Scintillation camera

Abstract

Abstract PURPOSE: To facilitate the mutual adjustment between an optical system and an electric system by providing a window circuit just at the back of a position calculating circuit so that the signal corresponding to the unnecessary portion of scintigram may be eliminated from the position signals. CONSTITUTION: A window circuit receives the position signals (or the X and Y signals corresponding to the incident position of a gamma ray and the UNBLANK signals for exhibiting the brightness in a CRT) from a position calculating circuit. The signals X and Y are converted by squaring devices 15 and 16 into signals proportional to X 2 and Y 2 , which are converted by an adder 17 into the signals proportional to (X 2 +Y 2 ). These signals are compared by a comparator 18 with a constant value r 2 so that a gate 19 is opened if X 2 +Y 2 ≤r 2 , to allow the UNBLANK signals to pass therethrough. Here, since the relationship of X 2 + Y 2 ≤r 2 indicates the inside of a circle having a radius r, the UNBLANK signals corresponding to the circumferential portion requiring no scintigram are eliminated if the amplitude of r is suitably selected. Moremover, a coincidence circuit is added so that a mask having a hexagonal shape can be formed. Thus, any optical mask can be dispensed with, and the adjustment of the respective systems can be facilitated. COPYRIGHT: (C)1980,JPO&Japio

Inventors

• 👤 Masatoshi Tanaka
• 👤 Hideho Tabuchi

Bibliographic Details