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Com.arison of two m.thods for assessing leakage radiation dose around the head of the m.dical linear accelerators

The Chinese-Germ.n Journal of Clinical Oncology 2013年第9期12卷 435-438页

作者： ehab m. attalla Departm.nt of Radiotherapy and Nuclear m.dicine National Cancer Institute Cairo University Children Cancer Hospital

Objective:The aim.of this study was to m.asure the leakage by two m.thods with ion cham.er and ready packs film.and to investigate the feasibility and the advantages of using two dosim.try m.thods for assessing leakage radiation around the head of the linear ***:m.asurem.nts were perform.d using a 30 cm.ion cham.er;the gantry at 0°,the X-ray head at 0°,the field size at between the central axis and a plane surface at a FSD of 100 as a reference,a series of concentric circles having radii of 50,75,and 100 cm.with their com.on centre at the reference *** absorbed dose was m.asured at the reference point,and this would be used as the reference *** the diaphragm.closed,the m.asurem.nts were taken along the circum.erence of the three circles and at 45°***:Leakage radiations while the treatm.nt head was in the vertical position varied between 0.016%–0.04%.With the head lying horizontally,leakage radiation was the sam. order m.gnitude and varied between 0.02%–0.07%.In the second m.thod,the verification was accom.lished by closing the collim.tor jaws and covering the head of the treatm.nt unit with the ready pack *** film. were m.rked to perm.t the determ.nation of their positions on the m.chine after exposed and *** the diaphragm.closed,and the ready packs film. around the linear accelerator the beam.turned on for 2500 cGy(2500 m.).The optical density of these film. was m.asured and com.ared with this of the reference *** radiation varied according to the film.positions and the m.gnitude of leakage was between 0.005%–0.075%.Conclusion:The differences between the values of the leakage radiation levels observed at different m.asurem.nt points do not only reflect differences in the effective shielding thickness of the head wall,but are also related to differences in the distances between the target and the m.asurem.nt *** experim.ntal errors involved in dosim.tric m.asurem.nt also contribute to such d

关键词： leakage radiation acceptance testing linear accelerator ion cham.er ready packs film

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The Dosim.tric Effects of Different Beam.Energy on Physical Dose Distributions in Im.T Based on Analysis of Physical Indices

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Journal of Cancer Therapy 2013年第11期4卷 33-43页

作者： Ism.il Eldesoky ehab m. attalla Wael m. Elshem.y Children’s Cancer Hospital Cairo Egypt Departm.nt of Biophysics Faculty of Science Cairo University Cairo Egypt

This work aim.d at evaluating the effect of 6- and 10-m. photon energies on intensity-m.dulated radiation therapy (Im.T) treatm.nt plan outcom. in different selected diagnostic cases. For such purpose, 19 patients, with different types of non CNS solid tum.rs, were selected. Clinical step-and-shoot Im.T treatm.nt plans were designed for delivery on a Siem.ns Oncor accelerator with 82 leafs;m.lti-leaf collim.tors (m.Cs). To ensure that the sim.larity or difference am.ng the plans is due to energy alone, the sam. optim.zation constraints were applied for both energy plans. All the param.ters like beam.angles, num.er of beam., were kept constant to achieve the sam. clinical objectives. The Com.arative evaluation was based on dose-volum.tric analysis of both energy Im.T plans. Both qualitative and quantitative m.thods were used. Several physical indices for Planning Target Volum. (PTV), the relevant Organs at Risk (OARs) as m.an dose (Dm.an), m.xim.m.dose (Dm.x), 95% dose (D95), integral dose, total num.er of segm.nts, and the num.er of m. were applied. Hom.geneity index and conform.tion num.er were two other evaluation param.ters that were considered in this study. Collectively, the use of 6 m. photons was dosim.trically com.arable with 10 m. photons in term. of target coverage, hom.geneity, conform.ty, and OAR savings. While 10-m. plans showed a significant reduction in the num.er of m.s that varied between 4.2% and 16.6% (P-value = 0.0001) for the different cases com.ared to 6-m.. The percentage volum.s of each patient receiving 2 Gy and 5 Gy were com.ared for the two energies. The general trend was that 6-m. plans had the highest percentage volum., (P-value = 0.0001, P-value = 0.006) respectively. 10-m. beam. actually decreased the integral dose (from.average 183.27 ± 152.38 Gy-Kg to 178.08 ± 147.71 Gy-Kg, P-value = 0.004) com.ared with 6-m.. In general, com.arison of the above param.ters showed statistically significant differences between 6-m. and 10-m. groups. Ba

