title: Gray scale of ultrasound instruments: evaluation using a test object.
abstract: B-mode scans of castor oil in a wedge-shaped container provide gray level maps. The relation between the gray levels and the amounts of absorbing medium can be used to measure the effects of electronic gain, transducer characteristics, and the overall gray level performance of different ultrasound systems. We report results from four units and ten transducers for varying scanning depths.
mesh_terms: D002368:Castor Oil; D005069:Evaluation Studies as Topic; D014465:Ultrasonics / Q000295:instrumentation*
chemical_list: D002368:Castor Oil