).Conclusion: Lung and diaphragm motion correlate better with tumor motion than the external marker. Diaphragm motion can be an excellent indicator for treatment based on RGRT.
{"title":"Assessment of Internal and External Surrogates for Lung Stereotactic Body Radiation Therapy","authors":"M. Savanović, B. Štrbac, D. Jaroš, Dejan Ćazić, G. Kolarević, J. Foulquier","doi":"10.22038/IJMP.2020.50131.1820","DOIUrl":"https://doi.org/10.22038/IJMP.2020.50131.1820","url":null,"abstract":"Purpose: To evaluate internal (lung, heart and diaphragm) and external (nine glass marbles) marker motion in correlation with lung tumor motion, to determine potential surrogate for respiratory gating radiation therapy (RGRT) depending on tumor localization, upper lobe (UL) vs lower lobe (LL).Methods: This study included 58 patients (34 male and 24 female) with small lung cancer (≤ 5cm), who underwent Stereotactic Body Radiation Therapy (SBRT). All patients were scanned and contoured in all ten phases (Varian Eclipse 13.7) after four-dimensional computed tomography simulation (4D-CT). The motion of internal markers and external markers were analyzed and correlated with tumor motion. The Pearson correlation coefficient (PCC) was used to evaluate the correlation between internal and external marker motion with tumor motion. Results: The median (range) values of tumor motion were 3.2 (0.6-11.0) vs 8.6 (4.0-24.0) mm in the UL vs LL. The median (range) values of organs motion and PCC comparing UL vs LL were: 2.0 (0.3-9.1) vs 6.0 (2.8-13.9) mm and 0.46 (0.30-0.95) vs 0.79 (0.50-0.94) to the lung; 11.9 (2.5-16.3) vs 12.5 (5.0-22.5) mm and 0.68 (0.11-0.93) vs 0.89 (0.30-0.99) to the diaphragm; and 3.9 (2.5-6.3) vs 7.6 (4.5-8.6) mm and 0.49 (0.20-0.70) vs 0.59 (0.36-0.83) to the heart. The external marker motion and correlation coefficient for UL and LL were 2.5 (0.9-7.4) vs 2.3 (1.0-5.9) mm and 0.54 (0.09-0.96) vs 0.73 (0.27-0.94).Conclusion: Lung and diaphragm motion correlate better with tumor motion than the external marker. Diaphragm motion can be an excellent indicator for treatment based on RGRT.","PeriodicalId":14613,"journal":{"name":"Iranian Journal of Medical Physics","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44802671","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 : 2020-08-10DOI: 10.22038/IJMP.2020.46778.1735
Hicham Asmi, F. Bentayeb, Youssef Bouzekraoui
Introduction: Detection of scattered photons in photo-peak window degrades image contrast and quantitative accuracy of single-photon emission computed tomography (SPECT) imaging. Increases image contrast lead to significant improvement of image quality. The triple energy window (TEW) method, which has developed to eliminate the counts of scatter photons in measured counts, was applied to I-111 SPECT study and its effect was examined in a simulation study. Materials and method: The Siemens SYMBIA gamma camera equipped with a medium energy (ME) collimator was simulated by the Simulating Medical Imaging Nuclear Detectors (SIMIND) program. We used the SIMIND Monte Carlo program to generate the I-111 SPECT projection data of the Jaszczak phantom. The phantom consists of six spheres with different diameters (9.5, 12.7, 19.1, 15.9, 25.4, and 31.8 mm) which are used to evaluate the image contrast. Geometric, scatter and penetration fraction and also, point-spread functions (PSFs) and contrast curves were drawn and compared. Results: Results showed that 171keV photo-peak compared to 245keV gave the best results with a ME collimator when the TEW scatter correction method was applied. This can be explained by the large amount of collimator scatter and penetration from the photo-peak and by the collimator for 245 photo-peak window. Conclusion: With TEW scatter correction method, it is better to use a 171keV photo-peak window because of the better spatial resolution and image contrast.
