نتایج جستجو برای: depth dose

تعداد نتایج: 468234  

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

background: radiosurgery is a focal brain irradiation technique that delivers, usually in a single session, high dose of ionizing radiation. the presence of lateral electronic disequilibrium and steep dose gradients in small fields demands special attention to the selection of a suitable detector with respect to its size, composition and response. materials and methods : small circular fields w...

Abaspour, Alireza , Khosroabadi, Mohsen , Naghiloo, Mahsa , Sadeghi, Hamid Reza , Sadoughi, Hamid-Reza ,

Introduction: Radiation therapy is one of the most important methods of cancer treatment. Radiation therapy uses symmetric and asymmetric fields in which the radiation dose distribution is different. To calculate the dose distribution, computer treatment planning systems are used which must have acceptable calculations accuracy. The aim of this study was to investigate the accuracy of the dose ...

Journal: :iranian journal of radiation research 0
s.m. abtahi university of shahid beheshti, radiation medicine department, p. o. box 19839- 63113, tehran, iran s.m.r. aghamiri university of shahid beheshti, radiation medicine department, p. o. box 19839- 63113, tehran, iran h khalafi nuclear science and technology research institute (nstri), tehran, iran f. rahmani university of shahid beheshti, radiation medicine department, p. o. box 19839- 63113, tehran, iran

background: the aim of this work was to establish how well gel dosimeters performed, as substitutes for brain tissue compared with standard phantom materials such as water, polymethyl-methacrylate (or pmma), a150 plastic and te- liquid phantom material for dosimetry of neutron beams in boron neutron capture therapy. materials and methods: thermal neutron fluence, photon dose and epithermal neut...

M Hazbavi M J Tahmasebi Birgani, M Tahmasbi N Chegeni, S M Hoseini

Background: In radiotherapy, low-energy photon beams are better adapted to the treated volume, and the use of high-energy beams can reduce hot spots in the radiation therapy. Therefore, mixing low and high energies with different ratios can control the rate of hotspots, as well as the dose distribution of the target volume.Material and Methods: The percentage depth doses (PDDs) were calculated ...

Background: External beam radiation therapy is often administered to patients implanted with silicone gel breast prosthesis. The aim of this study was to investigate the influence of silicone gel breast prosthesis on photon dose distributions. In the event of recurrence, the oncologist may be forced to irradiate through the prosthetic device. To quantify the dose enhancement or reduction below ...

B.M. Park, B.O. Choi, B.Y. Choe, J.B. Chung, J.W. Lee, J.Y. Jung, T.S. Suh, Y.J. Shin, Y.K. Bae, Y.L. Kim,

Background: Dose calculation algorithms play a very important role in predicting the explicit dose distribution. We evaluated the percent depth dose (PDD), lateral depth dose profile, and surface dose volume histogram in inhomogeneous media using calculation algorithms and inhomogeneity correction methods. Materials and Methods: The homogeneous and inhomogeneous virtual slab phantoms used in th...

Journal: :iranian journal of radiation research 0
a. mesbahi medical physics department, medical school and radiation oncology department, imam khomeini hospital, tabriz university of medical sciences, tabriz, iran

background: prediction of the absorbed dose in irradiated volume plays an important role in the outcome of radiotherapy. application of small fields for radiotherapy of thorax makes the dose calculation process inaccurate due to the existence of electronic disequilibrium and intrinsic deficiencies in dose calculation algorithms. to study the lung absorbed dose in radiotherapy with small fields,...

Journal: :Japanese Journal of Radiological Technology 1988

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
a.a. mowlavi physics department, sabzevar tarbiat moallem university, sabzevar, iran a. afzali physics department, sabzevar tarbiat moallem university, sabzevar, iran n. afzali physics department, imam khomeini university of sabzevar, sabzevar, iran

background: skin cancer can be treated by various methods. electron radiotherapy has been a useful therapeutic modality in the treatment of skin cancers in areas which are difficult to cure by other methods. depth dose distribution of 166ho using varskin2 code is presented in this work. material and methods: depth dose distribution of 166ho was calculated, using varskin2 code by adding of 166ho...

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