MXPA94008375A - Methods and apparatus for performing sonomammography and enhanced x-ray imaging - Google Patents
Methods and apparatus for performing sonomammography and enhanced x-ray imagingInfo
- Publication number
- MXPA94008375A MXPA94008375A MXPA/A/1994/008375A MX9408375A MXPA94008375A MX PA94008375 A MXPA94008375 A MX PA94008375A MX 9408375 A MX9408375 A MX 9408375A MX PA94008375 A MXPA94008375 A MX PA94008375A
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- Prior art keywords
- biological tissue
- gel pad
- ray
- ultrasonic transducer
- ultrasound images
- Prior art date
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Abstract
This invention relates to methods and apparatus for imaging breast tissue employing both X-ray and ultrasound technology to provide enhanced diagnostic capability, and enhanced X-ray imaging. In particular, the present invention provides methods and apparatus for augmenting conventional mammography equipment with an ultrasonic imaging system that provides geometrically registered X-ray and ultrasonic fields, and associated equipment which may be used to enhance imaging in conventional X-ray equipment.
Description
METHODS AND APPARATUS FOR MAKING THE SONOMAMOGRAFI AND THE HIGHLIGHTED FORMATION OF THE X-RAY IMAGE *
Inventor: ASCHER SHMULR ITZ, US citizen, domiciled at 4323 Lake Washington Boulevard N.R., Apt. 5213, Kirkland, Washington, 98033, United States of America.
Causaire: NEOV1SION CORPORATION, a company of United States nationality, domiciled at 204-E Central Way, Kirkland, Washington, 98033, United States of America.
ABSTRACT OF THE INVENTION The present invention describes an apparatus that combines the mammography equipment with an ultrasonic transducer to generate ultrasonic images of the internal structure of the breast tissue, which are in geometric coincidence on a mammogram. The apparatus includes a radiolucent and sonolucid compression plate, and in alternative embodiments, an ultrasound transducer driven by a gantry crane or an ultrasonic phasing transducer. Methods are provided for generating a mammogram and a plurality of corresponding ultrasound images without moving the breast between the exposure of the mammogram and the formation of the ultrasound image. Methods for visualizing and analyzing ultrasound images are also provided. The apparatus and methods for improving the X-ray images obtained from conventional mammography systems, and with a reduced total dose of exposure to the patient's X-rays are also provided. This invention relates to the methods and to the
F apparatus for breast tissue image forms, using both the technology for X-rays and ultrasound to provide better diagnostic capability and to improve the formation of the X-ray image. In particular, the present invention provides the apparatus and methods to increase the conventional mammography equipment with a system for the formation of the ultrasonic image that provides geometrically coinciding X-ray and ultrasonic fields and the associated equipment that can be used to improve the formation of the image in an X-ray equipment conventional.
BACKGROUND OF THE INVENTION It is well known to use X-ray technology to provide two-dimensional images of the tissue of
Ü ^ breast for the diagnosis of carcinoma or other abnormalities. The formation of the X-ray image has a series of limitations that are universally recognized by radiologists. In particular, the formation of the breast tissue image has the inherent limitation that the mammogram provides only a two-dimensional image of a three-dimensional object. Thus, although an area of potential interest may be indicated on a mammogram, the elevation of the area in question within the breast may be uncertain, which leads to a biopsy of broader scope than would otherwise be necessary. In addition to conventional mammograms, the device that has been developed uses ultrasound technology to form the image of the breast tissue. The devices for the formation of the ultrasound Jmagen receive echoes received from a piezoelectric transducer when the brightness levels are proportional to the amplitude of the backscattered echo. The brightness levels are displayed in the appropriate echo range and the position or orientation of the transducer, resulting in the cutting of the image of the object in a plane perpendicular to the emitter face of the transducer. Previously known ultrasound equipment, in the form of a specialized image-forming ultrasound machine, has met with limited acceptance by the medical community. For example, US Patent 3, 765, 403 to Brenden discloses the use of ultrasound technology to provide direct and holographic image formation of breast tissue. This device requires the patient to lie face down on a support surface while her breast is submerged in a tank full of water. The American Patent 4, 434, 799 of Taenzer describes an alternative device in which the patient's breast is immobilized between an ultrasonic transducer and an ultrasonic reception transducer. Both systems described in these patents are specialized ultrasound systems. In addition to the specialized device, portable ultrasound devices have found use in the performance of freehand examinations. Pulse analysis using a portable ultrasound transducer is described, for example, in Mendelson, "Ultrasound Secures Place In Brest Ca Management," Diagnostic Imaqinq, April 1991, pp. 120-129. One disadvantage of these hand-made analyzes, when used to supplement the mammogram, is the inability to provide a match or geometric record between the mammogram and the ultrasound images. This lack of registration or coincidence may result in the freehand ultrasound examination that targets a portion of the breast tissue different than what would have been indicated where it is possible to match sar or geometric registration. For example, recent studies have shown that over 10% of the masses detected with pulse ultrasound and that initially were thought to be masses detected by the mammogram, later they were found to represent different breast areas. Because ultrasound can represent two to three times more cysts than mammography, the possibility of representing a malignant lesion as benign is real. It has been suggested to add to the diagnostic criteria, in addition, the three-dimensional shape of the lesions, as reported in Hoer, "Imaging Features and Management of Characteristically Benign and Probably Benign Lesions, Ra. Cli. N. Am., 25: 939 -951 (1987) and the increased vascularity associated with carcinoma, as reported in Cosgrove et al., "Color Doppler Signals From Breast Tumors", Radiology, 176: 175-180 (1990). Space of ultrasonic data with a mammogram can not be achieved with previously known ultrasonic di.sposi.ti.vos.Although there is recognition within the medical community of the advantages offered by ultrasound technology, the manufacture of the equipment of conventional mammography and sonography has avoided the combination of these two technologies, in particular, polycarbonates such as Lexan®, are commonly used in mammography due to their resistance to traction and trans lack of X-rays
»These materials are acoustically opaque. On the other hand, the compression plates used in conventional breast ultrasound devices, for example, in Brenden American Patent 3, 765, 403, are composed of materials such as polystyrene or polyurethane, which have insufficient tensile strength for use in the mammography equipment. Due to their high densities, all potentially useful materials for the compression plate in the mammography equipment have relatively high attenuation and reflection coefficients (Table 1, below). These characteristics limit the use of ultrasound with low frequencies (3 MHz or less as described in the North American Patent 4, 434, 799 of Taenzer) and at a shallow depth. On a 10 MHz round trip path and 0.5 to 1 cm across a normal compression plate, the attenuation with most polymers would be 20-50 dB. For any interface thicker than a quarter of the wavelength (several hundred microns, depending on the frequency and nominal acoustic velocity of the material) the transmission loss (which could exceed 50 dB) must also be taken into account. In addition, the mismatch of the impedance between the biological tissues, the compression plate and the transducer results in a loss of at least 6 dB at each interface, or an additional total loss j of 24 dB round trip. Since the total dynamic range is not greater than lOOdB for a characteristic ultrasound system, the formation of the ultrasound image by means of the previously known mammographic compression plates would be impossible. Furthermore, since the acoustic propagation within the compression plate is considerably different than in water or in the coupling gel, the effects of the
$ refraction on each of the waves emitted from the elements of an alignment in phase, severely disturb the beam forming a process that considers a constant speed of 1540 m / sec.
TABLE 1 Material Attenuation Coefficient Imoedancia i ídB / MHz / cmls (Pa s / ml
Polyvinyl chloride 11.1 3.4 Polybutane. 6.1 3.2 Polyacetyl, Polyethylene, Polypropylene 2.5-3.3 -2.2 Polyamide (Nylon) 1.1 2.9 Polystyrene 1 2.5 Water 0.02 1.5 The lower frequencies used in the previously known ultrasonic devices would be inadequate for diagnostic applications, which currently require transducers of 7-10 MHz, although this higher frequency requirement would increase the transmission loss at least to triple (in dB). While it is possible to generate larger pulses in the transducer in the water bath process, the low electromechanical efficiency results in the production of heat. The placement of the transducer directly on the compression plate and
* therefore in close proximity to the biological tissue, it would still require higher energy pulses for each element. The resulting heat production would cause damage and should be avoided. Conway in "Occult Breast Masses: Use Of Mamographic Localizing Grid For US Evaluation", Radiology. 181: 143-146 (1991 and Bre and Gatewood, "Téplalate Guided Breast Ultrasound", Radioloqy, 184: 872-874 (1992), describe the
^^ attempts to achieve a match in the space between a mammogram and an ultrasound image by making a hole when cutting the compression plate of the mammography device to insert an ultrasound transducer. In Conway et al., A compression plate opened by the cut with a locating grid was used to allow acoustic transmission. Using a device
-Sai &A identical ultrasound, the ultrasound study was performed by pulse and through a localization grid. Several exposures to the additional X-rays were necessary to detect the lesion, the substitution of the compression plate by the cut-off mesh compression plate, and the subsequent placement of the cut-out over the coordinates of the lesion. The ultrasound adapted with the grid detected 24% more than pulse. 10% was misidentified using freehand ultrasound. None of the lesions was poorly identified with the compression guided by the grid.
