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A simple method for evaluation of half-value layer variation in CT equipment
Physics in Medicine and Biology, 2006Tandem systems, each formed by a pencil ionization chamber with and without a specific covering, were developed and tested in standard radiation beams. These systems were designed to be used in computed tomography radiation beams, where the half-value layer (HVL) determination is not an easy task.
Ana F, Maia, Linda V E, Caldas
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Radiology, 1957
The purpose of this communication is to present, in convenient form, values for the half-value depths and fall-off ratios corresponding to the entire range of radiation qualities, portal areas, and target-skin distances likely to be encountered in clinical roentgen therapy. Compilation of these data is believed to be useful for several reasons.
W. J. Tuddenham
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The purpose of this communication is to present, in convenient form, values for the half-value depths and fall-off ratios corresponding to the entire range of radiation qualities, portal areas, and target-skin distances likely to be encountered in clinical roentgen therapy. Compilation of these data is believed to be useful for several reasons.
W. J. Tuddenham
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A Note on the Determination of Half-value Layers of Soft X rays
The British Journal of Radiology, 1952A method is described of deriving a reliable half-value layer of X radiation from measurements made with a dose-meter whose readings require to be corrected for quality. The magnitude of the corrections to the observed half-value layer is considered and the effect this has on the dosemeter quality factor is discussed.
M T, MORRISON, G W, REED
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On the choice of material for half‐value‐layer measurements for megavoltage x rays
Medical Physics, 1977The relative sensitivity of various materials for the measurement of half‐value‐layer thickness has been calculated for bremsstrahlung x‐ray spectra in the energy range 5–40 MeV. It is concluded that low‐atomic‐number materials such as water are more sensitive to changes in spectral quality of megavoltage x rays than high‐atomic‐number materials such ...
R, Nath, R J, Schulz
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A parametric method for determining mammographic X‐ray tube output and half value layer
The British Journal of Radiology, 2001In the National Health Service Breast Screening Programme, regular assessment of the mean glandular doses received by a group of women is recognized as an important part of a quality assurance programme. The use of different tube voltages, to improve the beam penetration for thick or dense breasts, and of X-ray units with programmable exposure modes ...
K. Robson
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Problem of Determination of the First Half-Value Layer of X-Ray Radiation
Biomedical Engineering, 2009The methods for determination of the first half value layer of X-ray radiation are analyzed. The organized comparison revealed significant scatter from different sources of the first half value layer for identical conditions. The analytical expression was derived for calculation of the first half value layer based on the measured value and total ...
M. G. Petrushanskii
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Half-value layer determination using thermoluminescent dosimeters for digital mammography
Radiation Measurements, 2010Abstract The quality assurance of digital mammogram has been included in the Standards of Medical Exposure Quality Assurance in Taiwan since July, 2008. According to the Standards, determination of the half-value layer (HVL) is an integral part of mammographic dosimetry which requires the evaluation of patient's glandular dose.
C.J. Tung +5 more
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Use of the term `half-value-layer'
Physics in Medicine & Biology, 1969D E Charlton
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