Abstract: A PET equipment comprising a detection section, signal processing section, sorter section, N information processors, host computer and switching hub. N is an integer of 2 or more. Each information processor stores the coincidence counting information from the sorter section to produce a histogram. Each information processor performs image processing based on the histogram of the coincidence counting information, dividing the histogram into N partial histograms to process them. The host computer reconstructs an image representing the spatial distribution of generation frequency of photon pairs in the measurement space based on the result of the image processing in each information processor, and displays the image on the display device.

Abstract: A voltage detector comprises a light modulator which employs an electro-optic material whose refractive index changes according to the voltage developing in an object to be measured. A transparent anti-reflection film having a refractive index and thickness which are predetermined on the bases of a refractive index of the electro-optic material and a wavelength of incident light is formed on both light entrance and exit surfaces of the electro-optic material.