* The procedure described in the aforementioned articles has several practical disadvantages. For example, in Conway, the patient's breast is marked with an indelible pencil to help the personnel who prepare the mammogram by repositioning the patient's breast on the location grid after the compression plate is replaced by the plate. Open compression by the cut uses with the ultrasound transducer. As noted in this article, even the use of indelible marks on the skin of patients does not absolutely protect against movement of the underlying breast tissue. In addition, the personnel who prepare the mammogram had to be present during the examination to ensure correct placement, and the duration of the procedure was significantly longer. A compression plate opened by cutting with
&? ~ ^ ¡jj ^^ a location grid suffers the problem that the field
Ultrasonic is interrupted by the shadow of the compression plate, in all regions except the cut hole, so it requires prior knowledge of the lesion in which the impulses are emitted. As a result, to obtain a complete ultrasound diagnostic image of the desired region of interest, it would be necessary to carry out a complex and annoying handling of the mammographic compression procedure, and to expose the patient to the radiation of
_ ^ additional ionization. ^^ In addition to the above, the compression plates used in conventional X-ray mammography typically compress most of the mass of the breast to a uniform thickness. The amount of exposure to the X-rays necessary to form the image is then determined by the uniform thickness of the tissue between the plates. The nipple region and the external contours of the breast under compression have thicknesses that vary widely
WP of uniform thickness. Thus, the amount of radiation necessary to adequately expose tissue of uniform thickness causes the nipple region and the external contours of the breast to be highly overexposed. To obtain an acceptable image of the nipple region and the external contours of the breast, it is characteristic for the radiologist to perform a second exposure to the lower dose X-rays.
Yet another disadvantage associated with the previously known compression plates is the discomfort of the patient resulting from the force applied to the tissue of the breast to compress it to a uniform thickness. In view of the disadvantages of the previously known apparatus and methods for forming the breast image, it would be desirable to provide an apparatus and methods for obtaining breast tissue images geometrically in register or coincident in X-rays and ultrasound. ^ It would also be desirable to provide a plate of? compression that is both radiolucent and sonolucid, so that images of the mammogram and ultrasound of the patient's breast tissue can be obtained without moving the breast between exposure to X-rays and ultrasound image formation. It would also be desirable to provide an apparatus for moving an ultrasound transducer through a predetermined path to generate a plurality of
Wr ultrasound images of the breast tissue at previously selected intervals. It would also be desirable to provide an apparatus for maintaining a fluid, lubricating and acoustically coupling film between an ultrasound transducer and a compression plate to reduce the attenuation and reflection of the acoustic energy.
a- a < ag a ^ fcaks .. ^. & i ^ ^^ taaiS ^ -agsiéaBife ^.
In addition, it would still be desirable to provide a device capable of correlating geometrically matching X-ray and ultrasound images to obtain holographic views of the patient's breast tissue. Furthermore, it would be desirable to provide an apparatus for use with conventional mammography equipment, which improves the image formation in the nipple region and the external contours of the breast, so that a high quality image can be obtained with a single In addition, it would be desirable to provide an apparatus for use in conventional mammography equipment that reduces discomfort in the patient caused when the patient's tissue is compressed to a uniform thickness.
SUMMARY OF THE INVENTION In view of the aforementioned, an objective of the present invention is to provide an apparatus and methods for delivering geometrically matching X-ray and ultrasound images of the breast tissue. Another object of the present invention is to provide a compression plate for use in combination with the mammography / ultrasound apparatus (hereinafter referred to as "sonomatography") which is both radiolucent and sonolucid, such that a mammogram image and ultrasound of the breast tissue of < A patient can be obtained without moving the breast between exposure to X-rays and the formation of the ultrasound image. Another object of the present invention is to provide an apparatus for connecting an ultrasound apparatus with a compression plate to obtain ultrasound images of the breast tissue at previously selected intervals. Another object of the present invention is to provide an apparatus for maintaining a lubricating and coupling film between an ultrasonic transducer and a compression plate. Another objective of the present invention is to provide a radiolucent ultrasound transducer apparatus for use in a sonomatography apparatus, to provide a plurality of ultrasound images of the breast tissue that are in geometrical registration with a mammogram obtained by the equipment. Another objective of the invention is to provide methods for handling in digital form the ultrasound images of breast tissue, both individually and in conjunction with mammographic views, to isolate and diagnose potential tissue abnormalities. Still another object of the invention is
provide an apparatus capable of correlating geometrically coincident X-ray and ultrasound images to obtain holographic views of the patient's breast tissue. Still another object of the present invention is to provide an apparatus for use with conventional mammography equipment that improves the image formation of the nipple region and the external contours of the breast to obtain a high quality image using only one exposure to X-rays. Yet another object of the present invention is to provide an apparatus for use in conventional mammography equipment that reduces the discomfort of the patient caused when the tissue is compressed to a uniform thickness. These and other objects of the invention are achieved in accordance with the principles of a first embodiment of the invention by providing a radiolucent compression plate.
* and sonolúcida that enables the sonography apparatus to be combined with the conventional mammography equipment. Before or after exposure to X-rays, an ultrasound transducer mounted on a carriage is moved in increments through the compression plate, to generate a plurality of sectional views of the breast tissue. The X-ray and ultrasound images produced by the sonomatography apparatus of the present invention are by themselves. consequently in geometric coincidence. In turn, these images can be processed by a workstation based on a conventional microprocessor to provide the holographic views of the internal characteristics of the patient's breast. The compression plate according to the present invention may include a gel pad for acoustically coupling the nipple region and the external contours of the breast with the transducer. This gel pad can also advantageously be used individually in conjunction with conventional X-ray mammography equipment to provide improved X-ray image formation by attenuating incident X-ray radiation proportionally to the thickness of the tissue that is to be representing, and reducing the dispersion of X-ray radiation. The gel pad of the present invention also advantageously improves the placement of the breast and reduces discomfort in the patient relative to conventional compression plates. In a second embodiment of the present invention, a translucent ultrasound transducer is provided that fits the conventional mammography equipment. The transducer of the present invention, which may be in phase alignment, serves both as a transmitting and receiving ultrasound transducer, and is placed behind the diffraction grating that normally
* found on the mammography equipment to reduce the exposure of the X-ray film by the diffused radiation. The diffraction grating is modified to function as the component of the acoustic circuit in this mode. In a third embodiment of the present invention, an ultrasound transducer is installed in a carriage
^ mobile placed between the compression plate and the grid
~ diffraction of conventional mammography equipment. For this modality, there is no need for the sonolucid compression plate of the first modality, nor of the radiolucent ultrasound transducer of the second modality. The present invention also includes methods for image formation of a patient's breast tissue, using the mammography and sonography equipment to provide geometrically matching images. The methods further include the processing of those images using a workstation based on the conventional microprocessor to allow a biopsy guided by the image in the patient's tissue. Alternatively, the specialist doctor can perform a detailed review of the processed images and stored them in an offline arrangement.
a & akjfesgxsBaifc .. i ^^ ágjkSg The present invention also includes methods of handling ultrasound imaging, either individually or in conjunction with mammographic views, to assist the physician in identifying and diagnosing anomalies tissue potentials. For example, applicants have discovered that tissue abnormalities are less compressible than healthy tissue. Accordingly, applicants have discovered that by performing multiple ultrasound scans of a tissue mass under different compression loads, and then digitally subtracting the images, tissue abnormalities can be easily detected.
BRIEF DESCRIPTION OF THE DRAWINGS Other characteristics of the invention, its nature and the different advantages will be evident from the attached drawings and from the following detailed description of the preferred embodiments, in which: FIG. 1 is a perspective view of a first embodiment of the sonomatography apparatus of the present invention; FIG. 2 is a side elevational view of the sonomatography apparatus of FIG. 1; FIGS. 3A and 3B are, respectively, side views of a breast compressed in the conventional mammography apparatus and an X-ray image obtained with this apparatus; FIGS. 4A and 4B are, respectively, a side view of a breast compressed in the mammographic apparatus including the gel pad of the present invention and an X-ray image obtained with this apparatus; FIG. 5 is a detailed perspective view of one embodiment of a compression plate according to the present invention; FIGS. 6A and 6B are, respectively, a perspective view of a lubrication / coupling device of the illustrative ultrasonic transducer of the invention and a sectional view of the device of FIG.6A taken along the line 6B-6B; FIG. 7 is a schematic view of an illustrative embodiment of the driving means employed in the sonomatography apparatus of FIG. 1; FIG. 8 is a perspective view of a workstation and the digitizing tablet adapted for use with the present invention; FIG. 9 is a perspective view of an alternative embodiment of the sonomatography apparatus of the present invention; FIG. 10 is a sectional view taken along line 10-10 of FIG. 9;
FIG. 11 is a perspective view of the diffraction grating and ultrasonic transducer apparatus of the present invention; FIG. 12 is a sectional view of another alternative embodiment of the present invention; FIG. 13 is a block diagram of the elements of an ultrasonic imaging system according to the present invention; FIG. 14 is a perspective view of the ultrasonic images and the X-ray image generated with the apparatus of FIG. 1 according to the methods of the present invention.
