US3545971A - Rapid processing of photographic x-ray film - Google Patents

Description

Dec. 8, 1 970 .1. c. BARNES ETAL RAPID PROCESSING OF PHOTOGRAPHIC X-RAY FILM Filed June 28, 1966 X-RAY FILM N r r d q bq q d q DRY q o d d WASH FIX

d q o q d dpq DEVELOP United States Patent Olhce 3,545,971 RAPID PROCESSING OF PHOTOGRAPHIC X-RAY FILM John C. Barnes, Chester C. Wilt, and William W. Rees,

Rochester, N.Y., assignors to Eastman Kodak Company, Rochester, N.Y., a corporation of New Jersey Filed June 28, 1966, Ser. No. 561,265 Int. Cl. G03c 5/24, 5/38 US. Cl. 96-61 Claims ABSTRACT OF THE DISCLOSURE This invention relates to the rapid processing of photographic films and more particularly to methods for the rapid processing of medical X-ray films.

X-ray films in cut-sheet form have been processed for many years by conventional photographic processing methods including tray and tank processing methods and the quality of the X-ray images has been generally satisfactory. However, the processing times have been fairly long, of the order of 10 to minutes and even with the most careful control of processing conditions and processing solutions the results usually have not been reproducible. Thus, the radiologist could not be absolutely certain that changes appearing on the radiograph taken at a later date were due to physiological changes in the patient or due to processing variations. These circumstances tended to limit the use of X-ray images as a diagnostic tool.

In more recent years with the demand for the faster processing of X-ray films, processing has been carried out in roller transport systems such as shown schematically in the accompanying drawing, with improvement in quality and reproducibility. However, the processing time of the order of 5 to 10 minutes appeared unduly long. When attempts were made to speed up the existing roller transport processes primarily 'by raising the temperatures of the processing solution from about 80 to 90 F. and raising the drying temperature from about 110 to 130 F., a serious reduction in quality of the X-ray images was sustained. For example, at the higher temperatures the inherent pressure sensitivities of the silver halide emulsions became more apparent and were manifest by the appearance of patterns in the emulsion due to contact of the emulsions with the transport rollers. Thus, the pattern of an individual roller on the emulsion could sometimes be recognized but often one roller pattern was superimposed on the pattern of another roller. Accordingly, the radiologist could easily be confused by a higher density area of the image resulting from roller pattern rather than from some physiological condition of the patient. More particularly, when the higher processing temperatures and shorter processing times were used, development of the silver halide emulsions was incomplete and fixation was incomplete with concomitant fading of the silver image on storage. Also, drying was incomplete.

We have discovered a combination of X-ray films, processing solutions and processing conditions especially adapted to use in roller transport systems, cooperating to provide processed X-ray film of excellent quality in from Patented Dec. 8, 1970 about 30 to seconds actual processing time or about 60 to 120 seconds total time including time of transport between solutions and the drying chamber. These total processing times refer to the processing of a conventional sheet of X-ray film 14 by 17 inches square. Naturally, a smaller sheet of film can be processed in a shorter period of time primarily because of the smaller dimension of the sheet. It was previously thought not to be possible to obtain the desired quality of X-ray image in a total processing time of less than about 5 to 10 minutes. Moreover, our process produces image quality which is reproducible.

The accompanying drawing shows schematically one type of roller transport system representative of those adapted to use in our invention for the processing of X-ray film.

