Research facility for the development of a novel positron-emission based object tracking technique for medicine

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The research to be performed with the proposed facility is fundamental instrumentation physics and the application of a new 3D object motion and shape tracking technique. Tracking the 3D motion of objects and devices has wide application in medical physics, industrial engineering, biomedical engineering and health care.  Currently available motion tracking techniques include optical tracking, electromagnetic tracking and tracking with x-ray imaging. However, each technique has its limitations. The optical method cannot track an object inside a cavity. Due to interference, electromagnetic tracking can produce large tracking error when the transmitter or receiver is placed close to a metallic object. X-ray imaging introduces significant radiation dose. These techniques usually require a minimum size of the markers to provide adequate signal to noise ratios for accurate tracking, which further limits the application of these techniques. The proposed technique labels the target object with positron-emitting isotopes. The emitted positrons annihilate with electrons and produce pairs of back-to-back gamma rays. By detecting these annihilation gamma rays, the shape, location and orientation of the object can be reconstructed in real-time with sub-millimeter accuracy. We call the technique PeTrack. The positron isotope can be embedded into or deposited on the target in any form, point source marker, line marker and can even be "painted" on the surface of the target device. The activity of isotope for labeling is very low (less than 3MBq) and the effective radiation dose to the whole body of patient and operator is not significant: less than 10 uSv/h at distance between 15 and 60 cm, as compared with 4 mSv annual dose received by an average Canadian. The proposed technique can overcome the above limitations and can track objects that are too small for current techniques. We will construct the first PeTrack system from commercially available components. The instrument will be used to: 1) Develop tracking algorithms for both target motion and shape. 2) Develop isotope labeling techniques 3) Apply PeTrack to image guided Radiation therapy 4) Explore possible applications in other image guided procedures.