نتایج جستجو برای: photon dose measurement

تعداد نتایج: 796871  

2005
P. ANDREO

Modern radiotherapy relies on accurate dose delivery to the prescribed target volume. The ICRU has recommended an overall accuracy in tumour dose delivery of ±5%, based on an analysis of dose response data and on an evaluation of errors in dose delivery in a clinical setting. Considering all uncertainties involved in the dose delivery to the patient, the ±5% accuracy recommendation is by no mea...

Journal: :Medical physics 2012
Jose Perez-Calatayud Facundo Ballester Rupak K Das Larry A Dewerd Geoffrey S Ibbott Ali S Meigooni Zoubir Ouhib Mark J Rivard Ron S Sloboda Jeffrey F Williamson

PURPOSE Recommendations of the American Association of Physicists in Medicine (AAPM) and the European Society for Radiotherapy and Oncology (ESTRO) on dose calculations for high-energy (average energy higher than 50 keV) photon-emitting brachytherapy sources are presented, including the physical characteristics of specific (192)Ir, (137)Cs, and (60)Co source models. METHODS This report has be...

2012
Masahiro Nakano Robin F. Hill May Whitaker Jung‐Ha Kim Zdenka Kuncic

The present study quantified surface doses on several rectangular phantom setups and on curved surface phantoms for a 6 MV photon field using the Attix parallel-plate chamber and Gafchromic EBT2 film. For the rectangular phantom setups, the surface doses on a homogenous water equivalent phantom and a water equivalent phantom with 60 mm thick lung equivalent material were measured. The measureme...

H. Canakci, I. Akkurt,

Background: Radiation shielding properties is an important for a material wish can be used the photon attenuation coefficients of clay produced using different rate of boron have been measured for the purpose of radioactive waste disposal. Materials and Methods: The measurement has been performed using gamma spectrometer contains NaI (Tl) detector at the photon energies of 662, 1173 an...

2012
Eduardo de Paiva Luiz A. R. da Rosa

The skyshine radiation phenomenon consists of the scattering of primary photon beams in the atmosphere above the roof of a medical linear accelerator facility, generating an additional dose at ground level in the vicinity of the treatment room. Thus, with respect to radioprotection, this situation plays an important role when the roof is designed with little shielding and there are buildings ne...

Journal: :Medical physics 1999
X A Li

The peak scatter factor (PSF) for a photon beam is defined as the ratio of the total dose and the primary dose at the depth of dose maximum. The values of the PSF for photon beams ranging from 60Co to 24 MV are calculated using the EGS4 Monte Carlo technique, to avoid measurement difficulties. The calculation shows that the effect of SSD on PSF for high energy photon beams is not significant fo...

2013
Maria F. Chan Qinghui Zhang Jingdong Li Preeti Parhar Karen Schupak Chandra Burman

Purpose: To evaluate the measured dose distributions using radiochromic EBT2 films for small fields in iPlan (BrainLab) commissioning. Methods: Radiochromic EBT2 films were irradiated with 6 MV photons on a Varian Trilogy linac using polystyrene phantoms. The measurements included dose profiles and depth doses for field sizes of 1 × 1, 2 × 2, 3 × 3, 4 × 4, and 10 × 10 cm etc. The dose profile m...

Background: The purpose of this study is to fabricate inexpensive in-house low cost homogeneous and heterogeneous human equivalent thorax phantom and assess the dose accuracy of the Treatment Planning Systems (TPS) calculated values for different lung treatment dosimetery. It is compared with Thermoluminescent Dosimeter (TLD) measurement. Materials and Methods: Homogeneous and heterogeneous tho...

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,...

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