Patient identification and x-ray exam data collection bar code system

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FIELD OF THE INVENTION

This invention relates in general to storage phosphor radiography in which a latent x-ray image of a patient stored in a storage phosphor is converted to an x-ray image signal. More particularly, the present invention relates to a storage phosphor radiography patient identification system for matching patient x-ray exam data with the patient's x-ray image.

BACKGROUND ART

In conventional film/screen radiography, a commonly used patient identification system has the following features.

1. A requisition is filled out by the radiologist ordering a specific exam to be performed on a patient. The requisition is sent to the radiology department.

2. A technologist takes the requisition, an x-ray film cassette, and a portable x-ray generator to the patient bedside.

3. The technologist performs the exam and the film is exposed to x-rays.

4. The requisition is taped to the cassette and the exposed film is taken to the darkroom.

5. A preprinted information card is "flashed" on to the film. Such information includes the patient name, medical record number, birth date, hospital name, current date and other standard information.

6. The film is processed, and the radiology technologist verifies that a "good" image has been recorded.

7. A sticker is applied to the film which records the date, time of exposure, technique, and technologist identification.

8. The finished x-ray film is placed on a light box for review and diagnosis by a radiologist or physician.

Because of the inherent disadvantages of film radiography in the acquisition, storage and transmission of x-ray images, there has been proposed a storage phosphor radiography system. Temporary x-ray images stored in a storage phosphor are converted into an x-ray image digital signal which can be stored, processed and transmitted. As described in U.S. Pat. No. Re. 31,847, reissued Mar. 12, 1985 to Luckey, a photostimulable phosphor sheet is exposed to an image-wise pattern of short wavelength radiation, such as x-ray radiation, to record a latent image pattern in the photostimulable phosphor sheet. The latent image is read out by stimulating the phosphor with a relatively long wavelength stimulating radiation, such as red or infrared light. Upon stimulation, the stimulable phosphor releases emitted radiation of an intermediate wavelength, such as blue or violet light, in proportion to the quantity of x-ray radiation that was received. An x-ray image signal is produced by scanning the stimulable phosphor sheet in a raster pattern by means of a beam of laser light deflected by an oscillating or rotating scanning mirror. The emitted radiation is sensed by a photodetector to produce an electrical x-ray image signal. This signal may then be stored, transmitted, or displayed on a monitor or reproduced as an x-ray film.

As with film-based radiography, storage phosphor radiography requires the matching of an x-ray image with the patient. In situations where many x-rays are taken, such as in an intensive care unit of a large hospital, the management of identification of x-rays with patients can be monumental. In order to process an x-ray image signal as a function of x-ray exposure conditions, it is also desirable to match x-ray exposure conditions and other patient identification data with the x-ray image signal. Such matching results in proper diagnosis by a diagnostician (such as a radiologist) who views the x-ray image on a monitor or x-ray film reproduction.

In a known storage phosphor radiography system, patient information is entered into a workstation and is transferred to a magnetic card. (See, for example, U.S. Pat. No. 4,641,242, issued Feb. 3, 1987, inventor Kimura; U.S. Pat. No. 4,739,480, issued Apr. 19, 1988, inventors Oona et al.; U.S. Pat. No. 4,885,468, issued Dec. 5, 1989, inventor Shimura.) After an x-ray exposure on a storage phosphor is made, a technician places the cassette containing the exposed storage phosphor into a reader and dumps the patient data into the reader by swiping the magnetic card through an associated magnetic card reader. Many problems exist with this system, including double entry of patient data, which is typically entered into a computer at the time a patient is admitted into a hospital. Moreover, the specific ordering of computed radiography cassettes and patient data must be maintained.

The health care bar code identification systems disclosed in the following patents are not entirely suitable for use in storage phosphor radiography systems: U.S. Pat. No. 4,857,713, issued Aug. 15, 1989, inventor Brown; U.S. Pat. No. 5,006,699, issued Apr. 9, 1991, inventors Felkner et al.; U.S. Pat. No. 4,835,372, issued May 30, 1989, inventors Gombrich et al.; and U.S. Pat. No. 4,857,372, issued Aug. 15, 1989, inventors Gombrich et al.

A storage phosphor radiography patient ID system using a hand-held bar code scanner has been proposed in commonly-assigned, copending U.S. patent application Ser. No. 963,036, filed Oct. 19, 1992. The disclosed system records data using a hand-held bar code scanner. Because this image will be recorded, processed, transmitted, and archived digitally by a computer, the exam data also needs to be in digital form to travel with the image. The exam data is read in directly from the bar code scanner by the storage phosphor reader into a header file which is associated with the image file. The image is quality assured by a radiology tech using an electronic view box(video monitor), and the image is printed on film with the necessary information by a laser printer. Thus, no "post-processing" is required.

