JPS63173036A - Cassette for accumulative fluorescent sheet - Google Patents

Abstract

PURPOSE:To accurately and simply make a recording area of an object coincide with a prescribed partial reading area by displaying the prescribed reading area set up so as to be smaller than sheet size at the time of reading out radiation image information from a sheet on a cassette table plate parallel with the sheet. CONSTITUTION:Lines 5-7 indicating respective areas of large angle size smaller than half size, quarter size, 1/6 size are displayed on the table plate 2. For instance, the large angle size is regulated by a line 5 on the lower part of the half size, and the quarter size and 1/6 size are similarly regulated by lines 6, 7 respectively on the lower right part of the half size. Character displays 5a-7a indicating the size regulated by respective lines 5-7 are entered on positions along respective lines 5-7. In the case of using the cassette 1, an object is arranged so as to be opposed to the display part and then photographed with radiant rays, so that the object can be accurately recorded on a partial area to be read out thereafter.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention relates to a cassette for storing a stimulable phosphor sheet for storing and recording radiation image information, and more specifically, to a cassette for storing a stimulable phosphor sheet for storing and recording radiographic image information. The present invention relates to a cassette for stimulable phosphor sheets that allows the reading area and recording area to be accurately aligned when reading radiation image information on a stimulable phosphor sheet.

(Prior art) When a certain type of phosphor is irradiated with radiation (X-rays, α-rays, β-rays, γ-rays, ultraviolet rays, electron beams, etc.), part of the energy of this radiation is accumulated in the phosphor. Then, when the phosphor is irradiated with excitation light such as visible light, the phosphor exhibits stimulated luminescence depending on the accumulated energy. A phosphor exhibiting such properties is called a stimulable phosphor (n-reverse phosphor).

Using this stimulable phosphor, radiation image information of a subject such as a human body is recorded on a stimulable phosphor sheet (hereinafter referred to as a stimulable phosphor sheet), which is then scanned with excitation light and illuminated. A method has been proposed in which the stimulated emitted light is photoelectrically read to obtain an image signal, and the image signal is processed to obtain a radiographic image of a subject that is suitable for diagnosis (for example, Japanese Patent Application Laid-Open No. 1983-1981). No. 12429, No. 55-116340, No. 55-163472, No. 56-11395, No. 56-104645, etc.).

This system has the practical advantage of being able to record images over a much wider range of radiation exposure compared to conventional radiographic systems using silver halide photography. In other words, in a stimulable phosphor, it is recognized that the amount of emitted light that is stimulated to emit light due to excitation after accumulation is proportional to the amount of radiation exposure over an extremely wide range.
Therefore, even if the amount of radiation exposure varies considerably due to various imaging conditions, the amount of stimulated luminescence emitted from the stimulable phosphor sheet can be read by the photoelectric conversion means by setting the reading gain to an appropriate value. By converting the radiation image into an electric signal and using this electric signal to output the radiation image as a visible image to a recording material such as a photographic light-sensitive material or a display device such as a CRT, a radiation image that is not affected by fluctuations in radiation exposure amount can be obtained. be able to.

By the way, when recording (photographing) radiographic image information on the stimulable phosphor sheet mentioned above, in order to avoid increasing the size of the sheet used and complicating its handling, it is necessary to use a stimulable phosphor sheet of relatively large size. Sheets are often used for both large and small subjects. Record a small subject in a relatively large size (
When a photograph is taken), the reading process is not performed over the entire surface of the stimulable phosphor sheet, that is, excitation light irradiation and stimulated emission light detection, but only on a small area including the recorded area of the subject. It is preferable to do so. That is, by doing so, meaningless reading processing will not be performed on areas other than the subject recording portion, and the time required for reading will be shortened. In this way, in order to perform reading processing only on the recording area of the subject, if the radiation irradiation field is narrowed down to match the size of the subject, the irradiation field of each sheet is detected and the detection results are The reading area may be set based on the reading area, but the recording size should be selected from several predetermined sizes, such as cutout size, large size, etc., and the top position on the sheet of the recording range for each size should also be set at a predetermined position. If you decide, the reading process will be easier. In other words, by doing so, when reading radiation image information, the excitation light scanning range can be selected and set for each recording size from several predetermined ranges, without having to perform difficult irradiation field recognition. With a simple operation, you can read only the subject recording area. In addition, in this way, even if the radiation irradiation field is not narrowed down, only the partial area where the subject is recorded can be read.

On the other hand, the above-mentioned stimulable phosphor sheet is, for example,
As shown in No. 13350, it is often handled in a cassette. Of course, small objects may be recorded on the stimulable phosphor sheet housed in this cassette as described above, and in this case as well, as mentioned above, the reading range must be adjusted to speed up the reading process. often has to be limited to only a partial area on the sheet.

(Problems to be Solved by the Invention) However, when using a conventional cassette for stimulable phosphor sheets, it is difficult to set the subject recording (photographing) area on the sheet to coincide with a predetermined partial reading area. Ta.

