Development of minimally invasive laser device using composite-type optical fiberscope of 1.1 mm in diameter

Abstract

During conventional endoscopic laser treatments, only a two-dimensional view of the target is obtained. Therefore, it is difficult to keep distance between target tissue and fiberscope tip for effective laser irradiation. Moreover, the choice of laser power and diagnosis of a successful procedure depend on the operator's skill or instincts. Therefore, we developed a new minimally invasive laser device using a 1.1 mm in diameter composite-type optical fiberscope (COF) to overcome the above problems. This device is an integrated system consisting of the COF, coupling device, laser source, and a laser Doppler blood-flow meter. The COF consists of a centrally located 0.1 mm single fiber for laser transmission, which is surrounded by approximately 9,000 (φ5 μm/piece) fibers for image transmission. This device enables transmission of 50 W Yb fiber laser (1,070 nm) and an image in parallel. Yb fiber laser can be focused on 10 mm focal length by fixed two small lenses (φ0.5 mm) at the COF tip, and generate a beam waist. In addition, this COF enables the measurement of the blood-flow of target tissue and estimates of the distance between irradiation area and the fiber tip in real time by means of an embedded laser Doppler blood-flow meter. By applying our COF in laser treatment of various fields, it enables the acquisition of an image while simultaneously performing laser treatment, measuring the blood-flow, and estimating the irradiation distance only in one COF. Moreover, it can perform laser treatment safely and easily more than conventional device, and a burden of a patient and a doctor are reduced. In this paper, we present a configuration of the minimally invasive laser device using the 1.1 mm COF and the results of the basic performance experiments.