A method using a digital computer for reducing respiratory artifact on liver scans made with a camera.

Abstract

Respiratory motion is a major factor limiting the resolution obtainable on liver scans. It causes a dis turbing “scalloped― appearance of the liver margins on rectilinear scans. This visual effect can be reduced by close spacing of the scan lines (1 ), but this does not recover the information that has been lost because ofmotion (2). On liver scans made with a camera, respiratory motion degrades image quality by blurring margins. The better the intrinsic resolution of the camera, the more objectionable this blurring becomes. The blur ring is increased if dyspnea is present, and frequently patients having liver scans are very ill and somewhat dyspneic. An effective method is needed for reducing the respiratory motion artifact on liver scans made with a camera and recovering the information that has been lost because of this motion. One method is to have the patient hold his breath while the camera is collecting counts (3,4) . We use this method rou tinely, but it increases the time and difficulty of the study and unfortunately cannot be used for very ill, dyspneic, or uncooperative patients. A method of compensating for the motion of the liver during respiration is needed. Various ways of accomplish