There has been proposed in copending U.S. application Ser. No. 981,144, filed Nov. 24, 1992, inventors Godlewski et al., a quality control workstation linked to a storage phosphor reader. The quality control workstation provides a radiology technologist with several functions including checking images acquired from a storage phosphor reader (or other sources of digital radiographic images, correcting patient information and x-ray exam information, adjusting image parameters such as image orientation and window width and leveling, routing acceptable exams and images to designated destinations (such as, remote high resolution workstations, magnetic or optical archival image storage, radiographic laser, CRT or thermal printers). Although patient information entered at the time of an x-ray exam can be changed or supplemental at the workstation.

It is desirable that a patient identification x-ray exam collection bar code system have the following features which are not fulfilled in known ID/collection bar code systems.

1. Easier entry of patient and technologist IDs.

2. Ability to review all data that has been collected.

3. Common comments do not have to be entered in on a keypad.

4. Ability to easily delete a record.

5. Ability to have required data fields and default fields.

6. Support many common bar code standards.

There is thus a problem in providing a patient ID/x-ray exam data collection bar code system which incorporates these desirable features and obviates the disadvantages of the prior art.

SUMMARY OF THE INVENTION

According to the present invention, there is provided a patient ID/x-ray exam data collection bar code system which obviates the disadvantages of the prior art. The present invention has the following advantageous features.

1. Ability to review all of the data that has been collected.

2. Patient IDs (bar codes) have been encoded. This provides for easy entry of the patient ID. A two step entry process is now reduced to a one step operation.

3. Technologists IDs (bar codes) have been encoded. This provides for easy entry of the technologists ID. A two step entry process is now reduced to a one step operation.

4. Common comments do not have to be typed in with the key pad. Bar codes have been defined for common comments.

5. Ability to easily delete a record (file for one patient).

6. Ability to designate any of the fields as being Required fields. A technologist would then be required to enter this data before the patient record is completed. The fields that are required can be set by each customer at the customer site. A special application using a required fields bar code sheet has been developed.

7. Some of the fields may be defaulted to a predetermined value. This provides for faster data input at the patient bed side in the ICU. Fields that always have the same value for a given hospital can be defaulted to that value. For each patient, only exceptions are inputted. If no default values programming bar code sheet.

8. Support many common bar code standards to read existing bar code information in the hospital (patient ID, requisition number, etc.).

9. All bar codes on the exam data collection card are coded. This provides easy bar code printing and support for multiple languages.

According to the present invention there is provided a patient identification and x-ray exam data collection bar code system, comprising:

a patient bar code adapted to be located with a patient for identifying a patient;

a storage phosphor for storing an x-ray image of a patient, said storage phosphor having a storage phosphor bar code for identifying the storage phosphor;

x-ray exam bar code chart locatable with an x-ray source for identifying x-ray examination characteristics of said x-ray image stored in said storage phosphor, wherein said exam bar code chart includes sets of exam bar codes identifying unique body parts of a patient, x-ray exposure conditions, etc.;

hand-held bar code scanner having a user input, a memory, a digital controller, and a display, for scanning the patient bar code, the storage phosphor bar code and a bar code from at least one of said sets of bar codes on said exam bar code chart; and

a required fields control card having bar codes representing required fields bar code scanner commands and bar codes representing required exam bar code sets to be scanned by a bar code scanner user.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a storage phosphor reader.

FIGS. 2 and 3 are respectively a partially diagrammatic, partially schematic view and a perspective view of the components of the storage phosphor reader of FIG. 1.

FIG. 4 is a schematic diagram of a critical care system incorporating the present invention.

FIGS. 5-7 are screens depicting some of the functions of a quality control station of the system of FIG. 4.

FIG. 8 is a perspective view of a medical care facility incorporating an embodiment of the present invention.

FIG. 9 is a partially broken away perspective view of a storage phosphor cassette shown in FIG. 8.

FIG. 10 is a diagrammatic view of an x-ray exam type chart shown in FIG. 8.

FIG. 11 is a diagrammatic view of a patient ID chart shown in FIG. 8.

FIG. 12 is a block diagram of the bar code scanner of FIG. 8.

FIG. 13 is a block diagram of the system of FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now to FIG. 1, there is shown a storage phosphor reader 10 incorporating an embodiment of the present invention. Reader 10 is mounted on casters 11 for easy portability in a radiology environment. Reader 10 includes a multiunit housing 12 housing the components of storage phosphor reader 10 and a video monitor 14 having a touch screen 16 supported on housing 12. Housing 12 also includes a bar code reader docking station 18 for docking a hand held bar code reader and for transferring data from the hand held bar code reader to storage phosphor reader 10. Reader 10 includes storage phosphor cassette load platform 20 which receives cassettes containing storage phosphor plates which are to be read or erased by reader 10.

