Oct 9 2007
Structured Material Industries, Inc., (SMI) will develop compact low-cost dose sensors for use in ion beam and proton beam cancer therapy. High energy beams of ions and protons have been investigated for cancer treatment over the past four decades. Proton beam cancer therapy is fast becoming a mainstream technology in the US, offering the potential for successful cancer treatment, with minimal side effects and minimum damage to adjacent healthy tissue.
For successful treatment, it is critical to achieve the proper dose, and to target the dose to a specific volume within the patient. At present, there is a need for proton dose sensors for use "ex-vivo" (outside of the patient's body) for beam calibration, positioning and monitoring. These proton beam sensors need to have high accuracy, high sensitivity, low noise, and good radiation damage resistance.
In the near future, dose sensors will also be needed for use "in-vivo" (within the patient's body), in order to deliver dose with high precision to selected tissue volumes. The use of in-vivo dose sensors will enable beam position accuracy to within small fractions of a millimeter, even with the inevitable organ movement due to patient respiration and cardiovascular action. This increased level of beam position accuracy will enable treatment of advanced tumors, small tumors, and tumors intimately adjacent to healthy organs.
Our technical approach is based on thin films of man-made diamond prepared by microwave plasma chemical vapor deposition (MPCVD). Diamond is an ideal material for detecting a wide range of high energy radiation, including x-rays, ion beams and proton beams.
Diamond-based detectors can be produced with high sensitivity, low noise, and excellent radiation hardness. Diamond-based sensors also have the advantages of being chemically inert, non-toxic, sterilizable and (since both are essentially made of carbon) have beam interaction equivalency to human tissue. These properties make diamond-based dose sensors ideal for in-vivo dose monitoring during radiation therapy.
The result of this effort will be superior packaged diamond detectors for both ex-vivo and in-vivo radiation sensing applications.