US4774957A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Material for diagnosis by nuclear magnetic resonance imaging
Assignee: Toshiba Corp
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Filing: 1987-09-11
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Granted: 1988-10-04
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Expires: 2007-09-11
Abstract
Abstract A material for diagnosis by nuclear magnetic resonance imaging is provided. The material comprises a hydrogel having a high water content. The hydrogel is prepared by the steps of casting an aqueous polyvinyl alcohol solution into a mold, cooling the case aqueous solution to obtain a cooled frozen mass and thawing the cooled frozen mass. The cooling and thawing steps may be repeated up to eight cycles. The hydrogel is also prepared by subjecting the cooled frozen mass to a partial dehydration step in vacuum.
Inventors
- 👤 Masao Nambu
- 👤 Hitoshi Goshima
- 👤 Isamu Mano
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 17:41
CPC Classifications
G; G01; G01R; G01R33/00; G01R33/20; G01R33/44; G01R33/48; G01R33/54; G01R33/56; G01R33/5601; A; A61; A61K; A61K49/00; A61K49/06; A61K49/18; A61K49/1803; Y; Y10; Y10T; Y10T428/00; Y10T428/31504; Y10T428/31533
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
169 words
A method of determining positional relationship between a surface of a patient's body and an internal diseased site by nuclear magnetic resonance imaging comprising: (1) applying a hydrogel skin marker to the surface of patient's body and (2) photographing an image of both diseased site and hydrogel skin marker by the nuclear magnetic resonance imaging to thereby determine the positional relationship, said hydrogel skin marker being prepared by a process comprising casting an aqueous solution containing more than 8 wt. % and not more than 50 wt. % of a polyvinyl alcohol having a degree of hydrolysis of not less than 98 mol % and an average polymerization degree of not less than 1000 into a mold having desired shape and dimensions, cooling the cast aqueous solution to a temperature of not higher than minus 10° C. to obtain a cooled frozen mass and thawing the cooled frozen mass or partially dehydrating the cooled mass under vacuum until the percentage dehydration rate reaches not less than 3 wt. %.
Claim 2
Independent Claim
169 words
A method of determining positional relationship between a surface of a patient's body and an internal diseased site by nuclear magnetic resonance imaging comprising: (1) applying a hydrogel skin marker to the surface of patient's body and (2) photographing an image of both diseased site and hydrogel skin marker by the nuclear magnetic resonance imaging to thereby determine the positional relationship, said hydrogel skin marker being prepared by a process comprising casting an aqueous solution containing more than 8 wt. % and not more than 50 wt. % of a polyvinyl alcohol having a degree of hydrolysis of not less than 98 mol % and an average polymerization degree of not less than 1000 into a mold having desired shape and dimensions, cooling the cast aqueous solution to a temperature of not higher than minus 10° C. to obtain a cooled frozen mass and thawing the cooled frozen mass or partially dehydrating the cooled mass under vacuum until the percentage dehydration rate reaches not less than 3 wt. %.
Claim 3
Dependent Claim
54 words
The method of claim 1 wherein said hydrogel skin marker is cut to have shape and dimensions similar to those of the diseased site by stepwise cutting of peripheral portion of the skin marker during sequential operations of forming cross sectional images thereof together with the formation of the images of the diseased site.
Claim 4
Dependent Claim
18 words
The method of claim 1 wherein said hydrogel skin marker contains 80 to 92 wt. % of water.
Claim 5
Dependent Claim
24 words
The method of claim 1 wherein said hydrogel skin marker has a shape selected from the group consisting of circular, rectangular and elliptical plates.
Claim 6
Dependent Claim
28 words
The method of claim 1 wherein said hydrogel skin marker is cut to have a vacancy hollowed out so as to have a shape simulating the diseased site.
Claim 7
Dependent Claim
11 words
The process of claim 1 wherein said cooled mass is thawed.
Claim 8
Dependent Claim
12 words
The process of claim 1 wherein said cooled mass is partially dehydrated.
Claim 9
Dependent Claim
34 words
The method of claim 1 wherein the content of said polyvinyl alcohol in said aqueous solution is in the range of from more than 8 wt. % to not more than 20 wt. %.
