Investigating the temporal resolution limits of scintillation detection from pixellated elements: comparison between experiment and simulation
Investigating the temporal resolution limits of scintillation detection from pixellated elements: comparison between experiment and simulation
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DOI：
10.1088/0031-9155/56/3/013
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发表时间：
2011-02-07
影响因子：
3.5
通讯作者：
Levin, C. S.
中科院分区：
文献类型：
--
作者：
Spanoudaki, V. Ch;Levin, C. S.
本研究调查的物理限制，涉及提取准确的定时信息，从像素化闪烁探测器的正电子发射断层扫描（PET）。针对不同的探测器属性（例如晶体元件长度、光产率、衰减时间和表面处理），设计并执行从闪烁光产生到探测的闪烁探测过程的精确物理建模。光输出和时间分辨率对这些属性的依赖关系，以及对晶体体积内的湮灭量子的光子相互作用深度（DoI），进行了研究，并与实验结果进行了比较。一个理论背景，突出了不同的时间模糊因素的重要性，瞬时（“理想”）和指数（“现实”）闪烁衰减的开发和模拟数据相比。对于真实闪烁体的情况，我们的实验和模拟结果表明，与抛光表面相比，粗糙（“切割”）晶体元件的检测器性能对DoI的依赖性更明显（在模拟（测量）中，光输出和时间分辨率的最大观察差异分别为64%（25%）和22%（19%））。此外，我们观察到的探测器性能依赖于探测器元件的长度和表面处理的明显趋势。对于短晶体（3 x 3 x 5 mm（3）），观察到与抛光晶体相比，"切割“的光输出和时间分辨率的改善（模拟（测量）分别为3%（7%）和9%（9%））。对于较长的晶体（3 x 3 x 20 mm（3）），趋势相反，并且观察到与“切割”晶体相比，抛光晶体的光输出和时间不确定性的改善（模拟（测量）分别为36%（6%）和40%（20%））。本研究的结果用于指导PET探测器的设计与飞行时间（ToF）和DoI功能相结合。
This study investigates the physical limitations involved in the extraction of accurate timing information from pixellated scintillation detectors for positron emission tomography (PET). Accurate physical modeling of the scintillation detection process, from scintillation light generation through detection, is devised and performed for varying detector attributes, such as the crystal element length, light yield, decay time and surface treatment. The dependence of light output and time resolution on these attributes, as well as on the photon interaction depth (DoI) of the annihilation quanta within the crystal volume, is studied and compared with experimental results. A theoretical background which highlights the importance of different time blurring factors for instantaneous ('ideal') and exponential ('realistic') scintillation decay is developed and compared with simulated data. For the case of a realistic scintillator, our experimental and simulation findings suggest that dependence of detector performance on DoI is more evident for crystal elements with rough ('as cut') compared to polished surfaces (maximum observed difference of 64% (25%) and 22% (19%) in simulation (measurement) for light output and time resolution, respectively). Furthermore we observe distinct trends of the detector performance dependence on detector element length and surface treatment. For short crystals (3 x 3 x 5 mm(3)) an improvement in light output and time resolution for 'as cut' compared to polished crystals is observed (3% (7%) and 9% (9%) for simulation (measurement), respectively). The trend is reversed for longer crystals (3 x 3 x 20 mm(3)) and an improvement in light output and time uncertainty for polished compared to 'as cut' crystals is observed (36% (6%) and 40% (20%) for simulation (measurement), respectively). The results of this study are used to guide the design of PET detectors with combined time of flight (ToF) and DoI features.