HIGH PRESSURE XENON 3D IMAGING DETECTOR

描述（由申请人提供）：所有临床核医学成像都是专门使用晶体探测器系统完成的，这在成本和技术性能方面都有许多限制。在140 keV成像中，Nal/PMT相机，核医学的主力，是非常庞大，昂贵的，并在计数率和空间分辨率的限制。在511 keV PET成像中，对外来高Z晶体的需要导致高成本和有限的立体角。密度为0.55 g/cm 3的氙可以产生比NaI和LSO高10倍的能量分辨率，以及与LSO相当的时间分辨率。在前人工作的基础上，我们提出了一种高压氙圆柱形脉冲电离探测器（直径20-50 mm），它具有由非常低密度的高强度纤维复合材料组成的压力容纳壳体。通过使用这种复合材料，与容器壁的相互作用损失降低到可忽略的水平。此外，一个高度创新的读出技术已被提出和评估，其中管内部读出通过有效的透明壁。试验分析和实验研究已经证明，可以实现通用检测器元件，其能够进行140 keV和511 keV成像，并且具有1 mm量级的优异3D空间分辨率。实验研究还表明，通过使用由初级相互作用过程和阳极处的电子收集点附近的受激发射产生的光信号，接近放大器噪声极限的能量分辨率是可能的。 因此，相对于任何室温晶体，能量分辨率可以显著提高。所采用的氙的密度比NaI小约6倍，但仍在适当薄的检测器中提供140 keV的有效检测。对于511 keV检测，氙中发生的多个相互作用顶点在吸收阵列中的不同管之间充分展开，并且初级闪烁光提供1 ns的符合时间分辨率。因此，所提出的以适当阵列配置的探测器元件可以在两个主要的核医学成像领域中提供大大改进的性能。在第二阶段，将开发、构建和评估全尺寸探测器元件阵列，以预测在非常重要的SPECT和PET技术中可以实现的成像特性。

DESCRIPTION (provided by applicant):All clinical nuclear medicine imaging is done exclusively with crystal detector systems, which impose many limitations in both cost and technical performance. In 140 keV imaging, the Nal/PMT camera, the workhorse of nuclear medicine, is extremely bulky, costly, and limited in both count rate and spatial resolution. In 511 keV PET imaging, the need for exotic high Z crystals results in high cost and limited solid angle. Xenon at a density of 0.55 g/cm3 can produce a 10-fold energy resolution improvement over Nal and LSO and a time resolution comparable to LSO. Based on previous work, we propose a high pressure xenon cylindrical pulse ionization detector (20-50 mm diameter) having a pressure containing shell composed of a very low density high strength fiber composite. Through use of this composite, interaction losses with the walls of the vessel are lowered to negligible levels. Also, a highly innovative readout technique has been proposed and evaluated in which the tube interior is read out through effectively transparent walls. Pilot analytical and experimental studies have proven that a general purpose detector element can be achieved capable of both 140 keV and 511 keV imaging and having excellent 3D spatial resolution on the order of 1 mm. Experimental studies have also shown that, through use of light signals produced by both the primary interaction process and stimulated emission near the electron collection point at the anode, energy resolution approaching amplifier noise limits is possible. Thus energy resolution can be markedly improved relative to any room temperature crystal. The density of xenon employed is about 6-fold less than Nal but still affords efficient detection of 140 keV in a suitably thin detector. For 511 keV detection, the multiple interaction vertices that occur in xenon are adequately spread out among distinct tubes in an absorbing array and primary scintillation light provides coincidence time resolution of 1 ns. Thus, the proposed detector element configured in appropriate arrays can offer greatly improved performance in both of the major nuclear medicine imaging arenas. In Phase II, arrays of full sized detector elements will be developed, constructed and evaluated to predict imaging characteristics that can be achieved in very important SPECT and PET techniques.