{"title":"Contrast optimization using triple energy window scatter correction method for In-111 SPECT imaging: A SIMIND Monte Carlo study","authors":"Hicham Asmi, F. Bentayeb, Youssef Bouzekraoui","doi":"10.22038/IJMP.2020.46778.1735","DOIUrl":"https://doi.org/10.22038/IJMP.2020.46778.1735","url":null,"abstract":"Introduction: Detection of scattered photons in photo-peak window degrades image contrast and quantitative accuracy of single-photon emission computed tomography (SPECT) imaging. Increases image contrast lead to significant improvement of image quality. The triple energy window (TEW) method, which has developed to eliminate the counts of scatter photons in measured counts, was applied to I-111 SPECT study and its effect was examined in a simulation study. Materials and method: The Siemens SYMBIA gamma camera equipped with a medium energy (ME) collimator was simulated by the Simulating Medical Imaging Nuclear Detectors (SIMIND) program. We used the SIMIND Monte Carlo program to generate the I-111 SPECT projection data of the Jaszczak phantom. The phantom consists of six spheres with different diameters (9.5, 12.7, 19.1, 15.9, 25.4, and 31.8 mm) which are used to evaluate the image contrast. Geometric, scatter and penetration fraction and also, point-spread functions (PSFs) and contrast curves were drawn and compared. Results: Results showed that 171keV photo-peak compared to 245keV gave the best results with a ME collimator when the TEW scatter correction method was applied. This can be explained by the large amount of collimator scatter and penetration from the photo-peak and by the collimator for 245 photo-peak window. Conclusion: With TEW scatter correction method, it is better to use a 171keV photo-peak window because of the better spatial resolution and image contrast.","PeriodicalId":14613,"journal":{"name":"Iranian Journal of Medical Physics","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-08-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41435201","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 : 2020-08-06DOI: 10.22038/IJMP.2020.47698.1762
S. Pawiro, N. Nasution, W. Wibowo, Adi Purnomo
Purpose: To evaluate the dosimetric impact due to longitudinal motion in phantom on of the Tomotherapy machine.Material and Methods: This study used Cheese and Delta4 phantom+ placed on a respiratory motion platform. They moved in longitudinal directions using various amplitudes from 2, 4, 6, 8, to 10 mm. The period of that movement was 4 and 6 s at field width of 25 and 50 mm, respectively. The C-shaped complex target was modified according to the American Association of Physicists in Medicine (AAPM) Task Group (TG) 119. The planning verifications were evaluated through point dose, gamma index value, and dose-volume histogram (DVH).Results: For all movement variations, the discrepancy of the dose measurements was about -1.254 to -14.421%. The range of gamma index value was 61.2 ±1.23% to 100±0.00. The DVH evaluation showed that the homogeneity index (HI) and the minimum dose to receive by 95% (D95%) of the target structure were 0.247 to 0.389 and -0.061 to -0.271 Gy respectively. The maximum dose (DMax) of the organ at risk (OAR) structure was 0.082 to 0.327 Gy. Conclusions: The motion could induce dose discrepancies on Tomotherapy dose distribution. The selection of the jaw field width in Tomotherapy was crucial for intensity-modulated radiotherapy (IMRT) techniques with moving targets. For larger field width, the dose discrepancy between the planned and measured dose showed an excellent result for gamma index and dose coverage.