DETAILED DESCRIPTION OF THE INVENTION With reference to FIGS. 1 and 2, a first illustrative embodiment of the sonomatography apparatus 10 manufactured in accordance with the present invention is described. The sonomatography apparatus 10 contains a base 11, a vertical column 12, an X-ray tube 13 suspended from the arm 14, the compression plate 15, the ultrasound transducer 16 supported from the gantry crane 17, the support for the gantry crane 18, the diffraction grating 19, the film support 20 and a guide for the biopsy needle 21. The mammographic components of the sonomatography apparatus 10, that is, the base 11, the column 12, the tube X-rays 13, arm 14, diffraction grating 19 and film support 20 may include the features described below, but may otherwise be conventional. As in the previously known mammography equipment, the vertical elevation of the arm 14 in the column 12 can be determined selectively and manually by hand or using a motorized arrangement that is per se known. The X-ray film 22 is disposed below the diffraction grating 19 in the film holder 20 through a door on the end face of the film holder. While the illustrative modalities referred to herein refer to the mammography equipment that generates X-ray film, it should be understood by those familiar with radiology that digital X-ray systems (without film) or film can also be used. X-ray scan. It is sufficient for the purpose of the practice of this
# Invention that X-ray radiation emitted from a X-ray source passes through a biological tissue and forms an image on a receiver, be it an X-ray film or a digital X-ray receiver. Commercially available mammography equipment that can be enhanced in accordance with the present invention includes, for example, the Contour system of Bennett X-ray Technologies, Inc., Copiague, New York, the AVIVA system available at Kramex, Saddle BrooK, New Jersey, and the LORAD DSM system, available at Lorad, Danbury Connecticut. In addition to the components described above for the sonomatography apparatus 10 that are common to previously known mammography systems, the apparatus of the present invention includes the compression plate 15 and the ultrasonic transducer 16 movably supported on the crane. portico 17. As shown in FIGS. 1 and 2, the compression plate 15 includes a gel pad 13
* disposed on the underside of the compression plate, for example, by means of a polyethylene bag 24. The compression plate 15 may include fenestrations (not shown) to perform the tissue biopsies of the patient. Alternatively, depending on the composition of the gel pad, the gel pad 23 may be used without the polyethylene bag 24 and may include an adhesive or sticky surface to assist in the placement of the breast. The gel pad 23 makes contact with the front area of the patient's breast, i.e. the area of the nipple, to ensure adequate transmission of the acoustic waves from the transducer 16 to the most distal portion of the breast tissue. with a minimum mismatch of the impedance. As seen in FIGS. 1 and 2, the gel pad 23 takes the shape of the distal portion of the breast to reduce the mismatch of the impedance and reflectance
* Acoustic interface on the gel / breast pad. Accordingly, the gel pad can contain a gelatin agar composition and water or other suitable rheostatic materials, for example, the gelatinous elastomeric compositions described in US Pat. Nos. 4, 369, 284, 4, 618, 213 and 5. , 262 468. For hygiene purposes, the gel pad 23 (and the polyethylene bag 24, if used) may be disposable,
* and therefore be attached to the compression plate removably. Now with reference to FIGS. 3 and 4, another advantage of the gel pad of the present invention when used in conjunction with a conventional mammography system is described. With reference to FIG.3A, a portion of the previously known X-ray mammography system compresses the breast 104 between the compression plate
# 91 and lower plate 92 to a uniform thickness 105. As is known per se, exposure to X-rays is established to provide an exposure of adequate thickness 105. However, by adequately exposing the uniform thickness, the external contours of the breast 104, including the nipple region, are normally overexposed, as reflected in region 106 in the illustrative X-ray image 93. To compensate for this effect, it is typical for a radiologist to take a second exposure of breast 104 to a
* lower X-ray dose, thus an X-ray image is obtained where the external contours of the breast are adequately exposed, but the uniform thickness 105 then has insufficient exposure. Now with reference to FIGS. 4A and 4B, an important advantage of the present invention is illustrated. Applicants have determined that the gel pad 23 not only provides acoustic coupling when used in a sonomatography system as described above, but that the gel pad 23 also provides an ability to attenuate the X-rays. FIG. 4A the portion of the system of FIG. 3A, but also includes a gel pad 23 of the present invention. The gel pad 23 fits or adjusts to the thinner ones of the breast at external contours where the standard radiation doses cause overexposure. When the gel pad 23 is made of a material having an attenuation of X-rays close to that of human tissue, the gel pad attenuates the X-rays as if it were part of the uniform thickness of the breast tissue. As shown in FIG. 4B, the external contours of the breast, which includes the nipple region, in the
The resulting X-ray image 94 is no longer overexposed. Accordingly, the gel pad 23 can be used to improve conventional mammography equipment by making it easier for the radiologist to obtain an X-ray image having a properly exposed detail at the peripheral edges of the anatomy in matter with a total reduction in the dose of X-rays to the patient. In addition, because the gel pad 23 adapts to the shape of the patient's tissue, it distributes the force applied by the compression plate 15 on a
* Larger surface area, thus reducing the compression tension applied to the tissue and reducing the discomfort of the patient. Moreover, if the gel pad includes a slightly sticky or adherent surface, it will be better restrained to the patient's tissue and will reduce difficulties in tissue placement. Again with respect to FIGS. 1, 2 and 5, in the first embodiment of the present invention, the plate
* compression 15 contains an X-ray transparent ("radiolucent") and acoustically transparent ("sonolucid11) high-performance film that is sufficiently rigid to serve as a compression plate in a thickness of approximately 25 microns (1 mil). In particular, it is preferred that the compression plate 15 have sufficient stiffness such that the local slope of the plate under the load does not exceed one degree in the horizontal within the scanning area.
* compression 15 may include reinforcing metal bars 15 along their lateral end faces. The Kapton® manufactured by E.l. Du Pont de Nemours and Company, Wilmington, Delaware, is a suitable material for practicing the present invention, when it provides both the necessary sound / radiolucent qualities as well as the rigidity necessary to satisfactorily provide a compression plate. In particular, a
* 1 mil thickness (25 microns) of the Kapton®, when used as a compression plate, is expected to cause a transmission loss of less than 3 dB in acoustic energy, while providing a tensile strength equivalent to a 2 mm thick polycarbonate plate. In addition, Kapton® is not affected by exposure to X-ray radiation. Other materials suitable for use in the
* fabrication of a radiolucent and sonolucid compression plate includes the Surlyn® ionomers, such as Surlyn® 8940, available from E.l. Du Pont de Nemours and Company, Wilmington, Delaware, and polymethyl pentenes, such as TPX® MX-002 and MX-004, available from Mitsui & Co., Tokyo, Japan. The plates of these materials of approximately 6.4 mm (0.25 in) thick are expected
^^^ - w -i ^ _íitfÉiÉíii ». ^^^^^^ MfMi ^^ i that they are sufficiently rigid to satisfy the criterion of" deflection defined in the above if it is supported
»Suitably by means of a reinforcing frame around its periphery. In FIG. 5 shows a compression plate 15 comprising a 6.4 mm (0.25 inch) thick sheet of TPX® fixed to a metal frame 96. Three sides of the TPX® 95 sheet are fixed to the metal frame 96 by means of fasteners suitable, as with stepped screws 97, and the fourth side is joined to a slit 98 in the frame 96. Of the two materials, the polymethyl pentenes, and the TPX® in particular, are preferred due to their attenuation and acoustic impedance low and high resistance. A sheet made of a Surlyn® ionomer can also be used in a similar way although this one. It is softer and the acoustic losses are approximately double that with the TPX®. Referring now to FIGS: 6A and 6B, the ultrasonic transducer 16 may contain a single piston, an image forming device with phased or annular alignment of conventional design. These ordered devices can allow the focusing of the ultrasonic energy beam to provide high definition images of the internal structures of a patient's tissue. The ultrasound transducer 16 combines both the transmission and reception functions that are switched, respectively, between the transmission and reception functional modes at times selected by the series of control circuits. Because the internal structure and operation of the ultrasonic apparatus is known per se, the specific internal configuration of this apparatus is not part of the present invention. The transducer preferably operates in a range of about 2 to 15 MHz. More preferably, the signal produced by the transducer in the transmission mode is a burst of 10.
