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EP0218367A1
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Bone mineral analysis phantom
Assignee: Philips Nuclear Medicine Inc
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Filing: 1986-09-03
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Granted: —
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Expires: 2006-09-03
Abstract
Abstract A phantom (A,B) has a bone mineral standard (30) surrounded by tissue equivalent material (A) with a plurality of different cross sections. The phantom (A,B) is disposed in an image region (44) of a tomographic scanner. Scans are conducted through a plurality of different cross sections of the phantom (A,B) to reconstruct a plurality of phantom image representations. The plurality of phantom image representations are stored by size in a correction memory (70). Thereafter, a patient is disposed on a patient table (50) in the image region (44) and an image is taken through the patient's mid-section between the L2 and L5 vertebrae. A patient image representation is reconstructed and stored in an image memory (64). A slice size calculation circuit (72) determines the size of the patient slice. The correction memory (70) is addressed with the calculated size to retrieve the phantom image representation of the most similar size. An image correction circuit (74) calibrates the patient image representation in accordance with the retrived phantom image representation.
Inventors
- 👤 Rodney A. Mattson
- 👤 Leslie J. Williams
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-08 21:48
CPC Classifications
A; A61; A61B; A61B6/00; A61B6/58; A61B6/582; A61B6/583; A61B6/02; A61B6/03; A61B6/032; A61B6/48; A61B6/482; H; H05; H05G; H05G1/00; H05G1/08; H05G1/26; H05G1/60
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
263 words
A tomographic scanner, with bone mineral calibration, comprising: a source (40) of penetrating radiation for providing at least one generally planar beam of penetrating radiation; a radiation detection means (42) for detecting penetrating radiation impinging thereon; a gantry means (46) for mounting the radiation source (40) and the radiation detection means (42) across an image region (44) from each other such that the radiation beam transverses the image region (44) and impinges on the radiation detection means (42); a bone mineral phantom (A,B); a phantom positioning means (52) for positioning said phantom (A,B) within said image region (44); a radiation moving means (48) for moving at least the radiation beam relative to the phantom (A,B) such that the radiation beam traversing the image region (44) penetrates the phantom (A,B) along a plurality of directions when said phantom (A,B) is positioned within said image region (44); and an image reconstruction means (62) for reconstructing a representation of material density in the image region (44) from radiation detection data from the radiation detection means (42), the image reconstruction means (62) being operatively connected with the radiation detection means (42) and the radiation moving means (48) characterised in that: said bone mineral phantom (A,B) comprises a generally cylindrical bone mineral standard (30) which extends longitudinally through said phantom (A,B) and a tissue equivalent material (A) disposed around the said standard (30), the tissue equivalent material having a plurality of transverse cross sections; and said phantom positioning means (52) includes means for selectively positioning each of said plurality of transverse cross sections in said image region (44).
Claim 2
Dependent Claim
263 words
A tomographic scanner, with bone mineral calibration, comprising: a source (40) of penetrating radiation for providing at least one generally planar beam of penetrating radiation; a radiation detection means (42) for detecting penetrating radiation impinging thereon; a gantry means (46) for mounting the radiation source (40) and the radiation detection means (42) across an image region (44) from each other such that the radiation beam transverses the image region (44) and impinges on the radiation detection means (42); a bone mineral phantom (A,B); a phantom positioning means (52) for positioning said phantom (A,B) within said image region (44); a radiation moving means (48) for moving at least the radiation beam relative to the phantom (A,B) such that the radiation beam traversing the image region (44) penetrates the phantom (A,B) along a plurality of directions when said phantom (A,B) is positioned within said image region (44); and an image reconstruction means (62) for reconstructing a representation of material density in the image region (44) from radiation detection data from the radiation detection means (42), the image reconstruction means (62) being operatively connected with the radiation detection means (42) and the radiation moving means (48) characterised in that: said bone mineral phantom (A,B) comprises a generally cylindrical bone mineral standard (30) which extends longitudinally through said phantom (A,B) and a tissue equivalent material (A) disposed around the said standard (30), the tissue equivalent material having a plurality of transverse cross sections; and said phantom positioning means (52) includes means for selectively positioning each of said plurality of transverse cross sections in said image region (44).
