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UBC Theses and Dissertations
An x-ray dose comparator Mibus, Sidney Albert
Abstract
This thesis describes the design and construction of an instrument for comparison of x-ray doses at two different points in an x-ray field. Essentially, it consists of two ionization chambers each fed into a very stable, linear, d.c. amplifier. The outputs of the d.c. amplifiers are coupled in such a way that a fraction of the output of one amplifier is balanced against the total output of the other in a ratio circuit. The scale of the ratio circuit may be set to read directly the dose at any point as a percentage of the dose at an arbitrarily chosen reference point. This percentage is independent of fluctuations of the x-ray intensity with time. The instrument is battery-operated, light in weight and therefore easily portable. The principal use of the instrument is for the comparison of x-ray doses at different points in a tissue-equivalent medium — information required for dose estimates in radiotherapy. The accuracy of the instrument is better than one half percent of the maximum dose in the x-ray field. The instrument can be modified for automatic plotting of "isodose curves".
Item Metadata
Title |
An x-ray dose comparator
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Creator | |
Publisher |
University of British Columbia
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Date Issued |
1956
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Description |
This thesis describes the design and construction of an instrument for comparison of x-ray doses at two different points in an x-ray field. Essentially, it consists of two ionization chambers each fed into a very stable, linear, d.c. amplifier. The outputs of the d.c. amplifiers are coupled in such a way that a fraction of the output of one amplifier is balanced against the total output of the other in a ratio circuit. The scale of the ratio circuit may be set to read directly the dose at any point as a percentage of the dose at an arbitrarily chosen reference point. This percentage is independent of fluctuations of the x-ray intensity with time.
The instrument is battery-operated, light in weight and therefore easily portable. The principal use of the instrument is for the comparison of x-ray doses at different points in a tissue-equivalent medium — information required for dose estimates in radiotherapy. The accuracy of the instrument is better than one half percent of the maximum dose in the x-ray field. The instrument can be modified for automatic plotting of "isodose curves".
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Genre | |
Type | |
Language |
eng
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Date Available |
2012-01-30
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Provider |
Vancouver : University of British Columbia Library
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Rights |
For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use.
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DOI |
10.14288/1.0085399
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URI | |
Degree | |
Program | |
Affiliation | |
Degree Grantor |
University of British Columbia
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Campus | |
Scholarly Level |
Graduate
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Aggregated Source Repository |
DSpace
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Item Media
Item Citations and Data
Rights
For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use.