{"title":"Dosimetric Study in Tomotherapy Based on AAPM TG 119 Structures: A Longitudinal Moving Phantom Case","authors":"S. Pawiro, N. Nasution, W. Wibowo, Adi Purnomo","doi":"10.22038/IJMP.2020.47698.1762","DOIUrl":"https://doi.org/10.22038/IJMP.2020.47698.1762","url":null,"abstract":"Purpose: To evaluate the dosimetric impact due to longitudinal motion in phantom on of the Tomotherapy machine.Material and Methods: This study used Cheese and Delta4 phantom+ placed on a respiratory motion platform. They moved in longitudinal directions using various amplitudes from 2, 4, 6, 8, to 10 mm. The period of that movement was 4 and 6 s at field width of 25 and 50 mm, respectively. The C-shaped complex target was modified according to the American Association of Physicists in Medicine (AAPM) Task Group (TG) 119. The planning verifications were evaluated through point dose, gamma index value, and dose-volume histogram (DVH).Results: For all movement variations, the discrepancy of the dose measurements was about -1.254 to -14.421%. The range of gamma index value was 61.2 ±1.23% to 100±0.00. The DVH evaluation showed that the homogeneity index (HI) and the minimum dose to receive by 95% (D95%) of the target structure were 0.247 to 0.389 and -0.061 to -0.271 Gy respectively. The maximum dose (DMax) of the organ at risk (OAR) structure was 0.082 to 0.327 Gy. Conclusions: The motion could induce dose discrepancies on Tomotherapy dose distribution. The selection of the jaw field width in Tomotherapy was crucial for intensity-modulated radiotherapy (IMRT) techniques with moving targets. For larger field width, the dose discrepancy between the planned and measured dose showed an excellent result for gamma index and dose coverage.","PeriodicalId":14613,"journal":{"name":"Iranian Journal of Medical Physics","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-08-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41519505","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 : 2020-08-04DOI: 10.22038/IJMP.2020.48162.1775
V. Mhatre, P. Chadha, R. Chauhan, K. Talapatra, Abhaya P Kumar
Introduction : Present study focused on dosimetric evaluation of Edge and Novalis Tx (NTx) linear accelerator (LA) based radiosurgery system by using rapid arc (RA) and dynamic conformal arc (DCA) planning techniques.Materials and Methods: Forty patients with brain lesions of variable sizes (1.1-15.98 cc) were planned for Edge and NTx system by using RA and DCA planning techniques on eclipse treatment planning system version 13.6 (Varian Medical Systems, Palo Alto, CA, USA). All the plans were evaluated on the basis of paddick conformity index (PCI), homogeneity index (HI) and gradient index (GI). The maximum doses to organs at risk (OAR), V12Gy, V10Gy and V5Gy for healthy brain tissue were also evaluated for all the plans. The treatment delivery efficiency for both the systems was also evaluated. Results: The mean PCI and GI for both RA and DCA plans were found to be better in Edge as compared to NTx system (PCIEdge,RA=0.77±0.1, PCINTx,RA=0.66±0.11, PCIEdge,DCA= 0.69±0.12, PCINTx,DCA= 0.67±0.12). Significant difference in HI, doses to OAR and V12Gy, V10Gy and V5Gy brain volume was observed for both the systems with p-value less than 0.05. Reduced treatment time was observed in Edge LA as compared to NTx LA. Conclusion: Edge LA produced clinically better target volume conformity, rapid dose fall-off, reduced reduction in normal brain volume irradiation and treatment time compared to NTx. Thus in the set of patients plan evaluated it was noted that Edge stereotactic suite in more efficacious and diametrically suitable for intracranial radiosurgery.
摘要:本研究主要利用快速电弧(RA)和动态共形电弧(DCA)规划技术，对Edge和Novalis Tx (NTx)线性加速器(LA)放射手术系统进行剂量学评价。材料和方法:采用eclipse治疗计划系统版本13.6 (Varian Medical Systems, Palo Alto, CA, USA)上的RA和DCA计划技术，对40例不同大小(1.1-15.98 cc)的脑病变患者进行Edge和NTx系统的计划。采用帕迪克一致性指数(PCI)、均匀性指数(HI)和梯度指数(GI)对各方案进行评价。评估了所有方案对健康脑组织的最大危险器官剂量(OAR)、V12Gy、V10Gy和V5Gy。还对两种系统的处理输送效率进行了评估。结果:与NTx系统相比，RA和DCA方案Edge的平均PCI和GI (PCIEdge,RA=0.77±0.1,PCINTx,RA=0.66±0.11,PCIEdge,DCA= 0.69±0.12,PCINTx,DCA= 0.67±0.12)均优于DCA方案。两组HI、OAR剂量及V12Gy、V10Gy、V5Gy脑容量差异均有统计学意义，p值均小于0.05。与NTx LA相比，Edge LA的治疗时间缩短。结论:与NTx相比，Edge LA在临床上具有更好的靶体积一致性，剂量下降快，正常脑容量照射减少和治疗时间缩短。因此，在一组患者计划评估中，我们注意到Edge立体定向套件更有效，更适合颅内放射手术。