Claim 3
Dependent Claim
36 words
A scanner according to Claim 1 further including a bone density correction memory means (70) for storing information from the material density representations representing each of said plurality of transverse cross sections through the phantom (A,B).
Claim 4
Dependent Claim
47 words
A scanner according to Claim 2 further including a correction means (74,60) for correcting at least one of the radiation detection data and the material density representation of a patient with the information from one of the material density representations stored in the correction memory means (70).
Claim 5
Dependent Claim
49 words
A scanner according to Claim 3 further including size calculating means (72) for calculating a dimension of an imaged slice of a patient and a correction memory addressing means (72) for addressing the correction memory means (70) to retrieve information from the stored representation corresponding to a like size.
Claim 6
Dependent Claim
107 words
A scanner according to any one of the preceding claims wherein said tissue equivalent material (A) is housed within a hollow phantom housing (20) having a tapered side wall extending between a first end (10) and a second end (12), the phantom housing (20) side wall defining a first, smaller, generally ovoid cross section adjacent the first end (10) and a second,generally larger cross section adjacent the second end (12) the phantom housing (20) having a plurality of intermediate cross sections between the first (10) and second (12) ends which intermediate cross sections are larger than the first cross section and smaller than the second cross section.
Claim 7
Dependent Claim
31 words
A scanner according to Claim 5 wherein the phantom housing (20) further includes access means (22) for enabling the phantom housing (20) to be filled with said tissue equivalent material (A).
Claim 8
Dependent Claim
41 words
A scanner according to Claim 5 or Claim 6 wherein the bone mineral standard (30) includes a first cylindrical portion (32) which mimics the standards of trabecular bone mineral tissue and a surrounding layer (34) which mimics cortial bone mineral tissue.
Claim 9
Dependent Claim
41 words
A scanner according to Claim 7 wherein the phantom housing (20) has a continuum of intermediate cross sections between the first (10) and second (12) ends and further includes markings (16) indicating cross sectional sizes along the intermediate housing portion (14).
Claim 10
Dependent Claim
125 words
A phantom (A,B) for calibrating CT scanners for bone mineral examinations characterised in that it comprises: a housing (20) having a tapered side wall extending between a first end (10) and a second end (12) the housing side wall defining a first, smaller generally ovoid cross section adjacent the first end, a second, larger generally ovoid cross section adjacent the second end and a plurality of intermediate cross sections which are larger than the first cross section and smaller than the second cross section therebetween; and a generally cylindrical bone mineral standard (30)extending longitudinally generally between the first (10) and second (12) ends, whereby any one of the first, second, and intermediate cross sections are imageable in a tomographic scanner to provide a calibration reference.
Claim 11
Dependent Claim
125 words
A phantom (A,B) for calibrating CT scanners for bone mineral examinations characterised in that it comprises: a housing (20) having a tapered side wall extending between a first end (10) and a second end (12) the housing side wall defining a first, smaller generally ovoid cross section adjacent the first end, a second, larger generally ovoid cross section adjacent the second end and a plurality of intermediate cross sections which are larger than the first cross section and smaller than the second cross section therebetween; and a generally cylindrical bone mineral standard (30)extending longitudinally generally between the first (10) and second (12) ends, whereby any one of the first, second, and intermediate cross sections are imageable in a tomographic scanner to provide a calibration reference.
Claim 12
Dependent Claim
28 words
A phantom (A,B) according to Claim 9 wherein the housing (20) is hollow and includes an access opening (22) for receiving water or other tissue equivalent fluid(A) therein.
Claim 13
Dependent Claim
18 words
A phantom (A,B) according to Claim 10 wherein the housing (20) defines a continuum of intermediate cross sections.
