Radiation image recording and read-out apparatus

A radiation image recording and read-out apparatus is provided with a body comprising a system for conveying stimulable phosphor sheets for recording radiation images along a path, and an image recording section and an image read-out section which are positioned on the path. The apparatus body is provided with a section positioned at the upstream end of the path for feeding the stimulable phosphor sheets to the sheet conveying system, and a section positioned at the downstream end of the path for ejecting the stimulable phosphor sheets from the sheet conveying system. Or, the apparatus body is connected by conveyor belts with an erasing unit for erasing radiation energy remaining in the stimulable phosphor sheets after image read-out. The apparatus body and the erasing unit are positioned independently of each other in spaced relation by a predetermined distance.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
This invention relates to a radiation image recording and read-out 
apparatus for exposing stimulable phosphor sheets to a radiation passing 
through an object to have a radiation image of the object stored therein, 
exposing the stimulable phosphor sheet to stimulating rays which cause 
them to emit light in proportion to the stored radiation energy, and 
detecting and converting the emitted light into electric signals. 
2. Description of the Prior Art 
When certain kinds of phosphors are exposed to a radiation such as X-rays, 
.alpha.-rays, .beta.-rays, .gamma.-rays, or cathode rays or ultraviolet 
rays, they store a part of the energy of the radiation. Then, when the 
phosphor which has been exposed to the radiation is exposed to stimulating 
rays such as visible light, light is emitted by the phosphor in proportion 
to the stored energy of the radiation. A phosphor exhibiting such 
properties is referred to as a stimulable phosphor. 
As disclosed in U.S. Pat. Nos. 4,258,264, 4,276,473, 4,315,318 and 
4,387,428, and Japanese Unexamined Patent Publication No. 56(1981)-11395, 
it has been proposed to use a stimulable phosphor in a radiation image 
recording and reproducing system. Specifically, a sheet comprising the 
stimulable phosphor is first exposed to a radiation passing through an 
object to have a radiation image stored therein, and is then scanned with 
stimulating rays which cause it to emit light in proportion to the 
radiation energy stored. The light emitted from the stimulable phosphor 
sheet when the sheet is exposed to the stimulating rays is 
photoelectrically detected and converted to an electric image signal, 
which is processed as desired to reproduce a visible image having an 
improved quality, particularly a high diagnostic efficiency and accuracy. 
The finally obtained visible image may be reproduced in the form of a hard 
copy or may be displayed on a cathode ray tube (CRT). In this radiation 
image recording and reproducing system, the stimulable phosphor sheet is 
used to temporarily store the radiation image in order to reproduce the 
final visible image therefrom in a final recording medium. For economical 
reasons, therefore, it is desirable that the stimulable phosphor sheet be 
used repeatedly. 
In order to reuse stimulable phosphor sheets of the type described above, 
the radiation energy remaining on the stimulable phosphor sheet after it 
is scanned with stimulating rays to read out the radiation image stored 
therein should be erased by exposure to light or heat as described, for 
example, in Japanese Unexamined Patent Publication No. 56(1981)-12599 or 
U.S. Pat. No. 4,400,619. The stimulable phosphor sheet should then be used 
again for radiation image recording. 
From the aforesaid viewpoint, the applicant proposed in Japanese Patent 
Application No. 58(1983)-66730 a built-in type radiation image recording 
and read-out apparatus comprising: 
(i) a circulating and conveying means for conveying at least one stimulable 
phosphor sheet for recording a radiation image thereon along a 
predetermined circulation path, 
(ii) an image recording section positioned on said circulation path for 
recording a radiation transmission image of an object on said stimulable 
phosphor sheet by exposing said stimulable phosphor sheet to a radiation 
passing through said object, 
(iii) an image read-out section positioned on said circulation path and 
provided with a stimulating ray source for emitting stimulating rays for 
scanning said stimulable phosphor sheet carrying said radiation image 
stored therein in said image recording section, and a photoelectric 
read-out means for detecting light emitted from said stimulable phosphor 
sheet scanned with said stimulating rays to obtain an electric image 
signal, and 
(iv) an erasing section for, prior to the next image recording on said 
stimulable phosphor sheet for which the image read-out has been conducted 
in said image read-out section, having said stimulable phosphor sheet 
release the radiation energy remaining in said stimulable phosphor sheet, 
whereby said stimulable phosphor sheet is circulated through said image 
recording section, said image read-out section and said erasing section 
and reused for radiation image recording. 
