| 摘要 |
An ultrasonic applicator is illustrated for ultrasonic scanning of internal body regions, particularly for obtaining ultrasonic echo sectional views thereof for medical diagnostic purposes, wherein an ultrasonic transducer system directs sequential pulses of ultrasonic energy along successive beam paths converging toward a virtual focal point, and a planar reflector is interposed to reflect the energy pulses and is inclined at an angle deviating from 90 DEG relative to each incident beam path for the purpose of producing an actual convergence of the reflected beam paths externally of the applicator. The depth of the actual convergence point within the body to be scanned may be varied by means of a longitudinally adjustable acoustic window. The actual convergence point may also be shifted by angular adjustment of the reflector. The convergence of the reflected beam energy to a relatively narrow focus at a selectable distance in front of the acoustic window adapts the applicator to sector scanning of a body region accessible only through a relatively narrow acoustic aperture (e.g., between relatively dense bone structures).
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