{"title":"Dosimetric Comparison of two linear accelerator based radiosurgery system for Intracranial tumours with Rapid Arc and Dynamic conformal Arc therapy","authors":"V. Mhatre, P. Chadha, R. Chauhan, K. Talapatra, Abhaya P Kumar","doi":"10.22038/IJMP.2020.48162.1775","DOIUrl":"https://doi.org/10.22038/IJMP.2020.48162.1775","url":null,"abstract":"Introduction : Present study focused on dosimetric evaluation of Edge and Novalis Tx (NTx) linear accelerator (LA) based radiosurgery system by using rapid arc (RA) and dynamic conformal arc (DCA) planning techniques.Materials and Methods: Forty patients with brain lesions of variable sizes (1.1-15.98 cc) were planned for Edge and NTx system by using RA and DCA planning techniques on eclipse treatment planning system version 13.6 (Varian Medical Systems, Palo Alto, CA, USA). All the plans were evaluated on the basis of paddick conformity index (PCI), homogeneity index (HI) and gradient index (GI). The maximum doses to organs at risk (OAR), V12Gy, V10Gy and V5Gy for healthy brain tissue were also evaluated for all the plans. The treatment delivery efficiency for both the systems was also evaluated. Results: The mean PCI and GI for both RA and DCA plans were found to be better in Edge as compared to NTx system (PCIEdge,RA=0.77±0.1, PCINTx,RA=0.66±0.11, PCIEdge,DCA= 0.69±0.12, PCINTx,DCA= 0.67±0.12). Significant difference in HI, doses to OAR and V12Gy, V10Gy and V5Gy brain volume was observed for both the systems with p-value less than 0.05. Reduced treatment time was observed in Edge LA as compared to NTx LA. Conclusion: Edge LA produced clinically better target volume conformity, rapid dose fall-off, reduced reduction in normal brain volume irradiation and treatment time compared to NTx. Thus in the set of patients plan evaluated it was noted that Edge stereotactic suite in more efficacious and diametrically suitable for intracranial radiosurgery.","PeriodicalId":14613,"journal":{"name":"Iranian Journal of Medical Physics","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-08-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44911817","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 : 2020-07-26DOI: 10.22038/IJMP.2020.45759.1717
M. Sadeghi, S. Sina, A. Meigooni
Introduction: The long-half-life Cobalt-60 high dose rate (HDR) brachytherapy source is an appropriate alternative for Iridium-192 (HDR) source for treatment of GYN patients in developing countries. The aim of this study is to compare the treatment duration for HDR cervical cancer treatments using Cobalt-60 and Iridium-192 sources using Tandem and ovoid applicators. Materials and Methods: In this study, Iridium-192 source model mHDR-v2r, and BEBIG 60Co source model Co0.A86 were used. The TG-43 formalism was used to calculate the treatment time required for both radionuclides. The treatment data provided us with the exact dwell positions, and times of the source, and positions of the dosimetry points. The treatment time for Iridium source was calculated by using absorbed dose in treatment data and the TG-43 formalism. Then, the calculations were repeated with Cobalt-60 to determine the dwell times. Finally, the treatment duration obtained for the two sources were compared with each other. Results: The results of this study indicate that the treatment time for cobalt source with the activity of 2.131 Ci is almost the same as the treatment time for iridium source with the activity of 5.690 Ci. If we consider the maximum treatment duration is 16 minutes in one treatment session, the effective time window for Iridium-192 is about 160 days, while for Cobalt-60 this effective time window becomes 2000 days. Conclusion: According to the results obtained in this study, using Cobalt-60 instead of Iridium-192 will be economically beneficial in newly constructed departments where the selection of the equipment is still in progress. Changes the activities of the Iridium-192 versus Cobalt-60 require editing treatment planning system for a patient in total treatment time. These editing of treatment planning can cause errors and reduce accuracy.