Since the radiation image recording and read-out apparatus constructed as 
described above can continuously and efficiently conduct radiation image 
recording and read-out, it is suitable for mass medical examinations and 
for loading on a mobile X-ray diagnostic station in the form of a vehicle 
like a bus for the purposes of mass medical examinations or the like. 
In the aforesaid radiation image recording and readout apparatus, the 
erasing section is fabricated for exposing the stimulable phosphor sheet 
to erasing light or heat. When erasing light is used, in order to make the 
stimulable phosphor sheet practically reusable for image recording, the 
stimulable phosphor sheet must be exposed to a large light amount 
(illuminance.times.time), for example, to 10,000 1.times. for 100 seconds. 
In order to shorten the image erasing time, an erasing light source having 
as high an output (high illuminance) as possible should be installed at 
the erasing section. However, in this case, the apparatus becomes large, a 
power source of a high capacity is necessary, and the large amount of heat 
generated by the erasing light source has an adverse effect on the other 
sections of the apparatus. Therefore, the level of the output of the 
erasing light source has to be limited. Thus in the aforesaid radiation 
image recording and read-out apparatus, even though the image recording 
and image read-out processing speeds are increased, the processing speed 
of the overall apparatus cannot be increased substantially, because a long 
time is required for image erasing at the erasing section. 
SUMMARY OF THE INVENTION 
The primary object of the present invention is to provide a radiation image 
recording and read-out apparatus which continuously and efficiently 
conducts recording and read-out of a radiation image and which is compact. 
Another object of the present invention is to provide a radiation image 
recording and read-out apparatus wherein image recording and read-out 
processing speeds are increased substantially. 
The specific object of the present invention is to provide a radiation 
image recording and read-out apparatus wherein image recording, read-out 
and erasing speeds are substantially increased as a whole. 
The present invention provides a radiation image recording and read-out 
apparatus comprising: 
(i) a sheet conveying means for conveying at least one stimulable phosphor 
sheet for recording a radiation image thereon along a predetermined path, 
(ii) an image recording section positioned on said path for recording the 
radiation image of an object on said stimulable phosphor sheet by exposing 
said stimulable phosphor sheet to a radiation passing through said object, 
(iii) an image read-out section positioned on said path on the downstream 
side of said image recording section in the sheet conveyance direction and 
provided with a stimulating ray source for emitting stimulating rays for 
scanning said stimulable phosphor sheet carrying said radiation image 
stored therein at said image recording section, and a photoelectric 
read-out means for detecting light emitted by said stimulable phosphor 
sheet scanned by said stimulating rays to obtain an electric image signal, 
(iv) a sheet feeding section positioned at an upstream end of said path in 
the sheet conveyance direction for feeding said stimulable phosphor sheet 
to said sheet conveying means, and 
(v) a sheet ejecting section positioned at a downstream end of said path in 
the sheet conveyance direction for ejecting said stimulable phosphor sheet 
from said sheet conveying means after said stimulable phosphor sheet 
passes through said image read-out section. 