Claim 14
Dependent Claim
22 words
A phantom (A,B) according to Claim 11 further including markings (16) disposed along the housing (20) to indicate cross sectional areas thereof.
Claim 15
Dependent Claim
36 words
A phantom (A,B) according to any one of Claims 9 to 12 wherein the bone mineral standard (30) comprises a first cylindrical bone mineral standard (32) around which circumferentially extends a second bone mineral standard (34).
Claim 16
Dependent Claim
35 words
A phantom (A,B) according to Claim 13 wherein the first bone mineral standard (32) mimics the characteristics of trabecular bones and wherein the second bone mineral standard (34) mimics the characteristics of cortial bone tissue.
Claim 17
Independent Claim
216 words
A method of tomographic scanning comprising the steps of: (a) positioning a bone mineral phantom (A,B) within a region (44) of a tomographic scanner to be imaged; (b) rotating a source (40) of penetrating radiation to irradiate the phantom (A,B) from a plurality of directions; (c) detecting radiation which has traversed the phantom (A,B); (d) reconstructing an image representation from the detected penetrating radiation; (e) storing information from the phantom image representation; (f) repeating preceding steps (a) to (e) wherein instead of said phantom a mid-portion of a patient is disposed in the image region (44) to reconstruct an image representation of a planar slice through the patient's mid-section; and (g) calibrating the patient image representation with the phantom image representation information characterised in that: said bone mineral phantom (A,B) comprises a generally cylindrical bone mineral standard (30) which extends longitudinally through said phantom (A,B) and a tissue equivalent material (A) disposed around the said standard (30), the tissue equivalent material having a plurality of cross sections; the procedure of the said step (b) irradiates a planar slice of said phantom (A,B) from a plurality of directions, said planar slice being one of the said plurality of cross sections; and the procedure of the said step (c) detects radiation which has traversed the said planer slice.
Claim 18
Independent Claim
216 words
A method of tomographic scanning comprising the steps of: (a) positioning a bone mineral phantom (A,B) within a region (44) of a tomographic scanner to be imaged; (b) rotating a source (40) of penetrating radiation to irradiate the phantom (A,B) from a plurality of directions; (c) detecting radiation which has traversed the phantom (A,B); (d) reconstructing an image representation from the detected penetrating radiation; (e) storing information from the phantom image representation; (f) repeating preceding steps (a) to (e) wherein instead of said phantom a mid-portion of a patient is disposed in the image region (44) to reconstruct an image representation of a planar slice through the patient's mid-section; and (g) calibrating the patient image representation with the phantom image representation information characterised in that: said bone mineral phantom (A,B) comprises a generally cylindrical bone mineral standard (30) which extends longitudinally through said phantom (A,B) and a tissue equivalent material (A) disposed around the said standard (30), the tissue equivalent material having a plurality of cross sections; the procedure of the said step (b) irradiates a planar slice of said phantom (A,B) from a plurality of directions, said planar slice being one of the said plurality of cross sections; and the procedure of the said step (c) detects radiation which has traversed the said planer slice.
Claim 19
Dependent Claim
55 words
A method according to Claim 15 further including repeating steps (a) to (e) for a plurality of different cross sectional sizes of the phantom (A,B) and further including determining a size of the imaged slice of the patient and correcting the patient image representation with information from the most similarly sized phantom (A,B) image representation.
Claim 20
Dependent Claim
17 words
A method according to Claim 16 wherein the patient is imaged between the L2 and L5 vertebrae.
Claim 21
Dependent Claim
22 words
A method according to Claim 17 wherein the bone mineral standard (30) mimics the characteristics of at least trabecular bone mineral tissue.
Claim 22
Dependent Claim
21 words
A method according to Claim 18 wherein the bone mineral standard (30) further mimics the characteristics of surrounding cortical bone tissue.
References Cited (Backward Citations)
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