Breast Holder For Mammograph

Abstract

An apparatus for holding a female breast immobilized extended away from the chest cavity and flattened to allow examination by passing radiation through the breast. Two flexible sheets transparent to radiation are drawn together on the breast under examination by an apparatus which provides for controlling the angle between the two sheets.

Description

BACKGROUND OF THE INVENTION

This invention is related to female breast examination and more specifically to apparatus for holding a breast during radiation examination thereof.

During radiation examination of a breast for an internal abnormal growth such as cancerous tissue, some means is required for holding the breast immobilized while radiation is applied. Mammograph equipment which utilizes compressional wave energy in the ultrasonic range as the radiation passes through the breast under examination is fully described in the copending application by Byron B. Brenden entitled "Improved Ultrasonic Imaging Technique and Mammograph Equipment," Ser. No. 736,260 filed May 20, 1968, commonly assigned with the present application.

For best results, the breast should be immobilized so that it is not moved during such a radiation examination. Furthermore, the breast should be held away from the woman's chest cavity, a requirement especially important in ultrasonic mammograph equipment. Also, the breast should be flattened somewhat.

It is desirable that the breast be so held without severe discomfort to the woman patient. Also, the breast holder should not substantially attenuate the radiation passing through the breast or otherwise interfere with the examination. Furthermore, a breast holder must be effective for a large variety of breast sizes.

SUMMARY OF THE INVENTION

These desirable characteristics and objects of this invention are accomplished by an apparatus which includes two flexible sheets transparent to the examining radiation with means to draw the sheets together from either side of a breast under examination and further having means to control the angle between the sheets as they are so drawn together so that the breast may be first compressed near the chest cavity and then placed under substantially even compression.

Although the scope of this invention is defined in the appended claims, the following detailed description taken in light of the accompanying drawings is intended to aid an understanding of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates ultrasonic mammograph equipment in which the apparatus of the present invention may be utilized;

FIG. 2 illustrates a patient supporting surface for the ultrasonic mammograph equipment of FIG. 1 which may be used in conjunction with the breast holding apparatus of this invention; and

FIG. 3 shows a preferred embodiment of the breast holding apparatus of this invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT

There are several techniques for imaging the internal structure of a breast for medical diagnosis of abnormal growths therein, such as cancerous tissues. Passing X-rays through the breast give information of the density variations within the breast. Pulse-echo ultrasonic techniques will detect substantial variations in internal structure. The ultrasonic method of Byron B. Brenden as disclosed in the aforementioned copending application teaches passing a beam of ultrasonic energy through the breast to image density and molecular binding variations therein with greater detail than before. This method is disclosed with reference to FIG. 1 as one example of a use for the breast holder of this invention.

Since ultrasound is heavily attenuated in a gas such as air and is further heavily reflected when passing from air to a solid object, a female breast is best imaged by submersing it in an ultrasonic transmitting liquid medium of high efficiency. This medium should be compatible with the female breast so that no more than a small proportion of energy will be reflected as the ultrasound passes from the liquid medium to the breast and through to the liquid medium again. It has been found that water is quite satisfactory and, of course, available in large quantities and is further comfortable for the patient. To avoid having to submerse more of the patient in the water than the breast under examination, it has been found preferable to position the woman in a horizontal position and extend the breast under examination down through a top surface of the water and pass the ultrasonic energy beam substantially parallel to and immediately below the water surface through the breast.

FIG. 1 illustrates this preferred technique. A tank 200 contains an ultrasonic transmitting water 202 and a woman 204 is held in a prone position over the tank by a supporting surface 206. A breast 207 under examination is suspended into the water 202 through an opening in the supporting surface 206. A quartz transducer 208 held in place by a housing 210 is a preferred source of a substantially plane wave ultrasonic beam 212 which is propagated through the water 202 to the breast 207. The ultrasonic wavefront passing through the breast is imaged by an ultrasonic lens 213 onto an ultrasonic detector such as the area detector 214 which is shown to be of a type such as a Pohlman cell. A light source 216 illuminates the observer's side of the area detector 214, thereby displaying in the optical domain a representation of the ultrasonic wavefront which has passed out of the breast 207.

