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用晶体探测器系统完成的，这在成本和技术性能上都有很多限制。在140 keV成像中，Nal/PMT相机，核医学的主力，非常笨重，昂贵，并且在计数率和空间分辨率方面都受到限制。在511 keV PET成像中，需要外来的高Z晶体导致高成本和有限的立体角。密度为0.55 g/cm3的氙气可以产生比Nal和LSO提高10倍的能量分辨率和与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气圆柱形脉冲电离探测器（直径20- 50mm），其壳体由极低密度高强度纤维复合材料组成。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以忽略不计的水平。此外，还提出并评估了一种高度创新的读出技术，该技术通过有效的透明壁读出管内部。试点分析和实验研究已经证明，通用探测器元件可以实现140 keV和511 keV成像，并具有1毫米量级的优秀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电子收集点附近的受激发射产生的光信号，可以实现接近放大器噪声极限的能量分辨率。

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.