Title:
FILM-HOLDER FOR EXPOSING X-RAY FILM
United States Patent 3846635
Abstract:
A vacuum film-holder adapted for mounting in a radiographic table, where it holds film while the film is radiographically exposed. The film-holder comprises a shallow open-topped receptacle, a top plate that closes the receptacle, a pressure plate supported within the receptacle above the bottom of the receptacle, intensifying screens between the top plate and pressure plate, and an exhaust port for evacuating the film-holder.
US Patent References:
X-ray cassette
Powers - March 1945 - 2371843
Folded flexible vacuum exposure holder for radiography
Sherwood - November 1968 - 3412244
MARKING DEVICES FOR X-RAY FILM
Farmer - August 1972 - 3683182
X-RAY FILM CASSETTE
Paidosh - November 1972 - 3704369
X-ray cassette
Powers - March 1945 - 2371843
Folded flexible vacuum exposure holder for radiography
Sherwood - November 1968 - 3412244
MARKING DEVICES FOR X-RAY FILM
Farmer - August 1972 - 3683182
X-RAY FILM CASSETTE
Paidosh - November 1972 - 3704369
Application Number:
05/363966
Publication Date:
11/05/1974
Filing Date:
05/25/1973
View Patent Images:
Export Citation:
Assignee:
Minnesota Mining & Manufacturing Company (St. Paul, MN)
Primary Class:
Other Classes:
378/186, 378/166
International Classes:
G03B42/04; G03B41/16
Field of Search:
250/480,476,481
Primary Examiner:
Lawrence, James W.
Assistant Examiner:
Church C. E.
Attorney, Agent or Firm:
Alexander, Sell, Steldt & Delahunt
Parent Case Data:
This application is a continuation-in-part of a copending application, Ser. No. 266,125, filed June 26, 1972 now abandoned.
Claims:
What is claimed is
1. A vacuum film-holder adapted for mounting in a bucky tray of a radiographic table where it may be rapidly loaded with x-ray film to be exposed at the table, comprising 1) a shallow open-topped receptacle that comprises a rigid bottom plate and upwardly extending sidewalls which comprise at least at their upper extremity a resilient gasket member that extends continuously around the open top of the receptacle and whose upper edge defines a single plane; 2) an elastically bendable top plate attached to the receptacle in position to rest against the upper edge of the gasket member to close the receptacle and adapted to be drawn toward the bottom plate a uniform amount over the whole area enclosed by the gasket member; 3) a pressure plate supported above and parallel to the bottom plate; 4) first and second intensifying screens disposed between the pressure plate and the top plate; and 5) an exhaust port located in the receptacle or top plate for attachment to a vacuum source, whereby a vacuum may be formed within the film-holder to draw the top plate toward the bottom plate and tightly sandwich film between the two intensifying screens.
2. A film-holder of claim 1 in which the pressure plate is supported above the bottom plate by resiliently compressible means.
3. A film-holder of claim 1 in which the top plate is attached to the receptacle by hinge means fixed on the receptacle and extending through openings in the top plate so as to permit the top plate to move toward the bottom plate of the receptacle at the point of connection to the hinge means as well as to pivot with respect to the receptacle.
4. A film-holder of claim 1 in which holding means removably holds the top plate against the upper edge of the gasket member.
5. A film-holder of claim 4 in which the holding means comprises strips of magnet attached to sidewalls of the receptacle, and strips of magnet attached to the top plate that mate with the strips of magnet attached to the sidewalls so as to magnetically hold the top plate against the upper edge of the gasket member.
6. A film-holder of claim 5 in which the edge of the top plate opposite the point of attachment of the top plate to the receptacle comprises a metal strip that engages strips of magnet attached to a sidewall of the receptacle.
7. A film-holder of claim 5 in which the strips of magnet attached to the top plate comprise flexible polymer-based magnets.
8. A film-holder of claim 1 in which overlapping apertures are formed in the pressure plate and in the intensifying screen that is adjacent the pressure plate, and these overlapping apertures overlap a part of film in the film-holder; and a light-projecting panel is positioned in the aperture of the pressure plate and is adapted to project light through a data-bearing card laid over the panel, whereby the data on the card is imaged on the film.
9. A film-holder of claim 8 in which the light-projecting panel is the termination of a light pipe that extends underneath the pressure plate from a point adjacent a lamp.
10. A film-holder of claim 8 in which there is a slot between the pressure plate and the light-projecting panel into which part of the data-bearing card may be inserted.
