نتایج جستجو برای: Linear accelerator

تعداد نتایج: 493037  

Journal: :iranian journal of medical physics 0
mohammad taghi bahreyni toossi professor, medical physics research center, bu-ali research institute, mashhad university of medical sciences, mashhad, iran mehdi momen nezhad ph.d., linear accelerator dept., imam reza hospital, mashhad university of medical sciences, mashhad, iran seyed mohammad hashemi m.sc., medical physics research center, mashhad university of medical sciences, mashhad, iran

introduction: in recent decades, several monte carlo codes have been introduced for research and medical applications. these methods provide both accurate and detailed calculation of particle transport from linear accelerators. the main drawback of monte carlo techniques is the extremely long computing time that is required in order to obtain a dose distribution with good statistical accuracy. ...

Journal: :iranian journal of radiation research 0
m. hajizadeh saffar medical physics department, mashhad university of medical sciences, mashhad, iran m.r. ghavamnasiri h. gholamhosseinian

background: in radiotherapy, wedge filters are used for optimizing the tumor dose distribution in patients. the attenuation in beam intensity due to the presence of wedge filter is compensated by means of a wedge factor measured at the central axis of the beam. the field size, depth and ssd dependence of wedge factor have been assessed for 9mv radiations of neptun pc linear accelerator. materia...

Journal: :journal of biomedical physics and engineering 0
n mohammadi s h miri-hakimabad l rafat-motavalli

background: high-energy linear accelerator (linac) is a valuable tool and the most commonly device for external beam radiation treatments in cancer patients. in the linac head, high-energy photons with energies above the threshold of interaction produce photoneutrons. these photoneutrons deliver the extra dose to the patients in the planning treatment and increase the risk of secondary cancer. ...

Journal: :iranian journal of medical physics 0
zahra anjomani m.sc. in medical physics, nuclear engineering dept., shahid beheshti university, tehran, iran hasan nedaie assistant professor, radiotherapy physics dept., tehran university of medical science, tehran, iran majid shariari associate professor, nuclear engineering dept, shahid beheshti university, tehran, iran

introduction: nowadays new radiochromic films have an essential role in radiotherapy dosimetry. properties such as high sensitivity, good reproducibility, high spatial resolution, easy readout and portability have made them attractive for dosimetry, especially in high-dose-gradient regions. material and methods: in this study, electron-beam dose distributions in homogenous and heterogeneous pha...

Journal: :iranian journal of radiation research 0
m.t. bahreyni toossi department of medical physics, mashhad university of medical sciences, mashhad a.r. khoshbin khoshnazar

background: a set of hardware stereotactic radiosurgery is designed and constructed. the scope of this article is to describe how we have designed and developed stereotactic collimation assembly for a 9 mv neptun 10 pc linac. materials and methods: one collimator holder and six collimators were made, with their radiation field diameter between 12.5 mm to 25 mm at isocenter level. beam data, suc...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه شهید بهشتی 1387

چکیده ندارد.

Journal: :iranian journal of medical physics 0
mohammad amin mosleh-shirazi physics unit, department of radiotherapy and oncology, namazi hospital, shiraz university of medical sciences, shiraz, iran 2- ionizing and non-ionizing radiation protection research center, school of paramedical sciences, shiraz university of medical sciences, shiraz, iran saeed rahimi department of medical physics and engineering, school of medicine, shiraz university of medical sciences, shiraz, iran student research committee, shiraz university of medical sciences, shiraz, iran sareh karbasi physics unit, department of radiotherapy and oncology, namazi hospital, shiraz university of medical sciences, shiraz, iran

introduction in this study, we aimed to assess the medium-term energy stability of a 6mv elekta compacttm linear accelerator. to the best of our knowledge, this is the first published article to evaluate this linear accelerator in terms of energy stability. as well as investigating the stability of the linear accelerator energy over a period of several weeks, the results will be useful for esti...

C. Chen, C. Xie, D. Jiang, D. Wang, H. Liu, H.L. Zhao, J. Chen, J. Shen, J. Zhang, X. Wang, Z. Bao, Z. Dai,

Background: This paper aimed to analyze the output constancy of a medical linear accelerator using PTW QUICKCHECKwebline and studied the sensitivity of the PTW QUICKCHECKwebline. Materials and Methods:  The paper statistically analyzed the output doses of 6 MV and 10 MV of photons and 6 MeV, 9 MeV, and 12 MeV of electrons from a medical linear accelerator measured before the daily treatment to ...

Journal: :iranian journal of medical physics 0
m. t. bahreyni toosi professor, medical physics research center, bu-ali research institute, mashhad university of medical sciences, mashhad, iran. m. momen nezhad ph.d. student in medical physics, mashhad university of medical sciences, mashhad, iran h. saberi ph.d. student in medical physics, mashhad university of medical sciences, mashhad, iran m. h. bahreyni toosi professor, medical physics research center, bu-ali research institute, mashhad university of medical sciences, mashhad, iran. a. hashemian assistant professor, medical physics research center, bu-ali research institute, mashhad university of medical sciences, mashhad, iran. r. salek assistant professor, radiation oncology dept., imam reza hospital, mashhad university of medical sciences, mashhad, iran.

ntroduction:  monte  carlo  simulation  is  the  most  accurate  method  of  simulating  radiation  transport  and  predicting doses at different points of interest in radiotherapy. a great advantage of the monte carlo method  compared  to  the  deterministic  methods  is  the  ability  to  deal  accurately  with  any  complex  geometry.  its  disadvantage is the extremely long computing time r...

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