Effect of spatial distortion on anger camera field-uniformity correction: concise communication

The field uniformity of a computer-assisted Anger-camera system, and the effect of field correction on quantitative data, have been studied. Our results show that the total counts of a source imaged across the crystal face varies with a s.d. of only 2.0%, but routine flood-field correction degrades the data to a s.d. of 9.4%. On the other hand, the area of a source 1.75 in. in diameter, imaged across the crystal face, varies with a s.d. of 9.7%. We conclude that the major source of field nonuniformity for an Anger camera is spatial distortion and not varying sensitivity across the crystal face.