The objective of this Phase I SBIR grant is to advance the development of a novel Technetium 99m-based radiopharmaceutical, 99mTc-HYNIC-folate, as a tumor-targeted imaging agent. There are several advantages to using 99mTc as a radionuclide for imaging including cost, availability, and short half life. The successful incorporation of 99mTc into a folate- targeted system should enable development of a diagnostic tumor imaging product that can improve both image quality and sensitivity while reducing a patient's exposure to radiation at a fraction of the cost of other commercially available tumor-specific Imaging agents. The specific aims for this study are as follows: l) to establish the optimal conditions used for the large scale synthesis and purification of HYNIC-folate, 2) to develop a reliable method to prepare and purify 99mTc-HYNIC-folate, 3) to conduct in vitro cell uptake studies to verify the specificity of 99mTc- HYNIC-folate for the folate receptor, and 4) to conduct initial animal imaging and biodistribution studies. Following the completion of these specific aims, a phase II project will be initiated which includes the submission of a corporate IND application for 99mTc-HYNIC-folate to the FDA and the initiation of a lND Phase I/II clinical study at the Washington University Medical Center in St. Louis, MO. PROPOSED COMMERCIAL APPLICATION: The proposed project is aimed at developing Tc-99m-HYNIC-folate into a clinical radiopharmaceutical product to be used in the scintigraphic diagnostic imaging of tumors. This product may significantly impact the clinical management of certain cancer patients by providing a rapid and highly sensitive method of tumor detection.