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Glass microspheres
Assignee: University of Missouri System
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Filing: 1984-11-19
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Granted: 1988-12-06
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Expires: 2004-11-19
Abstract
Abstract A radioactive microsphere for radiation therapy of a mammal comprising a biologically compatible glass material containing a beta or gamma emitting radioisotope distributed substantially uniformly throughout the glass. Advantageously, the radioisotope is produced by irradiation of the microsphere.
Inventors
- 👤 Delbert E. Day
- 👤 Gary J. Ehrhardt
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 11:59
CPC Classifications
A; A61; A61K; A61K51/00; A61K51/12; A61K51/1241; A61K51/1255; A61P; A61P35/00; C; C03; C03C; C03C11/00; C03C11/002; C03C3/00; C03C3/04; C03C3/062; C03C3/076; C03C3/083; C03C4/00; C03C4/0007; G; G21; G21F; G21F9/00; G21F9/28; G21F9/30; G21F9/301; G21F9/302; G21F9/305; A61K2121/00; Y; Y10; Y10T; Y10T428/00; Y10T428/29; Y10T428/2982
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
122 words
A glass microsphere having a diameter of about 75 micrometers or less and adapted for radiation therapy of a mammal, said glass consisting essentially of an yttrium oxide-aluminosilicate glass composition lying substantially within a quadrilateral region of the ternary composition diagram of the yttria-alumina-silica system, the quadrilateral region being defined by its four corners having the following combination of weight proportions of the components: 20% silica, 10% alumina, 70% yttria; 70% silica, 10% alumina, 20% yttria; 70% silica, 20% alumina, 10% yttria; and 20% silica, 45% alumina, 35% yttria, the glass having a chemical durability such that subsequent to irradiation and administration of the microsphere to the mammal, the microsphere will not release a significant amount of yttrium-90 into the mammal's system.
Claim 2
Dependent Claim
122 words
A glass microsphere having a diameter of about 75 micrometers or less and adapted for radiation therapy of a mammal, said glass consisting essentially of an yttrium oxide-aluminosilicate glass composition lying substantially within a quadrilateral region of the ternary composition diagram of the yttria-alumina-silica system, the quadrilateral region being defined by its four corners having the following combination of weight proportions of the components: 20% silica, 10% alumina, 70% yttria; 70% silica, 10% alumina, 20% yttria; 70% silica, 20% alumina, 10% yttria; and 20% silica, 45% alumina, 35% yttria, the glass having a chemical durability such that subsequent to irradiation and administration of the microsphere to the mammal, the microsphere will not release a significant amount of yttrium-90 into the mammal's system.
Claim 3
Dependent Claim
19 words
A glass microsphere as set forth in claim 1 wherein said microsphere is substantially spherical having a smooth surface.
Claim 4
Dependent Claim
20 words
A glass microsphere as set forth in claim 1 wherein said diameter is between about 5 and about 75 micrometers.
Claim 5
Dependent Claim
20 words
A glass microsphere as set forth in claim 1 wherein said diameter is between about 20 and about 30 micrometers.
Claim 6
Dependent Claim
15 words
A glass microsphere as set forth in claim 1 wherein said microsphere is essentially void-free.
Claim 7
Dependent Claim
16 words
A glass microsphere as set forth in claim 1 wherein said microsphere has a hollow core.
Claim 8
Dependent Claim
18 words
A glass microsphere as set forth in claim 1 wherein said microsphere has a plurality of hollow cells.
Claim 9
Dependent Claim
23 words
A glass microsphere as set forth in claim 1 wherein said glass remains durable following neutron irradiation with an intense thermal neutron flux.
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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) | 1991-12-06 | 1992-06-06 | 1992-12-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-12-06 | 1996-06-06 | 1996-12-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-12-06 | 2000-06-06 | 2000-12-06 | $7700.00 | Window Closed / Lapsed |