A positron emission computed tomography apparatus according to an embodiment includes a detector, a coincidence counting information generating unit, and a body movement detecting unit. There is previously stored a location correlation data group including correlation data representing correlation situations of a plurality of arriving radio waves produced by the transmitted radio waves at respective ones of a plurality of sampling locations within the communication area, the location correlation data corresponding to respective locations. The photoresist material can thereby prevent water mark defects from immersion lithography. The electronic devices may be connected through a communication link that allows the electronic devices to share image data for producing images on any of the projected displays included within the shared workspace.