EAGER: Highly directional beam emission control of scintillator detectors for biomedical and security imaging applicatio

Regents Of The University Of Michigan - Ann Arbor, Ann Arbor MI

Investigators

Abstract

Proposal Title: EAGER: Highly directional beam emission control of scintillator detectors for biomedical and security imaging applications Project Goals: The project will exploit the basic scintillator device's photonic properties to determine the feasibility for lower dose, higher resolution imaging applications. Nontechnical Abstract: Medical imaging has become one of the most relied-upon tools in health-care for diagnosis and treatment of human diseases. In order to develop novel imaging techniques for early detection, screening, diagnosis, and image-guided treatment of life-threatening diseases and cancer, there is a clear need for extending imaging to much higher resolution level, information at fine resolution levels can lead to the detection of the early stages of the formation of a disease or cancer or early molecular changes during intervention or therapy. Radiation detection has also been widely used for airport and national security. The proposed research will exploit the basic scintillator device's photonic properties to determine the feasibility of ultimate goal for next generation scintillator detectors for lower dose, higher resolution imaging applications. The objective of the proposed research is to study and understand a new class of bio-inspired nano photonic structures applied on scintillator detectors. Ultimately, the results from the proposed EAGER project will enable us to further explore the possibility to achieve biomedical imaging at the cellular and molecular biology level and high imaging quality for national and airport security. Technical Abstract: Inorganic scintillator detector are key components used in modern medical imaging modalities as converter for the x-rays and ã-radiation that are used to obtain information about the interior of the body, like x-ray, CT and PET scan, as well as for national and airport security. One key problem in the development of the next generation radiation based imaging systems is the energy and time resolution of the detectors. They are influenced by the statistical fluctuations of the light output of the scintillators, i.e. by the number of photons that are detected when a particle deposits its energy in the scintillator. The light output of the scintillator depends not only on the absolute number of generated photons but also on the geometrical shape of the photonic devices, its transmission properties at the wavelength of scintillation, and its refractive index. Especially in tiny detector crystals with small aspect ratio, a significant fraction of photons is lost before conversion into an electronic signal in the photo detector. This effect increases the statistical fluctuations of the light output and therefore, deteriorates the resolution of imaging quality. Most of the high-density scintillators have a high refractive index, so most of light is trapped in the crystal, only 10-15% of the light from the scintillator devices can enter into the photo detector, the majority of light couldn't be effectively extracted, which seriously affected the scintillator detector's efficiency and detection sensitivity. The goal of the proposed EAGER research is to investigate a novel class of bio inspired nano scale photonic structures that function with efficient light extraction for scintillator devices. We propose to study the characteristics of various types of scintillator materials and devices, such as ã-CuI single crystal, doped Tb3+ glass and Lu2SiO5:Ce thin film, and design light extraction structures based on their optical properties, so that the overall efficiency of these scintillator devices will be increased significantly. Furthermore, we will utilize the unique properties of the nano scale photonic structures to engineer the output light beam shape so that we can control the angular behavior of the light, which will make smaller pixel, higher imaging resolution possible.