PROBLEM TO BE SOLVED: To make it possible by using less expensive time domain-based OCT to switch between lateral observation and front observation without exchanging a catheter.SOLUTION: There is provided a time domain-based OCT catheter system, comprising: a light source an optical fiber 11 for guiding light emitted by the light source an optical fiber coupler for branching the light from the light source into reference light to be guided through the reference light path and signal light to be guided to an observation object part a reference mirror for changing the optical path length of the reference light and reflecting the reference light a detector for detecting multiplexed light of the reference light reflected by the reference mirror and the signal light reflected from the observation object part a drive device 13 for rotationally driving the optical fiber 11 through which the signal light is transmitted and a reflection mirror 12 which is disposed near the light emitting end of the optical fiber 11, and which includes a central portion transmittable of light and has a reflection portion Rf around its outer periphery for reflecting in a lateral direction the light emitted from the light emitting end of the optical fiber 11.SELECTED DRAWING: Figure 1COPYRIGHT: (C)2018,JPO&INPIT【課題】安価なタイムドメイン式OCTを用いて、カテーテルを交換することなく、側方と、前方との観察の切り替えを可能とすることを課題とする。【解決手段】光源と、光源で発光された光を導く光ファイバ11と、光源からの光を参照光路への参照光と、観察対象部への信号光とに分岐する光ファイバカプラと、参照光の光路長を変化させ、参照光を反射する参照ミラーと、参照ミラーで反射された参照光と、観察対象部で反射された信号光との合波光を検出する検出器と、信号光が伝搬している光ファイバ11を回転駆動させる駆動装置13と、光ファイバ11の光射出端近傍に設けられ、中心部が光を透過可能であるとともに、光ファイバ11の光射出端から射出された光を側方へ反射させる反射部Rfを周囲に有する反射ミラー12と、を有することを特徴とする【選択図】図1
