US5071602A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of making phantom for nmr diagnosis
Assignee: Eneos Corp
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Filing: 1990-08-01
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Granted: 1991-12-10
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Expires: 2010-08-01
Abstract
Abstract A method of making a phantom for NMR diagnosis contains the steps of placing at least one small container having at least a portion of its wall made of a thin film of a plastic material in a large container made of a plastic material, charging a first aqueous solution of polyvinyl alcohol into the small container, charging a second aqueous solution of polyvinyl alcohol into a space defined by the outer wall of the small container and the inner wall of the large container, freezing the first and second aqueous solutions of polyvinyl alcohol to obtain frozen masses, and then thawing the frozen masses. A composition of the first aqueous solution of polyvinyl alcohol is different from a composition of the second aqueous solution of polyvinyl alcohol.
Inventors
- 👤 Masao Nambu
- 👤 Kazue Saitoh
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 19:48
CPC Classifications
G; G01; G01R; G01R33/00; G01R33/20; G01R33/44; G01R33/48; G01R33/58
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
156 words
A method of making a phantom for NMR diagnosis comprising the steps of placing at least one small container having its wall made of a thin film of a plastic material having a thickness of not more than 20 microns in a large container made of a plastic material, charging a first aqueous solution of polyvinyl alcohol into said at least one small container, charging a second aqueous solution of polyvinyl alcohol into a space defined by the outer wall of said at least one small container and the inner wall of said large container, a composition of said first aqueous solution of polyvinyl alcohol being different from a composition of said second aqueous solution of polyvinyl alcohol, freezing said first and second aqueous solutions of polyvinyl alcohol to obtain frozen masses, and then thawing said frozen masses whereby the thin film constitutes a boundary that is not imaged during the making of an NMR image.
Claim 2
Independent Claim
156 words
A method of making a phantom for NMR diagnosis comprising the steps of placing at least one small container having its wall made of a thin film of a plastic material having a thickness of not more than 20 microns in a large container made of a plastic material, charging a first aqueous solution of polyvinyl alcohol into said at least one small container, charging a second aqueous solution of polyvinyl alcohol into a space defined by the outer wall of said at least one small container and the inner wall of said large container, a composition of said first aqueous solution of polyvinyl alcohol being different from a composition of said second aqueous solution of polyvinyl alcohol, freezing said first and second aqueous solutions of polyvinyl alcohol to obtain frozen masses, and then thawing said frozen masses whereby the thin film constitutes a boundary that is not imaged during the making of an NMR image.
Claim 3
Dependent Claim
81 words
The method according to claim 1, wherein two or more small containers each having its wall made of a thin film of a plastic material having a thickness of not more than 20 microns are placed in said large container and wherein a third or subsequent aqueous solution or solutions of polyvinyl alcohol each having a different composition from those of said first and second aqueous solutions of polyvinyl alcohol are charged in each of said two or more small containers.
Claim 4
Dependent Claim
19 words
The method according to claim 1, wherein said large container has a diameter of from 15 to 45 cm.
Claim 5
Independent Claim
33 words
The method according to claims 1 or 2, wherein said polyvinyl alcohol has a degree of hydrolysis of not less than 98 mol % and a polymerization degree of not less than 1,000.
Claim 6
Independent Claim
34 words
The method according to claims 1 or 2, wherein each of said aqueous solutions contains said polyvinyl alcohol in a concentration of more than 8 wt % and not more than 50 wt %.
Claim 7
Dependent Claim
26 words
The method according to claim 1, wherein the water content of said first aqueous solution is different from the water content of said second aqueous solution.
Claim 8
Dependent Claim
30 words
The method according to claim 2, wherein the water content of said third and subsequent aqueous solutions is different from the water content of the first and second aqueous solutions.
Claim 9
Dependent Claim
48 words
The method according to claim 1, wherein the water content of said first aqueous solution is substantially the same as the water content of said second aqueous solution, and wherein at least one of said first and second aqueous solutions contains an agent for shortening the relaxation time.
Claim 10
Dependent Claim
49 words
The method according to claim 2, wherein the water content of at least two of the first to third and subsequent aqueous solutions is substantially the same, and wherein at least one of said first to third and subsequent aqueous solutions contains an agent for shortening the relaxation time.
Claim 11
Independent Claim
53 words
The method according to claims 8 or 9, wherein said agent for shortening the relaxation time is selected from the group consisting of gadolinium diethylenetriamine pentaacetate, Mn 2+ , Ni 2+ , Cu 2+ , Fe 2+ , Fe 3+ , glycerin, ethyl alcohol, isopropyl alcohol, agar, carrageenan, glucose, graphite and mixtures thereof.
Claim 12
Independent Claim
32 words
The method according to claims 1 or 2, wherein said aqueous solutions of polyvinyl alcohol are cooled to a temperature of not higher than minus 10° C. to obtain said frozen masses.
Claim 13
Independent Claim
16 words
The method according to claims 1 or 2, wherein the freezing and thawing steps are repeated.
Claim 14
Independent Claim
29 words
The method according to claims 1 or 2, wherein at least one of said aqueous solutions contains an additional ingredient which does not hinder gelation of said polyvinyl alcohol.
Claim 15
Dependent Claim
29 words
The method according to claim 13, wherein said additional ingredient is selected from the group consisting of sodium chloride, an agent for shortening the relaxation time and mixtures thereof.
Claim 16
Dependent Claim
51 words
The method according to claim 14, wherein said agent for shortening the relaxation time is selected from the group consisting of gadolinium diethylenetriamine pentaacetate, Mn 2+ , Ni 2+ , Cu 2+ , Fe 2+ , Fe 3+ , glycerin, ethyl alcohol, isopropyl alcohol, agar, carrageenan, glucose, graphite and mixtures thereof.
Claim 17
Independent Claim
21 words
The method according to claims 1 or 2, wherein each of said aqueous solutions contains 50 to 92 wt % water.
Claim 18
Independent Claim
34 words
The method according to claims 1 or 2, wherein said small and large containers are made of a material which is water-impermeable and which does not affect the magnetic field applied for NMR analysis.
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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) | 1994-12-09 | 1995-06-10 | 1995-12-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-12-09 | 1999-06-10 | 1999-12-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-12-09 | 2003-06-10 | 2003-12-10 | $7700.00 | Window Closed / Lapsed |