Apparatus And Method For Processing Flexible Medical Slides

Abstract

A medical specimen, such as a Pap smear, blood or bacteria sample, is placed on a thin transparent flexible slide which is transmitted to a processing laboratory. At the laboratory, the slides, in accordance with illustrative embodiments of my invention, are affixed to one another or to an elongated flexible carrier means and then wound on a reel. A plurality of such reels are typically loaded on top of one another into a vertical processing tank which is filled sequentially with chemicals and stains as required. Subsequently, the reel is removed from the tank and the slides are microscopically screened to detect diseases such as cancer and the like.

Description

BACKGROUND OF THE INVENTION

This invention relates to the processing of medical specimens and, more particularly, to apparatus and techniques for analyzing Pap smears.

In the United States alone Papanicolaou ("Pap") smears are being performed by physicians in their own offices, as well as in clinics and hospitals, in increasing numbers each year, currently estimated to be several million annually. The Pap smear is utilized in the diagnosis of suspected disease, especially cancer, as well as for routine screening of asymptomatic patients. Most often the smear is a vaginal specimen taken for the detection of cancer of the uterus; less frequently specimens of sputum are taken for the detection of lung cancer or body fluid specimens for the detection of metastatic cancer. In addition, examination of such specimens is useful not only for the detection of cancer but also for the diagnosis of various infections and inflammations.

For the past few decades the principal smear technique has been for a physician to place a swab or scraping of cellular material obtained from the anatomical site of examination on a pair of transparent glass slides each typically about one by three inches in size. Once placed on the slides, the specimens are promptly fixed in a chemical solution, usually alcohol or alcohol-ether, to prevent cellular degradation thereof. Before mailing the slides to a processing laboratory, the physician or his assistant inserts each pair of glass slides into a cardboard folder or plastic case, which in turn is placed in a special mailer, to protect the fragile glass from breakage. It has been a problem that this form of protection of the glass slides is expensive both in terms of the cost of the plastic cases or cardboard folders as well as in terms of the cost of postage arising from their bulk and the need for special mailers.

When received by the processing laboratory, the slides are stained and then covered with a thin piece of glass (termed a coverslip or coverglass) with an intervening drop of transparent glue-like material (termed a mounting medium) which dries and hardens in several hours. This coverslipping procedure protects the surface of the slide and prevents the stained material from being scratched or wiped away inadvertently during subsequent microscopic examination or filing in storage cabinets. After coverslipping, the slides are screened microscopically by trained cytotechnologists under the supervision of a pathologist who checks suspicious or unusual smears. While various methods for automated cytologic screening have been proposed, none are now clinically useful, which leaves the screening task to be manually performed by the approximately 2,500 certified cytotechnologists in the United States. In present staining techniques, the glass slides are inserted into a glass or metal rack that may hold up to 50 slides. The rack is then moved sequentially in accordance with a prearranged time schedule into a series of rectangular dishes that each contain various specific chemicals and stains. A technician with more than fifty slides to process, however, has to repeat the entire staining procedure for each batch by this method, a time consuming and expensive approach when one considers the millions of slides processed annually. One further problem arises because glass slides are frequently chipped or broken in the laboratory where frequent handling subjects them to a serious risk of being dropped. Often, too, the glass slides are broken or totally shattered when sent to the laboratory via the mail notwithstanding the use of the aforementioned protective covers. The dangers to the technician from slivers of broken glass are of course, self evident. In addition, however, damaged slides result in enormous inconvenience, as well as wasted time and increased expense, to both the physician and the processing laboratory, requiring the patient to return to the physician for the Pap smear to be repeated.

Finally, the bulk of glass slides takes its toll in terms of a costly storage problem arising from the need for numerous slide file cabinets in the processing laboratory.

It is therefore an important object of my invention to increase significantly the number of medical slides which can be processed in a single staining run.

It is another object of my invention to provide a flexible, transparent medical slide which is both inexpensive to fabricate and highly durable.

It is another object of my invention to eliminate the aforementioned coverslipping procedure.

It is still another object of my invention to virtually eliminate the incidence of breakage of slides which occurs both in the mailing thereof and in the processing laboratory, and hence eliminate the attendant loss of time and increased expense.

It is yet another object of my invention to reduce the amount of space required to store medical slides.

It is another object of my invention to reduce significantly the costs of mailing medical slides to a processing laboratory.

