Patent Document ID: 5396531
Application ID: 07971652
Patent Status: 1

Claim One:
1. A method of reduced dose X-ray imaging of a subject comprises the steps of: a) selecting a minimum signal-to-noise (P.sub.S /P.sub.Nmin) ratio; b) creating an X-ray image with an initial photon count Q.sub.init and X-ray tube voltage U; c) determining an average image intensity I from the image according to the equation: ##EQU24## where C is the total number of pixels in the image and i.sub.x,y is the pixels with coordinates (x,y); d) determining a variance .sigma..sup.2 from the image according to the equation: ##EQU25## e) determining P.sub.S /P.sub.N from the image according to the following equation: ##EQU26## f) determining the value of I.sub.opt required to produce an image with a signal-to-noise ratio at least as great as P.sub.S /P.sub.Nmin assuming that P.sub.S /P.sub.N is proportional to I according to: ##EQU27## h ) determining an optimal photon count Q.sub.opt required to produce an image with intensity I.sub.opt ; and i) creating subsequent images with the same X-ray voltage U and the optimal photon count Q.sub.opt having a signal-to-noise ratio at least as great as P.sub.S /P.sub.Nmin and with a reduced X-ray dose.