{"title":"Comparison the treatment duration for Cobalt-60, and Iridium-192 sources with different activities in HDR brachytherapy using tandem-ovoid applicator","authors":"M. Sadeghi, S. Sina, A. Meigooni","doi":"10.22038/IJMP.2020.45759.1717","DOIUrl":"https://doi.org/10.22038/IJMP.2020.45759.1717","url":null,"abstract":"Introduction: The long-half-life Cobalt-60 high dose rate (HDR) brachytherapy source is an appropriate alternative for Iridium-192 (HDR) source for treatment of GYN patients in developing countries. The aim of this study is to compare the treatment duration for HDR cervical cancer treatments using Cobalt-60 and Iridium-192 sources using Tandem and ovoid applicators. Materials and Methods: In this study, Iridium-192 source model mHDR-v2r, and BEBIG 60Co source model Co0.A86 were used. The TG-43 formalism was used to calculate the treatment time required for both radionuclides. The treatment data provided us with the exact dwell positions, and times of the source, and positions of the dosimetry points. The treatment time for Iridium source was calculated by using absorbed dose in treatment data and the TG-43 formalism. Then, the calculations were repeated with Cobalt-60 to determine the dwell times. Finally, the treatment duration obtained for the two sources were compared with each other. Results: The results of this study indicate that the treatment time for cobalt source with the activity of 2.131 Ci is almost the same as the treatment time for iridium source with the activity of 5.690 Ci. If we consider the maximum treatment duration is 16 minutes in one treatment session, the effective time window for Iridium-192 is about 160 days, while for Cobalt-60 this effective time window becomes 2000 days. Conclusion: According to the results obtained in this study, using Cobalt-60 instead of Iridium-192 will be economically beneficial in newly constructed departments where the selection of the equipment is still in progress. Changes the activities of the Iridium-192 versus Cobalt-60 require editing treatment planning system for a patient in total treatment time. These editing of treatment planning can cause errors and reduce accuracy.","PeriodicalId":14613,"journal":{"name":"Iranian Journal of Medical Physics","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-07-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47376909","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 : 2020-07-26DOI: 10.22038/IJMP.2020.48813.1786
Ummu Mar'atu Zahro, C. Anam, W. Budi, J. H. Saragih, P. Triadyaksa, D. A. Rukmana
Objective: The aim of this study is to investigate image qualities filtered by a selective mean filter (SMF) and its comparison to an adaptive statistical iterative reconstruction (ASIR).Materials and Methods: A CT AAPM performance phantom was used for the assessment of basic image quality. The phantom was scanned by 128 Multiple Slices Computed Tomography. The tube current was varied (i.e. 50, 100, 150, and 200 mA). The images of a phantom were reconstructed by FBP followed by SMF and ASIR (20, 40, 60, 80, and 100%). The image quality assessment was in terms of noise level, noise power spectrum (NPS), and modulation transfer function (MTF). Result: It was found that SMF reduced noise level by more than 65% compared with FBP. The noise level and NPS of SMF was similar with ASIR 100%. The values of the MTF10 and MTF50 of the FBP, ASIR filter at any level, and SMF were comparable. The MTF10 values of FBP, ASIR 60% and SMF with 50 mA (low) tube current were 0.747 ± 0.03, 0.755 ± 0.02, and 0.748 ± 0.02 cycle/mm, respectively. While the MTF10 of FBP, ASIR 60%, and SMF with 200 mA (high) tube current were 0.730 ± 0.00, 0.741 ± 0.00, and 0.732 ± 0.00 cycles/mm, respectively. The MTF50 values of FBP, ASIR 60%, and SMF with low tube current were 0.408 ± 0.05, 0.428 ± 0.03, and 0.446 ± 0.04 cycle/mm, respectively. While the MTF50 values of FBP, ASIR 60%, and SMF with high tube current were 0.416 ± 0.00, 0.428 ± 0.01, and 0.416 ± 0.00 cycle/mm, respectively.Conclusions: These results indicated that the SMF algorithm reduces noise level without affecting the spatial resolution. The performance of the SMF in reducing noise is equivalent to the maximum level of ASIR strength i.e. ASIR 100%.
