Patients undergoing FNA biopsy at the 5A UHC clinic were invited to participate in the study. After providing informed consent, patients underwent a routine FNA procedure using 4 passes per nodule (27 gauge needle). An on-site cytopathology team evaluated samples at the time of the procedure by staining using two needle rinse samples for cell block. If those samples were adequate for routine diagnosis, the remaining two samples were saved for Raman spectroscopy. Each pass was treated as a unique sample. In cases where additional material was needed for routine cytopathology, it took precedence over Raman specimens. In cases where no full passes were available for Raman spectroscopy, a portion of needle rinse was requested from cytology. At a later date, the patient’s medical records were reviewed for final cytopathologic and, if available, surgical diagnosis.

While the samples obtained and measured over the course of the study period did not display the range of clinical diagnoses we had hoped for, we were able to make significant progress toward developing a protocol for testing cells from thyroid fine needle aspiration, and in developing a Raman spectral database of cells from thyroid nodules. Spectra of three distinct cell types were measured, including platelets, presumed nodular cells, and an unknown cell type, and we began to work towards defining distinct Raman signatures of cells from colloid nodules versus follicular nodules.

Toward the goal of obtaining spectra from a larger variety of thyroid pathologies, we have developed a human subjects protocol to obtain cell scrapings from excised thyroid tumors. We feel that this will aid in rapidly developing a database of known cell types, as the diagnosis of the excised tissue can be obtained directly from the surgical pathology report, and abundant cells will be available for measurement.

In future work, we will also explore the use of immunohistochemistry and other dyes/stains which can be applied to provide accurate diagnosis of single cell measurements.