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

University Of South Dakota Main Campus, Vermillion SD

Investigators

Abstract

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.