INSERTION/EXTRACTION-AIDING MEANS

摘要

A spiral rotary member (130) includes a tubular main body section (131) that allows a inserting section (30) to be inserted thereinto and rotates around a longitudinal axis C and a fin section (133) that is disposed on an outer peripheral surface of the main body section (131) and spirally arranged around the longitudinal axis C. The spiral rotary member (130) further includes an X-ray cutoff section (135) that is arranged in at least a part of the spiral rotary member (130) in a longitudinal axis direction of the spiral rotary member (130), and arranged so that a clear region to be clearly imaged by X-rays and an unclear region to be unclearly imaged by X-rays are distinguished under X-ray observation in a peripheral direction of the spiral rotary member (130), to cut off X-rays.