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Description  |
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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. Nos. 4,641,242, issued Feb. 3, 1987, inventor
Kimura; 4,739,480, issued Apr. 19, 1988, inventors Oona et al.; 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.
U.S. Pat. No. 4,960,994, issued Oct. 2, 1990, inventor Muller et al.,
discloses a cassette which contains an x-ray film coated with a stimulable
phosphor layer and which has a cassette memory which is rigidly attached
to the cassette. The memory carries storable, recordable, readable, and
erasable data and is attached to the cassette at a position spaced a
predetermined distance from a given cassette corner. The rigidly attached
memory has four contacts for transfer of data and for power supply. This
patent does not disclose the use of a separate bar code on the cassette.
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. Nos. 4,857,713, issued Aug. 15, 1989, inventor Brown;
5,006,699, issued Apr. 9, 1991, inventors Felkner et al.; 4,835,372,
issued May 30, 1989, inventors Gombrich et al.; and 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.
A more recent development for use in healthcare identification systems is
suggested in the brochure entitled "Touch The Future", distributed by
Dallas Semiconductor, Dallas, Tex. A solid state read/write memory in a
self contained stainless steel can has a self-adhesive backing attachable
to a hospital bracelet to provide patient ID. A hospital bedside testing
application is also suggested in which the solid state memory container is
adhered to a nurse's badge and a reagent cannister. A hand-held meter
downloads the information received from these memories into a personal
computer. There is no suggestion in this brochure of using the solid state
memory container in a storage phosphor radiography system.
A problem therefore exists in storage phosphor radiography apparatus of
linking examination information associated with an x-ray exam with the
x-ray image recorded in a storage phosphor.
SUMMARY OF THE INVENTION
According to the present invention, there is provided a storage phosphor
radiography identification system which provides a solution to the
problems of known film-based radiography and computed radiography
identification systems. According to the present invention, a storage
phosphor radiography patient identification system comprises:
patient identifying bar code means adapted to be located with a patient for
identifying a patient;
a storage phosphor cassette means for containing a storage phosphor which
stores an x-ray image of a patient, said storage phosphor cassette means
having storage phosphor identifying bar code means for identifying said
storage phosphor and further having adhered to it a read/write
non-volatile memory contained in a self adhesive electrically conductive
cylindrical container;
x-ray examination type bar code means locatable with an x-ray source for
identifying x-ray examination type characteristics of an x-ray image
stored in said storage phosphor, wherein said x-ray examination type bar
code means includes a first set of bar codes identifying unique body parts
of a patient and a second set of bar codes identifying x-ray exposure
conditions;
hand-held bar code scanner means, having memory, for scanning said patient
identifying bar code means, said storage phosphor bar code identifying
means, and a bar code from each of said respective sets of said x-ray
examination type bar code means at the time said storage phosphor means is
exposed to an x-ray image of a patient, to produce patient identifying
information, storage phosphor means identifying information, and x-ray
examination type information which is stored in said memory; wherein said
bar code scanner means is further provided with a probe connected to said
memory for transferring said identifying information to said read/write
non-volatile memory, adhered to said storage phosphor means;
storage phosphor reader means for converting a stored x-ray image in said
storage phosphor into an x-ray image signal, said storage phosphor reader
means having, a) bar code reader means for reading said storage phosphor
bar code identifying means to produce a storage phosphor identifying
signal matched with said x-ray image signal, and b) a read/write memory
probe for contacting said read/write memory and for transferring said
identifying information stored in said memory to said storage phosphor
reader for matching said transferred information to said x-ray image
signal.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of a medical care facility incorporating an
embodiment of the present invention;
FIG. 2 is a partially broken away perspective view of a storage phosphor
cassette shown in FIG. 1;
FIG. 3 is a diagrammatic view of an x-ray exam type chart shown in FIG. 1;
FIG. 4 is a diagrammatic view of a patient ID chart shown in FIG. 1;
FIG. 5 is a block diagram of the bar code scanner of FIG. 1;
FIG. 6 is a perspective view of a storage phosphor reader for reading
storage phosphors used in the system of the present invention;
FIG. 7 is a partial block diagram, partial diagrammatic view of the storage
phosphor reader shown in FIG. 6.
FIG. 8 is a partial perspective view of a storage phosphor cassette showing
a read/write memory container adhered to a storage phosphor.
FIGS. 9 and 10 are respective top and side views of an exemplary read/write
memory for incorporation in the present invention.
FIG. 11 is a side view of a probe for transferring information to and from
the memory of FIGS. 9 and 10 and incorporated in the storage phosphor
reader of FIG. 7 and in the bar code scanner shown in FIG. 5.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now to FIG. 1, there will be described an embodiment of the
present invention as used in a multi-bed medical care facility such as the
intensive care unit of a hospital. As shown, the medical care facility
includes a plurality of beds 10, 12, 14, and 16 having respective patients
18, 20, 22, and 24 who require medical treatment. A portable x-ray unit 26
has an x-ray source 28 mounted on a moveable arm 30 supported by cabinet
32. Cabinet 32 includes controls and power supply for x-ray source 28.
Wheels 34 on cabinet 32 facilitate moving unit 26 from bed to bed.