SUMMARY OF THE INVENTION

These and other objects are accomplished in accordance with an illustrative embodiment of my invention, apparatus and method for preparing and processing Pap smears and the like. In accordance with an illustrative embodiment of my invention, a swab or scraping obtained from the anatomical examination site is placed on a chemically resistant, transparent flexible slide which is promptly fixed in the same kind of chemical solution in use today. Illustratively fabricated from a flexible plastic such as mylar, the slide due to its durability, thinness and light weight may be readily inserted into an ordinary envelope rather than a more expensive mailer required to handle the bulky prior art protection covers. Consequently, the cost of such expensive mailers and covers is eliminated and it is estimated that the smaller bulk and weight of thin plastic slides will reduce postage costs to about one fourth of the present costs. Optionally, the flexible slide may be provided with a frosted or opaque area, typically a frosted border, on which identifying indicia may be written. In addition, the transparent area of the slide may be subdivided by permanently defined lines (as by inscribing) to reverse areas prelabeled for specimens obtained from different anatomical sites, e.g., cervix, endocervix, vagina.

Once the flexible slides are received by the processing laboratory, important savings in both laboratory working space and personnel time are attained in accordance with a further aspect of my invention. In one embodiment, slides to be processed are affixed to elongated chemically resistant, flexible carrier means, typically one or more adhesive tapes, which is then wound on a chemically resistant reel. Alternatively, the carrier means may comprise a single elongated strip having a plurality of slits or pockets adapted to receive the corners of the slides. Furthermore, separate carrier means may be eliminated altogether by providing each slide with at least one adhesive edge which is made to overlap the adjacent edge of an adjacent slide. The slides, thus arranged in side-by-side fashion with overlapping adjacent edges adhered together, form an elongated strip-like structure which is wound directly on a reel.

A plurality of such reels may be loaded on top of one another into a vertical processing tank, using the same chemicals and stains as for glass slides, so that many hundreds of slides are processed simultaneously in a single tank. If work loads are lighter, however, fewer reels may be used or fewer slides on each reel. My technique permits all of the chemical and staining processes to be carried out in a single tank which may be sequentially filled from stock bottles of the respective stains and chemicals, and furthermore is readily adapted for use in automatic processing equipment. In contrast, the prior art method of carrying glass slides in racks requires that about twenty-four or more staining dishes permanently occupy a laboratory desk top, a cumbersome space-consuming and time-consuming approach to slide processing.

Additional advantages of my invention resulting primarily from the use of thin, flexible slides, include elimination of coverslipping procedures, elimination of breakage in the mail and in the laboratory; and reduction of costly storage space in laboratory file cabinets -- it is estimated that about two to three times as many thin plastic slides can be filed in a given slide file cabinet as compared to the prior art glass slides.

BRIEF DESCRIPTION OF THE DRAWING

The above and other objects of my invention, together with its various features and advantages, can be easily understood from the following more detailed discussion, taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a top view of an illustrative thin flexible slide for use in practicing my invention;

FIG. 2A is a schematic showing a plurality of such flexible slides affixed to illustrative carrier means comprising an elongated adhesive strip;

FIG. 2B is a schematic showing a plurality of such flexible slides affixed to illustrative carrier means comprising a pair of elongated adhesive tapes;

FIG. 2C is a schematic showing a plurality of such flexible slides affixed to illustrative carrier means comprising an elongated strip having a plurality of slits or pockets therein;

FIG. 2D is a schematic of a plurality of slides having adjacent edges adhesively affixed to one another to form a strip of slides without need for separate carrier means; and

FIG. 3 is a partially cut away isometric view of an illustrative processing tank for use in practicing my invention.

DETAILED DESCRIPTION

Turning now to FIG. 1, there is shown a medical slide 10 fabricated from a thin transparent flexible material, typically a plastic such as mylar. Illustratively, the slide 10 is rectangular in shape measuring about 1 .times. 3 inches and may optionally be provided with a frosted or opaqued border 12 on which is written identifying indicia such as the patient's name and laboratory number. Moreover, the transparent interior area 14 may be subdivided by permanently defined lines 16 and 18, typically inscribed, to reserve a plurality of separate regions prelabeled for cellular material obtained from specific anatomical sites. By way of example only, three such regions labeled cervix, endocervix and vagina are shown.

