A single photon avalanche diode for use in a CMOS integrated circuit includes a deep n-well region formed above a p-type substrate and an n-well region formed above and in contact with the deep n-well region. By polishing according to the CMP method, a through hole conductor 5 and a grounding wiring layer 10, which are made of copper, become concave in a dish-like shape and lowered in level, causing a dishing portion 17 since they have a hardness lower than that of a through hole insulator 11 made of silicon nitride. The baseline trace includes a baseline segment within the ischemia detection window; where the ischemia detection window and the fiducial point may constitute ischemia detection parameters. Each of the one or more short OFDM symbols is generated with a second number of OFDM that is a fraction 1N of the first number of OFDM tones, wherein N is a positive integer greater than one.