In the process of our invention an X-ray film is used provided with a film support such as polyethylene terephthalate, having 'on at least one side of the support a silver halide emulsion layer, and on the same side of the support about to 600 mgs. per square foot, preferably 200 to 500 mgs. per square foot of a hydrophilic colloid vehicle. All of the colloid vehicle may be in the emulsion layer or in a layer or layers adjacent thereo such as layers coated under or over the emulsion layer. Thus, when emulsion layers are coated on both sides of the support, the total hydrophilic colloid vehicle will be about 200 to 1200 mgs. per square foot. This is appreciably less colloid vehicle than would be expected to be useful to obtain good emulsion speed, low fog, and low grain in the X-ray image under processing conditions previously in the X-ray field. A proteinaceous colloid vehicle is preferred including, for example, casein, gelatin and gelatin derivatives such as obtained by reaction of gelatin with acid chlorides and anhydrides. Gelatin is a preferred vehicle although a substantial amount of other hydrophilic organic colloid vehicle can also be present, for example, casein, polyvinyl alcohol, partially hydrolyzed cellulose esters, partially hydrolyzed vinyl ester polymers and the mentioned gelatin derivatives. The emulsion should have a hardness determined by taping its melting point temperature in water which should be above about 190 F. Unhardened gelatin emulsions have a melting point of about 85 to 90 F. The gelatin emulsions can be hardened by use of conventional gelatin hardening agents such as formaldehyde, mucochloric acid, diacetyl, dichlorodioxane, dialdehyde starch, aziridines, epoxy compounds, vinyl sulfones, and the like. Emulsions of a lower degree of hardness can be used providing sufiicient gelatin hardening agent has been added to the processing solutions. Conversely, the harder emulsions will require less gelatin hardener in the processing solutions. The X-ray films should contain on at least one side of the support about 300 to 650 mgs. of silver per square foot as silver halide or a total of about 6-00 to 1300 mgs. of silver per square foot for double coated films. Such emulsions contain the amount of silver adequate to provide X-ray images of good density, yet the residual undeveloped silver halide is not too great as to require excessive fixing and washing times in the process.

The silver halide emulsions are not otherwise critical and may contain, for example, silver bromide, silve'r bromoiodide or silver chlorobromide. Upon proper selection of the proper processing solutions and processing conditions, the emulsions can be processed and dried properly in an actual processing time as short as 30 seconds (not including the time of transport between the various processing solutions and a drying chamber). A representative total processing time obtainable in our process is 60 to seconds from the point of feeding the X-ray film into a transport apparatus to the emergence of the dried film, as will be seen from the examples below.

The aqueous developer compositions used for processing the X-ray films contain conventional silver halide developing agents such as hydroquinone and derivatives thereof, and l phenyl-3-pyrazolidone and derivatives thereof, and mixtures of these developing agents. When the colloid vehicle of the X-ray film is gelatin, an aldehyde gelatin hardening agent such as given above should be present in the developing solution in an amount such that the pressure sensitivity of the emulsion is suppressed and drying is complete within the selected time of processing. Particularly efiicacious gelatin-hardening agents are the dialdehydes and bis-bisulphite derivatives thereof described in US. Pat. 3,232,764. These gelatin hardening agents are used in the developer compositions in concentrations of from about 3 to grams of the dialdehyde per liter, and in these amounts will quickly and adequately harden the gelatin emulsions. Useful dialdehydes include fi-methyl glutaraldehyde, glutaraldehyde, a-methyl glutaraldehyde, maleic dialdehyde, succinic dialdehyde, methoxy succinic dialdehyde, a,a-dimethyl glutaraldehyde, methyl maleic dialdehyde, methyl succinic dialdehyde, a-methyl-B-ethoxy glutaraldehyde, a-n-butoxy glutaraldehyde, on ethyl-13 ethoxy glutaraldehyde, B-n-butoxy glutaraldehyde, 04,0: dimethoxy succinic dialdehyde, fiisopropoxy succinic dialdehyde, a,a-diethyl succinic dialdehyde and butyl maleic dialdehyde. These dialdehydes are particularly effective when used in combination with organic antifoggant compounds. Antifoggant compounds of the benzotriazole, benzothiazole, tetrazole and thiazole series, for example, methylbenzyltriazole are very useful. Also anthraquinone sulfonic acid salts such as sodium l-anthraquinone sulfonate and sodium Z-anthraquinone sulfonate are also very useful when employed alone or in conjunction with other antifoggant compounds such as those mentioned immediately above. The pH of the developer should be maintained at from about 9.5 to 10.5 using, for example, caustic alkali or alkali metal carbonate. The pH is selected to insure that development produces an X-ray image of the desired density and contrast at the selected time and temperature. The temperature of the developing solutions should be maintained between about 80 and 120 F. Under these conditions, development is carried out until the required density and contrast is obtained and a useful development time is seconds in a 60-second actual processing cycle including drying time, in a roller transport system such as shown in the drawing, or 90 seconds total time when including the time of transport of the film between the tanks and drying chamber.