A primary consideration in the configuration shown in FIG. 1 is to allow room for the transducer housing 210 above a surface 218 of water filled container 200 which then permits the ultrasonic energy beam 212 to be propagated very close to the surface 218 and thus image a large portion of the breast 207 without having to immerse any more of the woman in the water. To allow as much of the breast 207 as possible to be placed into the liquid 202, the supporting surface 206 has been sloped from both directions to the breast opening.

A preferred range of frequencies of the ultrasonic energy beam 212 has been found to be between 1 and 10 Megahertz (MHz.). Below 1 MHz., resolution has been found to be inferior, and above 10 MHz., has been found to be preferred for breast examination. The transducer 208 is preferably an X-cut quartz crystal with a 1 MHz. fundamental frequency which is operated at 3 MHz. by a power supply at that frequency, according to well-known techniques. The power supply equipment could be housed within the examination equipment next to the tank 200 in an area 230 of FIG. 1.

The technique of ultrasonic imaging as described with respect to FIG. 1 provides for real time examination of a breast. This has the advantage that the breast may be properly positioned and flattened and other parts of the apparatus adjusted, such as the ultrasonic lens 213, in order to give a good image that is of value for medical diagnostic work.

A preferred female patient support surface and the breast holder of this invention are shown in FIGS. 2 and 3. A patient support surface 300 of FIG. 2 has a depressed surface area 302 for allowing the patient's chest cavity of her body to be placed close to the liquid medium below and her breast placed in the liquid through an opening 306. A further depression 304 in the depressed surface 302 is designed for the patient's right shoulder so that she may lie slightly on her right side and thereby cause her rib cage to contact the edges of the opening 306 for most of the breast's perimeter. This firm contact is necessary to prevent the breast from slipping up and out of the holder below. In a similar manner, another surface depression 308 is provided for the female patient's left shoulder to facilitate placing her left breast as far through the opening 306 as is possible without slipping out of the holder.

Surrounding the opening 306 on the underneath of the support surface 300 is a preferred embodiment of the breast holder of this invention which can be seen in detail by reference to FIG. 3. A boxlike frame 310 has as one end thereof a U-shaped support plate 312 which holds a thin membrane 314 in tension. The membrane 314 is preferably a polymeric film such as polyester, polyethylene or polypropylene, and should be substantially transparent to the ultrasonic wavelength used. A second U-shaped support plate 316 holds a similar membrane 318 in a stressed condition. The support plate 316 is placed within the frame 310 to form a breast cavity between the membranes 314 and 318. The support plate 316 further has cylindrical guide members 320 and 322 attached to the opposite sides thereof. These cylindrical members are mounted within guide slots 324 and 326 of opposite generally parallel sides of the frame 310 in a manner so that the support plate 316 may be rotated about the axial center line common to the cylindrical members 320 and 322 and further to be slideable along the two guide slots 324 and 326. The guide slots 324 and 326 are generally perpendicular to the support plate 312.

The support plate 316 is resiliently held away from the support plate 312 by a spring 327 connected between the cylindrical member 320 and the underside of the support surface 300, and a second spring (not shown) between the cylindrical member 322 and the support surface 300. When a breast is positioned between the membranes 314 and 318, the support plate 316 is drawn toward the support plate 312, thereby placing the breast under compression. This movement is made by operating a control knob 332 which is operably connected through a control gear box 335 with the upper side of the U-shaped plate 316 by means of ropes 328 and 330. Similarly, motion from the turning of a control knob 334 is communicated to the bottom edge of the U-shaped plate 316 by ropes 331 and 333 through the control gear box 335. Several pulleys are shown over which these four ropes move between the support plate 316 and the gear control box 335.

