نتایج جستجو برای: photon and neutron flux

تعداد نتایج: 16868852  

ژورنال: سنجش و ایمنی پرتو 2018

  In radiation therapy with high-energy photon beams (E > 10 MV) neutrons are generated mainly in LINACs head thorough (γ,n) interactions. These neutrons affect the shielding requirements in radiation therapy rooms. According to the AAPMTG-34 report, photon absorbed dose of 10Gy can cause permanent damage to the pacemaker and the dose of 2Gy can make minor changes in the functioning of the pac...

Asghar Hadadi, Maryam Dehghanpour Reza Molazadeh Somayeh Gholami,

Introduction: In radiation therapy with high-energy photon beams (E > 7 MeV) neutrons are generated mainly in LINACs head thorough (γ, n) interactions. These neutrons affect the shielding requirements in radiation therapy rooms. According to the protocol TG-34, photon absorbed dose of 10Gy can cause permanent damage to the pacemaker and the dose of 2Gy can make minor changes in...

Journal: :journal of biomedical physics and engineering 0
m azizi aa mowlavi

bachground: hadron therapy is a novel technique of cancer radiation therapy which employs charged particles beams, 1 h and light ions in particular. due to their physical and radiobiological properties, they allow one to obtain a more conformal treatment, sparing better the healthy tissues located in proximity of the tumor and allowing a higher control of the disease.   objective: as it is well...

Journal: :basic and clinical cancer research 0
hoda darestani 1nuclear engineering department, science and research unit, azad university, tehran, i.r. iran hassan ali nedaie radiotherapy oncology department, cancer institute, tehran university of medical sciences, tehran, i.r. iran azim arbabi radiation oncology department, imam hussein medical center, faculty of medicine, shahid beheshti university of medical sciences, tehran, i.r. iran kheirollah mohammadi nuclear engineering department, amirkabir industrial university, tehran, i.r. iran mahmood allahverdi radiotherapy oncology department, cancer institute, tehran university of medical sciences, tehran, i.r. iran arjang shahvar agricultural, medical and industrial research school, karaj, i.r. iran

background : in spite of clinically useful photon and electron beams, high energy linacs produce secondary particles such as neutrons (photo-neutron production). neutrons have important roles during treatment with high energy photons in terms of protection and dose escalation. in this project, neutron dose equivalent of 18 mv varian accelerators is calculated by tld600 and tld700. materials and...

Journal: :iranian journal of radiation research 0
kakavand 1 department of physics, zanjan university, zanjan, iran ghafourian atomic energy organization of iran, tehran, iran haji-shafeieha 1 department of physics, zanjan university, zanjan, iran

background: miniature neutron sources with high neutron flux have abundant applications in medicine, industry and researches. the most important general characteristic of miniature neutron sources is their diameter which is 3mm in average. in this research, we have surveyed and designed an am-be miniature neutron source fabrication. materials and methods: this investigation resulted in creation...

Amir Danyaei Farnaz Rahimli Hojattolah Shabazian Mansour Zabihzadeh Mohammad Ali Behrooz

Introduction: Boron neutron capture therapy (BNCT) is recommended to treat the glioblastoma tumor. It is well known that neuron beams are more effective treatment than photon beams to treat hypoxia tumors due to interaction of neutron with nucleus and production of heavy particles such as 7Li and alpha particle. In this study to evaluate the suitability of BNCT for treating of ...

Journal: :iranian journal of medical physics 0
mona zolfaghari department of physics, faculty of science, k. n. t university of technology, tehran, iran mahmood sedaghatizadeh department of physics, faculty of science, k. n. t university of technology, tehran, iran

introduction electron linear accelerator (linac) can be used for neutron production in boron neutron capture therapy (bnct). bnct is an external radiotherapeutic method for the treatment of some cancers. in this study, varian 2300 c/d linac was simulated as an electron accelerator-based photoneutron source to provide a suitable neutron flux for bnct. materials and methods photoneutron sources w...

Background: One of the main causes of induction of secondary cancer in radiation therapy is neutron contamination received by patients during treatment.Objective: In the present study the impact of wedge and block on neutron contamination production is investigated. The evaluations are conducted for a 15 MV Siemens Primus linear accelerator. Methods: Simulations were performed using MCNPX Monte...

Journal: :journal of biomedical physics and engineering 0
m t bahreyni toossi medical physics department, faculty of medicine, mashhad university of medical sciences, mashhad, iran b khajetash medical physics department, faculty of medicine, mashhad university of medical sciences, mashhad, iran m ghorbani medical physics department, faculty of medicine, mashhad university of medical sciences, mashhad, iran

background: one of the main causes of induction of secondary cancer in radiation therapy is neutron contamination received by patients during treatment. objective: in the present study the impact of wedge and block on neutron contamination production is investigated. the evaluations are conducted for a 15 mv siemens primus linear accelerator.  methods: simulations were performed using mcnpx mon...

حجازی, پیمان, سیستانی, سروش, صفری, محمد جواد,

Background and purpose: High-energy photon beams above 8-10 MV used in external radiation therapy produce neutron in dealing with the linear accelerator components and other parts in radiation field. The weakening of neutrons due to the closing jaws collimator angle, in smaller field sizes can also be a contributing factor in changing the neutron spectrum. Since a direct measurement of the...

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