Imaging method for monitoring delivery of high dose rate brachytherapy
Inventors
Weisenberger, Andrew G. • Majewski, Stanislaw
Assignees
Jefferson Science Associates LLC
Publication Number
US-8295910-B1
Publication Date
2012-10-23
Expiration Date
2027-11-16
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Abstract
A method for in-situ monitoring both the balloon/cavity and the radioactive source in brachytherapy treatment utilizing using at least one pair of miniature gamma cameras to acquire separate images of: 1) the radioactive source as it is moved in the tumor volume during brachytherapy; and 2) a relatively low intensity radiation source produced by either an injected radiopharmaceutical rendering cancerous tissue visible or from a radioactive solution filling a balloon surgically implanted into the cavity formed by the surgical resection of a tumor.
Core Innovation
The invention provides a method for in-situ monitoring both the balloon or cavity and the radioactive source during brachytherapy treatment by utilizing at least one pair of miniature gamma cameras. These gamma cameras acquire separate images of the radioactive source as it is moved through the tumor volume, and images of a relatively low intensity radiation source produced either by an injected radiopharmaceutical that renders cancerous tissue visible or from a radioactive solution that fills a balloon surgically implanted into the cavity formed by surgical resection of a tumor.
The problem being solved is the lack of an accurate, reliable, and reproducible method for determining the location of the radioactive source in the target area in-situ during brachytherapy. Current techniques only track dummy sources mechanically but cannot directly verify source placement or the relationship between the source and tissue undergoing treatment. This invention addresses the challenge of verifying correct and reproducible delivery of a highly radioactive pellet, such as Ir-192, to designated locations within the tumor volume across multiple treatment fractions.
Claims Coverage
The patent contains multiple independent claims describing methods for monitoring both the balloon/cavity and the radioactive source in brachytherapy treatment. The inventive features focus on introducing two different radioactive sources, acquiring separate images of these sources at different photon energies, and co-registering those images.
Simultaneous imaging of two different radioactive sources
The method involves introducing a high intensity non-liquid radioactive source and a relatively low intensity liquid radiation source into the patient, and simultaneously acquiring separate images of both sources as they emit photons at different energies during brachytherapy treatment.
Co-registration of images from different photon energies
The separate images obtained for the high intensity and low intensity sources, each emitting photons at different energies, are registered and displayed to ascertain the positions of the radioactive source relative to the balloon or cavity.
Use of energy-discriminating gamma cameras with different collimators
The method includes using a pinhole collimated gamma camera to image the high intensity radioactive source and a parallel hole collimated gamma camera to image the low intensity liquid radiation source. The gamma cameras are designed to discriminate between photons from the different radioactive sources enabling concurrent acquisition of images that are then registered.
In summary, the independent claims disclose a method that simultaneously images two distinct radiation sources at different photon energies using specialized gamma cameras and co-registers those images to monitor the location of the radioactive source relative to the balloon or cavity during brachytherapy treatment.
Stated Advantages
Provides accurate, reliable, and reproducible in-situ determination of the radioactive source location during brachytherapy.
Enables direct visualization and confirmation of both the balloon/cavity and the radioactive source positions simultaneously.
Allows non-invasive imaging with no impact on the treatment procedure, thereby improving dose verification.
Enhances the accuracy of dose calculations by providing input data on the position of the source relative to the treated tissue.
Documented Applications
Monitoring intracavity radiation delivery in balloon brachytherapy for breast cancer treatment post-lumpectomy.
Verification of source positioning and dose delivery in high dose rate brachytherapy treatments for tumors in breast, lung, and prostate cancers.
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