{"title":"Investigation of Noise Level and Spatial Resolution of CT Images Filtered with a Selective Mean Filter and Its Comparison to an Adaptive Statistical Iterative Reconstruction","authors":"Ummu Mar'atu Zahro, C. Anam, W. Budi, J. H. Saragih, P. Triadyaksa, D. A. Rukmana","doi":"10.22038/IJMP.2020.48813.1786","DOIUrl":"https://doi.org/10.22038/IJMP.2020.48813.1786","url":null,"abstract":"Objective: The aim of this study is to investigate image qualities filtered by a selective mean filter (SMF) and its comparison to an adaptive statistical iterative reconstruction (ASIR).Materials and Methods: A CT AAPM performance phantom was used for the assessment of basic image quality. The phantom was scanned by 128 Multiple Slices Computed Tomography. The tube current was varied (i.e. 50, 100, 150, and 200 mA). The images of a phantom were reconstructed by FBP followed by SMF and ASIR (20, 40, 60, 80, and 100%). The image quality assessment was in terms of noise level, noise power spectrum (NPS), and modulation transfer function (MTF). Result: It was found that SMF reduced noise level by more than 65% compared with FBP. The noise level and NPS of SMF was similar with ASIR 100%. The values of the MTF10 and MTF50 of the FBP, ASIR filter at any level, and SMF were comparable. The MTF10 values of FBP, ASIR 60% and SMF with 50 mA (low) tube current were 0.747 ± 0.03, 0.755 ± 0.02, and 0.748 ± 0.02 cycle/mm, respectively. While the MTF10 of FBP, ASIR 60%, and SMF with 200 mA (high) tube current were 0.730 ± 0.00, 0.741 ± 0.00, and 0.732 ± 0.00 cycles/mm, respectively. The MTF50 values of FBP, ASIR 60%, and SMF with low tube current were 0.408 ± 0.05, 0.428 ± 0.03, and 0.446 ± 0.04 cycle/mm, respectively. While the MTF50 values of FBP, ASIR 60%, and SMF with high tube current were 0.416 ± 0.00, 0.428 ± 0.01, and 0.416 ± 0.00 cycle/mm, respectively.Conclusions: These results indicated that the SMF algorithm reduces noise level without affecting the spatial resolution. The performance of the SMF in reducing noise is equivalent to the maximum level of ASIR strength i.e. ASIR 100%.","PeriodicalId":14613,"journal":{"name":"Iranian Journal of Medical Physics","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-07-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41797686","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 : 2020-07-17DOI: 10.22038/IJMP.2020.42430.1627
S. Sina, S. M. Naderi, M. Karimipourfard, Z. Molaeimanesh, M. Sadeghi, E. Zamani, F. Lotfalizadeh, Mohammad Entezarmahdi, R. Faghihi
The occupational safety of nuclear medicine staff working with radioactive iodine, I-131, has always been a great concern in nuclear medicine. As the radioiodine is a volatile substance it may enter the body during the respiration, and absorbed by the thyroid glands of the staff, and causing major problems for their health. This study aims to develop a simple method for determining the activity of the 131I absorbed in thyroid glands of nuclear medicine staff, using a home-made anthropomorphic neck-thyroid phantom. I-131 with the activity of 370kBq was injected inside the thyroid gland of the phantom. The dose rate was measured by putting a portable detector on the thyroid gland, at the surface of the neck phantom. The measurements were repeated for two months. Then a calibration curve was drawn, iodine activity inside the thyroid versus dose rate at the neck surface. Then the calibration curve was used to estimate the absorbed activity in the thyroids of the staff in one of the main hospitals of Shiraz city. Finally, new software was developed for assessing, and recording the activity concentration of 131I accumulated in the thyroid gland. Every day the dose rate was measured by putting the detector on the necks of the staff, and the dose rates were converted to the activity inside their thyroid using the above-mentioned calibration curve. The method used in this study can be used for estimation of the radioiodine concentration inside the thyroid glands of the staff; in normal working conditions and accidents.
{"title":"Developing a simple method for determination of the activity absorbed by thyroid glands of nuclear medicine staff","authors":"S. Sina, S. M. Naderi, M. Karimipourfard, Z. Molaeimanesh, M. Sadeghi, E. Zamani, F. Lotfalizadeh, Mohammad Entezarmahdi, R. Faghihi","doi":"10.22038/IJMP.2020.42430.1627","DOIUrl":"https://doi.org/10.22038/IJMP.2020.42430.1627","url":null,"abstract":"The occupational safety of nuclear medicine staff working with radioactive iodine, I-131, has always been a great concern in nuclear medicine. As the radioiodine is a volatile substance it may enter the body during the respiration, and absorbed by the thyroid glands of the staff, and causing major problems for their health. This study aims to develop a simple method for determining the activity of the 131I absorbed in thyroid glands of nuclear medicine staff, using a home-made anthropomorphic neck-thyroid phantom. I-131 with the activity of 370kBq was injected inside the thyroid gland of the phantom. The dose rate was measured by putting a portable detector on the thyroid gland, at the surface of the neck phantom. The measurements were repeated for two months. Then