Abstract: The tinnitus testing apparatus of this invention comprises a control part that in turn comprises: an auditory stimulus generation part that can generate a stimulus; and an AEP acquisition and amplitude measurement part that can acquire auditory evoked potential (AEP) brain waves of a examinee due to said stimulus and measure the specific amplitude of said acquired brainwaves; wherein said auditory stimulus is one or more of: a 1st stimulus containing continuous noise and pulse noise; and a 2nd stimulus containing pulse noise and continuous noise with a silent gap.

Abstract: The present invention provides a method for stabilizing the gain of an avalanche photodiode in a medical laser diode receiver. This method is characterized by comprising: (a) a step in which a high-voltage generation unit generates a high-voltage bias and applies same to an avalanche photodiode; (b) a step in which a temperature sensor senses the temperature of the avalanche photodiode; (c) a step in which a control unit controls a variable resistance value, which varies the voltage of the high-voltage bias, according to the value of the sensed temperature; (d) a step in which to detect if an output voltage signal is equivalent to the intensity of light received by the avalanche photodiode; and (e) a step in which a storage unit matches the sensed temperature value with the controlled variable resistance value and stores same. The present invention allows a reduction in production costs and also a significant reduction in the size of a measuring device itself.

Abstract: The present invention relates to a 9-hydroxypheophorbide-a derivative, pharmaceutically acceptable salt or acid addition salt used for photodynamic therapy represented by following formula (I) wherein R1 and R2 is each independently hydrogen, C1˜C6 linear or branched alkyl, or C3˜C8 aryl.