# MHz that has a bandwidth of 100%. To improve the transfer of the acoustic energy, the transducer 16 can also be acoustically coupled to the high surface of the compression plate 15 using a suitable coupling agent such as, for example, glycerol, or a thin additional gel pad disposed on the compression plate 15 (omitted from FIG 1 for clarity). With respect to the illustrative embodiment of the transducer 16 shown in FIGS. 6A and 6B, an apparatus for the application of a lubricating / coupling agent between the ultrasonic transducer 16 and the compression plate 15 is described. The transducer 16 is surrounded by a skirt or cover 110 including a spacer 11 formed throughout of its lower margin. The spacer 111 raises the contact surface of the transducer approximately 0.06
^ -éii? ^ '^^ i &ß ^ mm (2.5 mils) on the surface of the compression plate 15, and is formed to optimize lubrication and
»Acoustic coupling. A sponge-like material moistened with a suitable lubrication / coupling fluid, for example, a water-based solution of the surfactant and urine detergent, is disposed around the transducer 16 in such a way that the sponge-like material 112 and the spacer 111 comes into contact with the compression plate 15 at the same time. In this way, when the transducer assembly moves along
# of the surface of the compression plate 15, a thin film 113 of the lubricating / coupling fluid is disposed on the plate. The cover 110 also allows the transducer assembly to be manipulated without contacting the material 112. Referring again to FIGS. 1 and 2, the support of the gantry crane 18 is positioned vertically along the column 12 using a motorized adjustable mechanism or manually. The support of the gantry crane 18 includes the arms 18 'arranged on the lateral margins of the compression plate 15. The support of the gantry crane 18 movably supports the gantry crane 17 for movement in distal directions and proximal "A" and "B" using a motorized track or cable arrangement 25. The support of the gantry crane 18 moves the gantry crane 17 in precise increments in the distal and proximal directions. During exposure to X-rays of the
? In the patient's tissue, the gantry crane 17 is moved to the furthest position in the "A" direction so that it does not interfere with the exposure of the mammogram. Alternatively, the gantry crane 17 and the gantry crane support 18 can be hinged away from the compression plate, thereby giving free access for exposure to the X-rays. The gantry crane 17 ( shown with the lines
* dotted in FIG. 7) in turn contains a carriage 26 supporting the ultrasonic transducer 16. The gantry crane 17 includes its own motorized drive means 27 for moving the carriage 26 laterally in the "C" and "D" directions. The illustrative embodiments of the driving means 25 and 27 are described with respect to FIG. 7. The driving means 25 of the supporting arm of the gantry crane 18 may contain cables 30 extending through the arms 18 'of the support of the gantry crane 18. The cables 30 are captured on the pulleys 31 and the driving wheels 32 for forming the upper and lower sections 30A and 30B, respectively. The driving wheels 32 are synchronously driven by the motor 33. The gantry crane 17 is fixedly connected to the upper sections of the cables 30 at the points 34, so that when the stretches
_ * _._ & &g; upper of the cables 30 move in the directions "A" and "B", the gantry crane 17 moves in the direction
* correspondent. The motor 33 is of the type that facilitates the exact positioning of the gantry crane 17, for example, such that the gantry crane 17 can be moved in the distal and proximal directions in precise increments, such as from 1 to 10 mm. . Still with reference to FIG. 7, the gantry crane 17 includes its own cable arrangement 27 for the precise positioning of the carriage 26 and the transducer 16. In particular, in the illustrative embodiment, the cable 35 passes over the driving wheel 36 and the pulley 37 to form the upper and lower sections 35A and 35B, respectively. The carriage 26 is fixed to the lower section 35B of the cable 35 at the point 35 'in such a way that the carriage 26 moves in the directions "C" and "D" in response to the movement of the lower section 35B. The motor 38, which is supported on the gantry crane 17, facilitates the precise control of the carriage 26 and consequently of the transducer 16. Alternatively, a gear and toothed belt mechanism can be replaced by cables, pulleys and the driving wheels of the illustrative embodiment described above. As other alternatives, the driving means 25 and 27 can employ, for example, the conventional motorized track, a block with thread on a driving rod with thread controlled by an encoder and a stepper motor, or any other suitable means. * It should be understood that a set of control circuits suitably programmed for use is provided with any of the aforementioned driving means 25 and '27 such that the driving means is stopped at predetermined places during transit for a sufficient period to get an ultrasound image of the breast tissue on this site. further, the gantry crane and gantry crane support 18 can offer separation mechanisms that facilitate the operator manual placement of the transducer 16. As shown in FIG. 2, the arm 18 'of the support of the gantry crane 18 includes a slot 39, whereby an extension of the gantry crane 17 projects to contact the guide of the biopsy needle 21. In this way, when the gantry crane 17 moves in distal and proximal directions "A" and "B", the guide of the biopsy needle jt 21 remains in alignment with the ultrasonic transducer 16. The guide of the biopsy needle 21 includes a support element of the needle 40 having an opening through which the biopsy needle can be inserted to perform a tissue biopsy of the patient guided by ultrasound. The needle support element 40 can be placed in any position desired by the medical specialist and then
connect with the biopsy needle holder 21 to perform the image-guided biopsy. The lateral alignment of the biopsy needle according to this aspect of the present invention provides important physiological benefits to the patient. Since the biopsy needle is inserted laterally into the breast of the patient rather than through the surface of the upper part, it does not produce scarring on the anterior surface of the breast. Therefore, the patient will not be discouraged from wearing clothing (eg, nightwear) that exposes the anterior surface of the breast, because of the importance of a scar tissue with an unpleasant appearance of a visible biopsy puncture. The ultrasound transducer 16 generates an image corresponding to the internal structure of the tissue located in the plane perpendicular to the transducer at each site. wherein the carriage 26 stops during its transit through the compression plate 15. The images or pictures generated in each of these sites are stored on a workstation 41 based on the microprocessor, as shown in FIG. FIG. 8, for further processing and handling. With reference now to FIG. 8, for an embodiment of the present invention for use with the conventional mammography apparatus that generates an X-ray film, an X-ray film 42 is placed on a digitizing tablet 43 in such a manner that the index marks 44
> and 44 'on the X-ray film coincide with the positioning markings on the digitizing tablet 43. The digitizing tablet 43 includes a pencil 45 and is connected to the workstation 41 having a monitor 46. The workstation 41 includes a computer program suitable for interpreting the movement of the pencil 45 with respect to the digitizing tablet 43. When the x-ray film 42 is aligned
* on the digitizing pad 43, the pencil 45 of the digitizing tablet makes it easy for the specialist to display on the monitor 46 the orthogonal ultrasound image corresponding to a site on the X-ray film 42 by means of the touch of the pencil 45 on the digitizing tablet 43. Thus, the position of the contact of the pencil 45 towards the digitizing tablet 43 automatically brings with it the corresponding orthogonal ultrasound table in that site, providing the medical specialist with a holographic, ie three-dimensional, view of the internal structure of the tissue. In addition, the precise geometrical matching of the pictures of the ultrasound image and the X-ray film provided by the present invention enable the medical specialist to handle the ultrasound images, to perform, for example, the digital subtraction, consequently the improvement of the detection capacity of the breast lesion. The PowerPc® commercially available from Apple Computer, Cupertino, California, offers a workstation suitable for the use described above, while the HiSketch series of digitizing tablets, available from Kye International Corp., Ontario, California, provide digitizing tablet suitable for use in conjunction with the sonomatography apparatus of the present invention. Alternatively, a conventional X-ray film could be digitized using a scanner, or a conventional video camera. Now with respect to FIGS. 9-11, an alternative embodiment of a sonomatography apparatus 50 manufactured in accordance with the principles of the present invention is described. The sonomatography apparatus 50 includes the base 51, the vertical support column 52, the X-ray tube 53 supported on the vertical moving arm 54, the compression plate 55, the diffraction grating 56, the ultrasound technology 57 and the film support 58. Components 50-54 may constitute the elements of a conventional mammography system as described above. The X-ray sensitive film 59 is placed in the support of the film 58 below the ultrasound transducer 57.
, -ú ^. The sonomatography apparatus 50 differs from the apparatus 10 described above mainly in that the compression plate 15 is solid, the transducer 16, the gantry crane 17 and the support of the gantry crane 18 are replaced by the grid. modified diffraction 56 and ultrasound transducer 57. Compression plate 55 can be fenestrated to facilitate the performing of biopsies guided by ultrasound images to the medical specialist. Now with reference to FIG. 11, the diffraction grating 56 comprises an arrangement of an X-ray absorbing material 61, such as lead, which has its gaps filled with a non-absorbent material 62 such as aluminum or an organic material, this ordering, which is conventional for the systems of mammography, allows those X-rays that are perpendicular to the plane of the diffraction grating 56 to pass through the interstices 62, while the ordering of the lead lines 61 * 'absorb most of the diffuse radiation caused by the dispersion of the X-rays when they pass through the tissue of the patient 101. The diffraction grating 56 differs from previously known devices, in that the lower surfaces of the interstices 62 extend under the lower surfaces of the lead lines 61 approximately by 1 mm. The spaces between the extended interstices therefore create air sacs that serve as an acoustic absorbent between the ultrasonic transducer and the
# lead lines 61. The ultrasonic transducer 57 serves the same purpose as the ultrasound transducer 16 of the embodiment of FIGS. 1 -7, that is, to send and receive alternately the acoustic energy. The ultrasonic transducer 57 comprises a two-dimensional array of piezoelectric arrays 63, in phase or linear, placed in parallel relation. The arrays 63 may have their axes aligned orthogonally with the lead lines of the
# diffraction grating 56, as shown in FIG. 11, or they may have their axes aligned with the interstices 62. Each of the arrays contains a multiplicity of ultrasonic transducer elements 63 • which can be activated individually and in sequence. The spacing 64 between the alignments 63, which may be for example 1 cm, determines the spacing between the contiguous frames of the ultrasound images provided by the transducer
• 57. This resolution, like the elevation approach, can be improved to provide the appropriate circuitry to focus the acoustic energy emitted by the multiple ultrasonic transducer elements 63 ', that is, by activating the elements in the adjacent lines. Each of the transducer elements
Ultrasonic 63 is connected to an ultrasound controller circuit, hereinafter described, by a series of connecting wires (not shown in FIG 11). The connecting wires are sent through the two-dimensional array in such a way that they coincide with the lines of the X-ray absorbing material in the diffraction grating 56. By thus arranging the connecting wires towards the ultrasonic transducer elements 63 'the connecting wires They will not create images about the X-ray film during the exposure of this film. The high surfaces of the ultrasonic transducer elements 63 'are acoustically coupled to the interstices 61 of the diffraction grating 56 using a suitable coupling agent, for example, glycerol. The acoustic energy emitted by the ultrasonic transducer elements 63 'is transmitted through the interstices of the diffraction grating 56 and in the fabric i ajfc disposed between the upper compression plate 55 and the diffraction grating 56. A gel pad, as described in the above with respect to the FIGS modality. 1-7 can be used in conjunction with the compression plate 55 and the diffraction grating 56 to reduce the mismatch of the acoustic impedance at the interface between the diffraction grating and the furthest portion of the breast tissue of the patient 101.
'^ * ^^.
