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CN-122006145-A - Activity level of diffuse alpha-emitter radiotherapy

CN122006145ACN 122006145 ACN122006145 ACN 122006145ACN-122006145-A

Abstract

The present application relates to activity levels of diffuse alpha-emitter radiotherapy. Disclosed herein is a method for treating cancerous tumors by implanting in the cancerous tumor at least one diffuse alpha-emitter radiation therapy (DaRT) source having a suitable radon release rate for a given duration such that the source provides a cumulative activity of radon release of at least 10 megabells (MBq) hours per centimeter length during the given duration. Optionally, the sources are implanted in an array of sources, each source being spaced no more than 4.5 mm from its adjacent source in the array.

Inventors

  • Itzhak Kelsen
  • Milta Dumanchi
  • Isai Luz
  • Maya Hedwig Watarescu
  • Jonah caesary
  • A Munong.gaite
  • Robert Deng
  • Ove Magan
  • Willed domankovich
  • Leo Araz
  • Tomar Cooks
  • Guy Hegel

Assignees

  • 阿尔法陶医疗有限公司

Dates

Publication Date
20260512
Application Date
20220608
Priority Date
20210610

Claims (16)

  1. 1. A diffuse alpha-emitter radiation therapy source for implantation in melanoma tumors comprises radium-224 mounted on a support, Wherein the diffuse alpha-emitter radiation therapy source has a radon release rate of between 0.67 and 1.6 micro curies per centimeter of length.
  2. 2. The source of claim 1, wherein the diffuse alpha-emitter radiation therapy source has a radon release rate of between 0.8 and 1.5 micro curies per centimeter of length.
  3. 3. The source of claim 1, wherein the diffuse alpha-emitter radiation therapy source has a radon release rate of between 1.25 and 1.6 micro curies per centimeter of length.
  4. 4. A kit of diffuse alpha-emitter radiation sources for implantation in a melanoma tumor, wherein the kit comprises diffuse alpha-emitter radiation sources having radium-224 mounted on a support, wherein the diffuse alpha-emitter radiation sources are implanted in an array in which each diffuse alpha-emitter radiation source is spaced between 3mm and 4 mm from its adjacent diffuse alpha-emitter radiation source.
  5. 5. The kit of claim 4, wherein the diffuse alpha-emitter radiation therapy source is implanted in a hexagonal arrangement.
  6. 6. The kit of claim 4, wherein each diffuse alpha-emitter radiation therapy source is spaced between 3 millimeters and 3.5 millimeters from its neighboring diffuse alpha-emitter radiation therapy sources in the array.
  7. 7. A kit of diffuse alpha-emitter radiation therapy sources for implantation in a melanoma tumor, wherein the kit comprises diffuse alpha-emitter radiation therapy sources having radium-224 mounted on a support, the diffuse alpha-emitter radiation therapy sources having radon release rates between 0.67 and 1.6 micro curies per centimeter of length, and wherein the diffuse alpha-emitter radiation therapy sources are implanted in an array in which each diffuse alpha-emitter radiation therapy source is spaced no more than 4 millimeters from its adjacent diffuse alpha-emitter radiation therapy sources.
  8. 8. The kit of claim 7, wherein the diffuse alpha-emitter radiation therapy source is implanted in a hexagonal arrangement.
  9. 9. The kit of claim 7, wherein each diffuse alpha-emitter radiation therapy source is spaced between 3 millimeters and 3.5 millimeters from its neighboring diffuse alpha-emitter radiation therapy sources in the array.
  10. 10. The kit of any one of claims 7-9, wherein the diffuse alpha-emitter radiation therapy source has a radon release rate of between 0.8 and 1.5 micro curies per centimeter of length.
  11. 11. An apparatus for preparing a radiation therapy treatment, comprising: An input interface for receiving information about a tumor; A processor configured to identify a tumor as a melanoma tumor and generate an arrangement of diffuse alpha-emitter radiation therapy sources for the tumor, wherein the diffuse alpha-emitter radiation therapy sources in the arrangement have a radon release rate of between 0.67 and 1.6 micro curies per centimeter length and the diffuse alpha-emitter radiation therapy sources in the arrangement are arranged in a regular pattern with distances between adjacent diffuse alpha-emitter radiation therapy sources of no more than 4 millimeters, and An output interface for displaying the arrangement to a human operator.
  12. 12. The apparatus of claim 11, wherein the diffuse alpha-emitter radiation therapy sources in the arrangement are arranged in a hexagonal arrangement.
  13. 13. The apparatus of claim 11, wherein a distance between adjacent diffuse alpha-emitter radiation therapy sources is between 3 millimeters and 3.5 millimeters.
  14. 14. The apparatus of any one of claims 11-13, wherein the diffuse alpha-emitter radiation therapy source has a radon release rate of between 0.8 and 1.5 micro curies per centimeter of length.
  15. 15. A method of preparing a radiation therapy treatment, comprising: receiving a request for a diffuse alpha-emitter radiation therapy source for a melanoma tumor; determining the number of diffuse alpha-emitter radiation therapy sources required for said tumor such that the tumor area is covered by diffuse alpha-emitter radiation therapy sources with a spacing between the diffuse alpha-emitter radiation therapy sources of not more than 4 millimeters, and Providing a kit comprising a determined number of diffuse alpha-emitter radiation therapy sources, wherein the diffuse alpha-emitter radiation therapy sources have a radon release rate of between 0.67 and 1.6 micro curies per centimeter of length.
  16. 16. The method of claim 15, wherein the diffuse alpha-emitter radiation therapy source has a radon release rate of between 0.8 and 1.5 micro curies per centimeter of length.

