Forward-looking OCT Probe Using Single-fiber Scanning for Transbronchial Puncturing Cytodiagnosis

Abstract

Bronchoscopic diagnosis of peripheral lung cancer with ground-glass opacity (GGO) is difficult because GGO lesions cannot be visualized using currently available radial probe endobronchial ultrasound. Therefore, a forward-looking single fiber scanning optical coherence tomography (OCT) probe with a local observation function has been developed to achieve precise sampling. The new OCT probe is only 1 mm in diameter. The probe is composed of a patterned electroplated copper coil fabricated on a polyimide tube using non-planar photofabrication technique, and an optical fiber having a permanent magnetic tube with a diameter of 0.5 mm. When an electrical alternating current is supplied to the coil, the permanent magnet vibrates electromagnetically with the optical fiber. To increase the fiber vibration amplitude, a micro gradient-index (GRIN) lens is set in front of the tip of the optical fiber. Using the micro GRIN lens, the output beam is focused, and the scanning range is enlarged. The view angle becomes approximately 45 degrees, and image resolution becomes approximately 60 mu m. The structure of grating was successfully imaged using the new OCT probe. Further improvements and animal experiments are necessary to determine the clinical application of the probe.