The present invention also provides a radiation image recording and 
read-out apparatus comprising: 
(a) a recording and read-out apparatus body constituted by integrally 
incorporating therein: 
(i) a first sheet conveying means for conveying at least one stimulable 
phosphor sheet for recording a radiation image thereon along a 
predetermined path, 
(ii) an image recording section positioned on said path for recording the 
radiation image of an object on said stimulable phosphor sheet by exposing 
said stimulable phosphor sheet to a radiation passing through said object, 
and 
(iii) an image read-out section positioned on said path on the downstream 
side of said image recording section in the sheet conveyance direction and 
provided with a stimulating ray source for emitting stimulating rays for 
scanning said stimulable phosphor sheet carrying said radiation image 
stored therein at said image recording section, and a photoelectric 
read-out means for detecting light emitted by said stimulable phosphor 
sheet scanned by said stimulating rays to obtain an electric image signal, 
and 
(b) an erasing unit for, prior to next image recording on said stimulable 
phosphor sheet for which the image read-out has been conducted at said 
image read-out section, having said stimulable phosphor sheet release the 
radiation energy remaining in said stimulable phosphor sheet, wherein 
(c) said recording and read-out apparatus body and said erasing unit are 
positioned independently of each other in spaced relation by a 
predetermined distance, and 
(d) said path in said recording and read-out apparatus body is connected on 
the downstream side of said image read-out section in the sheet conveyance 
direction with a sheet inlet of said erasing unit by a second sheet 
conveying means, and is connected on the upstream side of said image 
recording section in the sheet conveyance direction with a sheet outlet of 
said erasing unit by a third sheet conveying means. 
In the radiation image recording and read-out apparatus of the present 
invention mentioned first, since the image recording section and the image 
read-out section are connected by the sheet conveyance path, and the 
stimulable phosphor sheets are automatically conveyed and fed to the image 
recording section and the image read-out section, it is possible to record 
and read out the radiation images continuously and efficiently. Also, the 
stimulable phosphor sheets after the image read-out are sequentially 
ejected from the sheet ejecting section of the apparatus, and subjected to 
image erasing in an erasing unit installed independently of the radiation 
image recording and read-out apparatus. The stimulable phosphor sheets 
after image erasing are sequentially fed to the radiation image recording 
and read-out apparatus from the sheet feeding section, and reused for 
image recording. Since the image erasing, which takes comparatively long 
time, is conducted outside of the radiation image recording and read-out 
apparatus, the recording and read-out processing speeds for the radiation 
images may be increased substantially. Further, since the radiation image 
recording and read-out apparatus of the present invention has no image 
erasing section, the power consumption is low and the apparatus is 
suitable particularly for loading on a mobile X-ray diagnostic station for 
the purposes of mass medical examinations or the like. 
In the second mentioned radiation image recording and read-out apparatus of 
the present invention, since the image recording section, the image 
read-out section and the erasing unit are connected by the sheet conveying 
means and the stimulable phosphor sheets are circulated by the sheet 
conveying means through the image recording section, the image read-out 
section and the erasing unit, it is possible to use the sheets repeatedly 
and to conduct the radiation image recording and read-out continuously and 
efficiently. Also, since the erasing unit is separated from the recording 
and read-out apparatus body, it is free from various limitations and can 
be provided with increased erasing capacity. As a result, it becomes 
possible to shorten the erasing time and to markedly increase the 
processing speed of the overall apparatus.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
The present invention will hereinbelow be described in further detail with 
reference to the accompanying drawings. 
Referring to FIG. 1, a sheet conveyance path 26 is constituted by endless 
belts 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 and 12, guide rollers 13, 14, 15, 
16, 17 and 18 rotated respectively by the endless belts 1, 2, 7, 8, 11 and 
12, and guide plates 19, 20, 21, 22 and 23. A plurality of stimulable 
phosphor sheets 30 are positioned in spaced relation to each other on the 
sheet conveyance path 26 and are conveyed in the direction as indicated by 
the arrow A by the endless belts 1 to 12 as the sheet conveying means. 
The endless belts 3 and 4 are positioned to vertically hold the stimulable 
phosphor sheet 30 therebetween. An image recording section 40 is 
constituted by an image recording stand 41 positioned on the left side of 
the endless belts 3 and 4, and a radiation source 42, e.g. an X-ray 
source, spaced from the image recording stand 41 to stand face to face 
with the endless belts 3 and 4. For recording a radiation image of an 
object 43 on the sheet 30, the sheet 30 is held between the endless belts 
3 and 4, and the radiation source 42 is activated with the object 43 
standing in front of the image recording stand 41. In this manner, the 
sheet 30 is exposed to a radiation passing through the object 43 to have a 
radiation image of the object 43 stored in the sheet 30. 