The fixing solution employed in the process of our invention is a conventional fixing solution containing a silver halide solvent such as alkali metal or ammonium thiosulfate. A useful concentration of the latter compound is shown in the following examples. When employing the shorter actual processing times of the order of seconds, a somewhat greater concentration of the silver halide solvent should be used and conversely, the temperature of the fixing solution should be maintained at from about 80 to 120 F. and a representative fixing time is 12 seconds in a -second actual processing time.

Following treatment of the film in the fixing solution, it is washed with water at about to 120 F. until substantially all of the solubilized silver salt has been removed from the film. A representative washing time is 20 seconds at 120 F. in a 60-second actual processing time.

After washing the film, it is preferably squeegeed to remove excess water and dried at about 120 to 200 F. by directing a stream of air against the emulsion surface. In a 60-second actual processing cycle, when the emulsion contains about 450 mgs. of gelatin per square foot, drying can be expected to be completed in 20 seconds or less using a stream of air of approximately 50% relative humidity.

In the process described it should be understood that the shorter processing times are best obtained by selection of emulsions containing the minimum amount of silver halide and organic colloid vehicle, the selection of the higher processing temperatures and developing at the higher pH values as well as fixing with the more concentrated acid fixing solutions. Emulsions containing the higher levels of organic colloid vehicle such as gelatin can be expected to require the use of more organic colloid hardener in the developer composition and drying for longer periods of time at higher temperatures or both.

The accompanying drawing shows in schematic form a representative roller transport system in commercial use for the development of X-ray film and particularly adapted to use in our invention. Cut sheet X-ray film is advanced along the path shown between staggered rollers through the development, fixing and washing tanks and through the drying section. An apparatus of this type is described in more detail in US. Pat. 3,025,779. In this apparatus, an actual processing time of 30 to seconds is adequate. Other types of roller transport apparatus can be employed in the process of our invention. For example, apparatus can be used of the type wherein the film is advanced by means of a series of rollers, through several chambers where processing solutions are sprayed onto the emulsion surface within the mentioned temperature ranges and the film dried at elevated temperature.

The following examples will serve to illustrate our invention.

EXAMPLE 1 Attempted rapid processing of commercial X-ray film in commercial processing compositions at elevated temperature A commercial X-ray film was provided having a polyethylene terephthalate support and silver halide emulsion layers on each side of the support each containing approximately 600 mgs. of gelatin per square foot. The emulsion contained about 500 mgs. of silver as silver halide per square foot. Over each emulsion layer was a gelatin layer, mgs. of gelatin per square foot. The recommended total processing time for the film using the developer and fixing solutions given below was seven minutes in a roller transport system such as shown in the drawing (including time of transport of the film between the processing tanks and drying chamber). The recommended temperature for the commercial processing solutions was about 80 F. and drying at about F.

The film was exposed and processed in a 90 second cycle as follows:

Development20 seconds at 105 F. Fixationl2 seconds at 105 F. Washing8 seconds at 105 F. Drying-20 seconds at F.

The remaining time was taken up in transporting the film betwen the tanks and the drying chamber. The developer composition was as follows:

G. 1-phenyl-3-pyrazolidone 1.5 Hydroquinone 25.0 Sodium sulfite, anhydrous 65.0 Sodium metaborate.8H O 124.0 Sodium hydroxide 12.5 Potassium bromide 12.0 Tetrasodium ethylenediamine tetraacetic acid 4.0 Glutaraldehyde (25% solution) 20.0 Sodium Z-anthraquinone sulfonate 0.1 S-methyl benzotriazole 0.1

Water to pH range 9.5 to 10.51 liter.

The fixing solution was a conventional ammonium thiosulfate acetic acid silver halide fixing composition as follows:

Water to pH range 3.9 to 4.5 1 liter.

As a result of processing the film in the 90-second cycle, fixation was incomplete and the highlights of the film were discolored by the presence of residual silver halide. In addition, the film was not dry and was found to stick to other films freshly processed in the same system. Also, roller pattern was seen in the image. The processed film was judged to be substantially useless. Moreover, graininess had increased to an unacceptable level.