After obtaining a specimen of cellular material from one or more of these sites, a physician places a swab or scraping thereof onto the correspondingly labeled transparent region of flexible slide 10 upon which a patient's name is, or already has been, written. In accordance with well known technieqes the cellular material is then fixed by immersing the slide in an appropriate chemical solution such as alcohol or alcohol ether. Of course, the mylar or other plastic material making up slide 10 must be resistant to the chemicals in the fixing solution. After fixation of the slides is completed, the physician or his assistant inserts the flexible slide into an ordinary envelope and mails same to a processing laboratory with the assurance that the slide will not be accidently broken or shattered in transit.

In accordance with one embodiment of my invention, at the processing laboratory technicians or other personnel affix the flexible slides 10 to elongated carrier means which illustratively comprises an elongated transparent tape 20a having an adhesive coating on one side thereof. Alternatively, each slide may be provided on its back side with an adhesive, preferably in the area of border 12 only, in which case the adhesive coating on carrier member 20a may be omitted.

Other illustrative carrier means are shown in FIGS. 2B and 2C. In the former, the carrier means comprises a pair of parallel adhesive tapes 20b across which opposite edges of the slides 10 are adhered in a side-by-side fashion. In the latter, the carrier means comprises an elongated strip 20c having a plurality of groups of four slits or pockets 21, each group being adapted to receive the four corners of a slide 10. Furthermore, separate carrier means may be eliminated altogether, as shown in FIG. 2D, by providing each slide 10 with at least one adhesive edge 23 which overlaps the adjacent edge of an adjacent slide.

In the next step of my technique, the slide strip (FIG. 2D) or the carrier means (FIGS. 2A-2C), with slides 10 affixed thereto, is wound upon a reel 22 of the type shown in FIG. 3 comprising an upper and lower spiral wire member 24 and 26 welded or otherwise joined to the horizontal portions 28 of U-shaped anchor members 30. The spaces between the wire members are adapted to receive the long edges of the slide strip or the carrier means member 20 so that no part of a plastic slide is in contact with any other slide or with radially adjacent areas of the coiled strip or carrier.

Once the carrier or slide strip is loaded, the reel is inserted into a vertical processing tank 32 which includes a removable top 34 and removable central rod 36 having a foot member 38 attached thereto. A plurality of such reels 22 may be so loaded on top of one another whereupon well-known chemical and staining solutions are sequentially poured into the tank 32. After a specified time period, each solution is then emptied through valve 40. Alternatively, the tank 32 may be emptied by inverting it and allowing the solutions to exit via a previously capped opening in tank lid 41. To this end, the spacing between wire portions of each spiral should be effective (typically 1/16 inches) to uniformly expose each slide to such chemicals. Of course, the reels and tank (typically fabricated of stainless steel), as well as the carrier and slides, must be chemically resistant to the processing solutions.

Simultaneous staining of hundreds of slides or more, depending on the size of the processing apparatus used, is readily accomplished by this technique. Illustratively, the slides are 1 .times. 3 inches and the carrier, about 3 inches wide and about 56 inches long, can therefore hold about 56 plastic slides. Up to seven reels each about 3.25 inches in height can fit into a single processing tank about 23 inches long. Consequently, up to 392 slides can be processed similtaneously in a single tank and in a single staining run. By using a plurality of such tanks, thousands of slides can be so processed.

After the staining procedure is complete, the reels are removed from the tank by lifting out central rod 36. Thereafter, the carriers are removed from the reels and the slides from the carriers. At this stage, instead of the usual coverslipping procedure common with glass slides, the plastic slides of my invention are typically covered with a fluid clear plastic hardening resin commercially available under tradenames such as DIALUX or PERMACLEAR manufactured by Scientific Products Inc. (a division of American Hospital, Inc.) of Edison, New Jersey, and Arban Scientific Co. of St. Louis, Missouri, respectively.

Finally, the transparent slides are screened microscopically by trained cytotechnologists under the supervision of a pathologist. After the screening is complete, a report is sent to the physician and an estimated two to three times as many slides as heretofore may be compactly stored in file cabinets in the processing laboratory.

It is to be understood that the above-described arrangements are merely illustrative of the many possible specific embodiments which can be devised to represent application of the principles of the invention. Numerous and varied other arrangements can be devised in accordance with these principles by those skilled in the art without departing from the spirit and scope of the invention. In particular, my invention is useful not only in the processing of Pap smears, but also in the processing of various other medical specimens such as blood and bacteria.

Claims

What is claimed is:

1. A method for processing medical specimens placed on transparent flexible slides comprising the steps of:

arranging said slides in side-by-side fashion in the form of at least one elongated continuous strip,

winding each of said strips onto an individual reel,

placing each said reel into a processing container,

exposing each of said slides to a plurality of processing solutions sequentially placed in said container,

removing a preceding one of said processing solutions from said container before a subsequent one of said solutions is placed therein, and

screening said slides to detect predetermined characteristics of the specimens.