An image read-out section 50 is positioned at the lower section of the 
sheet conveyance path 26. At the image read-out section 50, a laser beam 
source 51 is positioned above the endless belt 9 constituting a part of 
the image read-out section 50, and a mirror 53 and a galvanometer mirror 
54 are positioned for scanning a laser beam 52 emitted by the laser beam 
source 51 in the width direction of the sheet 30 placed on the endless 
belt 9. The galvanometer mirror 54 is swung in both ways to scan the laser 
beam 52 in the main scanning direction on the sheet 30 carrying the 
radiation image stored therein. The sheet 30 has been subjected to image 
recording at the image recording section 40 and then conveyed by the sheet 
conveying means to the image read-out section 50. A light guiding 
reflection mirror 55 and a light guide member 56 are positioned along the 
main scanning direction at the scanning portion of the laser beam 52 on 
the sheet 30. When the sheet 30 is exposed to the laser beam 52, the sheet 
30 emits light in proportion to the stored radiation energy. The light 
emitted by the sheet 30 directly towards the light guide member 56 and the 
light emitted by the sheet 30 and reflected by the light guide reflection 
mirror 55 enter the light guide member 56 from a light input face 56A 
thereof, and is guided inside of the light guide member 56 through total 
reflection to a light output face 56B thereof. The light is thus detected 
by a photomultiplier 57 connected to the light output face 56B of the 
light guide member 56. Simultaneously with the scanning of the sheet 30 by 
the laser beam 52 in the main scanning direction, the sheet 30 is moved by 
the endless belt 9 in the sub-scanning direction, as indicated by the 
arrow A, approximately normal to the main scanning direction, so that the 
whole surface of the sheet 30 is scanned by the laser beam 52. The 
electric image signal produced by the photomultiplier 57 is sent to an 
image processing circuit (not shown) for processing. The image signal thus 
processed is then sent to an image reproducing apparatus (not shown). The 
image reproducing apparatus may be a display device such as a CRT, or a 
device for recording a visible image by point-by-point scanning on a 
photographic film. Or, the image signal may be stored in a storage means 
such as a magnetic tape. 
After image read-out is finished, the sheet 30 is conveyed by the endless 
belts 10 and 11 along the guide plate 23 and is sent by the endless belt 
12 into a magazine 60 which is positioned at a sheet ejecting section 61 
releasably from the recording and read-out apparatus body. After the 
sheets 30 which have passed through the image read-out step are loaded 
into the magazine 60, they can be removed from the radiation image 
recording and read-out apparatus as housed in the magazine 60. 
The magazine 60 removed from the sheet ejecting section 61 is loaded into 
an image erasing unit 70 as shown in FIG. 2, and images remaining on the 
stimulable phosphor sheets 30 housed after image read-out in the magazine 
60 are erased. Specifically, when the magazine 60 is fitted to a sheet 
receiving section 70A of the image erasing unit 70, the sheets 30 in the 
magazine 60 are taken up one by one by a sheet feeding mechanism 71 
comprising a moveable suction cup or the like. After being taken up the 
sheet is conveyed upwardly by an endless belt 72 along a guide plate 73. 
An erasing light source 74 comprising, for example, many fluorescent lamps 
is positioned to stand face to face with the guide plate 73 and emits 
erasing light onto the sheet 30 conveyed along the guide plate 73. When 
the sheet 30 is exposed to the erasing light, the radiation energy 
remaining therein is released, and the residual image on the sheet 30 is 
thus erased. After the image erasing, the sheets 30 are conveyed by an 
endless belt 75 into a different magazine 60 fitted to a sheet ejecting 
section 70B of the image erasing unit 70. 
