Dual-energy photon attenuation for soft tissue analysis
The mass attenuation coefficients σI and σA of collimated low energy gamma radiation emitted from point sources of 125I and 241Am have been measured in components of lean beef and fatty tissue. The ratio R = σI/σA for comminuted fatty tissue/muscle mixtures was approximately linearly related to the...
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Veröffentlicht in: | Journal of the science of food and agriculture 1982-10, Vol.33 (10), p.1017-1029 |
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Sprache: | eng |
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Zusammenfassung: | The mass attenuation coefficients σI and σA of collimated low energy gamma radiation emitted from point sources of 125I and 241Am have been measured in components of lean beef and fatty tissue. The ratio R = σI/σA for comminuted fatty tissue/muscle mixtures was approximately linearly related to the extractable fat content determined by the standard method of soxhlet extraction and a least squares analysis gave a residual standard deviation of ±2% extractable fat. R was unaffected by fluctuations in sample temperature over the range 20 to − 10°C and could be measured without knowledge of the sample thickness or packing density. Comparative measurements of attenuation relative to that of water were more reproducible than absolute values. Factors influencing the attenuation in soft tissues were assessed by adopting a three‐component mixture model: that the soft tissues were composed of extractable fat (R/RW = 0.759 ± 0.004), fat‐free dry solids (R/RW = 1.089 ± 0.008) and water (R/RW = 1). The likely effects of variations in the fatty acid composition of the fat, and of variations in the protein and mineral contents of the dry solids, are discussed. |
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ISSN: | 0022-5142 1097-0010 |
DOI: | 10.1002/jsfa.2740331013 |