Digital Electronics for PSAPD-based Gamma Cameras

描述(由申请人提供)： 这项工作的长期目标是开发一种基于数字处理电子技术和位置敏感雪崩光电二极管(PSAPD)相结合的伽马射线成像相机的新技术。伽马相机在不同的医疗领域得到了越来越多的应用，从用于急诊室心脏筛查的SPECT相机，到用于检测乳腺癌的核素扫描相机，再到用于新陈代谢和药物开发研究的小型动物相机。目前使用位置灵敏光电倍增管和模拟处理电子设备构建的相机体积大、重量重、价格昂贵。我们已经开发了一种初步的伽马相机设计，它使用固态PSAPD探测器和高密度数字处理电子设备来创建紧凑型相机设计，重量仅为现有设计的10%-20%，成像质量显著提高，成本只有现有设计的一半。初步分析表明，为了获得这些好处，有必要充分了解PSAPD的电子噪声特性，并设计处理电子设备以最大化信号/噪声，以优化空间分辨率和图像质量。因此，第一阶段的工作将致力于广泛表征PSAPD的噪声特性作为温度和信号处理变量的函数，并利用小型闪烁体阵列进行测量，以确定可实现的空间分辨率。初步设计将转化为具有特定部件的完整设计，并进行建模和分析，以准确预测其性能特点和生产成本。第二阶段的工作将包括在第一阶段设计的基础上建造一对伽马相机：一台用于心脏病工作的21厘米x 21厘米空间分辨率的相机，以及一台用于小动物工作的固有空间分辨率为1毫米的10厘米x 10厘米相机。然后，这两台相机都将接受各种点源和体模成像测试，以充分表征和优化它们的性能。

DESCRIPTION (provided by applicant): The long term objective of this work is to develop a new technology for gamma-ray imaging cameras based on the combination of digital processing electronics and position sensitive avalanche photodiodes (PSAPDs). Gamma cameras are finding increasing applications in diverse medical fields ranging from SPECT cameras for emergency room cardiological screening through scintimammography cameras for detecting breast cancer to small animal cameras used in metabolic and drug development studies. Present cameras, constructed using position sensitive photomultiplier tubes and analog processing electronics are bulky, heavy, and expensive. We have developed a preliminary gamma camera design that uses solid state PSAPD detectors and high density digital processing electronics to create a compact camera design that will weigh only 10-20% of existing designs, have significantly improved imaging quality, and cost half as much. A preliminary analysis shows that, to reap these benefits, it is necessary to fully understand the PSAPD's electronic noise properties and design the processing electronics to maximize signal/noise in order to optimize spatial resolution and image quality. The Phase I effort will therefore be devoted to extensively characterizing a PSAPD's noise properties as a function of temperature and signal processing variables and making measurements with small scintillator arrays to determine achievable spatial resolution. The preliminary design will be turned into a complete design with specified parts and modeled and analyzed to accurately project both its performance characteristics and production costs. The Phase II effort would then consist of constructing a pair of gamma cameras based on the Phase I design: a 21 cm x 21 cm camera with 2 mm spatial resolution intended for cardiology work and a 10 cm x 10 cm camera with 1 mm intrinsic spatial resolution intended for small animal work. Both cameras would then be subjected to a wide variety of point source and phantom imaging tests to fully characterize and optimize their performance.