Claim 10
Independent Claim
167 words
A method for adjusting a nuclear magnetic resonance imaging system comprising: (1) placing a hydrogel phantom having a predetermined contour in a static magnetic field of a nuclear magnetic resonance imaging system (2) photographing an image of said hydrogel phantom on display means and (3) adjusting said system until said image has the predetermined contour of said hydrogel phantom and has uniform brightness and intensity throughout the whole area of said image, said hydrogel phantom being prepared by a process comprising casting an aqueous solution containing more than 8 wt. % and not more than 50 wt. % of a polyvinyl alcohol having a degree of hydrolysis of not less than 1000 into a mold having desired shape and dimensions, cooling the cast aqueous solution to a temperature of not higher than minus 10° C. to obtain a cooled frozen mass and thawing the cooled frozen mass or partially dehydrating the cooled mass under vacuum until the percentage dehydration rate reaches no less than 3 wt. %.
Claim 11
Independent Claim
167 words
A method for adjusting a nuclear magnetic resonance imaging system comprising: (1) placing a hydrogel phantom having a predetermined contour in a static magnetic field of a nuclear magnetic resonance imaging system (2) photographing an image of said hydrogel phantom on display means and (3) adjusting said system until said image has the predetermined contour of said hydrogel phantom and has uniform brightness and intensity throughout the whole area of said image, said hydrogel phantom being prepared by a process comprising casting an aqueous solution containing more than 8 wt. % and not more than 50 wt. % of a polyvinyl alcohol having a degree of hydrolysis of not less than 1000 into a mold having desired shape and dimensions, cooling the cast aqueous solution to a temperature of not higher than minus 10° C. to obtain a cooled frozen mass and thawing the cooled frozen mass or partially dehydrating the cooled mass under vacuum until the percentage dehydration rate reaches no less than 3 wt. %.
Claim 12
Dependent Claim
42 words
The method of claim 9 wherein said aqueous solution contains an additional ingredient which does not inhibit gelation of said polyvinyl alcohol in an amount of not more than one-half of the weight of said polyvinyl alcohol contained in said aqueous solution.
Claim 13
Dependent Claim
53 words
The method of claim 10 wherein said additional ingredient is selected from the group consisting of isopropyl alcohol, glycerin, propylene glycol, ethyl alcohol, casein, gelatin, albumin, lecithin, monostearin, tristearin, glucose, agar, carrageenan, butyl-p-hydroxybenzoate, phthalocyanine, flavanthrone, nickel salts, copper salts, manganese salts, iron salts, graphite, activated carbon, silica-alumina, zeolite, calcium silicate and mixtures thereof.
Claim 14
Dependent Claim
16 words
The method of claim 9 wherein said hydrogel phantom contains 50 92 wt. % of water.
Claim 15
Independent Claim
17 words
The method of clam 9 wherein said aqueous solution of said polyvinyl alcohol further contains a lipid.
Claim 16
Independent Claim
17 words
The method of clam 9 wherein said aqueous solution of said polyvinyl alcohol further contains a lipid.
Claim 17
Dependent Claim
38 words
The method of claim 9 wherein said aqueous solution of said polyvinyl alcohol is heated to a temperature of not lower than 70° C. and then a solid lipid which has been heated to be liquefied is added.
Claim 18
Dependent Claim
19 words
The method of claim 9 wherein a plurality of said hydrogel phantoms having different water contents are joined together.
Claim 19
Dependent Claim
29 words
The method of claim 9 wherein the contour of said hydrogel phantom is selected from the group consisting of circular, elliptical, spherical, annular, cylindrical and tubular shapes and strips.
Claim 20
Dependent Claim
11 words
The process of claim 9 wherein said cooled mass is thawed.
Claim 21
Dependent Claim
12 words
The process of claim 9 wherein said cooled mass is partially dehydrated.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-10-04 | 1992-04-04 | 1992-10-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-10-04 | 1996-04-04 | 1996-10-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-10-04 | 2000-04-04 | 2000-10-04 | $7700.00 | Window Closed / Lapsed |