To operate the breast holder, movement is applied to the ropes 328 and 330 initially to pull the top edge of the membrane 318 against the breast, thereby to hold the breast away from the chest cavity and without slipping out of the holder when the rest of the breast is placed under compression. Motion is then applied to the ropes 331 and 333 to pull the bottom portion of the membrane 318 against the breast to hold it at approximately uniform thickness over the area through which ultrasound is projected.

The membranes 314 and 318 have beads 315 and 319, respectively, along their open edges for contacting and conforming to the varied curves of the chest wall. These beaded edges are held taut to increase the initial pinch effect which prevents the breast from creeping up and out of the holder.

When the breast is so immobilized, ultrasonic energy is passed through the breast and its two surrounding membranes 314 and 318 without passing through the rib cage and is then imaged onto an area detector as hereinabove described. When the examination is complete, the support plate 316 is released from compression. This may be accomplished by some mechanism within the control gear box 335 to release tension on the ropes.

It shall be understood that the invention described herein is not limited to the specific arrangements shown and that changes and modifications may be made within the scope of the appended claims.

Claims

I claim:

1. Apparatus for holding a breast of a female in a flattened position away from her body, comprising:

a frame including at least two opposite generally parallel sides supported in a fixed spatial relationship with each other;

a first U-shaped plate held between the sides of said frame and generally perpendicular thereto, said first plate oriented to open upward and having a flexible membrane held in tension thereby, said membrane being substantially transparent to compressional wave radiation in at least the ultrasonic range;

a guide slot in each of said opposing frame members generally perpendicular to said first plate, said slots being substantially parallel with each other;

a second U-shaped plate having outwardly extending guide members on opposite sides thereof, said guide members mounted in said guide slots to hold said second plate rotatably and slidably between said frame sides, said second plate oriented to open upward and having a flexible membrane held in tension thereby, said membrane being substantially transparent to compressional wave radiation in at least the ultrasonic range; and

means for drawing said second U-shaped plate relative to said frame sides toward said first U-shaped plate in a manner that said second U-shaped plate may be rotated about an axis joining its guide members while being moved toward the first U-shaped plate.

2. Apparatus according to claim 1 wherein said flexible membranes are made of a polymeric film material.

3. Apparatus according to claim 1 wherein said means for drawing said second plate toward the first plate includes a first means operably connected to the second plate on one side of the axis joining its guide members and a second means independent of said first means operably connected to the second plate on an opposite side of the axis joining its guide members.

4. A female patient supporting table for compressional wave energy diagnostic examination of a female breast, comprising:

an open top tank adapted to contain a compressional wave energy transmitting liquid;

a rigid generally horizontal patient supporting member positioned over said tank and having a patient supporting surface on an upper side with an underneath side acting as a cover to said tank;

an opening through said supporting member adapted to accommodate a breast of a female patient lying on said table surface, said opening being surrounded by an area of said supporting surface that slopes gently toward the opening thereby to depress said opening somewhat into said tank;

a pair of surface depressions in the sloping area of the supporting surface on either side of said opening, each depression shaped to accommodate a shoulder of the patient, whereby a female patient lying partially on her side may engage one of said shoulder depressions to completely insert a breast into said tank through said opening;

a pair of flexible membranes in tension held by the underneath side of said patient supporting membrane and positioned within said tank on opposite sides of said opening, said membranes being substantially transparent to compressional wave radiation in at least the ultrasonic range and shaped to accommodate the female breast in compression therebetween; and

means for drawing at least one of said membranes relative to the patient supporting member toward the other membrane, including means for tilting at least one of said sheets relative to the patient supporting member as they are drawn together.

5. The female patient supporting table according to claim 4 wherein each of said flexible membranes is held stretched across a rigid U-shaped frame opening upward.

6. The female patient supporting table according to claim 5 wherein said flexible membranes are made of a polymeric film material.