Description

Activity level of diffuse alpha-emitter radiotherapy The present application is a divisional application with application number 202280005646.1, the application number of which is 2022, 6, 8, and the title of the application "activity level of diffuse alpha-emitter radiotherapy". Technical Field The present invention relates generally to radiation therapy and in particular to an apparatus and method for providing a tumor specific radiation dose in radiation therapy treatment. Background Ionizing radiation is commonly used to treat certain types of tumors, including malignant cancerous tumors, to destroy their cells. However, ionizing radiation also damages healthy cells of the patient and care is therefore taken to minimize the radiation dose delivered to the healthy tissue outside the tumor, while maximizing the dose delivered to the tumor. Ionizing radiation damages cells by causing damage to the DNA of the cells. The biological effectiveness of different types of radiation in killing cells is determined by the type and severity of DNA damage they cause. Alpha particles are a powerful means for radiation therapy because they induce clustered double strand breaks in DNA, which the cells cannot repair. Unlike conventional types of radiation, the destructive effects of alpha particles are largely unaffected by low cellular oxygen levels, which makes them equally effective against hypoxic cells (hypoxic cell), the presence of which in tumors is the primary cause of failure of conventional photon-or electron-based radiation therapies. Furthermore, the short distance of the alpha particles in the tissue (less than 100 microns) ensures that if the atoms emitting them are confined within the tumor volume, the surrounding healthy tissue will survive. On the other hand, the short distance of alpha radiation has so far limited its use in cancer therapy, as there is no practically viable method to deploy alpha emitting atoms in sufficient concentration throughout the tumor volume. Diffuse alpha-emitter radiotherapy (alpha-emitter radiation therapy, daRT), such as described in U.S. patent 8,834,837 to Kelson, expands the therapeutic range of alpha radiation by using radium-223 or radium-224 atoms, which produce several chains of radioactive decay, wherein the dominant half-life of radium-224 (governing half-life) is 3.6 days and the dominant half-life of radium-223 is 11.4 days. In DaRT, the radium atoms attach to the source implanted in the tumor (also referred to as "seed") at an intensity sufficient that they do not leave the source in a wasteful manner (cleared from the tumor by blood), but a substantial percentage of their daughter radionuclides (radon-220 in the case of radium-224 and radon-219) leave the source to enter the tumor upon decay of radium. These radionuclides and their own radioactive sub-atoms are dispersed by diffusion around the source up to a radial distance of a few millimeters before decay by alpha radiation. Thus, the range of destruction in a tumor is increased relative to the radionuclide that remains on the source with its daughter. For the treatment of tumors to be effective, daRT seeds used in the treatment should release a sufficient number of radon atoms to destroy the tumor with a high probability. If insufficient radiation is used, excessive cancer cells will remain in the tumor and these cells may reproduce and reform into malignant tumors. On the other hand, the kernels should not release too much radon atoms because some of their daughter is cleared from the tumor by the blood and thus may damage distant healthy tissues, including the patient's organs, such as bone marrow, kidneys and/or ovaries, etc. The amount of radium atoms on DaRT sources is quantified in terms of activity (i.e., rate of radium decay). DaRT Source Activity is measured in micro Curie (μCi) or kilo Beckler (kBq), where 1 μCi=37 kBq =37,000 decays per second. When DaRT is used, the dose of radiation delivered to the tumor cells depends not only on the radium activity of the source, but also on the probability of daughter radon atoms leaving the source to enter the tumor upon alpha decay of the radium. This probability is referred to herein as the "desorption probability (desorption probability)". Thus, one can use the "radon release rate" as a measure of the DaRT related activities of the source, as opposed to expressed in terms of the activity of the source, which is defined herein as the product of the activity on the source and the probability of desorption of radon from the source. Similar to activity, radon release rate is given in units of μCi or kBq. The activity and radon release rate values given herein are the activity and radon release rate values of the source at the time of implantation of the source into the tumor, unless otherwise specified. The above-mentioned Kelson U.S. patent 8,834,837 suggests using an activity of "about 10 nano-curies to about 10 micro-curies, more preferably about 10 nano-c