a calibration curve was drawn, iodine activity inside the thyroid versus dose rate at the neck surface. Then the calibration curve was used to estimate the absorbed activity in the thyroids of the staff in one of the main hospitals of Shiraz city. Finally, new software was developed for assessing, and recording the activity concentration of 131I accumulated in the thyroid gland. Every day the dose rate was measured by putting the detector on the necks of the staff, and the dose rates were converted to the activity inside their thyroid using the above-mentioned calibration curve. The method used in this study can be used for estimation of the radioiodine concentration inside the thyroid glands of the staff; in normal working conditions and accidents.","PeriodicalId":14613,"journal":{"name":"Iranian Journal of Medical Physics","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46209618","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 : 2020-07-09DOI: 10.22038/IJMP.2020.46309.1724
Majid Abiar, Mazyar Mahdavi, G. Haddadi
Introduction: Nowadays, the absorbed dose of patients is on the rise due to the widespread use of computed tomography (CT) during the diagnosis process. Patients' doses for similar procedures are very different due to diversity in scanners and protocols. Hence, the purpose of this study was to determine the diagnostic reference levels for routine CT scan procedures in Kohgiluyeh and Boyer-Ahmad province, Iran.Material and methods: In this study, four common brain, sinus, chest and abdominopelvic procedures in spiral mode were selected. Next, the doses were measured in head and body phantom. Then, the third quartile of CTDIw was considered as the diagnostic reference dose. Finally, considering the pitch factor and the mean scan length in each protocol, the diagnostic reference level values based on the third quartile of the dose length product (DLP) and volume CTDI (CTDIvol) were determined.Results:The dose reference level values according to CTDIw third quartile in the brain, sinus, chest and abdominopelvic procedures were 39.82, 20.88, 14.10 and 17.07 mGy, respectively. In terms of dose length product, the diagnostic reference level values in the above procedures were determined to be 702.75, 243.90, 422.02, 865.62 mGy.cm, respectively.Conclusion:The DRLs of the CTDIW, DLP and CTDIvol of brain and sinus scans calculated in this study, were comparable to other provinces, national DRL and eight other countries. However, the same quantities for the chest and abdominopelvic scans showed higher values compared to the mentioned studies, suggesting lowering mAs and increasing pitch number for patient’s dose optimization. In some centers to preserve image quality, it is necessary to optimize radiation conditions, especially for chest and abdominopelvic scans.
{"title":"Establishing local Diagnostic Reference Level for Adult Patients in Computed Tomography Examination in Kohgiluyeh and Boyer-Ahmad province","authors":"Majid Abiar, Mazyar Mahdavi, G. Haddadi","doi":"10.22038/IJMP.2020.46309.1724","DOIUrl":"https://doi.org/10.22038/IJMP.2020.46309.1724","url":null,"abstract":"Introduction: Nowadays, the absorbed dose of patients is on the rise due to the widespread use of computed tomography (CT) during the diagnosis process. Patients' doses for similar procedures are very different due to diversity in scanners and protocols. Hence, the purpose of this study was to determine the diagnostic reference levels for routine CT scan procedures in Kohgiluyeh and Boyer-Ahmad province, Iran.Material and methods: In this study, four common brain, sinus, chest and abdominopelvic procedures in spiral mode were selected. Next, the doses were measured in head and body phantom. Then, the third quartile of CTDIw was considered as the diagnostic reference dose. Finally, considering the pitch factor and the mean scan length in each protocol, the diagnostic reference level values based on the third quartile of the dose length product (DLP) and volume CTDI (CTDIvol) were determined.Results:The dose reference level values according to CTDIw third quartile in the brain, sinus, chest and abdominopelvic procedures were 39.82, 20.88, 14.10 and 17.07 mGy, respectively. In terms of dose length product, the diagnostic reference level values in the above procedures were determined to be 702.75, 243.90, 422.02, 865.62 mGy.cm, respectively.Conclusion:The DRLs of the CTDIW, DLP and CTDIvol of brain and sinus scans calculated in this study, were comparable to other provinces, national DRL and eight other countries. However, the same quantities for the chest and abdominopelvic scans showed higher values compared to the mentioned studies, suggesting lowering mAs and increasing pitch number for patient’s dose optimization. In some centers to preserve image quality, it is necessary to optimize radiation conditions, especially for chest and abdominopelvic scans.","PeriodicalId":14613,"journal":{"name":"Iranian Journal of Medical Physics","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-07-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41665690","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}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：