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http://hdl.handle.net/11375/22640
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DC Field | Value | Language |
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dc.contributor.advisor | Webber, C.E | - |
dc.contributor.author | Gordon, Christopher L. | - |
dc.date.accessioned | 2018-03-14T15:09:46Z | - |
dc.date.available | 2018-03-14T15:09:46Z | - |
dc.date.issued | 1992-04 | - |
dc.identifier.uri | http://hdl.handle.net/11375/22640 | - |
dc.description.abstract | During routine measurements of body composition using a 153Gd based dual photon densitometer, it was observed that negative values were being obtained for the body fat fraction in some adults, in children and in small animals. In these three groups, there appears to be a body size dependent error whereby the measured fat fraction becomes increasingly negative as subject size becomes smaller. The fat fraction is derived from relating the measured mass attenuation coefficient of soft tissue to an internal calibration based on the use of water and lard as substitutes for muscle and fat. To investigate whether this procedure for instrument calibration is the cause of the fat fraction errors, soft tissue phantoms which contained known amounts of fat, water and protein were prepared. Over the range of fat fractions used, accurate results were obtained. By using prepared soft tissue and water phantoms it was established that the measured fat fraction incorrectly became progressively smaller as object thickness decreased and incorrectly increased with object thickness. However, accurate measurements were obtained if the equivalent tissue thickness is greater than 9 em and less tnan 16 em of water. Equally reproducible measurements are obtained at all thicknesses investigated. When dual photon measurements of body composition in 13 adolescent females were compared with measurements obtained from skinfold thicknesses or bioimpedance, there was good agreement between techniques but dual photon results demonstrated a broader range of variation with body size. Comparisons between dual photon absorptiometry derived body composition measurements of 52 male athletes with results obtained from under water weighing allowed for derivation of a simple correction factor for the accuracy errors due to body size. | en_US |
dc.language.iso | en_US | en_US |
dc.subject | densitometer, dependent error, soft tissue | en_US |
dc.title | The Accuracy of Dual Photon Absorptiometry Measurements of Soft Tissue Composition | en_US |
dc.type | Thesis | en_US |
dc.contributor.department | Physics | en_US |
dc.description.degreetype | Thesis | en_US |
dc.description.degree | Master of Science (MSc) | en_US |
Appears in Collections: | Digitized Open Access Dissertations and Theses |
Files in This Item:
File | Description | Size | Format | |
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Gordon_Christopher_L_1992April_Masters.pdf | 2.12 MB | Adobe PDF | View/Open |
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