Radiochemistry & Instrumentation
The following program-project scale projects, in addition to many other projects not listed here, are based within the Radiotracer Development & Imaging Technology Department.
DOE Scientific Focus Area (SFA) "Radiotracer Imaging Technologies for Plant, Microbial, and Environmental Systems"
Research Director: William Moses
Project Leaders: Tom Budinger, Steve Derenzo, Grant Gullberg, William Moses, Jim P. O'Neil, and Bahram Parvin
The objective of this project is to modify and advance nuclear medical imaging techniques for non-human, non-animal applications, especially those involving microbial communities. These radiotracer imaging techniques do not alter the physical or biochemical properties of the object being imaged, allowing repeat studies to be perfomed on a single object. This allows the project to study how a system changes or evolves in time. In addition, different radiotracers can be used, which allow different properties of the system to be probed.
One use that these techniques are being applied to is environmental remediation. Sediment columns (tubes packed with sediment that mimic subsurface conditions) are commonly used to test environmental remediation strategies. The project has validated a conservative radiotracer, allowing for the mapping of both the 3-D flow and permeability of the column. The project also validated a tracer that identifies where iron reduction (an important component of bioremediation) is occurring. Work is in progress to validate tracers to image the microbes themselves - the metabolic activity of microbes, the concentration of microbes, and the concentration of specific species of microbes.
Another potential use the project is investigating is to study climate change. Interactions between the physical, chemical and biological components of soil regulate the geochemical flux of most life-critical elements, control the production of food and renewable energy products, purify water for the biosphere, and regulate atmospheric greenhouse gases. By using radiotracer imaging techniques, the project can gain understanding of the roles of microbial processes for C and N cycles and the impacts of climate change on these processes.
DHS High-Throughput Discovery of Improved Scintillation Materials
Leader: Stephen E. Derenzo
The overall objective of this research is the discovery of scintillation radiation detector materials that approach fundamental limits in terms of energy resolution, stopping power, response time, and cost. The discovery process is accelerated by (1) using a high-throughput synthesis and characterization facility developed for the work, (2) using empirical and first-principle calculations to improve our understanding of the conditions necessary for good scintillation and for guiding the search, (3) growing small crystals of the best materials found in the high-throughput screening, (4) characterizing their attributes as radiation detectors, and (5) developing methods for reliably producing larger crystals with excellent scintillation performance. These improved scintillator detectors will be used for imaging metabolic function in biological systems and for detecting nuclear materials. This research is a collaboration between the Life Sciences, Materials Sciences, and Computational Sciences Divisions.
NIH Neurodegenerative Diseases and Cognition
Leader: William Jagust
Research on cognition and neurodegeneration makes use of positron emission tomography (PET) with a number of different radiotracers that are aimed at understanding brain biochemistry and how biochemistry interacts with both brain structure and function in aging. Studies are ongoing looking at the deposition of beta-amyloid, the protein deposited in Alzheimer’s disease, in normal older subjects. Specifically, it is evaluated how this amyloid deposition affects brain structure, measured using magnetic resonance imaging (MRI) and memory function, with a view towards detecting signs of Alzheimer's disease in normal healthy older people. Brain dopamine function is also studied using PET in both normal older people and in those with Parkinson’s disease with the goal of understanding how dopamine is related to working memory and brain function using functional MRI. These are just some of the studies designed to assess relationships between in vivo measures of biochemistry, structure, and function to understand the aging brain.
NIH Cardiac Disease "Inverse Modeling of Cardiovascular Disease Using Nuclear Imaging"
Principal Investigator: Grant Gullberg
Heart disease is the leading cause of death and disability in the United States today. Early detection of disease and more accurate evaluation of therapy improves prognosis. Research in these NIH projects apply mathematical physics to solve inverse problems in cardiac nuclear imaging from data acquired using SPECT/CT and SPECT/MRI hybrid systems. Using preclinical animal studies, models are developed to measure cardiac perfusion, metabolism, deformation, innervation, and collagen synthesis. The quantification of these cardiac properties involves accurate modeling of the physics of the imaging detection process. The goal is to develop technologies to improve diagnosis and evaluation of therapy for patients with heart failure.