Polymer coatings for brachytherapy devices

Patent metadata

Field	Value
Publication number	US-11529432-B2
Application number	US-201816610507-A
Country	US
Kind code	B2
Filing date	May 9, 2018
Priority date	May 11, 2017
Publication date	Dec 20, 2022
Grant date	Dec 20, 2022

Abstract

Described embodiments include an apparatus (20, 21), which includes a support (22), including an outer surface (24) and configured for insertion into a body of a subject. The apparatus further includes multiple atoms (26) of a radionuclide, which radioactively decays to produce a daughter radionuclide, coupled to the outer surface, and a layer (28, 33) of a polymer, which is permeable to the daughter radionuclide, that covers the atoms. Other embodiments are also described.

First claim

The invention claimed is:

1. An apparatus, comprising:
a support, configured for insertion into a body of a subject;
an inner layer of an inner polymer, which coats the support;
multiple atoms of a radionuclide, which radioactively decays to produce a daughter radionuclide, coupled to an outer surface of the inner layer,
the inner layer allowing diffusion of the daughter radionuclide therethrough; and

an outer layer of an outer polymer, which covers the atoms so as to protect the atoms from being washed away, yet allows diffusion of the daughter radionuclide through the outer layer.

2. The apparatus according to claim 1 , wherein the support is cylindrically-shaped.

3. The apparatus according to claim 1 , wherein the radionuclide is an alpha-emitting radionuclide.

4. The apparatus according to claim 1 , wherein the radionuclide comprises an isotope of radium selected from a group of isotopes consisting of: Ra-224 and Ra-223.

5. The apparatus according to claim 1 , wherein the daughter radionuclide is an alpha-emitting daughter radionuclide.

6. The apparatus according to claim 1 , wherein a diffusion coefficient of the daughter radionuclide in the outer polymer is at least 10 −11 cm 2 /sec.

7. The apparatus according to claim 1 , wherein the outer polymer is selected from a group of polymers consisting of: polypropylene, polycarbonate, polydimethylsiloxane, polyethylene terephthalate, poly(methyl methacrylate), and polysulfone.

8. The apparatus according to claim 1 , wherein an inner-layer thickness of the inner layer is between 0.1 and 2 microns.

9. The apparatus according to claim 8 , wherein the inner-layer thickness is between 0.1 and 1 microns.

10. The apparatus according to claim 1 , wherein a thickness of the outer layer is greater than 10 nanometers.

11. The apparatus according to claim 10 , wherein the thickness is between 0.1 and 2 microns.

12. The apparatus according to claim 11 , wherein the thickness is between 0.1 and 1 microns.

13. A method, comprising:
coating an outer surface of a support, which is configured for insertion into a body of a subject, with an inner layer of an inner polymer;
depositing multiple atoms of a radionuclide, which radioactively decays to produce a daughter radionuclide, onto an outer surface of the inner layer,
the inner layer allowing diffusion of the daughter radionuclide therethrough; and

subsequently to depositing the atoms onto the outer surface of the inner layer, covering the atoms with an outer layer of an outer polymer that protects the atoms from being washed away, yet allows diffusion of the daughter radionuclide through the outer layer.

14. The method according to claim 13 , wherein the support is cylindrically-shaped.

15. The method according to claim 13 , wherein covering the atoms comprises covering the atoms by withdrawing the support from a solution of the outer polymer.

16. The method according to claim 13 , wherein the radionuclide is an alpha-emitting radionuclide.

17. The method according to claim 13 , wherein the radionuclide includes an isotope of radium selected from a group of isotopes consisting of: Ra-224 and Ra-223.

18. The method according to claim 13 , wherein the daughter radionuclide is an alpha-emitting daughter radionuclide.

19. The method according to claim 13 , wherein a diffusion coefficient of the daughter radionuclide in the outer polymer is at least 10 −11 cm 2 /sec.

20. The method according to claim 13 , wherein the outer polymer is selected from a group of polymers consisting of: polypropylene, polycarbonate, polydimethylsiloxane, polyethylene terephthalate, poly(methyl methacrylate), and polysulfone.

21. The method according to claim 13 , wherein an inner-layer thickness of the inner layer is between 0.1 and 2 microns.

22. The method according to claim 21 , wherein the inner-layer thickness is between 0.1 and 1 microns.

23. The method according to claim 13 , wherein a thickness of the outer layer is greater than 10 nanometers.

24. The method according to claim 23 , wherein the thickness is between 0.1 and 2 microns.

25. The method according to claim 24 , wherein the thickness is between 0.1 and 1 microns.

26. A method, comprising:
inserting a radiation source into a body of a subject, the radiation source including:
a support,
an inner layer of an inner polymer, which coats the support,
multiple atoms of a radionuclide, which radioactively decays to produce a daughter radionuclide, coupled to an outer surface of the inner layer,
the inner layer allowing diffusion of the daughter radionuclide therethrough, and

an outer layer of an outer polymer, which covers the atoms so as to protect the atoms from being washed away, yet allows diffusion of the daughter radionuclide through the outer layer; and

leaving the radiation source within the body of the subject, such that nuclei of the daughter radionuclide diffuse through the outer layer.

27. The method according to claim 26 , wherein inserting the radiation source into the body of the subject comprises inserting the radiation source into a tumor inside the body of the subject.

28. The method according to claim 26 , wherein inserting the radiation source into the body of the subject comprises inserting the radiation source such that the radiation source is within 0.1 mm of a tumor inside the body of the subject.

Assignees

• Alpha Tau Medical Ltd

Inventors

• Kelson Itzhak
• Keisari Yona
• Schmidt Michael
• Berkowitz Avia

Classifications

• A61N2005/1025

  Wires · CPC title

• A61K9/0024

  Solid, semi-solid or solidifying implants, which are implanted or injected in body tissue (compositions for intravenous administration, normal injectable solutions or dispersions for, e.g. subcutaneous administration A61K9/0019; brain implants A61K9/0085; (coated) prostheses, catheters or stents A61L) · CPC title

• A61L31/16

  Biologically active materials, e.g. therapeutic substances {(A61L31/047 takes precedence)} · CPC title

• A61L2420/02

  Methods for coating medical devices · CPC title

• A61N5/1007 Primary

  Arrangements or means for the introduction of sources into the body · CPC title