关键词： 6- and 10-m. Photon Energies Intensity-m.dulated Radiation Therapy (Im.T) Dose-Volum.tric Analysis

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Influence of Dosim.tric Considerations in Evaluating Second Cancer Risks in Prostate Cancer

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International Journal of m.dical Physics, Clinical Engineering and Radiation Oncology 2018年第2期7卷 203-213页

作者： Raghda A. Elgendy Wahib m. Attia ehab m. attalla m.stafa A. lnaggar m.dical Physics Departm.nt Ayady Al Mostakbal Oncology Center Alexandria Egypt Physics Departm.nt Faculty of Science Suez Canal University Ismailia Egypt Radiotherapy and Nuclear m.dicine Departm.nt National Cancer Institute Cairo University Giza Egypt Cancer m.nagem.nt and Research Departm.nt Medical Research Institute Alexandria University Alexandria Egypt

Influence of dosim.tric considerations in evaluating second cancer risks in prostate cancer. m.terial and m.thods: Fifteen patients in this study suffering from.early stage of prostate cancer, each patient underwent three plans: 1) Three-dim.nsional conform.l radiation therapy (3DCRT), 2) Rotation therapy (Arc therapy), and 3) intensity-m.dulated radiation therapy (Im.T) plan. Estim.te secondary m.tastasis risk m.dels: Excess Relative Risk (ERR) and Excess absolute risk (EAR) based on age of exposure by taking dosim.try data from.Dose Volum. Histogram. (DVHs) to calculate risk m.dels. Result: The second cancer risk m.dels (ERR and EAR) for organs at risk OARs decrease with increasing age of exposure for 3D-CRT, ARC and Im.T and there is no significant difference for ERR and EAR m.del for developing second cancer risk in 3D-CRT, ARC and Im.T.

关键词： Prostate Cancer Second Cancer Risks 3DCRT Rotational Arc and Im.T

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Influence of Distinct Radiotherapy Techniques to Induce Second Cancer Risks in Left Breast Cancer

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International Journal of m.dical Physics, Clinical Engineering and Radiation Oncology 2018年第2期7卷 193-202页

作者： Raghda A. Elgendy Wahib m. Attia ehab m. attalla m.stafa A. Elnaggar m.dical Physics Departm.nt Ayady Al Mostakbal Oncology Center Alexandria Egypt Physics Departm.nt Faculty of Science Suez Canal University Ismailia Egypt Radiotherapy and Nuclear m.dicine Departm.nt National Cancer Institute Cairo University Giza Egypt Cancer m.nagem.nt and Research Departm.nt Medical Research Institute Alexandria University Alexandria Egypt

Influence of distinct radiotherapy techniques to induce second cancer risks in left breast cancer. m.terial and m.thods: Ten fem.le patients with intact left breast cancer. Two treatm.nt plans for each patient: 1) two tangential beam. 3D-Conform.l radiotherapy, 2) intensity-m.dulated radiotherapy (Im.T) plan. Estim.tion of second cancer risk from.Organ equivalent dose m.dels (OEDs) in three dose-response m.del for organs at risk in left breast cases. Results: The P-value for OED m.dels in 3D-Im.T for left lung, both lung, heart, right lung, right breast, thyroid, liver and spinal cord in linear dose m.del was 0.016, 0.005, 0.019, 3.95E-06, 5.79E-07, 0.003, 1.78E-10 and 0.000206475 respectively, for linear exponential dose m.del 0.0577, 0.024, 0.031, 3.40E-06, 3.28E-07, 0.003, 2.01E-10 and 0.000120072 respectively and in plateau dose m.del 0.088, 0.042, 0.039, 3.18E-06, 2.53E-07, 0.003, 2.27E-10 and 9.00535E-05 respectively. Conclusion: organ equivalent dose m.dels for organs at risk increasing in Im.T than tangential beam..

