Methods and apparatus for performing sonomammography and enhanced x-ray imaging

In apparatus for obtaining images of biological tissue by passing X-ray radiation through a biological tissue to form an image in a receptor, the apparatus comprising an X-ray source for emitting X-ray radiation, first and second compression surfaces adapted for immobilizing the biological tissue therebetween, and a receptor disposed adjacent the second compression surface, the X-ray source disposed adjacent the first compression surface so that X-ray radiation emitted from the source passes through the biological tissue and is received by the receptor, the improvement comprising:

• an ultrasonic transducer disposed adjacent the second compression surface, the ultrasonic transducer being radiolucent;
• a coupling medium that acoustically couples the ultrasonic transducer to the second compression surface;
• and
• control circuitry for activating the ultrasonic transducer to generate a plurality of ultrasound images of the biological tissue while the biological tissue remains immobilized between the upper and lower compression surfaces.

In apparatus for obtaining images of a biological tissue having a shape by passing X-ray radiation through a biological tissue to form an image in a receptor, the biological tissue having an X-ray attenuation characteristic, the apparatus comprising an X-ray source for emitting X-ray radiation, first and second compression surfaces adapted for immobilizing the biological tissue therebetween so that the biological tissue has a portion of uniform thickness and a peripheral portion of non-uniform thickness, and a receptor disposed adjacent the second compression surface, the X-ray source disposed adjacent the first compression surface so that X-ray radiation emitted from the source passes through the biological tissue and is received by the receptor, the improvement comprising:

• an ultrasonic transducer disposed between the first and second compression surfaces;
• a gel pad disposed between the first and second compression surfaces and in contact with the biological tissue, the gel pad acoustically coupling a portion of the biological tissue to the ultrasonic transducer, comprising a material that conforms to the shape of the biological tissue and having an X-ray attenuation characteristic near the X-ray attenuation characteristic of the biological tissue, the gel pad enhancing the image of the peripheral portion formed in the receptor;
• and
• gantry means for moving the ultrasonic transducer along a curved path between the first and second compression surfaces while the biological tissue remains immobilized therebetween.

Apparatus for generating a plurality of ultrasound images of a biological tissue, the apparatus for use with an X-ray system that forms an image of the biological tissue in a receptor, the apparatus comprising:

• a compression plate that is radiolucent and sonolucent, the compression plate having first and second surfaces, the first surface forming a compression surface against which the biological tissue is immobilized;
• an ultrasonic transducer disposed adjacent the second surface;
• and
• drive means for moving the ultrasonic transducer across the second surface while the biological tissue remains immobilized against the compression surface.

Apparatus for generating a plurality of ultrasound images of a biological tissue, the apparatus for use with an X-ray system that forms an image of the biological tissue in a receptor, the receptor, the apparatus comprising:

• a compression surface against which the biological tissue is immobilized, the compression surface being radiolucent;
• an ultrasonic transducer disposed adjacent the compression surface;
• a coupling medium interposed between the ultrasonic transducer and the compression surface;
• and
• control circuitry for activating the ultrasonic transducer to generate a plurality of ultrasound images of the biological tissue while the biological tissue remains immobilized against the compression surface.

Apparatus for generating a plurality of ultrasound images of a biological tissue, including peripheral portions, the apparatus for use with an X-ray system that forms an image of the biological tissue in a receptor, so that when the apparatus is used with the X-ray system, the plurality of ultrasound images of the biological tissue may be correlated to the image formed in the receptor, the X-ray system including first and second compression surfaces adapted for immobilizing the biological tissue therebetween so that the biological tissue has a portion of uniform thickness and a peripheral portion of non-uniform thickness, the biological tissue having an X-ray attenuation characteristic the apparatus comprising:

• an ultrasonic transducer disposed between the first and second compression surfaces;
• a gel pad disposed between the first and second compression surfaces and in contact with the biological tissue, the gel pad acoustically coupling a portion of the biological tissue to the ultrasonic transducer, comprising a material that conforms to the shape of the biological tissue and having an X-ray attenuation characteristic near the X-ray attenuation characteristic of the biological tissue, the gel pad enhancing the image of the peripheral portion formed in the receptor;
• and
• gantry means for moving the ultrasonic transducer along a curved path between the first and second compression surfaces while the biological tissue remains immobilized therebetween, so that the ultrasonic transducer generates a plurality of ultrasound images of the biological tissue that may be correlated to the image formed in the receptor.

A method of obtaining an X-ray image of a biological tissue and an ultrasound image of the biological tissue that may be correlated to the X-ray image, comprising a series of steps of:

• (a) immobilizing the biological tissue with respect to a reference point using a compression plate that is radiolucent and sonolucent;
• (b) exposing the biological tissue to X-ray radiation to generate an X-ray image of the biological tissue in a receptor;
• (c) acoustically coupling an ultrasound transducer to the compression plate to generate a plurality of ultrasound images of the biological tissue without intervening movement of the biological tissue with respect to the reference point;
• and
• (d) displaying any one of the plurality of ultrasound images corresponding to a predetermined location on the X-ray image.

A method of screening a biological tissue for abnormalities, comprising a series of steps of:

• (a) immobilizing the biological tissue with respect to a reference point using a compression plate that is radiolucent and sonolucent;
• (b) exposing the biological tissue to X-ray radiation to generate an X-ray image of the biological tissue in a receptor;
• (c) applying a first compressive load to the biological tissue;
• (d) acoustically coupling an ultrasound transducer to the compression plate to generate a first plurality of digitally encoded ultrasound images of the biological tissue with respect to the reference point;
• (e) storing the first plurality of digitally encoded ultrasound images;
• (f) applying a second compressive load to the biological tissue, the second compressive load different than the first compressive load;
• (g) operating the ultrasound transducer to generate a second plurality of digitally encoded ultrasound images of the biological tissue with respect to the reference point;
• (h) digitally subtracting each one of the second plurality of digitally encoded ultrasound images from a corresponding one of the first plurality of digitally encoded ultrasound images with respect to the reference point;
• (i) displaying the difference of first and second digitally encoded ultrasound images;
• and
• (j) comparing the difference of the first and second digitally encoded ultrasound images at a predetermined location to a corresponding location on the X-ray image.