Application Adaptive PET

Positron emission tomography (PET), as a non-invasive functional imaging technology, is a powerful tool to detect the metabolic activity, the biochemical reaction, and the biological active of an organ in the body, dynamically and quantitatively. Due to these advantages and its high sensitivity to these processes, PET plays a unique and important role in the clinical diagnosis of oncology, cardiovascular and nervous system, as well as in tracer development, drug discovery, development of therapeutic targets and targeted therapies, and many other preclinical biomedical applications. As the application is wider, PET is expected to provide better performance and new geometry. An optimized PET for individual imaging objects and extensional application scenes is highly expected.Traditional PET systems have dedicated analog electronics and correlative components, and closed system architecture and fixed geometry. In such a PET system development, the main and difficulty point is hardware, and the upgrade of certain component usually causes global changes in other components, sometimes a redesign. In practice, the variation of the application requirements in individual imaging objects or application scenes exists everywhere. However, due to the limitation of the system architecture, it is hard for the traditional PET to process the application-oriented optimized PET imaging research. So, the problem solution needs an innovation on the system design.For the above application requirement and challenge, this dissertation proposed the imaging process of the application-oriented optimized PET and the application adaptive PET concept. And aimed at the limitations of the traditional PET, we proposed the system architecture requirement of the application adaptive PET, and then designed an application adaptive PET system architecture and built the platform of it. Based on this, this dissertation studied on the design and implementation of the application adaptive PET system for the pre-clinical imaging. Through simulation and physical evaluation experiments, we investigated the imaging performance and application. This work provides the key technologies and theoretical concepts for the application-oriented optimized PET imaging, and allows the PET system development to tap the fast growing of the modern digital electronics. It’s reasonable to believe that such application adaptive PET system will improve the depth and width of the PET application.Firstly, we described the imaging process of the application-oriented optimized PET, which starts from the analysis of application requirement, and then performs self-optimization, self-calibration and parameter adjustment, and arranges detector modules into different geometries, to meet different imaging needs. In order to performance such process, a PET system having high flexibility of the system geometry and performance is required, as the application adaptive PET. Thus, by using of the digital PET Data Acquisition (DAQ), this dissertation proposed a system architecture for the application adaptive PET, which is main composed of a digital scanner system, software coincidence system and imaging reconstruction system. As the signal from the detector is directly digitized, the analysis and further coincidence filtering could be performed by use of software. Such architecture maximizes the software development in the design and implementation of a PET system. And the components are decoupled that allows people to quickly optimize the imaging performance by upgrading or improving parts of the system for the requirement of the application. By using of such system architecture and the digital detector module, we built the platform of the architecture. On the platform, we quickly implemented several PET systems which have different geometries for different applications, which presented the advantages of the application adaptive PET system architecture.Small animal PET system is one of the most important tools for preclinical research. This dissertation processed the application adaptive PET system-Trans-PET design and implementation research in pre-clinical imaging. To meet the different requirements for the imaging of rat and mouse, we developed two different PET detector geometries. As using the application adaptive PET system architecture platform, all the components in the two systems are compatible. The two systems can be quickly switched to each other by updating the software for the pulse processing, coincidence filtering and imaging reconstruction. We analyzed the imaging characteristics of the Trans-PET based on simulation and physical evaluation experiments. The results indicated that the proposed system architecture has the potential to process the application adaptive PET imaging. By performing the dynamic imaging, rat brain imaging, several mouse simultaneous imaging and monkey brain imaging, we further demonstrated the advantages of the architecture. The results will provide the guidance for the system design and implementation of the application adaptive PET system. This work is also the first systematical implementation and performance evaluation for the PET system using digital PET detectors, which will be a reference for further implementation and performance evaluation of other systems with digital PET detectors.