نتایج جستجو برای: photon beam

تعداد نتایج: 178633  

1994
Kingman Cheung

We present the photoproduction of an intermediate mass Higgs (IMH) boson associated with a W boson at the future electron-proton colliders using bremsstrahlung photon beam or laser backscattered photon beam. With bremsstrahlung photon beam the search for the IMH boson is unfavorable because of the small signal rate. But with laser photon beam the search is viable due to a much larger rate, and ...

Journal: :iranian journal of cancer prevention 0
sh babazade breast cancer study group, isfahan university of medical sciences, isfahan, iran h emami school of medicine, isfahan university of medical sciences, isfahan, iran ar amouheidari breast cancer study group, isfahan university of medical sciences, isfahan, iran m roayaei breast cancer study group, isfahan university of medical sciences, isfahan, iran a hassanzade school of public health, isfahan university of medical sciences, isfahan, iran a akbari cancer research center, shahid beheshti university of medical sciences, tehran, iran

background: to compare the cosmetic results of whole breast radiotherapy between cobalt 60 and photon 9megavolt in patients underwent breast conserving surgery. methods: the patients with breast saving surgery who were treated by whole breast radiotherapy with either cobalt 60 or photon 9mv between 2001-2006 in sayed-al-shohada hospital entered the study. the cosmetic results were evaluated by ...

AbstractIntroduction Silicone gel breast implants are used for breast reconstruction post mastectomy. In the event of cancer recurrence, the radiation oncologists are forced to irradiate through the prosthesis device. Due to prosthesis higher atomic number dose perturbations occur during treatment. This study determined the influence of silicone gel thickness on the photon beam distribution. Ma...

2012
Yunfei Huang R. Alfredo Siochi John E. Bayouth

The purpose of this study was to report the characteristics of an equivalent quality unflattened (eqUF) photon beam in clinical implementation and to provide a generalized method to describe unflattened (UF) photon beam profiles. An unflattened photon beam with a beam quality equivalent to the corresponding flat 6 MV photon beam (WF) was obtained by removing the flattening filter from a Siemens...

Journal: :iranian journal of medical physics 0
seyed ali vaezzadeh ph. d. student in medical physics, tehran university of medical science, tehran, iran mahmood allahverdi associate professor, medical physics dept., tehran university of medical science, tehran, iran hasan nedaie assistant professor, radiotherapy dept., cancer institute, tehran university of medical science, tehran, iran mahdi aghili assistant professor, radiotherapy dept., cancer institute, tehran university of medical science, tehran, iran mahbod esfehani m.sc. in medical physics, radiotherapy dept., cancer institute, tehran university of medical science, tehran, iran ehsan mohammadi m.sc. in medical physics, radiotherapy dept., cancer institute, tehran university of medical science, tehran, iran

introduction: this study was designed to evaluate dosimetric parameters such as rectal dose, bladder dose, integral dose (id), homogeneity index (hi) and conformity index (ci) in various treatment plans for prostate cancer. materials and methods: pelvic computed tomography (ct) scans of 27 patients were acquired and transferred to the rtdoseplan treatment planning system. for each patient, 8 co...

D. Demir, G. Yegin, H.O. Tekin, I. Akkurt, K. Gunoglu, Z.N. Demirci,

Background: As bremsstrahlung photon beam fluence is important parameter to be known in a photonuclear reaction experiment as the number of produced particle is strongly depends on photon fluence. Materials and Methods: Photon production yield from different thickness of aluminum target has been estimated using artificial neural network (ANN) model. Target thickness and incoming electr...

Introduction: Craniospinal radiotherapy is a therapeutic technique for central nervous system (CNS) tumors, which requires meticulous attention to technique and dosimetry.Treatment planning system (TPS) is one of the main equipment in radiotherapy; therefore, the evaluation of its accuracy is essential for dose calculation. The present study evaluates the validity of Isogray TPS in craniospinal...

Introduction: In clinical electron beams, most of bremsstrahlung radiation is produced by various linac head structures. This bremsstrahlung radiation dose is influenced by the geometry and construction of every component of the linac treatment head structures. Thus, it can be expected that the amount of the contaminated photon dose due to bremsstrahlung radiation varies among different linacs,...

Journal: :journal of medical signals and sensors 0
hamid-reza sadoughi shahrokh nasseri mahdi momennezhad hamid-reza sadeghi mohammad hossein bahreyni

radiotherapy dose calculations can be evaluated by monte carlo (mc) simulations with acceptable accuracy for dose prediction in complicated treatment plans. in this work, standard, livermore and penelope electromagnetic (em) physics packages of geant4 application for tomographic emission (gate) 6.1 were compared versus monte carlo n-particle extended (mcnpx) 2.6 in simulation of 6 mv photon lin...

Hojatollah Shahbazian Jafar Fatahiasl Mansour Zabihzadeh Mohammad Ali Behrooz Mohammad Javad Tahmasebibirgani Nahid Chegeni Reza Maskani

Introduction: Photon contamination is a restriction on treatment with electron that increase dose to healthy tissue below the tumor. The aim of this study is to reduce the photon contamination using a magnet system. Materials and Methods: A mini-applicator equipped with two neodymium boron permanent magnets was designed which make it possible to adjust the d...

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