With reference still to FIG. 11, the alignments 63 comprise a series of layers including
»A piezoelectric material, such as the copolymers of vinylidene fluoride (VDF) and trifluoroethylene (TrFE), for example, available from Toray Industries, Kamakura, Japan. The use of these materials to form ultrasonic transducers is described in Ohigashi et al., "Piezoelectric and Ferroelectric Properties of P (VDF-TrFE) Copolymers and Their Application to Ultrasonic Transducers", page 189 et seq., In MEDICAL APPLICATIONS OF PIEZOELECTRIC POLYMERS (Galetti et al., Editors), Gordon and Breach Science Publishers SA (1988), which are incorporated herein by reference. The inventors have determined that a material layer of the gold-plated copolymer of about 25 microns (1 mil) is practically transparent to X-rays (and to ultrasound), the change in the signal received when the copolymer film is inserted between the X-ray source and the film is less than 1 dB. As shown in FIG. 11, the alignments 63 can form an in-phase alignment. An example of an array of VDF-TrFE acoustic transducer integrated in silicon demonstrated for use in the formation of the diagnostic image is described in Ohigashi et al., Supra. These arrangements or arrangements exhibit a lower degree of cross-coupling of the ordered element, may be
easily manufactured in high density, and provide excellent acoustic impedance adjustment for the fabric
»Biological. Still with reference to FIG. 11, the ultrasonic transducer 57 contains a metal counterplate 66 covered with piezoelectric film 67 of a suitable material described in the foregoing, for example, a copolymer of VDF and TrFE. The piezoelectric film 67 in turn is covered by an electrode element 68, and carries on its upper surface an inactive polymer layer 69. The wires of
* ^ F connection (not shown) are sent to the respective electrode elements of each of the elements of the ultrasonic transducer 63 'to match them with the lines of the X-ray absorbing material in the diffraction grating 56. The inactive polymer layer 69 is acoustically coupled to the lower ends of the material of the interstices of the diffraction grating using a suitable coupling agent as described above. It will be recognized by the person skilled in the art of ultrasonic transducer design that the ultrasonic transducer elements 63 of the ultrasonic transducer can be manufactured to operate at a predetermined frequency with the thickness selection of components 66 through 69. In addition, it will be recognized that because the acoustic signals received by the alignments during
? -.-, JtW, «W? M» ». "I • -. , - •. -., »..aai.,":., R & mti '.- the reception operation may include a strong reflection from the lower surface of the X-ray absorbent grating of the diffraction grating 56 (i.e., mismatch very strong impedance), it may be necessary to filter the echo signals to eliminate this artifact. For example, echo signals obtained using a water path can be stored in the series of filtering circuits and then subtracted from the echoes received by the ultrasonic transducer during actual operation. In addition, it should be understood that when using the
VBT suitable circuit set to control the activation of the ultrasonic transducer elements, only those transducer elements that correspond to a predetermined site can be activated. Thus, by using a biopsy needle holder, such as that shown in FIG. With a suitable mechanism for aligning the support with the ultrasonic transducer elements of interest, the medical specialist can perform a biopsy guided by the ultrasonic images, just as in the modality described in FIGS. 1-7. Now with reference to FIG. 12, another alternative embodiment of the sonomatography apparatus of the present invention is described. The sonomatography apparatus 70 includes the basic elements of a mammography system as described above, including the vertical column of
• j. "Ijr« rt ^ «« ^. Safci¿ £ afei &Aaa¡ < »Fafe_E -. . . t < < '? y4jMHa' 6a- support 71, the compression plate 72, the diffraction grating 73, "the support of the film 74 and the sensitive X-ray film 75, and the ultrasound transducer 76. In this embodiment, the plate The compression pad 72 does not need to be sonolucid, since the ultrasonic transducer 76 is placed between the compression plate and the diffraction grating.The gel pad 77 adhered to the compression plate 72 ensures the acoustic coupling of the ultrasound transducer 76 to the biological tissue 102. Unlike the gantry crane of the modality
# of the FIGS. 1-7, the ultrasound transducer 76 is installed on a horseshoe-shaped gantry crane 78, such that the transducer follows a curved path as it is traversed along the gantry crane 78. The ultrasound transducer 76 it moves in small angular increments, for example, from 1 to 3 degrees, when it traverses the length of the gantry crane 78. It will be recognized by those skilled in the art of ultrasonic transducer design that this third arrangement provides a greater depth for the penetration of acoustic energy in comparison with the modalities described in the foregoing. Consequently, it may be necessary to use lower frequency transducers for this modality than those that would be used in the modalities previously described. For more superficial injuries, however, it is expected that a high frequency transducer could provide satisfactory operation. * Now with reference to FIG. 13, the ultrasound circuit 80 is described to form the image of a tissue of the patient. The circuit 80 includes the ultrasonic transducer 81, a motor controller 82, a microprocessor 83 executed by the system computing program 83, a reception circuit 85, a transmit / receive switch 86, a driving circuit 87, an analog converter to digital or digital 88, the
# system storage 89 and display device 90. Transducer 81 receives energy by means of drive circuit 87 to output the ultrasonic signals. Once the transducer has emitted the acoustic energy for a suitable period, the transducer is switched to the reception mode. When the transducer 81 responds to echoes of the emitted signals, it generates electrical signals in the reception circuit 85. The reception circuit 85 preferably has a wide dynamic range, for example, 100 dB, to facilitate high definition of the contrast . Since the receiver circuit records the transmitted pulses as well as the return echoes, the first microseconds T0 corresponding to the time of flight from the surface of the transducer to the tissue are ignored. The receiver circuit 85 also includes an automatic preamplifier that can be adjusted to compensate for the attenuation of the return signal. The received signal is further amplified and processed by the receiver circuit 85 before being fed to the analog-to-digital converter circuit 88. The analog-to-digital converter transforms the analog electrical echo signals into digital signals. These digitally encoded ultrasound images are in turn stored in the storage device of the system 89. "9 The microprocessor 83 checks the motor controller 82, which in turn controls the movement of the ultrasonic transducer (e.g. the gantry crane 17 and the support of the gantry crane 18 in the embodiment of FIGS 1-7) and continuously calculates the position of the transducer 81. The digitized data corresponding to the site of the gantry crane at each site of the the ultrasound images are stored in the storage of the system 89 together with the ultrasound images in this site.Alternatively, because the digitized data gathered after each pulse is stored in the storage device of the system 89 in a form consecutive, and the propagation path for electronic or mechanical control may be predetermined, the
_s¿ * -a orientation and position of the transducer 81 can be correlated directly with the data site
• digitized stored in the storage of the system 89. It is known to use ultrasonic signals for the evaluation of the arrangement of the blood vessels in the tissue when calculating the frequency or temporal displacement due to the blood flow through the tissue represented. These systems, which are based on the Doppler principle, are described in Baker, "Pulse Ultrasound Doppler Blood Flow
* Sensing ", IEEE transactions on Sonics and Ultrasonics, Vol. SU-17, No. 3 (1970). The data related to blood flow can therefore also be acquired using the ultrasound transducer 81, whose data can be processed and stored in the storage of the system 89 together with the echo data.In addition, because the blood flow creates a streaked effect in the ultrasound images, it may be desirable to transmit different pulses in each image site and then u and then use standard techniques for noise reduction to averaging the effect of veining caused by blood flow Also, the variation in veining due to the movement of the transducer facilitates the different consecutive acquisitions of the return echo to make the average to reduce veining. The digital subtraction of the data received from a water path and more likely due to the repercussions could also n be subtracted from the digitized data to improve the ultrasound images. For an embodiment of the present invention such as that shown in FIGS. 9-11, the microprocessor 83 can control the sequential operation of the individual ultrasonic transducer elements 63 'of the two-dimensional ultrasonic transducer 57. The location of the ultrasound images in the storage system 89 can be
* used to correlate those images with specific sites in the alignment in phase, as described in the above. The program of the system 84, which can reside in a workstation based on a conventional microprocessor, enables the data stored in the storage device 89 to be handled in such a way that the holographic views can be generated and viewed. ^ from different angles. Furthermore, the program can facilitate the visualization of a particular region of interest determined in relation to the lines opaque to radiation (not shown in FIGS. 1 or 9) provided on the compression plate or according to the position of the pencil of the digitizing tablet, as described in the above with respect to FIG. 8. The images are displayed in a
^^ MilÉ I display device 90. The arrangement and operation of the apparatus of
> The sonomatography of the present invention is direct and can be executed by a single operator. The medical specialist or the operator places the breast for mammographic studies in the conventional way. After (or before) exposure to X-rays, the ultrasound transducer is activated to form the breast tissue image at different sites, storing those of ultrasound images for a review of the workstation. Since the views of the slices of the whole breast are stored, the resulting data can be handled, individually or in conjunction with a digitized X-ray image, according to the methods described below. The present invention further includes methods for obtaining a visualization of ultrasound images and an X-ray image / geometrically recorded ultrasound image of the biological tissue. A first method of obtaining an ultrasound image and the geometrically registered X-ray image comprises the steps of: (a) immobilizing the biological tissue with respect to a reference point; (b) Exposure of biological tissue to lightning
.? tf-Jtj "" * "- '• - - -»' * «• X to generate an X-ray film of the internal structure of the biological tissue; (c) Without the intervention of any movements of the biological tissue with respect to the reference point, the coupling of an ultrasonic transducer to the biological tissue to generate a plurality of ultrasound images of the biological tissue; and (d) The correlation of the plurality of ultrasound images with predetermined sites on the X-ray film. "Of course it will be understood that steps (b) and (c) of the exposure of tissue to X-ray radiation and The ultrasound scan can be easily exchanged when necessary in a particular application. The methods of the present invention also include the steps of processing, storing and handling ultrasound images to improve the diagnostic capabilities of stored images,
$ using, for example, noise filtering or digital subtraction techniques. With reference to FIGS. 1 and 14, a first method of displaying the stored ultrasound image data acquired with the apparatus of the present invention is described. As shown in the higher portion of FIG. 14, a three-dimensional coordinate system for the formation of the image 120, consisting of the directions X, Y, Z, can be imposed on the apparatus of FIG. 1 in such a way that the X-Y plane coincides with the surface of the lower compression plate 19, and the Z axis corresponds to the elevation. In the coordinate system 120, the ultrasonic transducer 16 provides an "A" image of the interior of the breast with the X-Z plane as it explores along the upper compression plate 15 in the C-D directions. When the ultrasonic transducer 16 moves in the directions A-B, it generates additional frames in the X-Z plane, indicated in FIG. 14 as "b" and "c". Since the views of the cuts in the X-Z plane are stored for the whole breast, it is possible to add each propagation line and obtain a two-dimensional projection map of the breast attenuation for use in breast cancer screening. In particular, according to a first method of the present invention, the data stored in each frame "a" through "c" shown in FIG.
