Boron Neutron Capture Therapy (BNCT) is a promising treatment for Glioblastoma Multiforme and other tumors involving the brain. A major technical issue impacting BNCT clinical efficacy is boron concentration and its variability as a function of inter/intracellular location. The proposed research is intended to develop a high-resolution, time-of-flight imaging instrument based upon resonance ionization spectroscopy (RIS) to map the spatial distribution of selected trace elements. RIS utilizes precisely tuned lasers to efficiently ionize a chosen element without interference from the immense background of other sample constituents. RIS, when combined with ion sputtering, SIRIS, or laser atomization, LARIS, provides an extremely efficient analytical technique having ultrahigh sensitivity and selectivity. The instrument will be capable of sub-micromole resolution at low part per million concentrations (SIRIS) and low part per billion detection at a few micromole resolution (LARIS) in biological matrices. It will be used in the proposed work to quantitate boron within individual cells and characterize the intracellular boron location and variability as a function of tumor characteristics, boron compound administration protocol, and time after administration. This new imaging instrument will be a significant stimulus to further improvements in the entire biomedical, pharmaceutical, and other research fields.