According to the present invention, an x-ray image of a body part of a
patient is produced in a stimulable storage phosphor contained in a
cassette. Thus, storage phosphor cassettes 36, 38, 40, and 42 are provided
for patients 18, 20, 22, and 24, respectively, Cassettes 36, 38, 40, and
42 have storage phosphor identifying bar codes 44, 46, 48 and 50 which
uniquely identify each storage phosphor. Storage phosphor cassettes 36,
38, 40, and 42 also have adhered thereto respective read/write memories
37, 39, 41, and 45.
As shown in FIG. 2, storage phosphor cassette 42 has a removable storage
phosphor plate 43 with bar code 50. Read/write memory 45 is shown adhered
to cassette 42. FIG. 8 shows an alternative placement for memory 45' as
adhered to storage phosphor plate 43. An exemplary storage phosphor
cassette is disclosed in commonly assigned, copending U.S. application
Ser. No. 617,121.
Each patient 18, 20, 22, and 24 is provided a unique patient identifying
bar code 52, 54, 56, and 58 on respective patient charts 60, 62, 64, and
66. An alternative patient identifying bar code can also be placed on an
identifying bracelet placed on a patient's wrist.
X-ray unit 26 has associated with it a chart 68 having a list of x-ray exam
types and/or x-ray exposure conditions with a set of bar codes identifying
each exam type and exposure condition. As shown in more detail in FIG. 3,
chart 68 has several sets 70A-70H of bar codes for different types of exam
information. These bar code sets are illustratively described as follows.
Bar code set 70A identifies x-ray source Projections, such as, AP,
Lateral, RLD, LLD, X-ray Table. Bar code set 70B identifies patient Body
Part, such as Chest, Skull, Abdomen, CSpine, Pelvis, Extremity. Bar code
set 70C identifies patient position, such as, supine semi-erect, erect.
Bar code set 70D identifies x-ray source Distance to patient, such as 40
cm, 42 cm, 45 cm, 50 cm, 72 cm. Bar code sets 70E and 70F identify x-ray
source exposure parameters, respectively, kilovolts-KVP, (such as 50, 60,
70, 80, 85) and milliamperes current-MAS (such as 1.25, 1.5, 2.5, 3.2, 50,
80). Bar code set 70G identifies storage phosphor plate orientation, such
as vertical, horizontal. Bar code set 70H identifies radiology
technologist comments.
According to the technique of the present invention, an x-ray technician
who is responsible for taking x-rays at the medical care facility is
provided with a portable bar code scanner 72. Bar code scanner 72 (see
FIG. 5) has a laser scanner 74 for scanning bar codes and converting the
scanned bar code into an electrical signal which is stored in memory 76.
Preferably, scanner 72 has a keyboard 78 for entering data which is stored
in memory 76 and also has a display 80 for displaying the input data and
other information. Control circuit 73, scanner 74, memory 76, display 80
and keypad 78 are internally connected by bus 82. Bar code scanner is also
provided with a memory probe 75 connected to bus 82 for transferring
information from scanner 72 to a memory on a storage phosphor cassette,
e.g., memory 45' on cassette 42 (FIG. 8)
At the time a patient is exposed to an x-ray, a technician scans the
patient identifying bar code, scans the storage phosphor identifying bar
code and scans the bar code identifying the x-ray exam type. Thus, for
example, as shown in FIG. 1, x-ray source 28 is positioned over patient 24
and storage phosphor cassette 42 is positioned under the chest area of
patient 24. At the time of taking an x-ray, the technician uses bar code
scanner 72 to scan patient identifying bar code 66 on patient chart 58, to
scan storage phosphor identifying bar code 50 on storage phosphor cassette
42, and to scan x-ray examination type bar codes 70A-70H on exam type
chart. A technician identifying bar code may also be read. The technician
can correct or manually enter data via keypad 78 at the time an x-ray exam
is effected. The technician then transfers the exam information from bar
code scanner 72 to a memory 45' on the storage phosphor 43 of cassette 42.
After the technician has finished an x-ray exam of patient 24, he can move
x-ray unit 26 to the bedside of patients 18, 20, and 22 to produce x-ray
images in storage phosphor cassettes 36, 38, and 40.
After a set of x-ray exposures have been taken, relevant data for each
exposure scanned by portable bar code scanner 72, and the data transferred
form scanner 72 to the respective cassette memories 37, 39, 41, 45, the
technician carries the storage phosphor cassettes 36, 38, 40, and 42 in a
stack to a storage phosphor reader station. Such a station is shown in
FIG. 6 and includes a storage phosphor reader 84 and a workstation 86.
Preferably, a storage phosphor or cassette stacker (not shown) is provided
adjacent to reader 84 to sequentially feed exposed storage phosphors into
slot 90 of reader 84.