* 14 can be added in the Z direction to provide a single line in the X-Y plane, in this way one of two-dimensional ultrasound images 121 is generated. By projecting the ultrasound data in the XZ plane into a single line in the XY plane to create an image 121, the tissue anomalies (indicated by the x in FIG.14) can be displayed in the same format as the conventional mammogram. digitized
-? atíS: -J ^^ JB »^. &9? & i i i go. . f, ",,. _ ... - > m ^ m. . " .Mr ?. "4 *% < & * £ & 122 obtained with the X-ray portion of the apparatus 10 as described above. When an ultrasound image 121 as obtained in the above is then superimposed on a digitized X-ray image 122, applicants have observed that the abnormalities in the tissue can be easily isolated and identified. In addition, applicants have observed that the color encoding the ultrasound image 121 and the X-ray image 122 accelerates this identification process. In another method according to the present invention, the views of the cuts "a" - "c" can also be displayed as a three-dimensional representation of a region of interest, for example, for use in Doppler analysis or data from the arrangement of blood vessels in the tissue. An alternate presentation of the data could consist of a loop of consecutive frames. Yet another method for visualizing and analyzing the data acquired with the apparatus of the present invention utilizes the principle that acoustic backscattering of tissue is a function of density and compressibility. Applicants have determined that there is a non-linear relationship with respect to compression for malignant tissue. In particular, applicants have discovered that tissue abnormalities tend to be more rigid and less comprehensible than in healthy tissue. This results
suggest that the detection of the tumor can be improved by the éSk compression of the breast tissue and the use of
^ Digital subtraction techniques to isolate dubious lesions. According to this method of the present invention, the tissue of the patient is first compressed using a compression plate 15 and a gel pad 23 with a first force F? . Then the ultrasonic transducer 16 is activated to generate a first
^ tissue scan and data are stored as
^^ describes in the above. The force applied to the patient's tissue is then changed to a new level F2, which can be larger or smaller than Flf and then a second ultrasound scan is performed and stored. The resulting data for the two compression levels are digitally subtracted, and the results are displayed in a three-dimensional or two-dimensional format as described above.
^ Applicants have observed that, because the
1 ^ lower compressibility of the lesions in relation to the healthy tissue, the lesions are well defined in the composite image. Still in accordance with another method of the present invention, knowledge of the relative position of a tissue segment in both breasts allows the user of digital subtraction techniques to utilize those of digitized ultrasound images to isolate suspicious lesions. For example, the pictures of ^^ ultrasound images of similar planes in both breasts can be subtracted in digital form and the difference in the intensities can be added. Based on the predetermined threshold, only images that are considered substantially different, using this test, are presented for review by the medical specialist. With respect to the gel pad 23 of the first embodiment described above, the present invention also comprises a method of improving the X-ray images obtained by the known X-ray equipment. previously, comprising the steps of: (a) immobilizing the biological tissue with respect to a reference point; (b) A gel pad is provided that fits the breast under study, the gel pad that has
-. an ability to attenuate X-rays similar to that of human tissue; (c) Exposure of the biological tissue to a single X-ray dosage to generate an X-ray film of the internal structure of the biological tissue that is substantially exposed to adequate and complete shape, even close to the external contours of the breast. It will be understood that the aforementioned is
; A ^ A ^ ás ^ x. - & ¡* * *
Claims (80)
- simply illustrative of the apparatus and methods of the present invention, and that the various modifications are • ^^ can be done by those skilled in the art without departing from the scope and spirit of the invention. CLAIMS: 1. In the apparatus for radiological imaging of biological tissue by passing X-ray radiation through a biological tissue to form an image on a receiver, the apparatus comprising an X-ray source for emitting radiation from rays. X, a superior compression surface and a lower compression surface adapted to immobilize the biological tissue therebetween, and a receiver disposed below the lower compression surface, the X-ray source disposed on the superior compression surface in such a way that the X-ray radiation emitted from the source passes through the biological tissue and is received by the receiver, the improvements include: a compression plate that is radiolucent and sonolucid, the compression plate has an upper surface and a lower surface, the lower surface forms the upper compression surface; an ultrasonic transducer disposed on the compression plate; an impelling means for moving the ultrasonic transducer along a predetermined path through the upper surface of the compression plate while the biological tissue remains immobilized between the compression surfaces, upper and lower, such that the ultrasonic transducer generates a plurality of ultrasound images of the biological tissue that are in geometric coincidence of the image formed in the receiver. The apparatus according to claim 1, characterized in that the compression plate contains a material selected from the group consisting of Kapton®, Surlyn® ionomer and a polymethyl pentene. 3. The apparatus according to claim 2, characterized in that the polymethyl pentene is TPX®. 4. The apparatus according to claim 2, characterized in that the material has a periphery and the material is coupled around the periphery of a rigid frame. The apparatus according to claim 1 characterized in that it further comprises a gel pad for the acoustic coupling of a portion of the biological tissue to the ultrasonic transducer. 6. The apparatus according to claim 5 characterized in that the biological tissue ^ ¡^ Has an attenuation characteristic of X-rays, the gel pad is disposed between the upper compression surface and the lower compression surface and in contact with the biological tissue, and the gel pad contains a material that fits to the shape of the biological tissue and has a characteristic of attenuation of X-rays close to the characteristic of attenuation of the X-rays of the biological tissue. The apparatus according to claim 6, characterized in that the gel pad reduces the dispersion of the X-ray radiation in relation to the dispersion of the X-ray radiation in the air. 8. The apparatus according to claim 5 characterized in that the biological tissue consists of the portion of a patient and has a non-uniform shape and a surface area, the compression plate imposes a force on the biological tissue to compress the biological tissue up to a uniform thickness, and the gel pad adapts to the non-uniform shape to distribute the force over the surface area and reduces the discomfort of the patient. The apparatus according to claim 8 characterized in that the gel pad contains an adherent surface that aids in the positioning of the biological tissue between the upper compression surface and the lower compression surface. 10. The apparatus according to claim 1, further comprising lubricating means for providing a fluid film between the ultrasonic transducer and the compression plate for acoustically lubricating and coupling the ultrasonic transducer to the compression plate. The apparatus according to claim 1 characterized in that the driving means further comprises: a gantry crane support; a movable gantry crane connected to the support of the gantry crane for movement in distal and proximal directions; a mobile carriage connected to the gantry crane for lateral movement. The apparatus according to claim 11 characterized in that the driving means further comprises: a first motorized cable arrangement for driving the gantry crane along the support of the gantry crane; a second arrangement of motorized cable to drive the car along the gantry crane; a set of circuits to control the operation of the first and second cable arrangement , r & r. motorized ^^ 13. The apparatus according to claim 1 further comprises: a holder for a biopsy instrument; means for aligning the support of the biopsy instrument with the ultrasonic transducer in such a way that the medical specialist can perform the biopsy guided by the plurality of ultrasonic images. ^ 14. In the apparatus for obtaining radiological images of the biological tissue by passing x-ray radiation through a biological tissue to form an image on a receiver, the apparatus comprises an X-ray source for emitting the radiation of X-rays, an upper compression surface and a lower compression surface adapted to immobilize the biological tissue therebetween, and a receiver disposed * below the lower compression surface, the X-ray source disposed on the < _f upper compression surface in such a way that the X-ray radiation emitted from the source passes through the biological tissue and is received by the receiver, the improvements include: an ultrasonic transducer disposed below the lower compression surface and acoustically coupled to this one to transmit the acoustic energy towards the tissue biological, the ultrasonic transducer is radiolucent and sonous; # a set of control circuits for activating the ultrasonic transducer to generate a plurality of ultrasound images of biological tissue while the biological tissue remains immobilized between the upper and lower compression surfaces, the plurality of ultrasound images of the biological tissue are found in geometric coincidence with the image formed in the receiver. 15. The apparatus in accordance with Claim 14 also contains a gel pad to acoustically couple a portion of the biological tissue to the ultrasonic transducer. 16. The apparatus according to claim 14 characterized in that the biological tissue has a characteristic of attenuation of X-rays, the gel pad is disposed between the upper compression surface and the lower compression surface and in contact with the biological tissue , and the gel pad contains a material that adapts to the shape of the biological tissue and has a characteristic of X-ray attenuation close to the characteristic of attenuation of the X-rays of the biological tissue. 17. The apparatus according to claim 16 characterized in that the gel pad . 4 reduces the dispersion of X-ray radiation with & relation to the dispersion * of the radiation of X-rays in the air. 18. The apparatus according to claim 14 characterized in that the biological tissue comprises a portion of a patient and has a non-uniform shape and a surface area, the upper and lower compression surfaces impose a force on the biological tissue to compress the biological tissue to a uniform thickness, and the gel pad adapts to the non-uniform shape to distribute the force over the surface area and reduces discomfort in the patient. 19. The apparatus according to claim 18, characterized in that the gel pad contains an adherent surface that aids in the positioning of the biological tissue between the upper compression surface and the lower compression surface. ^ 20. The apparatus according to claim 14 characterized in that the ultrasonic transducer comprises a multiplicity of piezoelectric transducer elements. 