Nuclear medicine within the Medical Sciences Division has been on a progressive track of biotechnological advancement and modernization to evolve into a new molecular nuclear medicine program.
As identification of genes and their products by structural biology (including genetic engineering) continues to permit the characterization of function of molecules regulating biochemical pathways and biochemistry in health and disease; nuclear medicine technology is exploited to study biochemical dysfunctions and the mechanisms of dysfunctions associated with pathological states.
The knowledge generated feeds into the development of new powerful radiotracer/ radiopharmaceutical tools and advanced medical imaging technologies for identification and detection of biochemical dysfunctions as early signs of disease (including cancer, brain diseases, and mental disorders), for molecular correction of biochemical defect and for the treatment of the disease and disorder.
Molecules are especially tailored for targeting the disease or a biochemical dysfunction, labeled with appropriate radioisotopes as radiotracers/radiopharmaceuticals to become measurable for clinical diagnosis, or effective therapeutically, when they interact with their targets in the body. These radiopharmaceuticals are in a way radiolabeled molecular "guided missiles" in the living body for targeting a disease.
The function of selected radiopharmaceuticals at various sites in the body is imaged by nuclear medical instruments, such as gamma-cameras and positron emission tomographs. This type of imaging refines diagnostic differentiation between various diseases, such as of the heart, brain, and in cancer, often leading to more effective therapy. If labeled with high energy-emitting radioisotopes, the molecular "guided missiles" such as monoclonal antibodies, may be powerful tools for targeted therapy especially of cancer.
Prem C. Srivastava, Ph.D.
e-mail: prem.srivastava@oer.doe.gov
The program functions in concert with radiochemistry, organic chemistry, organic and organometallic synthesis, molecular modeling, genetic engineering and combinatorial chemistry for preparing precursors of desired organic structure and biological properties, and radiolabeling of precursor molecules with radioisotopes of appropriate half-lives and energy properties suitable for clinical investigations and potential human clinical use for diagnosis and therapy.
Radiochemistry and radiolabeling synthesis for attaching radioisotopes to organic structures is an integral part of radiopharmaceutical development for which radioisotopes are available from commercial resources or collaborative arrangements. Positron emission tomography (PET) research, a relatively large part of radiotracer research, continues to support cyclotron production of certain highly selected radioisotopes such as fluorine-18 and carbon-11, used in PET diagnosis research. These radioisotopes are short lived (half-life ranging from few minutes to approximately 2 hours) and must be produced onsite from a cyclotron dedicated to a PET facility immediately before planned clinical or research use.
Drugs and other protein, nucleic acid, and steroid based new pharmaceuticals are prepared, radiolabeled, and screened in laboratory animals for tumor, heart and brain specificity, and targeting cancer and diseases and disorders of the brain and heart.
Radiotracers with optimum properties showing brain, heart, and cancer specificity through preliminary biological screening are chosen for preclinical evaluation to study clinical potential in humans for diagnosis and therapy.
Prem C. Srivastava, Ph.D.
e-mail: prem.srivastava@oer.doe.gov
For radionuclide imaging, BER medical imaging and instrumentation program functions include: 1) developing new 3-D PET imaging technology with improved high resolution, 2) developing new technologies for merging individual imaging capabilities (PET, Single Photon Emission Computing Tomograph, Magnetic Resonance Imaging, and Magnetoencephalography) for synergy, 3) applying new techniques for solving complex diagnostic problems, i.e., study of neurochemical status of the brain in patients with neurodegenerative diseases, substance abuse, and for improved confidence in management of disease such as cancer (diagnosis, design and planning treatment, and monitoring course of therapy), and 4) rapidly advancing and making nuclear imaging more compatible to current and advancing future molecular nuclear medicine needs such as imaging gene expression and monitoring gene therapy.
Dean A. Cole, Ph.D
e-mail: dean.cole@oer.doe.gov
Prem C. Srivastava, Ph.D.
e-mail: prem.srivastava@oer.doe.gov