11. A vacuum film-holder adapted for mounting in a bucky tray of a radiographic table where it may be rapidly loaded with x-ray film to be exposed at the table, comprising 1) a shallow open-topped receptacle that comprises a rigid bottom plate and upwardly extending sidewalls which comprise a rigid base wall and, mounted on the base wall to form the upper extremity of the sidewalls, a resilient gasket member that extends continuously around the open top of the receptacle and whose upper edge defines a single plane; 2) an elastically bendable top plate attached to the receptacle in position to rest against the upper edge of the gasket member to close the receptacle, the top plate being attached to the receptacle by hinge means that permit the top plate to move toward the bottom plate of the receptacle at the point of connection to the hinge means as well as to pivot with respect to the receptacle; 3) a pressure plate supported above and parallel to the bottom plate by resiliently compressible means; 4) first and second intensifying screens disposed between the pressure plate and the top plate; and 5) an exhaust port located in the receptacle or top plate for attachment to a vacuum source, whereby a vacuum may be formed within the film-holder to draw the top plate toward the bottom plate and tightly sandwich film between the two intensifying screens.
12. A film-holder of claim 11 in which holding means removably holds the top plate against the upper edge of the gasket members.
13. A film-holder of claim 12 in which the holding means comprises strips of magnet attached to sidewalls of the receptacle, and strips of magnet attached to the top plate that mate with the strips of magnet attached to the sidewalls so as to magnetically hold the top plate against the upper edge of the gasket member.
14. A rapidly loaded vacuum film-holder for x-ray film comprising 1) a shallow open-topped receptacle that comprises a rigid bottom plate and upwardly extending sidewalls which comprise at least at their upper extremity a resilient gasket member that extends continuously around the open top of the receptacle and whose upper edge defines a single plane; 2) a top plate attached to the receptacle in position to rest against the upper edge of the gasket member to close the receptacle and adapted to be drawn toward the bottom plate a uniform amount over the whole area enclosed by the gasket member; 3) a pressure plate supported above and parallel to the bottom plate; 4) first and second intensifying screens disposed between the pressure plate and the top plate; and 5) an exhaust port located in the receptacle or top plate for attachment to a vacuum source, whereby a vacuum may be formed within the film-holder to draw the top plate toward the bottom plate and tightly sandwich film between the two intensifying screens.
15. A film-holder of claim 14 in which the pressure plate is supported above the bottom plate by resiliently compressible means.
16. A film-holder of claim 14 in which the top plate is attached to the receptacle by hinge means fixed on the receptacle and extending through openings in the top plate so as to permit the top plate to move toward the bottom plate of the receptacle at the point of connection to the hinge means as well as to pivot with respect to the receptacle.
17. A film-holder of claim 14 in which holding means removably holds the top plate against the upper edge of the gasket member.
1. A vacuum film-holder adapted for mounting in a bucky tray of a radiographic table where it may be rapidly loaded with x-ray film to be exposed at the table, comprising 1) a shallow open-topped receptacle that comprises a rigid bottom plate and upwardly extending sidewalls which comprise at least at their upper extremity a resilient gasket member that extends continuously around the open top of the receptacle and whose upper edge defines a single plane; 2) an elastically bendable top plate attached to the receptacle in position to rest against the upper edge of the gasket member to close the receptacle and adapted to be drawn toward the bottom plate a uniform amount over the whole area enclosed by the gasket member; 3) a pressure plate supported above and parallel to the bottom plate; 4) first and second intensifying screens disposed between the pressure plate and the top plate; and 5) an exhaust port located in the receptacle or top plate for attachment to a vacuum source, whereby a vacuum may be formed within the film-holder to draw the top plate toward the bottom plate and tightly sandwich film between the two intensifying screens.
2. A film-holder of claim 1 in which the pressure plate is supported above the bottom plate by resiliently compressible means.
3. A film-holder of claim 1 in which the top plate is attached to the receptacle by hinge means fixed on the receptacle and extending through openings in the top plate so as to permit the top plate to move toward the bottom plate of the receptacle at the point of connection to the hinge means as well as to pivot with respect to the receptacle.
4. A film-holder of claim 1 in which holding means removably holds the top plate against the upper edge of the gasket member.
5. A film-holder of claim 4 in which the holding means comprises strips of magnet attached to sidewalls of the receptacle, and strips of magnet attached to the top plate that mate with the strips of magnet attached to the sidewalls so as to magnetically hold the top plate against the upper edge of the gasket member.
6. A film-holder of claim 5 in which the edge of the top plate opposite the point of attachment of the top plate to the receptacle comprises a metal strip that engages strips of magnet attached to a sidewall of the receptacle.
7. A film-holder of claim 5 in which the strips of magnet attached to the top plate comprise flexible polymer-based magnets.
