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

拟利用该设施进行的研究是基础仪器物理和一种新的3D物体运动和形状跟踪技术的应用。跟踪物体和设备的三维运动在医学物理、工业工程、生物医学工程和医疗保健中有着广泛的应用。目前可用的运动跟踪技术包括光学跟踪、电磁跟踪和X射线成像跟踪。然而，每种技术都有其局限性。光学方法不能跟踪腔内的物体。当发射器或接收器靠近金属物体时，由于干扰，电磁跟踪会产生很大的跟踪误差。X射线成像引入了显著的辐射剂量。这些技术通常需要最小尺寸的标记来提供足够的信噪比来进行准确跟踪，这进一步限制了这些技术的应用。所提出的技术用发射正电子的同位素标记目标物体。发射出的正电子与电子湮没，产生成对的背靠背伽马射线。通过探测这些湮没伽马射线，可以以亚毫米精度实时重建物体的形状、位置和方向。我们称这项技术为皮特里克。正电子同位素可以以任何形式嵌入或沉积在靶体上，点源标记、线标记，甚至可以在目标设备的表面上绘制。用于标记的同位素活度很低(小于3MBq)，对患者和操作员全身的有效辐射剂量并不显著：在15-60厘米之间的距离小于10uSv/h，而加拿大人平均每年收到的剂量为4mSv。该技术可以克服上述局限性，并且可以跟踪对于现有技术来说太小的目标。我们将用商业上可用的组件建造第一个PetRack系统。该仪器将用于：1)开发目标运动和形状的跟踪算法。2)开发同位素标记技术3)将PetRack应用于图像引导放射治疗4)探索在其他图像引导程序中的可能应用。

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.