21. The apparatus according to claim 20, characterized in that the set of control circuits also contains a set of circuits for activating the predetermined multiplicity of piezoelectric transducer elements to provide a beam that forms a focus on raising the acoustic energy. • The apparatus according to claim 20 characterized in that the control circuitry contains a set of circuits to activate a predetermined plurality of the multiplicity of piezoelectric elements to generate an ultrasonic image at a predetermined site, the apparatus further contains: an instrument holder for biopsy; means for aligning the support of the biopsy instrument with the predetermined plurality of piezoelectric elements in such a way that the medical specialist can perform a biopsy guided by the ultrasonic image at a predetermined site. 23. In the apparatus for obtaining the radiological images of the biological tissue by passing the X-ray radiation through a biological tissue to form an image in a receiver, the apparatus comprises a source of # X-rays to emit X-ray radiation, an upper compression surface and a lower compression surface adapted to immobilize the biological tissue between them, and a receiver disposed below the lower compression surface, the X-ray source arranged on top the upper compression surface in such a way that the X-ray radiation emitted from the source passes through of the biological tissue and is received by the receiver, the improvements include: • an ultrasonic transducer disposed between the upper and lower compression surfaces; a driving means for moving the ultrasonic transducer along a predetermined path between the upper and lower compression surfaces while the biological tissue remains immobilized therebetween, such that the ultrasonic transducer generates a pluty of ultrasound images of the biological tissue that is $ find in geometric match with the image formed in the receiver. 24. The apparatus according to claim 23 further contains a gel pad for acoustically coupling a portion of the biological tissue to the ultrasonic transducer. 25. The apparatus according to claim 24 characterized in that the biological tissue has a characteristic of attenuation of X-rays, the gel pad is disposed between the upper compression surface and the lower compression surface and in contact with the biological tissue , and the gel pad contains a material that conforms to the shape of the biological tissue and has a characteristic of X-ray attenuation close to the characteristic of attenuation of the X-rays of the biological tissue. WF 26. The apparatus according to claim 25, characterized in that the gel pad reduces the scattering of X-ray radiation relative to the dispersion of X-ray radiation in the air. 27. The apparatus according to claim 24, characterized in that the biological tissue comprises a portion of a patient and has a non-invasive shape. -1 M uniform and a surface area, the upper and lower compression surfaces impose a force on the biological tissue to compress the biological tissue to a uniform thickness, and the gel pad adapts to the non-uniform shape to distribute the force over the surface area and reduces discomfort in the patient. 28. The apparatus according to claim 27 characterized in that the gel pad &L contains an adherent surface that aids in the placement of the biological tissue between the upper compression surface and the lower compression surface. 29. An apparatus for use with the conventional X-ray system to obtain radiological images of the biological tissue by passing X-ray radiation through a biological tissue to form an image on a receiver, the X-ray system includes a source to emit X-ray radiation, a superior compression surface ffa and a lower compression surface adapted to immobilize the biological tissue therebetween, and a receiver disposed below the lower compression surface, the source disposed on the surface of superior compression in such a way that the X-ray radiation emitted from the source passes through the biological tissue and is received by the receiver, the apparatus contains: a compression plate that is radiolucent and ^ t. Sonolúcida, the compression plate has a surface. . . . . . . r ^ upper and a lower surface, the lower surface forms the upper compression surface; an ultrasonic transducer disposed on the compression plate; a driving means for moving the ultrasonic transducer along a predetermined path through the upper surface of the compression plate while the biological tissue remains immobilized between the surfaces ^^ of upper and lower compression, in such a way that the ultrasonic transducer generates a plurality of ultrasound images of the biological tissue that are in geometrical coincidence with the image formed in the receiver. 30. The apparatus according to claim 29, characterized in that the compression plate contains a material selected from the group consisting of Kapton®, Surlyn® ionomer and a polymethyl pentene. 31. The apparatus according to claim 2, characterized in that the polymethyl pentene is PX®. 32. The apparatus according to claim 30, characterized in that the material has a periphery and the material is coupled around the periphery of a rigid frame. 33. The apparatus according to claim 29 further comprises a gel pad for acoustically coupling a portion of the biological tissue to an ultrasonic transducer. 34. The apparatus according to claim 33 characterized in that the biological tissue has a characteristic of attenuation of X-rays, the gel pad is disposed between the upper compression surface and the lower compression surface and in contact with the biological tissue , and the gel pad contains a material that conforms to the shape of the biological tissue and has a characteristic of X-ray attenuation close to the characteristic of attenuation of the X-rays of the biological tissue. 35. The apparatus according to claim 34, characterized in that the gel pad reduces the dispersion of the X-ray radiation relative to the dispersion of the X-ray radiation in the air. f > 36. The apparatus in accordance with ^^ claim 33 characterized in that the biological tissue consists of the portion of a patient and has a non-uniform shape and a surface area, the compression plate imposes a force on the biological tissue to compress the biological tissue to a uniform thickness, and The gel pad adapts to the non-uniform shape to distribute the force over the surface area and reduces discomfort in «^ _ The patient. 37. The apparatus according to claim 36, characterized in that the gel pad contains an adherent surface that aids in the placement of the biological tissue between the upper compression surface and the lower compression surface. 38. The apparatus according to claim 29 further contains a lubricating medium to provide a fluid film between the transducer Ultrasonic W and the compression plate to lubricate and acoustically couple the ultrasonic transducer to the compression plate. 39. The apparatus according to claim 29, characterized in that the driving means further comprises: a support of the gantry crane; _jéaaS¡fe? 3M & rf_. . . r -. »? , , To you. «« AtheiSaiBifaS: a mobile gantry crane connected to the support of the gantry crane for movement in directions # Distal and proximal; a mobile carriage connected to the gantry crane for lateral movement. 40. The apparatus according to claim 39 characterized in that the driving means further comprises: a first arrangement of motorized cable to drive the gantry crane along the support of the crane of «Portico; a second motorized cable arrangement to drive the car along the gantry crane; and a set of circuits for controlling the operation of the first and second arrangement of motorized cables. 41. The apparatus according to claim 29 further comprises: a holder for a biopsy instrument; means for aligning the support for biopsy instruments with the ultrasonic transducer in such a way that the medical specialist can perform the biopsy guided by the plurality of ultrasonic images. 42. An apparatus for use with the conventional X-ray system to obtain radiological images of biological tissue by passing X-ray radiation through a biological tissue to form an image on a receiver, the X-ray system includes a source for emitting X-ray radiation, an upper compression surface and a lower compression surface between which the biological tissue is immobilized, and a receiver disposed below the lower compression surface, the source arranged on the upper compression surface in such a way that the X-ray radiation emitted from the source passes through the biological tissue and is received by the receiver, the apparatus contains: an ultrasonic transducer disposed below the lower compression surface and acoustically coupled to it to transmit the acoustic energy to the biological tissue, the ultrasonic transducer is radiolucent and sonolucid; a set of control circuits 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, the plurality of ultrasound images of the biological tissue being found in geometric match with the image formed in the receiver. 43. The apparatus according to claim 42 further contains a gel pad for acoustically coupling a portion of the biological tissue towards SP the ultrasonic transducer. 44. The apparatus according to claim 43 characterized in that the biological tissue has a characteristic of attenuation of X-rays, the gel pad is disposed between the upper compression surface and the lower compression surface and in contact with the biological tissue , and the gel pad contains a material that adapts to the shape of the fabric ^ s = L biological and has an attenuation characteristic of x-rays close to the characteristic of attenuation of the X-rays of biological tissue. 45. The apparatus according to claim 44, characterized in that the gel pad reduces the scattering of X-ray radiation in relation to the dispersion of X-ray radiation in the air. 46. The apparatus according to claim 43 characterized in that the biological tissue comprises a portion of a patient and has a non-uniform shape and a surface area, the upper and lower compression surfaces impose a force on the biological tissue to compress the biological tissue to a uniform thickness, and the gel pad adapts to the non-uniform shape to distribute the force over the surface area and reduces discomfort in the patient. 47. The apparatus according to claim 46, characterized in that the gel pad contains an adherent surface that aids in the positioning of the biological tissue between the upper compression surface and the lower compression surface. 48. The apparatus according to claim 43 characterized in that the ultrasonic transducer contains a multiplicity of piezoelectric transducer elements. ^ P 49. The apparatus according to claim 48 characterized in that the control circuitry further contains a set of circuits for activating the predetermined multiplicity of piezoelectric transducer elements to provide a beam that forms a focus in elevation of the acoustic energy 50. The apparatus according to claim 48 characterized in that the control circuitry contains a set of circuits for activating a predetermined plurality of the multiplicity of piezoelectric elements to generate an ultrasonic image at a predetermined location, the apparatus further contains: a support for biopsy instruments; means for aligning the biopsy instrument holder with the predetermined plurality of piezoelectric elements in such a way that the medical specialist can perform a biopsy guided by the ultrasonic image at a predetermined site. 51. The apparatus for use with a conventional X-ray system to obtain radiological images of biological tissue by passing X-ray radiation through a biological tissue to form an image on a receiver, the X-ray system has a X-ray source for emitting X-ray radiation, an upper compression surface and a lower compression surface between which the biological tissue is immobilized, and a receiver disposed below the lower compression surface, the source disposed on the surface With a higher compression ratio such that the X-ray radiation emitted from the source passes through the biological tissue and is received by the receiver, the apparatus contains: an ultrasonic transducer disposed between the upper and lower compression surfaces; a driving means for moving the ultrasonic transducer along a predetermined path between the upper and lower compression surfaces while the biological tissue remains immobilized therebetween, such that the ultrasonic transducer generates a plurality of ultrasound images of the biological tissue that is .., , TO ?? Item . tfek »are in geometric coincidence with the image formed in the receiver. 52. The apparatus according to claim 51 further contains a gel pad for acoustically coupling a portion of the biological tissue to the ultrasonic transducer. 