8. A film-holder of claim 1 in which overlapping apertures are formed in the pressure plate and in the intensifying screen that is adjacent the pressure plate, and these overlapping apertures overlap a part of film in the film-holder; and a light-projecting panel is positioned in the aperture of the pressure plate and is adapted to project light through a data-bearing card laid over the panel, whereby the data on the card is imaged on the film.
9. A film-holder of claim 8 in which the light-projecting panel is the termination of a light pipe that extends underneath the pressure plate from a point adjacent a lamp.
10. A film-holder of claim 8 in which there is a slot between the pressure plate and the light-projecting panel into which part of the data-bearing card may be inserted.
11. A vacuum film-holder adapted for mounting in a bucky tray of a radiographic table where it may be rapidly loaded with x-ray film to be exposed at the table, comprising 1) a shallow open-topped receptacle that comprises a rigid bottom plate and upwardly extending sidewalls which comprise a rigid base wall and, mounted on the base wall to form the upper extremity of the sidewalls, a resilient gasket member that extends continuously around the open top of the receptacle and whose upper edge defines a single plane; 2) an elastically bendable top plate attached to the receptacle in position to rest against the upper edge of the gasket member to close the receptacle, the top plate being attached to the receptacle by hinge means that permit the top plate to move toward the bottom plate of the receptacle at the point of connection to the hinge means as well as to pivot with respect to the receptacle; 3) a pressure plate supported above and parallel to the bottom plate by resiliently compressible means; 4) first and second intensifying screens disposed between the pressure plate and the top plate; and 5) an exhaust port located in the receptacle or top plate for attachment to a vacuum source, whereby a vacuum may be formed within the film-holder to draw the top plate toward the bottom plate and tightly sandwich film between the two intensifying screens.
12. A film-holder of claim 11 in which holding means removably holds the top plate against the upper edge of the gasket members.
13. A film-holder of claim 12 in which the holding means comprises strips of magnet attached to sidewalls of the receptacle, and strips of magnet attached to the top plate that mate with the strips of magnet attached to the sidewalls so as to magnetically hold the top plate against the upper edge of the gasket member.
14. A rapidly loaded vacuum film-holder for x-ray film comprising 1) a shallow open-topped receptacle that comprises a rigid bottom plate and upwardly extending sidewalls which comprise at least at their upper extremity a resilient gasket member that extends continuously around the open top of the receptacle and whose upper edge defines a single plane; 2) a top plate attached to the receptacle in position to rest against the upper edge of the gasket member to close the receptacle and adapted to be drawn toward the bottom plate a uniform amount over the whole area enclosed by the gasket member; 3) a pressure plate supported above and parallel to the bottom plate; 4) first and second intensifying screens disposed between the pressure plate and the top plate; and 5) an exhaust port located in the receptacle or top plate for attachment to a vacuum source, whereby a vacuum may be formed within the film-holder to draw the top plate toward the bottom plate and tightly sandwich film between the two intensifying screens.
15. A film-holder of claim 14 in which the pressure plate is supported above the bottom plate by resiliently compressible means.
16. A film-holder of claim 14 in which the top plate is attached to the receptacle by hinge means fixed on the receptacle and extending through openings in the top plate so as to permit the top plate to move toward the bottom plate of the receptacle at the point of connection to the hinge means as well as to pivot with respect to the receptacle.
17. A film-holder of claim 14 in which holding means removably holds the top plate against the upper edge of the gasket member.
Description:
The present invention provides a film-holder that uses a recently developed x-ray film to make possible improved radiographic or x-raying procedures. This new x-ray film has a low sensitivity to a portion of the visible spectrum of light, and the result is that the film is not "fogged" or prematurely exposed if handled openly in an x-ray room that is lighted only with the described portion of the visible light spectrum.
The new film-holder of the invention may be conveniently incorporated into existing x-ray tables to form a ready-to-use apparatus that permits rapid, reliable, and accurate radiography. Briefly, a film-holder of the invention comprises 1) a shallow open-topped receptacle that comprises a rigid bottom plate and upwardly extending sidewalls which comprise at least at their upper extremity a resilient gasket member that extends continuously around the open top of the receptacle and whose upper edge defines a single plane; 2) an elastically bendable top plate attached to the receptacle in position to rest against the upper edge of the gasket member to close the receptacle and adapted to be drawn toward the bottom plate a uniform amount over the whole area enclosed by the gasket member; 3) a pressure plate supported above and parallel to the bottom plate; 4) first and second intensifying screens disposed between the pressure plate and the top plate; and 5) an exhaust port located in the receptacle or top plate for attachment to a vacuum source, whereby a vacuum may be formed within the film-holder to draw the top plate toward the bottom plate and tightly sandwich film between the two intensifying screens.