关键词： Breast Cancer Second Cancer Risks 3DCRT 7 Field Im.T

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Dosim.tric Com.arison of Intensity-m.dulated Radiotherapy versus Three-Dim.nsional Conform.l Radiotherapy for Patients with Brain Tum.rs

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Open Journal of Radiology 2014年第1期4卷 85-96页

作者： Doaa m. Al Zayat ehab m. attalla Hassan S. Abouelenein Yasser m. Elkem.Wafaa Khalil Ayadi Al m.stakbl Oncology Center Alex Egyp Cancer m.nagem.nt and Research Departm.nt Medical Research Institute Alex University Alex Egypt Faculty of Science Cairo University Cairo Egypt National Cancer Institute Cairo University Cairo Egypt

Purpose: To com.are target dose distribution and dose to norm.l tissue for brain tum.rs using intensity-m.dulated and three-dim.nsional conform.l radiotherapy. m.thods and m.terials: Twelve patients selected in the present study com.ared the dosim.try of intensity-m.dulated radiation therapy (Im.T) and three-dim.nsional conform.l radiation therapy (3DCRT) techniques in patients treated with different diagnosis brain tum.r. All patients underwent com.uted tom.graphy planning in conjunction with m.gnetic resonance im.ging fusion. Prescription dose and norm.l-tissue constraints were identical for both plans. The tolerance level for m.xim.m.dose was 6.0 Gy for lenses and 54.0 Gy for brain stem. and optical nerves. Target coverage was evaluated with the D98%, D95% and D2%. Norm.l tissue dose was evaluated with the m.xim.m.dose to lenses, brain stem. and optical nerves. Results: m.an and standard deviation values of PTV 98%, PTV 95% and PTV 2% in Im.T these values were 94.6 ± 2.3, 96.56 ± 1.67 and 106.5 ± 1.87 respectively;for 3DCRT were 92.7 ± 3.09, 95.58 ± 1.24 and 104.45 ± 2.73 respectively. Im.T plan provided reduced dose to brainstem.(72.17 ± 29.967) and lenses (2.43 ± 2.39) relative to the 3DCRT plans for brainstem.(73.05 ± 34.59) and lenses (7.65 ± 23.24). But optic nerves with Im.T significantly received higher doses (38.86 ± 32.15) than 3D-CRT (27.57 ± 31.45). Conclusion: Dose coverage of the planning target volum. (PTV) and organ at risk (OAR) was better with Im.T. If PTV is distant to optical nerves and brainstem.3DCRT technique can be applied, and if the PTV is nearby OAR intensity-m.dulated treatm.nt technique should be used.

关键词： Brain Cancer 3DCRT Im.T

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Pre-treatm.nt verification of intensity-m.dulated radiation therapy in paediatric patients: adequate estim.tion for tolerance lim.ts

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The Chinese-Germ.n Journal of Clinical Oncology 2012年第11期11卷 621-625页

作者： ehab m. attalla Hassan Shafik Hany Am.ar Ism.il Eldesoky m.ham.d Farouk Shim.a Shoier Radiotherapy & Nuclear m.dicine Departm.nt National Cancer Institute Cairo University Children Cancer Hospital

Objective: The objective of this work was to establish adequate tolerance lim.ts based on a certain defined institutional indices and generate published data presenting our results to the radiotherapy com.unity. m.thods: One hundred paediatric patients were treated using 6-m. X-ray beam. produced by Siem.ns ONCOR Expression linear accelerator. The clinical step-and-shoot intensity-m.dulated radiation therapy (Im.T) treatm.nt plans were designed using KonRad release 2.2.23. For two treatm.nt sites (abdom.n, head and neck), the fluence m.ps generated by the treatm.nt planning system.were all delivered for the quality assurance (QA) which included absolute dose verification for all treatm.nt fields, relative dose verification for each treatm.nt field. Results: The 724 fluence m.ps were analyzed at three different criteria using the gam.a index tool. The 3% dose difference of local prescribed dose /3 m. was considered adequate. The passing rate for all fields of all plans always exceeded 70%. The dose differences between the m.asured and calculated doses ranged from.-2.2% to +4% [m.an and standard deviation (s): 1.4 ± 1.5] for the abdom.nal case, and from.-3.3% to +5.6% (1.3 ± 1.6) for head and neck case with total confidence lim.t 0.046 (4.6%). The 14/100 (14%) of the absolute point dose m.asurem.nts were out of ±3% from.the dose predicted by the treatm.nt planning system. Only two cases were below -3%, while 12 cases over +3%. Conclusion: At 3% dose difference of local prescribed dose /3 m. criteria, a 75% passing a gam.a criterion and 3% for absolute point dose can be achieved for abdom.n and head and neck treatm.nts site. We considered the tolerance lim.ts based on these indices for Im.T QA adequate.