2. The method of claim 1 wherein

each of said slides has a translucent border adapted to receive dentifying indicia and a transparent interior adapted to receive at least one specimen,

said transparent interior of each of said slides is permanently subdivided into a plurality of regions each adapted to receive a separate specimen,

said specimens being Pap smears which have been previously fixed in an appropriate chemical solution,

after said exposing step, the steps of removing each said reel from said container,

removing said strips from each said removed reel,

applying a protective coating of a clear plastic hardening resin to each slide and

microscopically screening each slide.

3. The method of claim 1 wherein each of said reels comprises a pair of spaced spiral members each defining a spiral slot into which said strip is inserted.

4. The method of claim 3 wherein said slots are of a width effective to expose each of said slides substantially uniformly to said processing solutions and effective to prevent one slide from contacting another and from contacting radially adjacent portions of said strip.

5. The method of claim 1 wherein at least one edge of each of said slides is adhesively coated and adjacent edges of adjacent slides are made to overlap one another to form said strip.

6. The method of claim 1 including separate elongated carrier means, and wherein said arranging step comprises affixing said slides to said carrier means.

7. The method of claim 6 wherein at least one surface of said carrier means has an adhesive coating thereon, said slides being affixed to said coating in a side-by-side arrangement.

8. The method of claim 6 wherein said carrier means comprises an elongated strip member and a border surface of each of said slides opposite the side on which said specimen is located has an adhesive coating, the border surface being placed in contact with said strip member so that said slides are arranged in a side-by-side fashion.

9. The method of claim 6 wherein said carrier means comprises an elongated strip member having a plurality of groups of four slits therein, each group being adapted to receive the corners of a single slide.

10. The method of claim 6 wherein said carrier means comprises a pair of substantially parallel adhesive tapes, said slides being affixed in side-by-side fashion across said tapes.

11. A method for processing chemically fixed Pap smears placed on transparent flexible plastic slides comprising the steps of

affixing each of said slides in side-by-side fashion to at least one elongated carrier tape,

winding each of said carrier tapes onto a reel comprising a pair of spaced wire members each wound in the shape of a spiral and each defining a slot into which the elongated edges of said carrier tape are inserted, said slots being of a width effective to prevent one slide from contacting another and from contacting radially adjacent portions of said carrier tape,

placing said reels on top of one another into a vertical processing container,

sequentially placing a plurality of processing solutions into said container, a preceding solution being removed before a subsequent solution is inserted, thereby to simultaneously expose each of said slides to each of said solutions,

removing said reels from said container,

removing said carrier tapes from said reels,

applying a protective coating to each slide, and

microscopically screening each of said slides to detect predetermined characteristics of said Pap smear.

12. Apparatus for processing medical specimens comprising, in combination,

a processing container adapted to receive processing solutions,

at least one reel removably inserted into said container,

at least one flexible elongated carrier means wound upon said reel, and

a plurality of flexible transparent slides removably affixed to said carrier means, said specimens having been chemically fixed on said slides.

13. The apparatus of claim 12 wherein said carrier means comprises an elongated strip member and each of said slides is adhesively affixed to said strip member.

14. The apparatus of claim 12 wherein said carrier means comprises a pair of substantially parallel adhesive tapes, said slides being affixed in side-by-side fashion across said tapes.

15. The apparatus of claim 12 wherein

each said reel comprises a pair of spaced parallel spiral members defining a pair of spiral slots into which said carrier means is inserted,

a plurality of U-shaped anchor members each having a vertical member and a pair of horizontal members, one of said horizontal members being rigidly connected to one of said spiral members and the other of said horizontal members being connected to the other of said spiral members,

the width of said slots effective to prevent any slide from contacting an adjacent slide and from contacting a radially adjacent portion of said carrier means, and

said container comprises an elongated vertical tank having a central rod adapted to guide each said reel in said tank and said rod having a foot member at the bottom end thereof adapted to carry each said reel when said rod is lifted from said container tank.

16. Apparatus for processing medical specimens comprising, in combination,

a processing container adapted to receive processing solutions,

at least one reel removably inserted into said container, and

a plurality of flexible transparent slides upon which said specimens are chemically fixed, said slides being affixed to one another in side-by-side fashion to form at least one elongated continuous strip wound upon at least one of said reels.