A film-holder of the invention also preferably includes apparatus for marking film within the film-holder. In a preferred embodiment of such film-holders, overlapping apertures are formed in the pressure plate and in the intensifying screen that is adjacent the pressure plate, and these overlapping apertures overlap a part of the film in the film-holder. A light-projecting panel is positioned in the aperture in the pressure plate, and this panel is adapted to project light through a data-bearing card laid over the panel, whereby the data on the card is imaged on the film.
DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of an x-ray table that incorporates a film-holder of the invention;
FIG. 2 is a plan view, with parts broken away, of a film-holder of the invention;
FIG. 3 is a section view of the film-holder of FIG. 2, taken generally along the lines 3--3 in FIG. 2, and additionally showing a bucky tray in which the film-holder is mounted;
FIG. 4 is a plan view, with parts broken away, of a different film-holder of the invention; and
FIG. 5 is a section view of a part of the film holder of FIG. 4, taken along the lines 5--5 of FIG. 4.
DETAILED DESCRIPTION
FIG. 1 shows a conventional x-ray or radiographic table 10 that incorporates a film-holder 11 of the invention. As shown, the table 10 includes a panel 12 on which a patient lies to be x-rayed and a carriage 13 beneath the panel that is moveable along the length of the table in the direction of the arrows 14. A tray 15, commonly called a "bucky" tray, is slideable into and out of the carriage, and conventionally each time an x-ray is to be taken an x-ray cassette freshly loaded with film is inserted into the tray. A film-holder 11 of the invention is used instead of an x-ray cassette and may be loaded with film while in the bucky tray. In the illustrated embodiment, the film-holder 11 is semi-permanently mounted in the tray 15, meaning that, while the film-holder may be used for repeated x-ray exposure, it may also be rapidly and conveniently removed if there is a desire to insert special-use cassettes or film-holders (having high-detail intensifying screens, for example).
FIGS. 2 and 3 show the film-holder 11 in more detail. As illustrated, the film-holder 11 includes a shallow open-topped receptacle 17 that comprises a bottom plate 18, short upwardly-extending sidewalls that comprise a base sidewall 19, and a resilient gasket 20 mounted over the base sidewall. As shown in FIG. 2, a top plate 21 is attached to the back edge of the receptacle 17 by hinges 22 that extend through apertures 23 in the top plate. A pressure-plate 24 is supported above and parallel to the bottom plate by a plurality of spacing means 25 that are preferably resiliently compressible and that are distributed at different locations under the pressure plate; in the illustrated embodiment the spacing means comprise flat foam rubber sheets 25, through compression springs or the like or rigid spacing means could also be used. Two radiation-intensifying screens 26 and 27 are included, one being adhered to the pressure plate 24 and the other being attached to the top plate 21. An exhaust port 28 fitted with a rubber grommet is formed in the bottom plate 18, and upon mounting of the film-holder in the bucky tray, the rubber grommet engages the bottom panel of the bucky tray, with the grommet surrounding an opening 30 in the bucky tray. An exhaust fixture 31 is attached to the bottom of the bucky tray, with an o-ring 32 being located between the fixture and bucky tray to form a seal around the opening 30. A tube 33 connected to the fixture 31 leads to an exhaust pump by which a vacuum may be developed inside the film-holder. It will be seen that the film-holder 11 may be removed from the tray 15 without disconnecting any tubing or other connections, and in general the mounting and removal of the film-holder 11 is generally the same as inserting a conventional cassette into the tray. Clamps 29 at the front and back of the tray hold the film-holder in place.
The exhaust port 28 may be located at various places in the holder, including the top plate, but it is most desirably and conveniently formed in the bottom plate or a sidewall. The space between the pressure plate 24 and bottom plate 18 is a vacuum chamber, and air is exhausted from around the edge of the film 34, out past the edge of the pressure plate 24, and down into the exhaust port 28. The vacuum draws the top plate 21 down against the resilient gasket 20 and develops pressure urging the top plate toward the pressure plate so that full and intimate contact is developed between the intensifying screens and a sheet of film 34 contained in the film-holder. Stop means in the form of flat sheets of plastic 36 attached to the bottom four corners of the pressure plate 24 limit movement of the pressure plate within a desired range that assures contact between the intensifying screen 27 and the film.
The top plate 21 is preferably made of an elastically bendable material so that even though the bucky tray 15 is not withdrawn completely from under the panel 12, the top plate can be lifted and bent to permit convenient insertion of film into the holder (by elastically bendable it is meant that the top plate may be bent into a curve around the edge of the panel 12, the curve typically having a radius less than about 10 inches, without forming a permanent set in the plate or rupturing it). When an intensifying screen is attached to the top plate, it should also preferably be elastically bendable. The top plate may be transparent to light, and of course, must pass x-rays to permit exposure of the film.
