Robotic Cytology Using Extra-Fine Needles-Derivation of Suction Conditions for Collecting the Necessary Amount While Reducing Specimen Contamination with Blood

Fine-needle aspiration cytology (FNAC) is an inexpensive, quick, and minimally invasive diagnostic method for cancer. Physicians need to be highly skilled to perform FNAC as they are required to collect the appropriate quality and quantity of specimens. Many research have reported the robotic needle insertion method for improving the accuracy of needle placement using fine needles. These methods can expand the applicability of FNAC to organs deeper in the body, enabling less-invasive FNAC. However, there is little research focusing on the suction conditions and quality and quantity of specimens with extra-fine needles. In this study, we analyzed the suction conditions for reducing blood contamination and securing the necessary collection amount. The magnitude and duration of suction were chosen as the suction condition parameters. The effect of these parameters on collection amount and blood contamination was experimentally analyzed using pig organs. Blood contamination was evaluated by injecting ink into the organs to simulate blood and measuring the mass ratio of the liquid components of the specimen. The results showed that a long suction duration was effective in increasing the collection amount, and the collection amount reached saturation. Conversely, a small magnitude of suction was effective in reducing blood contamination in the specimens.