Fault-Tolerant, Passively Integrating In-Vivo Dosimeters for Feedback-Enabled Radiation Therapy (IF2D, or Integrating Feedback F-Center Dosimeter)

Technology #17803

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How patient breathing complicates radiation therapy planning and increases uncertainty associated with the dose received at the site of the tumor,  measured on patients with abdominal (a) and thoracic (b) tumors.  The figures show how often path length differences between 0 and 25 mm occurred for each group of patients. Beyer et al. measured the radiation dose received by breast cancer and prostate cancer patients using in vivo wireless MOSFET dosimeters.  It was discovered that there was often a significant difference between the prescribed and received dose.
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Inventors
Professor Michael Short
Department of Nuclear Science and Engineering, MIT
External Link (pripyat.mit.edu)
Rajiv Gupta
Department of Mechanical Engineering, MIT
External Link (mdic.mit.edu)
Cody Dennett
Department of Nuclear Science and Engineering, MIT
Sara Ferry
Department of Nuclear Science and Engineering, MIT
Managed By
Ben Rockney
MIT Technology Licensing Officer
Patent Protection

Integrating Radiation Dosimetery

PCT Patent Application WO 2017-054008

Applications

This technology may be used to monitor radiation therapy during cancer treatment to reduce co-irradiation, improve treatment accuracy, and ensure radiation is delivered directly to tumors.

Problem Addressed

In cancer radiation therapy, a beam of radiation, which damages DNA, is directed toward tumors. Co-irradiation of surrounding, healthy tissue is unavoidable, especially during inevitable movement of the surrounding tissue. In current treatments, dosage is prescribed before the procedure. Unfortunately, there are a number of uncertainties associated with this method including, but not limited to, organ movement, possible software or hardware failures, or slight differences in patient position. Dosimeters that measure radiation levels are most usually measured after treatment and therefore cannot be used to reduce uncertainties and provide more accurate dosage, nor can they control the radiation devices (such as proton accelerators) in real-time. While dosimeters that measure radiation during the procedure exist, they are inherently fault-susceptible and are not commonly used.  Since it is almost impossible to completely reduce uncertainties during radiation therapy, a real-time, fault-tolerant feedback method is desired. This invention is a novel dosimeter that can provide feedback during a procedure to allow for more accurate delivery of radiation.

Technology

This technology, the IF2D, consists of a set of implantable salt crystals that work in conjunction with a thin bundle of optical fibers and can be read using a hand-held USB spectrometer. The device may be implantable as a bundle of fibers with an external reader, or deployed as an implanted “lab on a chip” to wirelessly transmit dosimetry data in real-time. The salts transmit various colors which correspond to precise dosage after radiation creates f-centers, causing photon absorption at particular wavelengths. The device is inherently fault-tolerant since the salts change color without being influenced by any other mechanisms. The data acquired from this dosimeter is also highly accurate and can be used in a real-time feedback loop to control the irradiation system. The device is implanted only once to avoid multiple procedures. This technology is simple and does not need specialized equipment making it a viable option for developing countries which have more limited resources devoted to medical care.  Furthermore, a smartphone with a spectrometer may be developed making this technology even more accessible as it would consist of just a phone and the dosimeter. This invention allows for real-time feedback during radiation therapy to minimize damage to healthy tissue while destroying cancerous cells.

Advantages

  • Improvement on standard thermoluminescent dosimeters which only provide data after procedure
  • Passive integration means fault-tolerant, a major improvement on current real-time devices
  • Simple design allows for inexpensive equipment 
  • Simultaneous measurement of total dose and dose rate increases accuracy and ability for feedback in proton irradiation procedures