EP0157417A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
X-ray diagnostic apparatus for eliminating scattered x-ray components
Assignee: Toshiba Corp
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Filing: 1985-04-02
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Granted: —
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Expires: 2005-04-02
Abstract
Abstract In an X-ray diagnostic apparatus (100), it is very desirable to mittigate the adverse effect of the scattered X-ray components. When the X-ray shield member (50) is positioned in the X-ray projection area (38) during the first X-ray projection period, the first X-ray transmission image data is obtained. From this X-ray transmission image data, the scattered X-ray component data is calculated in the interpolation method of a SINC function. When the X-ray shield member (50) is removed from the X-ray projection area (38) during the second X-ray projection period, the second X-ray transmission image data is obtained that includes not only the primary X-ray components (lp(x, y) but also the scattered X-ray components (Isc(x, y). The desirable X-ray transmission image data is obtained by subtracting the first image data from the second image data.
Inventors
- 👤 Katsuya C/O Patent Division Kikuchi
- 👤 Michitaka Honda
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-09 13:43
CPC Classifications
A; A61; A61B; A61B6/00; A61B6/06; H; H04; H04N; H04N23/00; H04N23/30
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
314 words
An X-ray diagnostic apparatus (100) characterized by comprising: an X-ray source (11) for successively generating X-rays; means (22) for detecting an X-ray image of an object (34) under examination by projecting the X-rays from the X-ray source (11) toward the object (34), and for converting the detected image into X-ray transmission signals; an analogue-to-digital converter (23) for converting the X-ray transmission signals into corresponding digital transmission data; an X-ray shield member (50) having a plurality of X-ray shields (56), for partially blocking the transmission of the X-rays over an X-ray projection area (38) defined by projecting the X-rays from the X-ray source (11) to the X-ray detection means (22) through the object (34); first memory means (24) for temporarily storing at least first X-ray transmission data acquired during a first X-ray projection period under the condition that the X-ray shield member (50) is inserted into the X-ray projection area (38); second memory means (25) for temporarily storing at least second transmission data (Im(x, y)) acquired during a second X-ray projection period under the condition that the X-ray shield member (50) is removed away from the X-ray projection area (38); first arithmetic operation means (26) for performing a first subtraction between the first X-ray transmission data and the second X-ray transmission data so as to obtain first scattered X-ray intensity data of portions within the X-ray projection area (38) which are shielded by the X-ray shields (56), and for performing a second subtraction between second scattered X-ray intensity data (Isc(x, y)) and the second X-ray transmission data (Im(x, y)) so as to obtain third X-ray transmission data (Ip(x, y)) free from the scattered X-ray components; and second arithmetic operation means (28) for performing data interpolation by a SINC function to the first scattered X-ray intensity data so as to obtain the second scattered X-ray intensity data (Isc(x, y)) over the entire X-ray projection area (38).
Claim 2
Dependent Claim
314 words
An X-ray diagnostic apparatus (100) characterized by comprising: an X-ray source (11) for successively generating X-rays; means (22) for detecting an X-ray image of an object (34) under examination by projecting the X-rays from the X-ray source (11) toward the object (34), and for converting the detected image into X-ray transmission signals; an analogue-to-digital converter (23) for converting the X-ray transmission signals into corresponding digital transmission data; an X-ray shield member (50) having a plurality of X-ray shields (56), for partially blocking the transmission of the X-rays over an X-ray projection area (38) defined by projecting the X-rays from the X-ray source (11) to the X-ray detection means (22) through the object (34); first memory means (24) for temporarily storing at least first X-ray transmission data acquired during a first X-ray projection period under the condition that the X-ray shield member (50) is inserted into the X-ray projection area (38); second memory means (25) for temporarily storing at least second transmission data (Im(x, y)) acquired during a second X-ray projection period under the condition that the X-ray shield member (50) is removed away from the X-ray projection area (38); first arithmetic operation means (26) for performing a first subtraction between the first X-ray transmission data and the second X-ray transmission data so as to obtain first scattered X-ray intensity data of portions within the X-ray projection area (38) which are shielded by the X-ray shields (56), and for performing a second subtraction between second scattered X-ray intensity data (Isc(x, y)) and the second X-ray transmission data (Im(x, y)) so as to obtain third X-ray transmission data (Ip(x, y)) free from the scattered X-ray components; and second arithmetic operation means (28) for performing data interpolation by a SINC function to the first scattered X-ray intensity data so as to obtain the second scattered X-ray intensity data (Isc(x, y)) over the entire X-ray projection area (38).
Claim 3
Dependent Claim
63 words
An apparatus (100) as claimed in Claim 1, characterized by further comprising third arithmetic operation means (27) coupled to the first arithmetic operation means (26) for performing bilevel quantization to the first scattered X-ray intensity data of the shielded portions so as to obtain bileveled intensity data one of which represents effective intensity data of the scattered X-ray components of the shielded portions.
Claim 4
Dependent Claim
122 words
An apparatus as claimed in Claim 2, characterized by further comprising system processing means (20) coupled to the third arithmetic operation means (27) for at least processing the bileveled intensity data derived from the third arithmetic operation means (27) and the first X-ray transmission data stored in the first memory means (24) so as to obtain memory data for the shielded portions and average values of the scattered X-ray intensity data, whereby the second arithmetic operation executes the data interpolation by the SINC function on the average values of the scattered X-ray intensity data based upon the memory data for the shielded portions so as to obtain the second scattered X-ray intensity data (Isc(x, y)) over the entire X-ray projection area (38).
Claim 5
Dependent Claim
45 words
An apparatus (100) as claimed in Claim 3, characterized in that the memory data for the shielded portions contains central addresses of the respective shielded portions with respect to the first memory means (24) and also addresses indicating distances between the adjoining central addresses thereof.
Claim 6
Dependent Claim
39 words
An apparatus (100) as claimed in Claim 1, characterized in that the X-ray shield member (50) is constructed by a synthetic resin film (58) and the X-ray shields which are lead pieces (56) equidistantly arranged in a matrix form.
Claim 7
Dependent Claim
25 words
An apparatus (100) as claimed in Claim 5, characterized in that each of said lead pieces (56) is a square having 2 x 2 millimeters.
Claim 8
Dependent Claim
51 words
An apparatus (100) as claimed in Claim 1, characterized in that the interrupted insertion of the X-ray shield member (50) into the X-ray projection area (38) is effected by a mechanical slide device (54) along a longitudinal axis of a couch (36) on which the object (34) under examination lies down.
Claim 9
Dependent Claim
30 words
An apparatus (100) as claimed in Claim 1, characterized in that the X-ray shield member (50) is positioned adjacent to the X-ray source (11) within the X-ray projection area (38).
Claim 10
Dependent Claim
29 words
An apparatus (100) as claimed in Claim 1, characterized in that all the first, second and third arithmetic operation means (26:28:27) are united into a single arithmetic operation device.
Claim 11
Dependent Claim
45 words
An apparatus (100) as claimed in Claim 1, characterized in that all the first, second and third arithmetic operation means (26:28:27) are united into a single arithmetic operation device, and both the first and second memory means (24:25) are merged into a single memory device.
Claim 12
Dependent Claim
75 words
An apparatus (100) as claimed in Claim 1, characterized in that the first arithmetic operation of the first arithmetic operation means (26) to obtain the data representing the intensity distribution of scattered X-ray components of the shielded portions is effected prior over the second arithmetic operation so as to subtract the data (Isc(x, y)) representing the intensity distribution of scattered X-ray components over the entire projection area (38) from the second transmission data (Im(x, y)).
References Cited (Backward Citations)
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