Dual-modality mammography

A method of manufacturing a scanning assembly for a dual-modality biological tissue imaging device used for imaging biological tissue having first and second compression surfaces for compressing and immobilising the biological tissue therebetween, comprising the steps of:

• mounting an ultrasonic transducer to a drive within a housing in a manner such that the ultrasonic transducer is adjacent to a scanning surface defined by the housing, for movement of the ultrasonic transducer on the drive in a plane parallel to the scanning surface and imaging of the biological tissue through the scanning surface;
• mounting an X-ray detector within the housing for forming an X-ray image of the biological tissue based on X-ray radiation passed through the biological tissue and scanning surface from an X-ray source;
• providing an electrical connector on a surface of the housing for connecting the ultrasound transducer, X-ray detector and drive to control circuitry of the biological tissue imaging device;
• filling the housing with a non-conductive fluid with an acoustic impedance similar to that of the biological tissue, completely immersing the ultrasonic transducer, X-ray detector and drive in the fluid;
• bleeding and drying the filled housing so as to remove substantially all air and water from the housing;
• and
• hermetically sealing the housing, thus ensuring that the fluid is kept at a constant volume during use.

A method of setting the X-ray exposure in a dual-modality mammography system used for imaging biological tissue comprising the steps of:

• gathering a volume data set representing the biological tissue by means of an ultrasound pre-scan utilising an ultrasound transducer of the system;
• determining a measure of density of the biological tissue using the volume data set;
• and
• setting the X-ray exposure according to the measure of density of the biological tissue.

A method of enabling a reduction in compression of a breast between first and second compression surfaces adapted for compressing and immobilising the breast therebetween, in a dual-modality mammography system incorporating both X-ray and ultrasound imaging techniques for imaging the breast, comprising the steps of:

• mounting a three-dimensional ultrasound transducer and a linear slot X-ray detector to a drive in side-by-side configuration within a housing defining a scanning surface which acts as one of the compression surfaces, to form a combined scanning assembly capable of acquiring both X-ray and ultrasound images simultaneously and linearly across the scanning surface;
• filling the housing with a non-conductive fluid with an acoustic impedance corresponding to that of the breast, completely immersing the ultrasound transducer, X-ray detector and drive in the fluid;
• and
• using the combined scanning assembly inside the filled housing to obtain ultrasound and X-ray images of a breast located between the scanning surface and a second compression surface.

A method of enabling a reduction in a dose of X-ray radiation utilised in a dual-modality mammography system incorporating both X-ray and ultrasound imaging techniques for imaging a breast, comprising the steps of:

• mounting an ultrasound transducer and a linear slot X-ray detector to a drive in side-by-side configuration within a housing defining a scanning surface which acts as one of two compression surfaces between which the breast is compressed, to form a combined scanning assembly capable of acquiring both X-ray and ultrasound images simultaneously and linearly across the scanning surface;
• filling the housing with a non-conductive fluid with an acoustic impedance corresponding to that of the breast, completely immersing the ultrasound transducer, X-ray detector and drive in the fluid;
• and
• using the scanning assembly inside the filled housing to obtain ultrasound and X-ray images of a breast located between the scanning surface and a second compression surface.