EXAMPLE 2 Rapid processing of X-ray film to obtain satisfactory development, fixation and drying An X-ray film was provided having on each side of the polyethylene terephthalate support gelatin emulsion layers containing about 350 mgs. of gelatin per square foot and the same amount of silver halide as the film of Example 1, 500 mgs. silver per square foot, and the same amount of gelatin in the overcoat, 100 mgs. per square foot. The emulsion had a hardness determined by its melting point in water which was about 200 F. The

film was exposed and processed for 90 seconds total processing time in the same roller transport system used in Example 1 as follows:

Development20 seconds at 105 F. Fixing-12 seconds at 105 F. Washing-8 seconds at 105 F. Drying20 seconds at 150 F.

The remaining time was used in transporting the film between the tanks and developing and drying sections. The developer and fixing solutions were the same as those used in Example 1. As a result of processing as described, the film was found to have excellent density and contrast and was dry. More particularly, there was no evidence of roller pattern in the image. Also, storage of the X-ray film at elevated temperature and humidity showed that the silver image was stable and, therefore, that fixation had been complete. Graininess was not perceptably higher than normal.

EXAMPLE 3 The process of Example 2 is repeated except that the processing conditions are adjusted so as to obtain a completely processed film in an actual processing time of 30 seconds (60 seconds total time) as follows:

Developing-10 seconds at 120 F. Fixing10 seconds at 120 F. Washing5 seconds at 120 F. Drying-5 seconds at 180 F.

Under these conditions, the film is adequately developed, fixed and dried, an image of good density and contrast being obtained. However, to provide more tolerance in the processing times, the silver halide and gelatin content of the emulsion layers can be reduced to the lower levels mentioned above particularly to facilitate the fixing, washing and drying steps. Similarly, single emulsion coated X-ray films can be expected to be processed completely 1n the above 30-second cycle.

EXAMPLE 4 The process of Example 2 is repeated except that the processing conditions are adjusted so as to obtain a completely processed film in an actual processing time of seconds (two minutes total processing time) as follows:

Developing-3O seconds at 90 F. Fixing18 seconds at 90 F. Washingl2 seconds at 90 F. Drying-30 seconds at 120 F.

This processing cycle produces a completely processed film having an image of good density and contrast. However, the higher levels of silver halide and gelatin mentioned above can also be used in the emulsion layers in this 90-second processing cycle.

EXAMPLE 5 An X-ray film is prepared similar to that used in Example 2 except that the emulsion containing 450 mgs. gelatin per square foot and 500 mgs. silver per square foot is coated upon only one side of the film support. The film processes satisfactorily under the conditions given in Example 2 to provide an X-ray image of suitable density, contrast and stability.

In the manner of the above examples other hydrophillic organic colloid vehicles can be substituted wholly or in part for gelatin. Other developing agents, gelatin hardening agents and antifoggant compounds can be used in the developer. Bromide is usually not sufiicient for reducing fog and is preferably employed in combination with organic antifoggant compounds as illustrated above.

As described above, the successful, preferably continuous, processing of the X-ray film in a cycle of about 30 to 90 seconds depends partly on control of the concentration of colloid vehicle in the emulsion, in the case of gelatin there being about to 600 mgs. gelatin per square foot present. However, more or less than this amount of colloid vehicle can be used depending, in part, upon the solution penetration and drying properties of the particular hydrophilic colloid vehicles present. Thus, larger amounts of faster drying vehicles can be used. Also, the silver halide concentration in the emulsion is maintained in the mentioned range of 300 to 650 mgs. silver per square foot as silver halide so as to provide good image quality in the selected processing time. The developer solution should contain sufficient hardner such as a dialdehyde gelatin hardener to suppress roller pattern and to facilitate transport of the film. The pH of the developer solution should be 9.5 to 10.5 and development is carried out as required, e.g., 10 to 30 seconds, at about 80 to F. Similarly, fixation and washing times are adjusted as required to remove the residual undeveloped silver halide. Ordinarily, 10 to 30 seconds at 80 to 120 F. is adequate for fixation when followed by washing for about 8 to 12 seconds at 80 to 120 F. The drying time and temperature are adjusted to effect complete drying of the emulsion, and ordinarily about 10 to 20 seconds is adequate when drying at temperatures of 120 to 200 F., the emulsion containing the larger amounts of gelatin in the 100 to 600 mgs. range usually requiring the longer drying times.