Preferably the film-holder includes a lead foil (not shown) or similar structure between the bottom intensifying screen 26 and pressure plate 24 to prevent secondary radiations from imaging the film; the pressure plate itself can also serve this function if made of appropriate material. The sidewalls of the film-holder may be wholly formed of a resilient material instead of comprising a resilient gasket over a rigid base sidewall, though use of a rigid base sidewall such as the sidewall 19 is preferred. As in the illustrated film-holder 11, one corner 35 may be cut away so that the holder mates within the bucky tray, which conventionally has a raised portion at the corner so as to assure that a cassette is properly inserted.
In a typical use of a film-holder of the invention that has the features thus far described and is in place in a bucky tray 15, an x-ray technologist simply slides the tray 15 part way out of the x-ray table 10, lifts the top plate 21, lays a sheet of film having the described low sensitivity to at least one portion of the spectrum of visible light (as described in U.S. Pat. Ser. No. 137,179) between the intensifying screens, lowers the top plate against the open edge of the gasket 20, and slides the tray back into the x-ray table. The x-ray technologist then activates the exhaust pump, whereupon the top plate 21, which rests freely on the edge of the gasket 20 and is free to slide vertically on the hinge 22, is drawn down toward the pressure plate 24. After a few seconds during which the vacuum is drawn, the loading operation is complete, and the x-ray source may be activated to radiographically expose the film.
The illustrated film-holder also includes apparatus for marking identifying information onto a film in the holder. In the illustrated embodiment this apparatus comprises a flat light-projecting panel 37; a light pipe that is adhered to the light-projecting panel 37 and that comprises a flat sheet 38 of light-conducting plastic and two cylindrical rods 39 adhered to the sheet of plastic; and two low-voltage lamps 40 adhered to the ends of the rods 39. The lamps 40 are supplied electric power through wires extending through the back sidewall of the film holder. The end 41 of the sheet 38 and the ends 42 of the rods 39 may be beveled to direct light in the light pipe, and the light pipe may be coated with white paint to further improve transmission. An opaque sheath 43 is wrapped around the lamps and light pipe to eliminate any transmission of ambient light to the film 34.
The light-projecting panel 37 is located in an aperture 45 in the pressure plate 24, and the intensifying screen 26 also has an aperture 46 that overlaps the aperture 45 and the light-projecting panel 37. A lead foil 44 or the like is adhered to the top intensifying screen 27 to prevent radiographic exposure of the film 34 in the area of the film that overlaps the apertures 45 and 46. When a sheet of film 34 is loaded into the film-holder 11, a translucent card 47 on which has been printed or written identifying information or data is inserted into the aperture 46 in the screen 26. The aperture 45 in the pressure plate 24 is large enough to receive a part of the card 47 not bearing data through a slot between the light-projecting panel 37 and an edge of the intensifying screen 26 that defines the aperture 46. Such an insertion of a large card provides a definite and firm fixing of the card over the light-projecting panel 37.
After the top plate 21 has been closed, and preferably after a vacuum has been drawn so that the film 34 is pressed against the card 47, the lamps 40 are energized (as for 3 seconds). Thereupon light is projected through the card and onto the film to image the film with the identifying information. The film should be pressed against the card, and the data on the card should be against the film, to obtain the best image by this contact-printing technique. If desired, the electric circuitry of the film-holder can be such that the lamps are automatically energized, after a short time delay, when the exhaust pump is activated to draw a vacuum in the film-holder.
Instead of using a lamp and a light pipe, light-projecting panels such as electroluminescent panels, may be used. Or a lamp or lamps may be positioned directly beneath or near the aperture 45 of the pressure plate, though in that case, a good light-diffusing plate should be inserted between the lamps and the film so as to assure a uniform exposure of the film.
FIGS. 4 and 5 show a different embodiment of the invention. In this embodiment, a film-holder 50 is permanently attached (as by screws) to a bucky tray 51, which may conveniently be wholly removed from a radiographic table (if it is desired to use x-ray cassettes loaded with special film, for example). In this embodiment air is exhausted from the film-holder through a port 52 in the back sidewall of the film-holder. A hose 53 leads from the port 52 to a tubular fitting 54 in a fixture 55 that is attached to the back wall 56 of the bucky tray. When the bucky tray is fully inserted into the radiographic table, the tubular fitting 54 engages a fixture 57 attached to a wall 58 of the radiographic table and mates with a tubular fitting 59 that is connected through a hose 60 to a vacuum pump.
