CAREER: Utilization of Unique Atomic and Nuclear Properties of Gadolinium in Nuclear and Radiological Sciences

University Of Massachusetts Lowell, Lowell MA

Investigators

Abstract

Gadolinium (Gd) is an intriguing element that has a variety of interesting properties. One of its isotopes, Gd-157, has the largest rate of capturing thermal neutrons than all other known stable nuclei. In Gadolinium Neutron Capture Therapy (GdNCT), the radiation emitted as a result of neutron capture can be used for cancer treatment. A striking advantage of GdNCT compared to other radiation therapy treatments is that the initial pharmaceutical solution with the gadolinium content is non-radioactive. Nuclear and atomic excited states are induced only after neutron interactions, and the resultant radiations can be used to destroy nearby cancer cells. The focus of this project will be the characterization of the radiations associated with GdNCT and their radiological dose using various gadolinium nanoparticle-based materials. The materials will be irradiated by neutrons from the UMass Lowell Research Reactor (UMLRR), and the resultant gamma rays and electrons will be measured using a new detector array recently designed at UMass Lowell. In parallel, the potential use of gadolinium in a novel thin-film neutron and x-ray detector will be studied. The radiation detection technologies are at the forefront of all experimental discoveries in low and high energy nuclear physics. New technologies are needed in security applications, counter terrorism, nuclear medicine imaging and scanning. Proposed work on a novel radiation detection technology based on thin films with Gd layer will advance the field of radiation detection with designs of small flexible films capable of measuring doses of x-rays and neutrons. The involvement of undergraduate and graduate students will be a strong emphasis of these research activities. Students from three different accredited graduate programs: (1) Radiological Sciences and Protection, (2) Medical Physics and (3) Physics and Applied Physics, will contribute to the activities proposed herein. The capabilities developed during this project will be used to launch a new course, “Advanced Radiological Measurements Laboratory”, in the UMass Lowell Physics and Applied Physics Department. The nuclear de-excitation of gadolinium after neutron capture results in the emission of gamma rays and internal conversion electrons, followed by the emission of Auger electrons to resolve atomic excitations. These electrons can efficiently deliver local dose to tumors saturated with a pharmaceutical solution containing gadolinium. In this project, the resultant gamma rays and electrons produced by neutron capture reactions on gadolinium in nanoparticle-based materials will be measured using the combination of high-resolution gamma-ray spectroscopy and high-efficiency calorimetry. Details of correlated emissions will be probed using fast nanosecond coincidence methods. Comprehensive computational simulations of the capture cascades and the dose distributions in local tissue and neighboring organs also will be performed based on validated physics models and new improved correlated atomic and nuclear data libraries. The size and morphology of the nanoparticles will be studied to control and optimize the range of emitted electrons to potentially tune the local dose to the tumor. Likewise, high-fidelity Monte-Carlo radiation transport simulations will guide design and development of the thin-film neutron and x-ray detector. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.