53. The apparatus according to claim 52 characterized in that the biological tissue has a characteristic of attenuation of X-rays, the gel pad is disposed between the upper compression surface and the lower compression surface and in contact with the biological tissue, and the gel pad contains a material that conforms to the shape of the biological tissue and has a dimming characteristic of the X-rays close to the characteristic of attenuation of the X-rays of the biological tissue. 54. The apparatus according to claim 53, characterized in that the gel pad reduces the scattering of the X-ray radiation relative to the dispersion of the X-ray radiation in the air. 55. The apparatus according to claim 52 characterized in that the biological tissue comprises a portion of a patient and has a non-uniform shape and a surface area, the surfaces of -. Upper and lower compression impose a force on the biological tissue to compress the biological tissue to a uniform thickness, and the gel pad adapts to the non-uniform shape to distribute the force over the surface area and reduce discomfort in the patient. 56. The apparatus according to claim 55, characterized in that the gel pad contains an adherent surface that aids in the positioning of the biological tissue between the upper compression surface and the lower compression surface. 57. An apparatus for use with the conventional X-ray system to obtain radiological images of the biological tissue by passing X-ray radiation through a biological tissue to form an image in a receptor, the biological tissue has a characteristic of attenuation of X-rays, the X-ray system includes a source for emitting X-ray radiation, an upper compression surface and a lower compression surface adapted to immobilize the biological tissue between them, and a receiver disposed below the surface of the lower compression, the source disposed on the upper compression surface in such a way that the X-ray radiation emitted from the source passes through the biological tissue and is received by the receiver, the apparatus contains: a gel pad disposed between the superior compression surface and the surface of inferior compression and in contact with the biological tissue, the The gel pad contains a material that adapts to the shape of the biological tissue, the gel pad has a characteristic of X-ray attenuation close to the attenuation characteristic of the biological tissue. 58. The apparatus according to claim 57, characterized in that the gel pad reduces the dispersion of the X-ray radiation with respect to the dispersion of the X-ray radiation in the air. ^^ 59. The apparatus according to claim 57 characterized in that the biological tissue consists of the portion of a patient and has a non-uniform shape and a surface area, the superior compression surface imposes a force on the biological tissue to compress the biological tissue to a uniform thickness, and the gel pad distributes the force over the surface area and reduces the discomfort in the patient. * r 60. The apparatus according to claim 59, characterized in that the gel pad contains an adherent surface that aids in the placement of the biological tissue between the upper compression surface and the lower compression surface. 61. A method for obtaining an X-ray image and a geometrically coincident ultrasound image, which ^^ - s ^ tí ^ í comprises a series of stages of: ¿fo ^ * immobilization of biological tissue with respect to ^^ a point of reference; exposing biological tissue to X-ray radiation to generate an X-ray image of the biological tissue in a recipient; generation of a plurality of ultrasound images of the biological tissue by acoustically coupling an ultrasonic transducer to the biological tissue, without the intervention of the movement of the biological tissue with respect to ^ to the reference point; and displaying one of a plurality of ultrasound images that correspond to a predetermined site on the X-ray image. 62. The apparatus according to claim 61, characterized in that the step of exposing the biological tissue to the radiation of the X-rays. is done after the stage of making a F0 plurality of ultrasound images. 63. The method according to claim 61 further comprises the steps of: generating and repeatedly displaying a plurality of ultrasound images based on time; insert a biopsy instrument into the biological tissue in such a way that a portion of the instrument for - $ & - - * -% £! biopsy is visible in the plurality of ultrasound images; and% driving the biopsy instrument to a desired site within the biological tissue based on the X-ray image and the plurality of ultrasound images. 64. The method according to claim 61 further comprises the steps of: storing the plurality of ultrasound images in a storage medium; and recovering one of the plurality of ultrasound images from the storage medium corresponding to a predetermined site on the X-ray image. 65. The method according to claim 61 further comprises the step of processing the plurality of ultrasound images to improve the diagnostic capabilities of these images. 66. The method according to claim 61 further comprises the step of: repeatedly making and displaying a plurality of ultrasound images based on time, at a site of the biological tissue; processing of the plurality of ultrasound images on the site to provide a corresponding indicator of blood flow. 67. The method according to claim jjt 61 further comprises the steps of: making a plurality of Doppler signals for the biological tissue by acoustically coupling an ultrasonic transducer to the biological tissue, without the intervention of biological tissue movement with respect to the reference point; and displaying an indicator corresponding to the plurality of Doppler signals for a predetermined site on the X-ray image. 68. A method for obtaining an ultrasound image of the interior characteristics of a biological tissue, comprising a series of stages: immobilization of the biological tissue with respect to a reference point; elaboration of a plurality of ultrasound images of the biological tissue with respect to the point of # reference when acoustically coupling an ultrasonic transducer to the biological tissue; storage of the plurality of ultrasound images in a storage medium; displaying the selected images of the plurality of ultrasound images to provide a holographic view of the interior characteristics of the biological tissue. 69. The method in accordance with the claim 68 characterized in that the ultrasonic transducer has a surface in an XY plane and each of the ultrasound images contains a multiplicity of digitally encoded data values obtained at a multiplicity of planes along the Z axis orthogonal to the XY plane, the method further comprises the steps of: adding the multiplicity of digitally encoded data values along the Z axis to generate a projection of the plurality of ultrasound images in the XY plane; and display the projection. 70. The method according to the claim 69 further comprises a series of steps of: exposing the biological tissue to the X-ray radiation to generate an X-ray image of the biological tissue in. a receiver 'with respect to a reference point; and comparing the X-ray image with the projection to isolate the selected images from the interior characteristics of the biological tissue. 71. The method of compliance with the claim 70 characterized in that the X-ray image and the projection are color coded. 72. The method according to claim 70, characterized in that the step of exposing the biological tissue to the X-ray radiation is carried out before the step of generating a plurality of ultrasound images. 73. The method according to claim 68 further comprises the steps of: generating and repeatedly displaying the plurality of ultrasound images based on time; insert a biopsy instrument into the biological tissue in such a way that a portion of the instrument for ^ Biopsy is visible in the plurality of ultrasound images; and manipulating the biopsy instrument to a desired site within the biological tissue based on the display of the selected images of the plurality of ultrasound images. 74. The method according to claim 68 further comprises the steps of: repeatedly making and displaying a plurality of ultrasound images based on time, at a biological tissue site; processing of the plurality of ultrasound images on the site to provide a corresponding indicator of blood flow at this site. 75. The method of compliance with the claim 68 also includes the steps of: i generation of a plurality of Doppler signals for the biological tissue by acoustically coupling an ultrasonic transducer to the biological tissue, without the intervention of movement of the biological tissue with respect to the reference point; and displaying an indicator corresponding to the plurality of the Doppler signals. 76. A method of obtaining the ultrasound image of a biological tissue to explore tissue abnormalities, comprising a series of steps of: immobilization of the biological tissue with respect to a reference point; application of a first comprehensive charge to the biological tissue; generating a plurality of digitally encoded ultrasound images of the biological tissue with respect to the reference point by acoustically coupling an ultrasonic transducer to the biological tissue; storage of the first plurality of digitally encoded ultrasound images; application of a second comprehensive load to the biological tissue, the second comprehensive load different from the first comprehensive load; generation of a second plurality of digitally encoded ultrasound images of the biological tissue with respect to the reference point by acoustically coupling an ultrasonic transducer to the biological tissue digital subtraction of each of the second plurality of digitally encoded ultrasound images from an image that corresponds to the first plurality of digitally encoded ultrasound images with respect to the reference point; and displaying the difference of the first and second digitally encoded ultrasound images. 77. The method according to claim 75, characterized in that the first and second pluralities of digitally encoded ultrasound images are color coded. 78. A method of examining breast tissue to look for abnormalities in the tissue, comprising a series of stages of immobilization of a first breast with respect to a reference point; generating a first plurality of digitally encoded ultrasound images with respect to the reference point by acoustically coupling an ultrasound transducer to the first breast; storage of the first plurality of digitally encoded ultrasound images; immobilization of the second breast with respect to the reference point; generating a second plurality of digitally encoded ultrasound images with respect to the reference point by acoustically coupling an ultrasonic transducer to the second breast; subtraction in digital form of each is the second plurality of digitally encoded ultrasound images from an image corresponding to the first plurality of ultrasound images digitally encoded with respect to the reference point; display of the difference of the first and second digitally encoded ultrasound images. 79. The method according to claim 75 characterized in that the first and second plurality of digitally encoded ultrasound images are color coded. JSk 80. A method for obtaining an X-ray image of the biological tissue, the biological tissue having a shape with a periphery and an ability to attenuate the X-rays, the method comprises a series of steps of: (a) immobilization of the biological tissue with respect to a reference point; (b) providing a gel pad that conforms to the shape of the biological tissue, the gel pad has an ability to attenuate X-rays similar to the ability to attenuate the X-rays of biological tissue; (c) exposure of the biological tissue and the gel pad to a single dose of X-rays to generate the X-ray image, the X-ray image that is substantially and completely exposed adequately, even near the periphery. In testimony of which, I sign the present in this city of Mexico, Federal District, on the twenty-eighth day of October one thousand nine hundred and ninety four. Lie Julio Javier Cristian Representative. F
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US08145958 | 1993-10-29 | ||
| US08277894 | 1994-07-20 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| MXPA94008375A true MXPA94008375A (en) | 2002-07-25 |
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