Two new strategies to increase the signal to noise ratio in positron volume imaging

Two new strategies to increase the signal to noise ratio in positron volume imaging
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提高正电子体积成像信噪比的两种新策略

DOI：
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发表时间：
1993
期刊：
影响因子：
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通讯作者：
Y. Picard
Y. Picard
中科院分区：
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文献类型：
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作者：
C. Thompson;Y. Picard

文献摘要

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提出了两种新的硬件技术来提高正电子体积成像(PVI)系统的散射分数。第一种利用了康普顿散射光通过大角度散射的能量较低的事实。光线可以散射并仍在扫描仪视场(FOV)中的角度范围取决于响应线的半径。通过使用与响应线(LOR‘s)半径成正比的低能量阈值，图像边缘的散射分数大大降低。第二种技术是基于在NaI晶体中观察到的许多511keV的射线被反向散射，然后散射的光子逃脱而不被检测到。提出了一种包括光谱峰和后向散射峰的缺口能量接受窗，但去掉了其间的散射事件。&gt；
Two new hardware techniques which improve the scatter fraction of positron volume imaging (PVI) systems are presented. The first uses the fact that Compton scattered rays scattered through a large angle have a lower energy. The range of angles through which rays can be scattered and still be in the scanner field of view (FOV) depends on the radius of the line of response. By using a low-energy threshold which is proportional to the line of response's (LOR's) radius, the scatter fraction at the edges of the image is substantially reduced. The second technique is based on the observation that in NaI crystals many of the 511-keV rays are backscattered, and the scattered photon then escapes undetected. The use of a notched energy acceptance window, which includes the photo-peak and the backscatter peak, but discards the scattered events in between, is proposed. >