RECTILINEAR LIVER SCANNING WITH TECHNETIUM 99m SULFIDE COLLOID

Abstract

Initial washing of the Tc99m generator should yield uniformly high quality TcS [technetium sulfide]. Short scanning time is desirable and provides time for lateral views. The post-injection waiting period to commence scanning for TcS is not dissimilar from that of Au198 colloid and should be at least 30 min. to allow for abnormalities of liver blood flow. Respiratory liver movement limits the resolution of a rectilinear scan at the speeds used with Tc99m. Perhaps the best solution to this problem is to use some variation of a gamma camera with shorter exposure times. A 31 hole lead collimator would probably yield resolution not significantly different from that observed with the 163 hole lead collimator for TcS liver scanning because of the limitations imposed by liver movement. The coarser collimator would yield higher count rates and still allow rapid scanning. The desirability of more rapid rectilinear liver scanning will remain uncertain until the liver motion problem is solved.