The exposed storage phosphor is read by reader 84 and converted to an x-ray
image signal which is stored in a suitable memory. At the same time,a bar
code reader in reader 84 reads the storage phosphor bar code and links the
storage phosphor ID with the read x-ray image signal. As each storage
phosphor is inserted into reader 84, and the stored x-ray image is
converted into an x-ray image signal, the storage phosphor identifying bar
code is read by a bar code reader in storage phosphor reader 84.
Additionally, a memory probe in reader 84 transfers exam information from
the cassette read/write memory to reader 84 where it is matched with the
read x-ray image signal. Thus, the x-ray image signal read from a storage
phosphor will be matched with the proper patient, x-ray exam type and
other related information for further processing in workstation 86.
Workstation 86 includes keyboard 110 and monitor 112.
Referring now to FIG. 7, there is shown in more detail, storage phosphor
reader 84. As shown, a storage phosphor 122 containing a storage phosphor
plate 124 is loaded on cassette load platform 120. Load lever 126 is
rotated to clamp cassette 122 in place and unlatches the cassette 122 by
an extraction device 128. Extraction device is slidably mounted on
translation stage 134 and includes hooks 136 which engage storage phosphor
plate 124. Extraction device 128 extracts storage phosphor plate 124 from
cassette 122 onto translation stage 134.
Translation stage 134 is slidably mounted on rails 140 and 142 for movement
in opposite directions 144 which are perpendicular to the directions 146
of loading and unloading of plate 124 relative to translation stage 134.
Translation stage 134 is driven by a screw motor 150 mounted on block 152.
Rails 140 and 142 are supported by frame member 154 of reader 84.
The laser scanning components will now be described. Reader 84 includes a
laser 156 (such as a helium neon gas laser) for stimulation of storage
phosphor plate 124. Laser 156 produces a laser beam 158 which passes
through a shutter 160. Beam 158 is reflected off mirror 164 and passes
through beam splitter 166 which directs a portion of the laser beam 158 to
reference photodetector 168. Following the beam splitter 166 laser beam
158 passes through collimator 170. The collimated laser beam is deflected
by an oscillating scan mirror 172 driven by galvanometer 174. Scan mirror
172 provides the line scan raster motion of the laser beam 158.
Galvanometer 174 drives mirror 172 with a constant angular velocity.
An f-theta lens 176 produces a flat field of focus and constant linear
velocity at the plane of storage phosphor plate 124. Folding mirror 178
directs the laser beam through light collector 180 onto storage phosphor
plate 124. Collector 180 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 158 causes the storage phosphor in plate
124 to emit light (blue) which is a function of the x-ray image stored in
plate 124. Collector 180 directs this emitted light onto photomultiplier
tube (PMT) 182. A filter 184 in front of the face of PMT 182 blocks the
scattered stimulating laser light and passes the light emitted by storage
phosphor plate 124. Once a storage phosphor plate 24 is on translation
stage 134 a scan is begun. From the home position of stage 134, it moves
under collector 180. At this point, acquisition of the latent x-ray image
on storage phosphor plate 124 begins. At the end of the scan, translation
stage 34 is returned to the home position.
Immediately after translation, stage 34 reaches the home position, an erase
lamp (not shown) is turned on. Following a predetermined erase time (such
as 30 seconds), the erase lamp is turned off and extraction mechanism 128
returns storage phosphor plate 124 in the direction of arrow 146 to
storage phosphor cassette 122. The storage phosphor reader user can now
rotate load lever 126 and remove cassette 122 from loading platform 120.
During the scan of storage phosphor plate 124, an emitted x-ray light image
is converted by PMT 182 into an x-ray electrical current signal. This
signal is converted to a digital image signal by amplifier ADC 186.
Patient identification and examination information are transferred into
reader 84 from memory probe 194. As each storage phosphor plate 124 is
extracted from its cassette 122 cassette bar code reader 196 reads the bar
code on plate 24. The image data and corresponding patient and exam
information are stored in memory 188 and correlated by computer 190.
The nonvolatile read/write memory is shown in FIGS. 9 and 10. As shown,
memory 200 includes a cylindrical electrically conductive (such as
stainless steel) container 202 which contains a non-volatile solid state
memory. Can 202 has an adhesive backing 204 which mounts memory 200 to a
storage phosphor cassette or storage phosphor plate. Memory 200 has an
inner face 206 which is insulated from container 202. The rim 208 of
container 202 is an electrical ground contact and face 206 is a data
contact. Data is transferred to and from memory 200 via the one-wire
protocol which needs only a single data contact and a ground return.
FIG. 10 shows a probe 210 which is adopted to engage memory 200. Probe 210
includes a body 212 having a data contact face 214 and an electrical
ground rim 216 insulated from face 214. Wires 218,220 provide connection
to the system control.
Although the invention has been described with reference to preferred
embodiments there, it will be understood that variations and modifications
can be effected with the spirit and scope of the invention as described
above as defined in the appended claims.
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