The magazine 60 loaded with a predetermined number of the sheets 30 after 
the image erasing is fitted to a sheet feeding section 62 of the radiation 
image recording and readout apparatus shown in FIG. 1. The erased sheets 
30 housed in the magazine 60 are taken out of the magazine 60 one by one 
by use of a sheet feeding mechanism 63 comprising a moveable suction cup 
or the like, and are fed by the endless belt 1 onto the sheet conveyance 
path 26. The sheets 30 fed to the sheet conveyance path 26 are sent along 
the guide plate 19, conveyed by the endless belts 2, 3 and 4 to the image 
recording section 40, and reused for recording radiation images as 
described above. 
In the aforesaid embodiment, the sheets 30 which have passed through the 
image read-out step at the image readout section 50 are not erased in the 
apparatus but are ejected into the magazine 60 fitted to the sheet 
ejecting section 61, and new sheets 30 are fed from the sheet feeding 
section 62. Therefore, the radiation image recording and read-out 
apparatus is free from the problem that a long time is taken for image 
erasing. When many sheets 30 and many magazines 60 are used and image 
erasing for the sheets 30 is conducted by use of the image erasing unit 70 
by efficiently utilizing the time for which the radiation image recording 
and read-out apparatus is not operated, it becomes possible to 
continuously conduct recording and read-out of radiation images. 
In the present invention, the magazines 60 need not necessarily be used for 
ejection and feeding of the sheets 30. However, it is advantageous to use 
the magazines 60 for facilitating the sheet handling and improving the 
working efficiency. 
FIG. 3 shows another embodiment of the radiation image recording and 
read-out apparatus in accordance with the present invention. The apparatus 
comprises a recording and read-out apparatus body 106 and an erasing unit 
107 positioned independently of the apparatus body 106 in spaced relation 
by a predetermined distance. The apparatus body 106 is fabricated by 
integrally incorporating therein a first sheet conveying means 103 
composed of conveying rollers, conveyor belts and guide plates for 
conveying stimulable phosphor sheets 101 along a predetermined path 102, 
an image recording section 104 positioned on the path 102, and an image 
read-out section 105 positioned on the path 102 on the downstream side of 
the image recording section 104 in the sheet conveyance direction as 
indicated by the arrow A. 
At the image recording section 104, the stimulable phosphor sheet 101 is 
exposed to a radiation emitted by a radiation source 110 and passing 
through an object 111 to have a radiation image of the object 111 stored 
in the sheet 101. 
The sheet 101 is then conveyed by the first sheet conveying means 103 in 
the direction as indicated by the arrow A along the path 102 to the image 
read-out section 105. 
The image read-out section 105 comprises a stimulating ray source 152 for 
emitting stimulating rays 151 such as a laser beam for scanning the sheet 
101, and a photoelectric read-out means 153 constituted by a 
photomultiplier or the like for detecting light emitted by the sheet 101 
when it is exposed to the stimulating rays 151 and converting the emitted 
light into an electric image signal. Reference numeral 154 denotes a 
galvanometer mirror. 
The path 102 is connected on the downstream side 102a of the image read-out 
section 105 with a sheet inlet 107a of the erasing unit 107 by a second 
sheet conveying means 108 constituted by a belt conveyor. The path 102 is 
also connected on the upstream side 102b of the image recording section 
104 with a sheet outlet 107b of the erasing unit 107 by a third sheet 
conveying means 109 constituted by a belt conveyor. 
The erasing unit 107 comprises an inlet side stacker 171 for receiving the 
sheets 101 conveyed through the sheet inlet 107a by the second sheet 
conveying means 108, a subsidiary sheet conveying means 173 for conveying 
the sheets 101, which are sent from the inlet side stacker 171, into an 
erasing unit body 172, a subsidiary sheet conveying means 175 for taking 
the sheets 101 out of the erasing unit body 172 and conveying them into an 
outlet side stacker 174, and the outlet side stacker 174 for receiving the 
sheets 101 conveyed by the subsidiary sheet conveying means 175. The 
sheets 101 received by the outlet side stacker 174 are then sent through 
the sheet outlet 107b to the third sheet conveying means 109. 
