Patent ID: 8874194

Claim:
A leak detecting apparatus which detects leak of a liquid injected through an injection needle into a blood vessel of a human body near a surface thereof, comprising: at least one light ray emitter, each light ray emitter configured to emit a light ray containing a at least one first particular wavelength at which the reflectivity for the liquid is different from the reflectivity for internal tissues of the human body and at least one second particular wavelength at which the reflectivity for the liquid is lower or equal to the reflectivity for the internal tissues of the human body, to the human body at a position thereof where an injection needle is inserted; at least one light ray detector configured to detect the light ray at the first particular wavelength and the light ray at the second particular wavelength which are reflected inside the human body; a microprocessor configured: to measure the intensity of the detected light ray at the first particular wavelength; to measure the intensity of the detected light ray at the second particular wavelength; to calculate the ratio of the intensity at the first particular wavelength to the measured intensity at the second particular wavelength; and to determine an occurrence of a leak when the calculated ratio is changed from a predetermined reference value; and a leak alarm configured to output and notify a leak alarm when the occurrence of leak is determined.