I-Corps: Development of Imaging System with Large-Size Germanium Detectors

该提案将建立一个I-Corp团队，寻求体验式学习机会，以帮助确定最先进的锗探测器的开发技术的商业准备程度，这将改善对物体辐射的探测，包括人类疾病（癌症），个人旅行物品和机场和港口门口的货物，用于核医学诊断，材料筛选，监测核电站的退役和国土安全。成像相机具有两个检测平面，其将由具有优异能量分辨率的高纯度锗晶体制成。考虑到其便携性、紧凑性、低患者剂量、多放射性同位素示踪能力、在固定位置处的固有三维（3D）成像能力，成像相机作为筛查检测器或医学成像设备具有光明的前景。然而，目前，康普顿相机的图像分辨率不足以用于医学成像。在该项目中，I-Corps团队打算使用具有高灵敏度能量分辨率和位置分辨率的锗探测器来改进成像系统。所开发的技术特别有助于检测身体组织的异常生长或淋巴结的生长，这些技术使用伽马射线源作为诊断辐射工具。类似地，人体中的肿瘤生长或癌症（例如乳腺癌）可以通过该技术检测，因为伽马射线源通常用于癌症治疗以及诊断目的。近年来，癌症已成为全球最具破坏性的疾病之一。用于治疗癌症的技术之一是具有辐射示踪剂的核医学，其可以发射伽马射线。飞利浦、通用电气和西门子是癌症治疗扫描技术领域的领先公司。拟议的探测器技术是基于动态读出，提供了出色的能量分辨率和位置分辨率，因为相机可以通过许可证、建立合资企业或建立独立公司的方式商业化。该项目的目标是开发和商业化使用锗探测器的成像相机，这将改善对人类疾病（癌症）、个人旅行用品和机场、港口门口的货物。其范围是在三年内分两个阶段开发该技术。第一阶段项目是在一年内开发一个具有23 × 23动态读出系统的大型锗探测器，用于概念验证。动态读出系统将通过测量电极上感应的电荷来实现，电极具有多个通道，这些通道靠近但不与检测器材料电连接。将在电路板上制造多个电极，该电路板位于距离收集电荷的检测器表面0.5 mm处。多通道动态读出系统将采用劳伦斯伯克利国家实验室开发的邻近读出技术，利用其简化探测器制造、扩大电极几何形状选择和通过简单信号插值大大提高位置分辨率的优点。在第二阶段，该团队将在两年内制造锗正交动态读出探测器（GODD），用于测试成像系统的新探测器技术创新。然后，GODD将在乘客的旅行物品和货物上进行测试，模仿机场和港口的核和非核成像测试。模拟机场和港口的测试将在南达科他州大学（USD）进行，并比较GODD在机场或港口情况下与现代成像系统的相对优点。将确定GODD对实际测试目标的响应。采用动态读出系统，大大提高了锗探测器的位置分辨率，可以探测小的、低对比度的物体，包括辐射源的位置，甚至人体内的肿瘤。接触的新制造方法，改进的电子学和锗探测器长期稳定性的经验，使它们对国家安全任务非常重要。

This proposal will establish an I-Corp team for seeking an experiential learning opportunity to help in determining the commercial readiness of the developed technology for the state-of-the-art germanium detectors, which will improve the detection of radiation from objects including human diseases (cancer), personal travel items and cargos at the gate of airports and harbors for the applications of diagnosis in nuclear medicine, materials screening, monitoring of decommissioning of nuclear power plants, and homeland security. An imaging camera has two detection planes, which will be made of high purity germanium crystals with excellent energy resolution. The imaging camera has a bright future as a screening detector or medical imaging device considering its portability, compactness, low patient dose, multiple-radioisotope tracing capability, inherent three dimensional (3D) imaging capability at a fixed position. Currently, however, the image resolution of the Compton camera is not sufficient for medical imaging. In this project, the I-Corps team intends to improve imaging system using germanium detectors with high sensitive energy resolution and position resolution. The developed technology can be especially helpful for detecting abnormal growth in body tissue or the growth of lymph nodes, which use gamma-ray sources as diagnostic radiation tools. Similar, tumor growth or cancer, such as breast cancer, in the human body can be detected by this technology because gamma-ray sources are often used for cancer treatment as well as diagnostic purposes. Recently, cancer has become one of the most devastating diseases worldwide. One of the techniques used for treating cancers is nuclear medicine with radiation tracers, which can emit gamma rays. Philips, GE and Siemens are some of the leading companies in the domain with scanning technology for cancer treatment. The proposed detector technology is based on a dynamic read-out that provides both excellent energy resolution and position resolution as a camera can be commercialized through either through licensing, establishing a joint venture or establishing a standalone company.The goal of the project is to develop and commercialize an imaging camera using germanium detectors that will improve the detection of radiation from objects including human diseases (cancer), personal travel items, and cargos at the gate of airports and harbors. The scope is to develop the technology in two phases within three years. The Phase I project is to develop a large germanium detector with 23 × 23 dynamic read-out system for proof-of-concept in a year. A dynamic read-out system will be accomplished by measuring the charge induced on electrodes with multiple channels that are positioned close but not electronically connected to the detector materials. The multiple electrodes will be fabricated on a circuit board that is positioned 0.5 mm from the detector surface onto which charge is collected. A dynamic read-out system with multiple channels will adopt the proximity read-out technique developed at Lawrence Berkeley National Laboratory by utilizing its advantages of simplified detector fabrication, expanded electrode geometry options, and greatly improved position resolution through simple signal interpolation. In Phase II, the team will fabricate a germanium orthogonal dynamic read-out detector (GODD) for testing new detector technology innovations as an imaging system in two years. The GODD will then be tested on passengers' travel items and cargos, mimicking airport and harbor nuclear and non- nuclear imaging tests. The simulated airport and harbor tests will be performed at The University of South Dakota (USD) under a subcontract and compare the relative merits of the GODD in airport or harbor situations with modern imaging systems. GODD response to realistic test objectives will be established. With a dynamic read-out system that greatly improves position resolution of a germanium detector, which can detect small, low contrast objects, including position of the source of radiation and even tumors in human body. New fabrication methods for contacts, improved electronics and experience with long term stability of germanium detectors, make them important for national security tasks.