2014年2月24日学术报告--Recent advances in ......

报告题目：Recent advances in avalanche amorphous selenium (a-Se) and polycrystalline lead oxide (PbO) technologies for direct conversion medical imaging detectors
报告人：Prof. Alla Reznik, Department of Physics, Lakehead University, Canada
主持人：陈军 教授
时间： 2月24日（星期一） 上午9：00点
地点： 广东省显示材料与技术重点实验室讲学厅
摘要：
Direct conversion x-ray detectors revolutionized radiation medical imaging due to the number of benefits inherent in direct conversion methods, i.e.: (a) high spatial resolution limited only by the pixel size and (b) potentially with the right photoconductor, dose efficiency down to the lowest required radiation exposure is possible. In addition, the direct conversion system is simpler than indirect conversion one, and hence potentially more economical to manufacture.
These advantages were realized in direct conversion mammographic detectors with amorphous selenium (a-Se) layer as x-ray –to-charge transducer. Indeed, a-Se mammographic detectors manufactured by our industrial partner, Analogic Canada, show breast image quality superior to any other existing commercial detectors.
Although a-Se properties suite well applications in mammography, for mammography tomosynthesis or general radiographic and fluoroscopic applications a-Se has to be replaced by a material with higher x-ray-to-charge conversion gain. Avalanche a-Se and polycrystalline Lead Oxide (PbO) are most promising materials to realize the advantages of direct conversion method at diagnostic range or for reduced dose at mammographic range. In addition, they are technologically compatible with advanced readout techniques (CMOS, TFT and Active Matrix arrays). However, both materials are still experimental being developed to the point where engineering approaches have to be applied to bring them for commercialization. In my talk I’ll show our recent technological solutions to improved stability, charge collection efficiency and temporal performance in these materials.
报告人简介：
Dr. Alla Reznik is specializing in photoconducting materials used as radiation-to-charge transducers in x-ray and gamma-ray direct conversion detectors. She holds PhD degree in Solid State Physics from the Technion-Israel Institute of Technology where she studied wide-band gap semiconductors for radiation detection applications. As a specialist in wide-band gap semiconductors, in 1999 Dr. Reznik was hired by GE Medical Systems Functional Imaging to work as a Senior Physicist on advanced CZT solid state gamma camera. Her major projects were devoted to detectors for scintimammography and intra-operative gamma-camera for image-guided excision of radiolabelled lymph nodes during breast-conserving surgery for breast cancer patients.
In 2003 Dr. Rezik returned to Academia. In 2008 she was appointed a Canada Research Chair in Physics of Molecular Imaging and recently (2013) re-appointed as a Canada Research Chair in Physics of Medical Imaging. She is jointly affiliated as an Associate Professor, Department of Physics, Lakehead University and a Senior Scientist, Thunder Bay Regional Research Institute (TBRRI). She acquired state-of-the-art facilities at TBRRI for different photoconductive layers and structures deposition and characterisation. The focus of her work is on advanced low-dose direct conversion flat panel x-ray imaging detectors based on amorphous selenium (a-Se) and polycrystalline Lead Oxide (PbO) as x-ray-to-charge transducers. Another focus of her work is on solid-state technology for Positron Emission Tomography (PET). The goal is an improvement in resolution and sensitivity over commercially available PET imagers to make organ-specific PET imagers as well as PET/MR dual-modality systems.