# US 12,183,476 B2 · Low density iridium and low density stacks of iridium disks

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- Number: US 12,183,476 B2
- Document ID: US12183476B2
- Status: Granted
- Kind: B2
- Application number: 17/419,371
- Filed: 2020-02-11
- Published: 2022-03-10
- Granted: 2024-12-31
- Earliest claimed: 2019-02-11
- Assignees: Qsa Global, Inc.
- Applicants: Mark G. Shilton; Mark W. Vose; QSA Global, Inc.
- Inventors: Mark G. Shilton; Mark W. Vose
- Web page: https://patentgrep.com/patent/US12183476B2

## CPC

- G21G 4/04: Radioactive sources other than neutron sources (radioactive dressings A61N5/1029)
- G21G 4/06: characterised by constructional features
- G21G 4/08: specially adapted for medical application (radiation therapy using radioactive sources A61N5/10)
- G21G: CONVERSION OF CHEMICAL ELEMENTS; RADIOACTIVE SOURCES (applications of radiation in general G21H5/00; handling particles, e.g. neutrons, or electromagnetic radiation not otherwise provided for G21K)

## Abstract

The disclosure pertains to improvements in a gamma radiation source, typically containing low-density alloys or compounds or composites of iridium in mechanically deformable and compressible configurations, within an encapsulation, and methods of manufacture thereof.

## Claims

### Claim 1

A radiation source including a stack of disks containing iridium or an iridium alloy of 100 percent density wherein the stack contains spaces between adjacent disks thereby reducing the average stack density in the range 30-85% of the density of 100% dense pure iridium wherein the disk stack is subsequently compressed, deformed or worked after irradiation to form a quasi-spherical shape inside a source capsule.

### Claim 2 (depends on 1)

A radiation source of claim 1 comprising:
a plurality of stacked disks, the disks including Iridium-192, the disks having a center and an edge, wherein the center is thicker than the edge;
wherein the average stack density prior to compression, deformation or working is in the range of 30-80 percent.

### Claim 3 (depends on 2)

The radiation source of claim 2 wherein the average stack density prior to compression, deformation or working is in the range of 40-70 percent.

### Claim 4 (depends on 2)

The radiation source of claim 2 wherein the average stack density prior to compression, deformation or working is in the range of 50-60 percent.

### Claim 5 (depends on 2)

The radiation source of claim 2 wherein material of the disks is 80 to 100 percent iridium.