The fixture 55 on the bucky tray also includes four electrically conducting pins 61-64 that engage contacts 65-68 on the fixture 57 that is mounted on the wall 58 of the radiographic table. Two of the pins, 61 and 62, are electrically connected together to form a bridge, and when the bucky tray is fully inserted into the radiographic table so that the pins engage contacts 65 and 66, an electrical circuit is completed to activate the vacuum pump. The pins 63 and 64 engage the contacts 67 and 68 and thus connect a source of electric power to lamps in the film-holder 50 (such as the lamps 40 of the embodiment in FIGS. 2 and 3) by which identifying information is photographed onto the film. The pins 61-64 are springloaded into the position shown in FIG. 4, so that they resiliently engage the contacts 65-68.
The film-holder 50 is generally the same as the film-holder 11 shown in FIGS. 2 and 3 with the exception of holding means that removably hold the top plate 70 of the film-holder 50 tightly against the resilient gasket member 71, even when a radiographic table is tilted to take an x-ray of an individual in a more upright position. The holding means of the illustrated embodiment comprise strips 72 of magnet attached to the side sidewalls of the receptacle portion of the film-holder, the strips 72 of magnet being supported by and generally adhesively secured to, brace members 73 attached (as with screws) to the sidewalls; strips 74 of magnet attached as by adhesive to the inside of the top plate 71 that mate with the magnets attached to the sidewalls; magnets 75 attached to the front sidewall of the receptacle; and a steel plate 76 attached to the front edge of the top plate 71 that mates with the magnets 75. Magnet strips may be positioned only at intervals along the side sidewalls of the receptacle, though for the best holding action magnet strips extend over at least a major part of the length of the side sidewalls of the film-holder. At least the magnet strips attached to the top plate 71 are preferably flexible polymer-based magnets. In alternative embodiments, the top plate is removably held against the gasket member by hook and loop fasteners of the type taught in U.S. Pat. No. 3,009,235.
The new film-holder of the invention may be conveniently incorporated into existing x-ray tables to form a ready-to-use apparatus that permits rapid, reliable, and accurate radiography. Briefly, a film-holder of the invention comprises 1) a shallow open-topped receptacle that comprises a rigid bottom plate and upwardly extending sidewalls which comprise at least at their upper extremity a resilient gasket member that extends continuously around the open top of the receptacle and whose upper edge defines a single plane; 2) an elastically bendable top plate attached to the receptacle in position to rest against the upper edge of the gasket member to close the receptacle and adapted to be drawn toward the bottom plate a uniform amount over the whole area enclosed by the gasket member; 3) a pressure plate supported above and parallel to the bottom plate; 4) first and second intensifying screens disposed between the pressure plate and the top plate; and 5) an exhaust port located in the receptacle or top plate for attachment to a vacuum source, whereby a vacuum may be formed within the film-holder to draw the top plate toward the bottom plate and tightly sandwich film between the two intensifying screens.
A film-holder of the invention also preferably includes apparatus for marking film within the film-holder. In a preferred embodiment of such film-holders, overlapping apertures are formed in the pressure plate and in the intensifying screen that is adjacent the pressure plate, and these overlapping apertures overlap a part of the film in the film-holder. A light-projecting panel is positioned in the aperture in the pressure plate, and this panel is adapted to project light through a data-bearing card laid over the panel, whereby the data on the card is imaged on the film.
DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of an x-ray table that incorporates a film-holder of the invention;
FIG. 2 is a plan view, with parts broken away, of a film-holder of the invention;
FIG. 3 is a section view of the film-holder of FIG. 2, taken generally along the lines 3--3 in FIG. 2, and additionally showing a bucky tray in which the film-holder is mounted;
FIG. 4 is a plan view, with parts broken away, of a different film-holder of the invention; and
FIG. 5 is a section view of a part of the film holder of FIG. 4, taken along the lines 5--5 of FIG. 4.
DETAILED DESCRIPTION
FIG. 1 shows a conventional x-ray or radiographic table 10 that incorporates a film-holder 11 of the invention. As shown, the table 10 includes a panel 12 on which a patient lies to be x-rayed and a carriage 13 beneath the panel that is moveable along the length of the table in the direction of the arrows 14. A tray 15, commonly called a "bucky" tray, is slideable into and out of the carriage, and conventionally each time an x-ray is to be taken an x-ray cassette freshly loaded with film is inserted into the tray. A film-holder 11 of the invention is used instead of an x-ray cassette and may be loaded with film while in the bucky tray. In the illustrated embodiment, the film-holder 11 is semi-permanently mounted in the tray 15, meaning that, while the film-holder may be used for repeated x-ray exposure, it may also be rapidly and conveniently removed if there is a desire to insert special-use cassettes or film-holders (having high-detail intensifying screens, for example).