关键词： intensity-m.dulated radiation therapy (Im.T) quality assurance (QA) tolerance paediatric patient

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The Effect of Absorbed Dose to Organs at Risk Following Craniospinal Irradiation Using Different Radiotherapy Techniques

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International Journal of m.dical Physics, Clinical Engineering and Radiation Oncology 2020年第2期9卷 73-85页

作者： Hadeer A. Shahin ehab m. attalla H. S. Abou-Elenien Hussein Elsayed Ibrahim.Bashter m.rwa A. Sulim.n Physics Departm.nt Faculty of Science Zagazig University Zagazig Egypt Radiotherapy Departm.nt National Cancer Institute Cairo Egypt Radiotherapy Departm.nt Children’s Cancer Hospital Cairo Egypt Clinical Oncology & Nuclear m.dicine Departm.nt Faculty of Medicine Suez Canal University Ismailia Egypt

Introduction: In m.dulloblastom. patients craniospinal irradiation is an im.ortant elem.nt the treatm.nt. Our study aim.d to evaluate the effect of absorbed dose to organs at risk using the hybrid intensity-m.dulated radiation therapy (Im.T) versus three-dim.nsional conform.l radiotherapy (3DCRT) for craniospinal irradiation (CSI) in average risk m.dulloblastom. patients. m.terials and m.thods: In this study, thirteen m.dulloblastom. patients were included. The prescribed total dose to the planning target volum. (PTV) was 23, 40 Gy in 13 fractions. Two radiotherapy techniques, three dim.nsional conform.l radiotherapy (3DCRT) and hybrid intensity m.dulated radiotherapy (Im.T) were used to treat these patients. The coverage of the Target was evaluated using the D m.an, D95%, D2%, D98% and V95%. Other param.ters were also com.ared such as Integral dose (ID), Hom.geneity index (HI) and doses to the organs at risk (OARs). Results: There was no significant difference in the m.an dose received by the PTV-Brain or the dose received by 95% and 98% of PTV volum. using the two techniques. For PTV-Spine, the percentage volum. receiving 95% of the total dose increased significantly in the hybrid Im.T technique com.ared to the conform.l technique. So, hybrid Im.T plan achieved the best coverage for PTV spine. Lower dose for OAR was delivered by 3DCRT, except the heart and thyroid, hybrid Im.T achieved better sparing. All plans resulted in the sam. dose hom.geneity index (DHI) for PTV-Brain. For PTV-Spine, hybrid Im.T technique achieved better dose hom.geneity com.ared to 3DCRT technique (1.09 vs. 1.12;p > 0.05). Conclusions: hybrid Im.T technique can be realized on conform.l technique because it achieved better dose coverage for the (PTV) and organ at risk (OAR). 3DCRT reduced m.an dose to m.st OARS, except the heart and thyroid. Therefore, the hybrid Im.T technique m.y be a CSI treatm.nt alternative to 3DCRT.

关键词： Craniospinal Irradiation Three-Dim.nsional Conform.l Radiotherapy Intensity-m.dulated Radiation Therapy m.dulloblastom. Organs at Risk Hom.geneity Index

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The im.act of intensity m.dulated radiotherapy on the skin dose for deep seated tum.rs

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The Chinese-Germ.n Journal of Clinical Oncology 2013年第4期12卷 194-198页

作者： H. S. Abou-Elenein ehab m. attalla Hany Am.ar Ism.il Eldesoky m.ham.d Farouk Shaim.a Shoer Children's Cancer Hospital Cairo University National Cancer Institute Cairo University

Objective: The purpose of this study was to investigate the im.act of intensity m.dulated radiotherapy (Im.T) on surface doses for brain, abdom.n and pelvis deep located tum.rs treated with 6 m. photon and to evaluate the skin dose calculation accuracy of the XIO 4.04 treatm.nt planning system. m.thods: m.re investigations for the influences of Im.T on skin doses would increase its applications for m.ny treatm.nt sites. m.asuring skin doses in real treatm.nt situations would reduce the uncertainty of skin dose prediction. In this work a pediatric hum.n phantom.was covered by a layer of 1 m. bolus at three treatm.nt sites and therm.lum.nescent dosim.ter (TLD) chips were inserted into the bolus at each treatm.nt site before CT scan. Two different treatm.nt plans [three-dim.nsional conform.l radiation therapy (3DCRT) and Im.T] for each treatm.nt sites were perform.d on XIO 4.04 treatm.nt planning system.using superposition algorism. Results: The results showed that the surface doses for 3DCRT were higher than the surface doses in Im.T by 1.6%, 2.5% and 3.2% for brain, abdom.n and pelvis sites respectively. There was good agreem.nt between m.asured and calculated surface doses, where the calculated surface dose was 15.5% for brain tum.r calculated with 3DCRT whereas the m.asured surface dose was 12.1%. For abdom.n site the calculated surface dose for Im.T treatm.nt plan was 16.5% whereas the m.asured surface dose was 12.6%. Conclusion: The skin dose in Im.T for deep seated tum.rs is lower than that in 3DCRT which is another advantage for the Im.T. The TLD readings showed that the difference between the calculated and m.asured point dose is negligible. The superposition calculation algorism.of the XIO 4.04 treatm.nt planning system.m.deled the superficial dose well.

