Low-density magnesium-aluminum-silicate (MAS) microparticles for radiotherapy and/or radioimaging

1. A radioactive low density microparticle for radioimaging or radiation therapy of a mammal comprising a biologically compatible magnesium-alumina-silicate glass microparticle having a density of about 3.0 g/cc or less said microparticle containing at least one beta or gamma radiation emitting isotope distributed substantially throughout the magnesium-alumina-silicate glass which emits a therapeutic intensity and amount of beta or gamma radiation, and a balance of elements selected from the group consisting of elements that do not become radioactive upon neutron irradiation and elements that have a half-life that is sufficiently short so that the elements do not emit a significant amount of beta or gamma radiation at the time of administration, the microparticle having a chemical durability such that subsequent to administration of the microparticle to the mammal, the microparticle will not release a significant amount of the radiation emitting radioisotope into the mammal's system;

wherein the glass microparticle comprises 8-14 wt % MgO, 32-35 wt % Al 2 O 3 , and 47-52 wt % SiO 2 .

2. The radioactive low density microparticle of claim 1 , wherein the isotope is at least one medical isotope selected from the group consisting of Samarium-153, Yttrium-90, and Lutetium-177.

3. The radioactive low density microparticle of claim 1 , wherein the isotope is a combination of Samarium-153 and Yttrium-90.

4. The radioactive low density microparticle of claim 1 , wherein the density is about 2.8 g/cc or less.

5. The radioactive low density microparticle of claim 1 , wherein the isotope is 90 Y (Yttrium-90) and has specific activity of 162 mCi per 10 7 microparticles for therapy.

6. The radioactive low density microparticle of claim 5 , further comprising a second radiation emitting isotope consisting of 177 Lu (Lutetium-177), wherein the 177 Lu has specific activity of 32 mCi per 10 7 microparticles for imaging.

7. The radioactive low density microparticle of claim 5 , further comprising a second radiation emitting isotope consisting of 153 Sm (Samarium-153), wherein the 153 Sm has a specific activity of 12 mCi per 250,000 microparticles for imaging.

8. A method of administering radioactive magnesium-alumina-silicate glass microparticles to a patient in need thereof, comprising delivering by catheter to an artery that feeds an organ or a tumor of a patient a composition comprising the radioactive low density microparticles of claim 1 , and a physiologically acceptable carrier.

9. The method of claim 8 , further comprising wherein the isotope is a combination of samarium-153 and yttrium-90.

10. The method of claim 8 , further comprising wherein the isotope is lutetium-177.

11. The method of claim 8 , further comprising wherein the isotope is samarium-153.

12. The method of claim 8 , wherein the organ or tumor is selected from the group consisting of liver, spleen, brain, kidney, head & neck, uterine, and prostate.

13. A method of obtaining a radiologic image of a patient's organ, comprising administering by catheter to an artery that feeds an organ of a patient a composition containing radioactive magnesium-alumina-silicate glass microparticles that contain samarium-153 or lutetium-177 as the medical isotope in a physiologically acceptable carrier, and obtaining the radiologic image of the patient's organ by capturing the radiation emitted by the samarium-153 or lutetium-177 using a suitable radionuclide imaging technique;

wherein the glass microparticles comprise 8-14 wt % MgO, 32-35 wt % Al 2 O 3 , 47-52 wt % SiO 2 , and said samarium-153 or lutetium-177.

14. The method of claim 13 , further comprising wherein the radionuclide imaging technique is single photon emission computed tomography (SPECT).

15. The method of claim 13 , wherein the organ or tumor is selected from the group consisting of liver, spleen, brain, kidney, head & neck, uterine, and prostate.

16. A method of administering radioactive magnesium-alumina-silicate glass microparticles that contain both samarium-153 as a radiodiagnostic medical isotope and yttrium-90 as a radiotherapeutic medical isotope to a patient in need thereof, comprising delivering by catheter to the hepatic artery of a patient a composition comprising radioactive magnesium-alumina-silicate glass microparticles that contain a radiodiagnostic amount of samarium-153 and a radiotherapeutic amount of yttrium-90, and a physiologically acceptable carrier;

wherein the glass microparticles comprise 8-14 wt % MgO, 32-35 wt % Al 2 O 3 , 47-52 wt % SiO 2 , the radiodiagnostic amount of samarium-153, and the radiotherapeutic amount of yttrium-90.

17. The radioactive low density microsphere of claim 1 wherein the glass microparticle comprises the 8-14 wt % MgO, 32-35 wt % Al 2 O 3 , the 47-52 wt % SiO 2 and one of a) Lu-177, b) Y-90, c) Sm-153, d) Lu-153+Y-90, or e)Sm-153+Y 90, as said at least one beta or gamma radiation emitting isotope.

18. The radioactive low density microsphere of claim 17 wherein the glass microparticle consists essentially of the 8-14 wt % MgO, the 32-35 wt % Al 2 O 3 , the 47-52 wt % SiO 2 and the one of a) Lu-177, b) Y-90, c)Sm-153, d) Lu-153+Y-90, or e) Sm-153+Y 90 as said at least one beta or gamma radiation emitting isotope.

19. The method of claim 16 wherein the magnesium-alumina-silicate glass microparticles are about 20 to about 200 um in diameter.

20. The method of claim 16 wherein the magnesium-alumina-silicate glass microparticles are about 5 to about 75 um in diameter.

21. The method of claim 16 wherein the magnesium-alumina-silicate glass microparticles are about 20 to about 40 um in diameter.

22. The radioactive low density microparticle of claim 1 , wherein the microparticle is melt-derived from a mixture of particles comprising MgO, Al 2 O 3 , SiO 2 and an oxide of the radiation-emitting isotope.