title: Acoustic shadow formation by gallstones.
abstract: Schlieren photography of gallstones and models of gallstones made from amorphous substances has demonstrated that acoustic shadowing depends primarily on the orientation of the surface of the stone in relation to the sound beam, not the composition of the stone.
mesh_terms: D002769:Cholelithiasis / Q000175:diagnosis*; D006801:Humans; D014465:Ultrasonics / Q000379:methods*; D014463:Ultrasonography