نتایج جستجو برای: air kerma strength

تعداد نتایج: 408460  

Journal: :Physics in medicine and biology 2011
O A Awunor A R Lecomber N Richmond C Walker

This paper details a practical method for deriving the reference air kerma rate calibration coefficient for Farmer NE2571 chambers using the U.K. Institute of Physics and Engineering in Medicine (IPEM) code of practice for the determination of the reference air kerma rate for HDR (192)Ir brachytherapy sources based on the National Physical Laboratory (NPL) air kerma standard. The reference air ...

2006
Shuying Wan Chandra P. Joshi Greg Carnes L. John Schreiner

Automated seed loaders for permanent prostate implants are now commercially available. Besides improved radiation safety, these systems offer seed assay capability and ease of needle loading, making preplanned as well as intra-operative implant procedures more time-efficient. The Isoloader (Mentor Corp., CA) uses individual I125 seeds (SL-125 ProstaSeed) loaded in up to 199 chambers inside a sh...

Journal: :Radiologia brasileira 2016
Beatriz de Lucena Villa-Chan Cantalupo Aline Carvalho da Silva Xavier Clemanzy Mariano Leandro da Silva Marcos Ely Almeida Andrade Vinícius Saito Monteiro de Barros Helen Jamil Khoury

OBJECTIVE To estimate the entrance surface air kerma (Ka,e) and air kerma in the region of radiosensitive organs in radiographs of pediatric paranasal sinuses. MATERIALS AND METHODS Patient data and irradiation parameters were collected in examinations of the paranasal sinuses in children from 0 to 15 years of age at two children's hospitals in the city of Recife, PE, Brazil. We estimated the...

2017
Madan Rehani M. Rehani

Y. Lemoigne and A. Caner (eds.), Radiation Protection in Medical Physics, NATO Science for Peace and Security Series B: Physics and Biophysics 1, DOI 10.1007/978-94-007-0247-9_2, © Springer Science+Business Media B.V. 2011 Abstract A number of radiation units exist for representing radiation dose to patients, staff, public and quantities for radiation equipment performance in radiological pract...

2010
Michelle O’Brien Ronaldo Minniti Stanslaus Alwyn Masinza

Air kerma calibration coefficients for a reference class ionization chamber from narrow x-ray spectra and cesium 137 gamma-ray beams were compared between the National Institute of Standards and Technology (NIST) and the Kenya Bureau of Standards (KEBS). A NIST reference-class transfer ionization chamber was calibrated by each laboratory in terms of the quantity air kerma in four x-ray referenc...

Journal: :Physics in medicine and biology 2001
J Pérez-Calatayud F Ballester Y Limami L A DeWerd K Nelson

In this study, a procedure to test the linear reference air kerma rate of 192Ir wires using a well-type chamber is described. The method is based on a special lead insert with a 1 cm acrylic aperture that provides a differential response of the well chamber. The wire is considered divided into 1 cm parts. Using an external positioning system it is possible to place every part of the wire at the...

Journal: :Radiological physics and technology 2015
Atsushi Fukuda Kosuke Matsubara Tosiaki Miyati

Conventional diagnostic X-ray units are used for radiographic imaging in many countries. For obtaining entrance surface doses, a numerical dose determination method has been applied in Japan. Although this technique is effective, it has to account for errors, particularly fluctuations, due to the beam quality and output of X-ray tubes. As a part of our quality control procedures, we recorded th...

2000
M. O’Brien P. Lamperti T. Williams T. Sander

A direct comparison was made between the air kerma primary standards used for the measurements of low-energy x rays at the National Institute of Standards and Technology (NIST) and the National Physical Laboratory (NPL). The comparison was conducted at the NPL using NPL reference radiation qualities between 10 kV and 80 kV. The results show the primary air-kerma standards to agree within 0.6 % ...

2008
Alessandro Martins da Costa Linda V. E. Caldas

OBJECTIVE: To develop a double-faced plane-parallel ionization chamber for measurement of air kerma and air kerma rate in X-radiation fields utilized in conventional radiography and mammography. MATERIALS AND METHODS: The chamber has entrance windows made of aluminized polyester film, inner and guard electrodes of aluminum at one side (face A) and graphite at the other side (face G). The presen...

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