The invention has been described in considerable detail with particular reference to certain preferred embodiments thereof, but it will be understood that variations and modifications can be effected within the spirit and scope of the invention as described hereinabove, and as defined in the appended claims.

We claim:

1. In a process for the rapid development of a photographic X-ray filrn wherein the film emulsion in contact with a series of transport rollers is treated with a number of warm aqueous processing solutions and dried with warm air, the steps of (1) developing the exposed film having on at least one side of a support a silver halide emulsion layer having a hardness determined by its melting point in water, of more than about F., about 300 to 650 mgs. silver per square foot as silver halide, on the same side of the support about 100 to 600 mgs. per square foot of hydrophilic organic colloid vehicle, with a silver halide developing solution having a pH of about 9.5 to 10.5 at a temperature of about 80 to 120 F., (2) fixing and washing the developed film at a temperature of about 80 to 120 F. until substantially all solubilized silver salt has been removed from said film and (3) drying the film at a temperature of about 120 to 200 F.

2. The process of claim 1 wherein the colloid vehicle is gelatin and the developing solution contains a gelatin hardening agent.

3. The process of claim 1 wherein the colloid vehicle is gelatin and the developing solution contains a dialdehyde gelatin hardening agent and an organic antifoggant compound.

4. The process of claim 3 wherein the developing solution contains sodium Z-anthraquinone sulfonate as an antifoggant and glutaraldehyde bis-sodium bisulfite or ,B-methyl glutaraldehyde bis-sodium bisulfite is a gelatin hardener.

5. In a process for the rapid development of a photographic X-ray film wherein the film emulsion in contact with a series of transport rollers is treated with a number of warm aqueous processing solutions and dried with warm air, the steps of (1) developing the exposed film having on each side of a support a silver halide emulsion layer having a hardness determined by its melting point in water, of more than about 190 F., about 300 to 650 mgs. of silver per square foot as silver halide, on each side of the support 100 to 600 mgs. per square foot of hydrophilic organic colloid vehicle, with a silver halide developing solution having a pH of about 9.5 to 10.5 at a temperature of about 80 to 120 F., (2) fixing and washing the developed film at a temperature of about 80 to 120 F. until substantially all solubilized silver salt has been removed from said film and (3) drying the film at a temperature of about 120 to 200 F.

6. The process of claim 5 wherein the colloid vehicle of each emulsion layer comprises a major amount of gelatin.

7. The process of claim 6 wherein the developing solution contains about 5 gms. per liter of glutaraldehyde or fl-methyl glutaraldehyde and about 0.1 gm. per liter of sodium Z-anthraquinone sulfonate.

8. The process of claim 5 wherein the development time is at least about 10 seconds, fixation is at least about 10 seconds, washing is at least about 8 seconds and drying is at least about 5 seconds.

9. The process of claim 1 wherein the time of treatment of the film with the processing solutions and drying is from about to seconds when from about to 600 rngs. per square foot of the colloid vehicle is present in the emulsion layer.

10. The process of claim 1 wherein the colloid vehicle is gelatin present in the amount of about 200 to 500 mgs. per square foot.

References Cited UNITED STATES PATENTS 3,303,341 2/1967 Fran et al. 250-65 OTHER REFERENCES PSA Journal, vol. 15, February 1949, pp. -135.

Journal of Photographic Science, November 1944, pp. 541-550.

Mason, Photoprocessing Chemistry, 1966, pp. 149-152.

Glafkides, Photographic Chemistry, vol. I, 1958, pp. 314, 402 and 403.

NORMAN G. TORCHIN, Primary Examiner M. F. KELLEY, Assistant Examiner U.S. Cl. X.R.

Disclaimer 3,545,97L-J0hn 0. Barnes, Uhester 0'. Wilt and William W. Rees, Rochester, NY. RAPID PROCESSING OF PHOTOGRAPHIC X-RAY FILM. Patentdated Dec. 8, 1970. Disclaimer filed July 17, 1974, by the assignee, Eastman Kodak Company. Hereby enters this disclaimer to all claims (claims 1-10) of said patent.

[Ofioial Gazette April 22, 1975.]

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