FIGS. 2 and 3 show the film-holder 11 in more detail. As illustrated, the film-holder 11 includes a shallow open-topped receptacle 17 that comprises a bottom plate 18, short upwardly-extending sidewalls that comprise a base sidewall 19, and a resilient gasket 20 mounted over the base sidewall. As shown in FIG. 2, a top plate 21 is attached to the back edge of the receptacle 17 by hinges 22 that extend through apertures 23 in the top plate. A pressure-plate 24 is supported above and parallel to the bottom plate by a plurality of spacing means 25 that are preferably resiliently compressible and that are distributed at different locations under the pressure plate; in the illustrated embodiment the spacing means comprise flat foam rubber sheets 25, through compression springs or the like or rigid spacing means could also be used. Two radiation-intensifying screens 26 and 27 are included, one being adhered to the pressure plate 24 and the other being attached to the top plate 21. An exhaust port 28 fitted with a rubber grommet is formed in the bottom plate 18, and upon mounting of the film-holder in the bucky tray, the rubber grommet engages the bottom panel of the bucky tray, with the grommet surrounding an opening 30 in the bucky tray. An exhaust fixture 31 is attached to the bottom of the bucky tray, with an o-ring 32 being located between the fixture and bucky tray to form a seal around the opening 30. A tube 33 connected to the fixture 31 leads to an exhaust pump by which a vacuum may be developed inside the film-holder. It will be seen that the film-holder 11 may be removed from the tray 15 without disconnecting any tubing or other connections, and in general the mounting and removal of the film-holder 11 is generally the same as inserting a conventional cassette into the tray. Clamps 29 at the front and back of the tray hold the film-holder in place.
The exhaust port 28 may be located at various places in the holder, including the top plate, but it is most desirably and conveniently formed in the bottom plate or a sidewall. The space between the pressure plate 24 and bottom plate 18 is a vacuum chamber, and air is exhausted from around the edge of the film 34, out past the edge of the pressure plate 24, and down into the exhaust port 28. The vacuum draws the top plate 21 down against the resilient gasket 20 and develops pressure urging the top plate toward the pressure plate so that full and intimate contact is developed between the intensifying screens and a sheet of film 34 contained in the film-holder. Stop means in the form of flat sheets of plastic 36 attached to the bottom four corners of the pressure plate 24 limit movement of the pressure plate within a desired range that assures contact between the intensifying screen 27 and the film.
The top plate 21 is preferably made of an elastically bendable material so that even though the bucky tray 15 is not withdrawn completely from under the panel 12, the top plate can be lifted and bent to permit convenient insertion of film into the holder (by elastically bendable it is meant that the top plate may be bent into a curve around the edge of the panel 12, the curve typically having a radius less than about 10 inches, without forming a permanent set in the plate or rupturing it). When an intensifying screen is attached to the top plate, it should also preferably be elastically bendable. The top plate may be transparent to light, and of course, must pass x-rays to permit exposure of the film.
Preferably the film-holder includes a lead foil (not shown) or similar structure between the bottom intensifying screen 26 and pressure plate 24 to prevent secondary radiations from imaging the film; the pressure plate itself can also serve this function if made of appropriate material. The sidewalls of the film-holder may be wholly formed of a resilient material instead of comprising a resilient gasket over a rigid base sidewall, though use of a rigid base sidewall such as the sidewall 19 is preferred. As in the illustrated film-holder 11, one corner 35 may be cut away so that the holder mates within the bucky tray, which conventionally has a raised portion at the corner so as to assure that a cassette is properly inserted.
In a typical use of a film-holder of the invention that has the features thus far described and is in place in a bucky tray 15, an x-ray technologist simply slides the tray 15 part way out of the x-ray table 10, lifts the top plate 21, lays a sheet of film having the described low sensitivity to at least one portion of the spectrum of visible light (as described in U.S. Pat. Ser. No. 137,179) between the intensifying screens, lowers the top plate against the open edge of the gasket 20, and slides the tray back into the x-ray table. The x-ray technologist then activates the exhaust pump, whereupon the top plate 21, which rests freely on the edge of the gasket 20 and is free to slide vertically on the hinge 22, is drawn down toward the pressure plate 24. After a few seconds during which the vacuum is drawn, the loading operation is complete, and the x-ray source may be activated to radiographically expose the film.