In general, storage phosphor reader 10 processes images captured on a storage phosphor plate using conventional radiographic equipment. Reader 10 then scans the storage phosphor plate and converts the latent x-ray image therein into an electrical x-ray image signal which can be viewed on monitor 14. The scanned image is then delivered to a receiving device (such as a quality control station, laser printer or archival device) for image processing, image enhancement, viewing, printing and/or storage. The storage phosphor reader 10 is operated using touch screen 16 which also displays the image. The storage phosphor plates which are used to hold the unexposed x-ray images are mounted in standard size x-ray cassettes of different sizes. These storage phosphor plates can be erased and reused repeatedly. The optional hand held bar code reader can be used to collect exam information which is transferred to the storage phosphor reader 10 when it is mounted in station 18. The exam information is then associated with the scanned images.

As will be described in greater detail later, the storage phosphor reader 10 is used in storage phosphor patient identification system according to the present invention. Following is a general description of a storage phosphor patient identification system.

When a radiology technologist receives a request for an x-ray examination of a patient, the technologist exposes a body part of the patient to an x-ray which is stored as a latent x-ray image in the storage phosphor plate of a storage phosphor cassette. Several images may be taken at this time. Using the optional portable bar code reader (scanner), the technologist scans the patient identification bar code label and the label on the storage phosphor cassette. Exam related information can be scanned from a bar code chart that is usually attached to the portable x-ray generator. Such information includes body part type, x-ray exposure conditions, position of patient and the like.

The image is now captured by the technologist performing the x-ray exam using the cassette containing the storage phosphor plate from which the bar code label was scanned. When the x-ray exam is complete the technologist takes the storage phosphor cassette to storage phosphor reader 10 to be processed. If the optional bar code reader is used, the technologist transfers the patient identification and exam information by inserting the bar code reader into the bar code reader station 18 on the front of reader 10. The scanned information is then transferred to the control system of the storage phosphor reader 10. The technologist then loads the cassette containing the exposed storage phosphor plate into reader 10 by loading on load platform 20. Scanning is initiated when the technologist presses a start button on touch screen 16.

Inside storage phosphor reader 10 the storage phosphor plate is extracted from the cassette and scanned with a laser light. As the plate is scanned, the image appears on touch screen 16 as it is being scanned. After the scanning is complete the image is sent to a receiving device where it can be tonescaled, enhanced, viewed, printed and/or stored. After the storage phosphor plate has been completely scanned it is erased by exposure to light which removes any remnants of the image. The storage phosphor reader 10 then places the storage phosphor plate back into its cassette. The technologist can now remove the cassette from reader 10 to be reused for another exam.

Referring now to FIGS. 2 and 3 there will be described in greater detail a preferred embodiment of storage phosphor reader 10. As shown, a storage phosphor cassette 22 containing a storage phosphor plate 24 is loaded on cassette load platform 20. Load lever 26 is rotated to clamp cassette 22 in place and to latch the cassette 22 to permit extraction of storage phosphor plate 24 therefrom. Storage phosphor plate 24 is extracted from cassette 22 by extraction device 28 (FIG. 3) which is actuated by extraction motor 30 under software control from control 32. Control 32 includes standard computer components such as a microprocessor, a magnetic disk drive for storing images, software applications and computer operating system and input and output devices to communicate with the components of reader 10. Such microcomputer systems are well known in the art and will not be described in detail herein.

Extraction device 28 is slidably mounted on translation stage 34 and includes hooks 36 which engage storage phosphor plate 24. Extraction device 28 extracts storage phosphor plate 24 from cassette 22 onto translation stage 34. As the storage phosphor plate 22 is loaded onto stage 34 it passes over plate size detecting switches 36 which detect the plate size and communicate this information to control 32. There are sufficient plate size detectors 36 to detect the different plate sizes that can be processed by reader 10. The beginning and end of travel of extraction mechanism 28 are sensed by extraction begin and end travel switches 38 connected to control 32.

Translation stage 34 is slidably mounted on rails 40 and 42 for movement in opposite directions 44 which are perpendicular to the directions 46 of loading and unloading of plate 24 relative to translation stage 34. Translation stage 34 is driven by a screw drive mechanism 48 actuated by stepper motor 50 mounted on block 52. Rails 40 and 42 are supported by frame member 54 of reader 10.