The erasing unit 107 is provided with many erasing light sources 176 
constituted by fluorescent lamps, tungsten filament lamps, sodium lamps, 
xenon lamps, iodine lamps or the like. 
Each of the stackers 171 and 174 stores a plurality of the sheets 101 and 
delivers them, in the order received by delivery rollers 171a and 174a. 
In the embodiment of FIG. 3, the sheet 101 carrying a radiation image 
stored therein at the image recording section 104 is conveyed by the first 
sheet conveying means 3 in the direction as indicated by the arrow A, and 
the radiation image is read out of the sheet 101 at the image read-out 
section 105. Then, the sheet 101 is conveyed by the second sheet conveying 
means 108 to the erasing unit 107 at which the image remaining in the 
sheet 101 is erased. The sheet 101 is then conveyed by the third sheet 
conveying means 109 into the image recording section 104. Thereafter, the 
sheet 101 is circulated through the image recording section 104, the image 
read-out section 105 and the erasing unit 107 in the same manner. 
The stackers 171 and 174 are not absolutely necessarily and one or both can 
be omitted. Moreover, when provided, they need not be installed in the 
erasing unit 107, but can be positioned outside of the erasing unit 107. 
In the embodiment of FIG. 3, the single recording and read-out apparatus 
body 106 is connected with the single erasing unit 107. However, it is 
also possible to connect a plurality of recording and read-out apparatus 
bodies 106 with a single erasing unit 107. In this case, the second and 
third sheet conveying means 108 and 109 for connecting the recording and 
read-out apparatus bodies 106 and the erasing unit 107 with each other may 
be constituted as shown in FIG. 4. 
In FIG. 4, the third sheet conveying means 108 comprises outlet belt 
conveyors 81 connected with the first sheet conveying means of the 
recording and read-out apparatus bodies 106 on the downstream sides of the 
image read-out sections, relay belt conveyors 82, and main belt conveyors 
83 for conveying the stimulable phosphor sheet to the inlet 107a of the 
erasing unit 107. As shown in FIG. 5, the outlet belt conveyors 81 and the 
relay belt conveyors 82 are positioned at different heights. When the 
stimulable phosphor sheets are delivered from the outlet belt conveyors 81 
to the relay belt conveyors 82, the relay belt conveyors 82 are stopped. 
The relay belt conveyors 82 are driven after they receive the stimulable 
phosphor sheets. 
The third sheet conveying means 109 comprises main belt conveyors 91 for 
conveying the erased stimulable phosphor sheets from the outlet 107b of 
the erasing unit 107 to the recording and read-out apparatus bodies 106, 
relay belt conveyors 92, inlet belt conveyors 93 connected with the first 
sheet conveying means of the apparatus bodies 106 on the upstream sides of 
the image recording sections, and nip rollers 94 positioned between the 
relay belt conveyors 92 and the inlet belt conveyors 93. When the 
stimulable phosphor sheets are delivered from the main belt conveyors 91 
to the relay belt conveyors 92, the relay belt conveyors 92 are stopped. 
As shown in FIG. 6, the sheets 101 are moved by pushing members 95 (not 
shown in FIG. 4) in the direction as indicated by the arrow, held by the 
nip rollers 94, and sent to the inlet belt conveyors 93. When the 
stimulable phosphor sheet is conveyed to the apparatus body 106 farther 
from the erasing unit 107, the relay belt conveyor 92 at the apparatus 
body 106 closer to the erasing unit 107 is not stopped and conveys the 
stimulable phosphor sheet to the next main belt conveyor 91. 
When a plurality of the apparatus bodies 106 are connected with the single 
erasing apparatus 107 as in the embodiment mentioned last, it is 
advantageous that the stackers as shown in FIG. 3 be used. In this case, 
it becomes possible to temporarily store the erased stimulable phosphor 
sheets in the outlet side stacker and to sequentially supply the sheets to 
the apparatus bodies 106 which require the sheets. In this manner, it is 
possible to decrease the number of the sheets required as a whole, and the 
manner in which the sheets are used becomes uniform.