The illustrated film-holder also includes apparatus for marking identifying information onto a film in the holder. In the illustrated embodiment this apparatus comprises a flat light-projecting panel 37; a light pipe that is adhered to the light-projecting panel 37 and that comprises a flat sheet 38 of light-conducting plastic and two cylindrical rods 39 adhered to the sheet of plastic; and two low-voltage lamps 40 adhered to the ends of the rods 39. The lamps 40 are supplied electric power through wires extending through the back sidewall of the film holder. The end 41 of the sheet 38 and the ends 42 of the rods 39 may be beveled to direct light in the light pipe, and the light pipe may be coated with white paint to further improve transmission. An opaque sheath 43 is wrapped around the lamps and light pipe to eliminate any transmission of ambient light to the film 34.
The light-projecting panel 37 is located in an aperture 45 in the pressure plate 24, and the intensifying screen 26 also has an aperture 46 that overlaps the aperture 45 and the light-projecting panel 37. A lead foil 44 or the like is adhered to the top intensifying screen 27 to prevent radiographic exposure of the film 34 in the area of the film that overlaps the apertures 45 and 46. When a sheet of film 34 is loaded into the film-holder 11, a translucent card 47 on which has been printed or written identifying information or data is inserted into the aperture 46 in the screen 26. The aperture 45 in the pressure plate 24 is large enough to receive a part of the card 47 not bearing data through a slot between the light-projecting panel 37 and an edge of the intensifying screen 26 that defines the aperture 46. Such an insertion of a large card provides a definite and firm fixing of the card over the light-projecting panel 37.
After the top plate 21 has been closed, and preferably after a vacuum has been drawn so that the film 34 is pressed against the card 47, the lamps 40 are energized (as for 3 seconds). Thereupon light is projected through the card and onto the film to image the film with the identifying information. The film should be pressed against the card, and the data on the card should be against the film, to obtain the best image by this contact-printing technique. If desired, the electric circuitry of the film-holder can be such that the lamps are automatically energized, after a short time delay, when the exhaust pump is activated to draw a vacuum in the film-holder.
Instead of using a lamp and a light pipe, light-projecting panels such as electroluminescent panels, may be used. Or a lamp or lamps may be positioned directly beneath or near the aperture 45 of the pressure plate, though in that case, a good light-diffusing plate should be inserted between the lamps and the film so as to assure a uniform exposure of the film.
FIGS. 4 and 5 show a different embodiment of the invention. In this embodiment, a film-holder 50 is permanently attached (as by screws) to a bucky tray 51, which may conveniently be wholly removed from a radiographic table (if it is desired to use x-ray cassettes loaded with special film, for example). In this embodiment air is exhausted from the film-holder through a port 52 in the back sidewall of the film-holder. A hose 53 leads from the port 52 to a tubular fitting 54 in a fixture 55 that is attached to the back wall 56 of the bucky tray. When the bucky tray is fully inserted into the radiographic table, the tubular fitting 54 engages a fixture 57 attached to a wall 58 of the radiographic table and mates with a tubular fitting 59 that is connected through a hose 60 to a vacuum pump.
The fixture 55 on the bucky tray also includes four electrically conducting pins 61-64 that engage contacts 65-68 on the fixture 57 that is mounted on the wall 58 of the radiographic table. Two of the pins, 61 and 62, are electrically connected together to form a bridge, and when the bucky tray is fully inserted into the radiographic table so that the pins engage contacts 65 and 66, an electrical circuit is completed to activate the vacuum pump. The pins 63 and 64 engage the contacts 67 and 68 and thus connect a source of electric power to lamps in the film-holder 50 (such as the lamps 40 of the embodiment in FIGS. 2 and 3) by which identifying information is photographed onto the film. The pins 61-64 are springloaded into the position shown in FIG. 4, so that they resiliently engage the contacts 65-68.
The film-holder 50 is generally the same as the film-holder 11 shown in FIGS. 2 and 3 with the exception of holding means that removably hold the top plate 70 of the film-holder 50 tightly against the resilient gasket member 71, even when a radiographic table is tilted to take an x-ray of an individual in a more upright position. The holding means of the illustrated embodiment comprise strips 72 of magnet attached to the side sidewalls of the receptacle portion of the film-holder, the strips 72 of magnet being supported by and generally adhesively secured to, brace members 73 attached (as with screws) to the sidewalls; strips 74 of magnet attached as by adhesive to the inside of the top plate 71 that mate with the magnets attached to the sidewalls; magnets 75 attached to the front sidewall of the receptacle; and a steel plate 76 attached to the front edge of the top plate 71 that mates with the magnets 75. Magnet strips may be positioned only at intervals along the side sidewalls of the receptacle, though for the best holding action magnet strips extend over at least a major part of the length of the side sidewalls of the film-holder. At least the magnet strips attached to the top plate 71 are preferably flexible polymer-based magnets. In alternative embodiments, the top plate is removably held against the gasket member by hook and loop fasteners of the type taught in U.S. Pat. No. 3,009,235.