Assertion: catheter's lumen | /r/HasProperty | needed
Facets:
Source sentences:
text: Therefore, in the prior art catheter tube constituting an endoscope, a tube body was formed with a special lumen for accommodating an optical fiber, a first special lumen was needed to provide as a flowpath for a fluid for inflating or contracting the balloon, and a second special lumen was needed to act as a flowpath for injecting a clear fluid for displacing the blood.