Ultrasonograph

• US 20070293758A1
• Filed: 08/07/2007
• Published: 12/20/2007
• Est. Priority Date: 12/12/2001
• Status: Active Grant

• Current Assignee: FUJIFILM Healthcare Corp. (Fujifilm Holdings Corporation)
• Original Assignee: Hitachi Medical Corporation (Hitachi, Ltd.)
• Inventors: Azuma, Takashi, Umemura, Shin-ichiro, Sugiyama, Takashi, Kuribara, Hiroshi, Miwa, Yuichi
• Granted Patent: US 8,167,806 B2
• Time in Patent Office: Days
• US Class Current: 600/443
• CPC Class Codes: A61B 8/481 involving the use of contrast agent, e.g. microbubbles introduced into the bloodstream analysis of echo signal exploiting properties of a contrast enhancer in devices for short-range imaging with acoustic waves G01S7/52039
• CPC Class Codes: G01S 15/8963 using pulse inversion
• CPC Class Codes: G01S 7/5202 for pulse systems
• CPC Class Codes: G01S 7/52026 Extracting wanted echo signals Doppler systems G01S15/50; Doppler short range imaging systems G01S15/8979
• CPC Class Codes: G01S 7/52038 involving non-linear properties of the propagation medium or of the reflective target
• CPC Class Codes: G01S 7/52047 for elimination of side lobes or of grating lobes; for increasing resolving power
• CPC Class Codes: G10K 11/346 using phase variation

Abstract

To provide an ultrasonograph capable of generating a transmission beam comprising a main beam having a uniform width over a wide range in an ultrasonic wave propagation direction by one-time transmission of an ultrasonic pulse. A weighted mean value of a plurality of transmission delay time values corresponding to focal lengths of transmission pulse waves having a plurality of focal points which are set in the ultrasonic wave propagation direction is calculated for each of elements constituting a transmission aperture and used as the delay time. Waves are actually transmitted with the weighted mean value as delay time. As the weight used for obtaining the delay time mean value, first, a transmission effective aperture width according to each transmission focal length is selected, and a weight in the direction of the transmit aperture realizing the width is calculated and is used in a focal length direction. As a result, the curvature of a wave front of a wave transmitted is close to that of the wave front of a short focal length in the center portion of the transmit aperture, and is close to that of the wave front of a long focal length in the peripheral portion. Consequently, a non-cylindrical wave front is formed. Thus, a transmission beam including a relatively narrow main beam with a uniform width over a wide range in the ultrasonic wave propagation direction can be generated by one-time transmission of an ultrasonic pulse.

Claims

1. An ultrasonograph for obtaining an image of the inside of a subject comprising a transducer array for transmitting/receiving an ultrasonic pulse to/from the subject, the transducer array having a plurality of elements constituting a transmit aperture of the transducer array,

wherein a plurality of focal points are defined for each element in an ultrasound propagation direction, one transmission delay time defined from a plurality of delay time corresponding to the plurality of focal points, respectively, corresponds to transmission pulse wave from corresponding element.

2. An ultrasonograph according to claim 1, wherein main beam width of the transmission pulse wave is function of a focal length.

3. An ultrasonograph according to claim 1, wherein main beam width of the transmission pulse wave is proportional to interval of scan line.