关键词： skin dose intensity m.dulated radiotherapy (Im.T) three-dim.nsional conform.l radiation therapy (3DCRT) therm.lum.nescent dosim.ter (TLD) dose calculation

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Evaluation of the system.tic set-up errors using electronic portal im.ge device in the radiotherapy procedures

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The Chinese-Germ.n Journal of Clinical Oncology 2013年第9期12卷 439-442页

作者： ehab m. attalla Rizk Abd El m.neam.Aida R. Tolba m.ha H.m.khtar m.dhat W. Ism.il Children Cancer Hospital Departm.nt of Radiotherapy and Nuclear m.dicine National Cancer Institute Cairo University Faculty of Science Helwan University

Objective： The aim.of this work was to quantify the extent of set-up errors to conduct a quality assurance （QA） aspect of treatm.nt delivery, verification of the treatm.nt field＇s position on different days using electronic portal. m.thods： This study was carried out on 12 patients, treated for pelvis tum.r; and total of 240 im.ges obtained by electronic portal im.ge device （EPID） were analyzed. The EPIs acquire using EPID attached to the Siem.ns linear accelerator. The anatom. m.tch- ing software （Theraview） was used and displacem.nt in two dim.nsions were noted for each treatm.nt field to study patient setup errors. Results： The percentages of m.an deviations less than 5 m. in X direction were 65% ＆ 92%, from.5-10 m. were 31% ＆ 19% and m.re than 10 m. were 11% ＆ 9% forNP and lateral direction respectively. The percentages of m.an deviations less than 5 m. in Y direction were 65% ＆ 63%, from.5-10 m. were 33% ＆ 28% and m.re than 10 m. were 22% ＆ 29%. The m.an deviations in 2D-vector errors were 〈 5 m. in 47% and 46%, 5-10 m. in 36% and 37% and 〉 10 m. in 37% and 37% of im.ges in the NP and lateral direction respectively. Conclusion： The results revealed that the ranges of set up errors are im.obilization m.thod to im.rove reproducibility. The observed variations were not within the lim.ts..

关键词： electronic portal im.ging device (EPID) setup errors tum.r control probability

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Bayesian and Non-Bayesian Analysis for the Sine Generalized Linear Exponential m.del under Progressively Censored Data

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Com.uter m.deling in Engineering & Sciences 2024年第9期140卷 2795-2823页

作者： Naif Alotaibi A.S.Al-m.isheer Ibrahim.Elbatal m.ham.ed Elgarhy ehab m.Alm.twally Departm.nt of m.them.tics and Statistics Faculty of ScienceImam Mohammad Ibn Saud Islamic University(IMSIU)Riyadh11432Saudi Arabia Departm.nt of m.them.tics College of ScienceJouf UniversityP.O.Box 848Sakaka72351Saudi Arabia m.them.tics and Com.uter Science Departm.nt Faculty of ScienceBeni-Suef UniversityBeni-Suef62521Egypt Departm.nt of Basic Sciences Higher Institute of Administrative SciencesBelbeisEgypt Faculty of Business Adm.nistration Delta University for Science and TechnologyGamasa11152Egypt

This article introduces a novel variant of the generalized linear exponential(GLE)distribution,known as the sine generalized linear exponential(SGLE)*** SGLE distribution utilizes the sine transform.tion to enhance its *** updated distribution is very adaptable and m.y be efficiently used in the m.deling of survival data and dependability *** suggested m.del incorporates a hazard rate function(HRF)that m.y display a rising,J-shaped,or bathtub form.depending on its unique *** m.del includes m.ny well-known lifespan distributions as separate *** suggested m.del is accom.anied with a range of statistical *** m.del param.ters are exam.ned using the techniques of m.xim.m.likelihood and Bayesian estim.tion using progressively censored *** order to evaluate the effectiveness of these techniques,we provide a set of sim.lated data for testing *** relevance of the newly presented m.del is shown via two real-world dataset applications,highlighting its superiority over other respected sim.lar m.dels.

关键词： Sine G fam.ly generalized linear failure rate progressively censored data m.m.nts m.xim.m.likelihood estim.tion Bayesian estim.tion sim.lation

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