研制成本可负担的高空间分辨率正电子发射断层成像（positron emission tomography，PET）系统在PET成像应用中具有决定性的意义，也是PET成像面临的关键性挑战之一。设想一种PET系统，能够根据应用的需求对不同性能的探测器进行布局，在一个具体时刻，对部分成像区域获得很高的性能，而在其他的区域获得普通性能。提出了一种应用适应性PET系统原型，由大部分普通固有空间分辨率的探测模块和少量更高甚至极端高固有空间分辨率的探测模块组成。研究了在含有连续放置的一段高固有空间分辨率探测模块的PET系统中，高性能模块的布局位置和数量对视场内不同位置点的空间分辨率的影响。初步研究结果表明，所提出的系统能够为局部区域带来高空间分辨率，其空间分辨率提升程度与高性能模块布局位置有关，在同一高性能模块布局位置下，视场中不同位置点的提升程度不同。该研究结果也显示，根据应用需求规划探测模块的构成和布局以在感兴趣区域获得局部高空间分辨率是可能的。

A critical challenge in positron emission tomography (PET) is to develop affordable systems having high spatial resolution. We imagine a PET system, for imaging a region of interest (ROI) with ultra high performances and other regions with normal performances by use of inhomogeneous performances PET detectors. We propose such a prototype, consisting of a few ultra high intrinsic spatial resolution PET detectors and quite a few normal ones. In this paper, we investigate the effect of the location and the number of high resolution detectors. The high resolution detectors are grouped in a continuous partial ring. The initial results show that such a prototype is capable to bring the advantages of significantly improving the spatial resolution in a ROI. For a specified area, the improvement is influenced by the location and fraction of high resolution detectors in a ring. The encouraging results also indicate the possibilities to regulate detectors to achieve high spatial resolution according to the application, which is possibly formulated.

谢庆国（1972— ） ，男，浙江余姚市人，华中科技大学教授，主要研究方向为 ＰＥＴ 成像与应用