The laser scanning components will now be described. Reader 10 includes a laser 56 (such as a helium neon gas laser) for stimulation of storage phosphor plate 24. Laser 56 produces a laser beam 58 which passes through a shutter 60. Shutter 60 is controlled by digital signals received from control 32. Shutter 60 closes with activation of cover interlock switches 62 which detect closure of the housing 12 covers.

Beam 58 is reflected off mirror 64 and passes through beam splitter 66 which directs a portion of the laser beam 58 to reference photodetector 68. Following the beam splitter 66 laser beam 58 passes through collimator 70. The collimated laser beam is deflected by an oscillating scan mirror 72 driven by galvanometer 74 under the control of control 32. Scan mirror 72 provides the line scan raster motion of the laser beam 58. Galvanometer 74 drives mirror 72 with a constant angular velocity.

An f-theta lens 76 produces a flat field of focus and constant linear velocity at the plane of storage phosphor plate 24. Folding mirror 78 directs the laser beam through light collector 80 onto storage phosphor plate 24. Collector 80 may be of the type disclosed in commonly assigned U.S. Pat. No. 5,151,592, issued Sep. 29, 1992, inventors Boutet et al. The stimulating light of laser beam 58 causes the storage phosphor in plate 24 to emit light (blue) which is a function of the x-ray image stored in plate 24. Collector 80 directs this emitted light onto photomultiplier tube (PMT) 82. A filter 84 in front of the face of PMT 82 blocks the scattered stimulating laser light and passes the light emitted by storage phosphor plate 24. Once a storage phosphor plate 24 is on translation stage 34 a scan is begun. Movement of translation stage 34 in the direction of arrow 44 is under software control of control 32. Control 32 sends commands to stepper motor 50 to initiate a scan, to start translation stage 34, to start galvanometer 74 and to turn on PMT 82. From the home position of stage 34 the control 32 counts stepper motor 50 steps to the point where the storage phosphor plate 24 is under collector 80. At this point acquisition of the latent x-ray image on storage phosphor plate 24 begins. At the end of the scan (determined by the number of scan lines for the appropriate storage phosphor plate size), PMT 82 and galvanometer 74 are turned off and translation stage 34 is returned to the home position which is determined by one of the stage position optical sensors 85. A stage end of travel switch 86 is located just beyond the position of optical sensors 84 to prevent damage in case of failure of optical sensors 84.

Immediately after translation stage 34 reaches the home position, erase lamp 88 is turned on by actuation of erase power supply 90 under software control from control 32. Following a predetermined erase time (such as 30 seconds) erase lamp 88 is turned off and extraction mechanism 28 returns storage phosphor plate 24 in the direction of arrow 46 to storage phosphor cassette 22. When the extraction mechanism 28 trips the extraction end of travel switch 38, the lock for load lever 26 is released. The storage phosphor reader user can now rotate load lever 26 and remove cassette 22 from loading platform 20.

During the scan of storage phosphor plate 24 an emitted x-ray light image is converted by PMT 82 into an x-ray electrical current signal. This signal is converted to a voltage by amplifier 92. As described in greater detail in commonly assigned U.S. patent application Ser. No. 965,657, filed Oct. 23, 1992, inventor S. Dhurjaty, entitled "Noise Reduction in a Storage Phosphor Data Acquisition System", laser noise which is present in the x-ray image signal produced by PMT 82 is corrected by subtracting a reference signal detected by reference photodetector 68. The corrected digital signal is corrected for the light collection signature of light collector 80 by a correction lookup table in control 32. The correction lookup table is loaded during calibration of reader 10 when it is initially set up.

As will be described in greater detail later, patient identification and examination information are downloaded into reader 10 from a hand held bar code scanner 94 positioned in station 18 of reader 10. As each storage phosphor plate 24 is extracted from its cassette 22 cassette bar code reader 96 reads the bar code on plate 24. The image data and corresponding patient and exam information are correlated by control 32.

The physical size of the cassettes 22 containing the storage phosphor plates 24 are identical to that of conventional radiographic film/screen cassette sizes. Typically storage phosphor reader 10 is capable of reading the following storage phosphor plate sizes: 18.times.24 centimeters, 24.times.30 centimeters, 35.times.35 centimeters, and 35.times.43 centimeters. The raster pattern or matrix pixel size for each storage phosphor plate that can be processed is, for example, as follows: 18.times.24 cm - 1792.times.2400; 24.times.34 cm - 2048.times.2500; 35.times.35 cm - 2048.times.2048; and 35.times.43 cm - 2048.times.2500.

The storage phosphor reader 10 of FIG. 1 can be part of a critical care system made up of hardware and software that allows radiology technologists to (