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EP0432730A2
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Bone mineral content measuring apparatus
Assignee: Hitachi Ltd
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Filing: 1990-12-11
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Granted: —
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Expires: 2010-12-11
Abstract
Abstract A bone mineral content measuring apparatus for obtaining the bone mineral content of an object to be examined by irradiating X-rays onto the object and measuring the X-rays which have passed through the object. An X-ray generating device generates X-rays having a continuous spectrum. The X-rays generated pass through an X-ray filter before the irradiation of the object or after the transmission of the object. The X-ray filter is composed of a substance having an X-ray absorbing characteristic with the K-absorption edge at a predetermined energy value. The X-rays which have passed through the X-ray filter and the object are detected by the X-ray detector. A data analyzer inputs the detected X-ray detection data and analyzes the bone mineral content of the object on the basis of the X-ray absorbing characteristic of the X-ray filter.
Inventors
- 👤 Toshiaki C/O Aloka Co. Ltd. Tamegai
- 👤 Kazuyuki C/O Aloka Co. Ltd. Tamura
- 👤 Shigeo C/O Aloka Co. Ltd. Kimura
- 👤 Koichi C/O Aloka Co. Ltd. Kawamura
- 👤 Shizuo C/O Aloka Co. Ltd. Ninomiya
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-10 01:26
CPC Classifications
G; G01; G01N; G01N23/00; G01N23/02; G01N23/06; G01N23/083; A; A61; A61B; A61B6/00; A61B6/40; A61B6/4035; A61B6/48; A61B6/482; A61B6/50; A61B6/505; G21; G21K; G21K1/00; G21K1/02; G21K1/04; G21K1/043; G21K1/10
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
199 words
A bone mineral content measuring apparatus comprising: (a) an X-ray generating device for generating X-rays having a continuous spectrum; (b) an X-ray detecting device for detecting the X-rays which have passed through the object to be examined; (c) a filtering device including at least one pair of X-ray filters which are switched over each other and provided in an X-ray beam path between said X-ray generating device and said X-ray detecting device, and a filter switching device for switching said X-ray filters, said pair of X-ray filters being composed of substances having different X-ray absorbing characteristics with K-absorption edges at different energy values which are approximate to each other; (d) a data analyzer for inputting the X-ray detection data from said X-ray detecting device and analyzing said data, said data analyzer including a bone mineral content analyzing circuit for obtaining the bone mineral content of said object on the basis of the difference between the X-ray detection data obtained by using one of said pair of X-ray filters and the X-ray detection data obtained by using the other of said pair of X-ray filters; and (e) a display unit for displaying the result of analysis of said data analyzer.
Claim 2
Dependent Claim
62 words
A bone mineral content measuring apparatus according to Claim 1, wherein said filtering device includes: a pair of X-ray filters for a low energy which are composed of substances having the K-absorption edges in a low energy region; and a pair of X-ray filters for a high energy which are composed of substances having the K-absorption edges in a high energy region.
Claim 3
Dependent Claim
56 words
A bone mineral content measuring apparatus according to Claim 2, wherein each of said X-ray filters is formed into a sector having a predetermined angle and a combination of all the pairs of X-ray filters constitutes a circular filter disc; and said filter switching device switches said X-ray filters by the rotation of said filter disc.
Claim 4
Dependent Claim
26 words
A bone mineral content measuring apparatus according to Claim 3, wherein said filter disc is rotated at a constant angular velocity for bone mineral content measurement.
Claim 5
Dependent Claim
132 words
A bone mineral content measuring apparatus according to Claim 1, wherein said filtering device includes: a first pair of X-ray filters for a low energy which are composed of substances having the K-absorption edges in a low energy region; a second pair of X-ray filters for a low energy which are composed of said first pair of X-ray filters for a low energy overlaid with an X-ray attenuating substance having a predetermined thickness; a first pair of X-ray filters for a high energy which are composed of substances having the K-absorption edges in a high energy region; and a second pair of X-ray filters for a high energy which are composed of said first pair of X-ray filters for a high energy overlaid with an X-ray attenuating substance having a predetermined thickness.
Claim 6
Dependent Claim
56 words
A bone mineral content measuring apparatus according to Claim 5, wherein each of said X-ray filters is formed into a sector having a predetermined angle and a combination of all the pairs of X-ray filters constitutes a circular filter disc; and said filter switching device switches said X-ray filters by the rotation of said filter disc.
Claim 7
Dependent Claim
26 words
A bone mineral content measuring apparatus according to Claim 6, wherein said filter disc is rotated at a constant angular velocity for bone mineral content measurement.
Claim 8
Dependent Claim
54 words
A bone mineral content measuring apparatus according to Claim 3, wherein one of said pair of X-ray filters for a low energy is composed of Gd, the other being composed of Ce; and one of said pair of X-ray filters for a high energy is composed of Pb, the other being composed of Au.
Claim 9
Dependent Claim
73 words
A bone mineral content measuring apparatus according to Claim 6, wherein one of said first pair of X-ray filters for a low energy is composed of Gd, the other being composed of Ce; one of said first pair of X-ray filters for a high energy is composed of Pb, the other being composed of Au; and said X-ray attenuating substance contains at least one selected from the group consisting of copper and brass.
Claim 10
Dependent Claim
33 words
A bone mineral content measuring apparatus according to either of Claims 3 and 6, wherein said data analyzer includes an average bone mineral density analyzing circuit for obtaining an average bone mineral density.
Claim 11
Dependent Claim
31 words
A bone mineral content measuring apparatus according to either of Claims 3 and 6, wherein said filtering device is disposed between said X-ray generating device and said object to be examined.
Claim 12
Dependent Claim
109 words
A bone mineral content measuring apparatus comprising: (a) an X-ray generating device for generating X-rays having a continuous spectrum; (b) an X-ray detecting device for detecting the X-rays which have passed through the object to be examined; (c) an X-ray filter provided in an X-ray beam path between said X-ray generating device and said X-ray detecting device and having an X-ray absorbing characteristic with the K-absorption edge at a predetermined energy value; and (d) a data analyzer for inputting the X-ray detection data from said X-ray detecting device and obtaining the bone mineral content of said object on the basis of said X-ray absorbing characteristic of said X-ray filter.
Claim 13
Dependent Claim
108 words
A bone mineral content measuring apparatus according to Claim 12, wherein said data analyzer includes: a low energy detector for extracting X-ray detected data within a predetermined energy width in a low energy region; a counter for counting the output of said low energy detector; a high energy detector for extracting X-ray detected data within a predetermined energy width in a high energy region; a counter for counting the output of said high energy detector; and a bone mineral content analyzing circuit for obtaining the bone mineral content of said object on the basis of the count values of said low energy counter and said high energy counter.
Claim 14
Dependent Claim
27 words
A bone mineral content measuring apparatus according to Claim 13, wherein said X-ray filter is disposed between said X-ray detecting apparatus and said object to be examined.
References Cited (Backward Citations)
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