Therefore, the present invention provides a stimulable phosphor sheet that, when recording a small object on a relatively large stimulable phosphor sheet, can accurately and easily match the recording area of this object with a predetermined partial reading area. The purpose of this project is to provide a cassette for personal use.

(Means for Solving the Problems) The cassette for a stimulable phosphor sheet of the present invention has a portion set on the cassette top plate parallel to the stimulable phosphor sheet when reading radiation image information from the sheet. It is characterized by a display indicating the reading area.

(Function) When using the above-mentioned cassette, if radiography is performed with the subject placed so as to face the above-mentioned display area, the subject can be correctly placed and recorded in the partial area that will be read later.

(Example) Hereinafter, the present invention will be described in detail based on an example shown in the drawings.

FIG. 1 shows a cassette for a stimulable phosphor sheet according to an embodiment of the present invention. The cassette 1 consists of a flat top plate 2 and a lid 4 which is hinged to the top plate 2 with a hinge 3 and covers the top plate 2 so as to be openable and closable. Although not shown, latch means for connecting the top plate 2 and the lid 4 is provided on the side opposite to the side to which the hinge 3 is attached. The stimulable phosphor sheet 10 is stored in the cassette 1 in parallel with the top plate 2 and the lid 4. - For example, the stimulable phosphor sheet 10 is cut in half, and the cassette 1 is sized to tightly accommodate the sheet 10 of this size.

Lines 5, 6, and 7 are displayed on the top plate 2 to indicate the areas of the large size, cut size, and important size, which are smaller than the half cut size. In this example, line 5 indicates that the large-angle size is on the lower side of the half-cut size, and line 6
．． According to 7, the cut size and important size are defined as the lower right side of the half cut size. At positions along each line 5, 6, and 7, characters 5a, 5a, and 7a indicating the size defined by each line are written. ``The cassette 1 having the above structure is set on the imaging table 8 as shown in FIG. 2 and used for radiographic imaging. At this time, if the object 9 is small enough to be photographed without using the entire half-sized stimulable phosphor sheet 10, the object 9 will fall within the size defined by the line 5.6 or 7. The cassette 1 is arranged so that it can be opened. As an example, FIG. 2 shows a state in which the cassette 1 is arranged so that the subject 9 can fit within the important size defined by the line 7. After arranging cassette 1 in this way, for example
! Radiation is emitted from a radiation source such as a tube toward a cassette 1, and a transmitted radiation image of a subject 9 is stored and recorded on a stimulable phosphor sheet 10 within the cassette 1. Note that during this imaging, the radiation irradiation field may or may not be narrowed down according to the size of the subject 9.

The stimulable phosphor sheet 10 on which the radiation image of the subject 9 has been stored and recorded as described above is taken out from the cassette 1 and placed in a radiation image information reading device as shown in FIG. 3, for example. In this device, a stimulable phosphor sheet 10
is carried out by a sheet conveying means 11 such as an endless belt,
The excitation light is transported in the direction of arrow Y for sub-scanning. Further, the laser beam 13 as excitation light emitted from the laser light source 12 is deflected by an optical deflector 14 such as a galvanometer mirror, and the stimulable phosphor sheet 10 is deflected in the direction of arrow X, which is substantially perpendicular to the sub-scanning direction Y. Main scan. From the part of the sheet 10 irradiated with the laser beam 13 in this way,
A photostimulated luminescent light 15 corresponding to the accumulated and recorded radiographic image information is emitted, and this stimulated luminescent light 15 is transmitted to the condenser 1.
6 and is photoelectrically detected by a photomultiplier (photomultiplier tube) 17 as a photodetector.

The light condenser 16 is made by molding a light guide material such as an acrylic plate, and has a linear incident end surface 16a extending along the beam scanning line on the stimulable phosphor sheet 10. The light receiving surface of the photomultiplier 17 is coupled to the output end surface 16b formed in an annular shape. The stimulated luminescent light 15 that enters the light condenser 16 from the incident end face 16a travels through the light condenser 16 through repeated total reflection, exits from the output end face 16b, and is received by the photomultiplier 11. , the amount of stimulated luminescent light 15 carrying the radiation image information is determined by this photomultiplier.
17.

The analog output signal of the photomultiplier 17 is logarithmically converted and amplified in the log amplifier 20, and the read image signal @ which carries the light amount of the stimulated luminescence light 15, that is, radiation image information.
The signal S is input to the A10 converter 21. The read image signal S is this A/D! It is digitized by converter 21. The digital read image signal Sd obtained in this way is then subjected to image processing such as gradation processing in the image processing device 23, and then input to an image reproduction device 24 such as a CRT or optical scanning recording device, and the image In the playback device 24,
The radiation image stored and recorded by the stimulable phosphor sheet 10 is reproduced.

Here, a drive control signal S1 is inputted from the reading control device 32 to the drive control circuit 30 of the optical deflector 14 and the drive control circuit 31 of the sheet conveying means 11, respectively, and the stimulable fluorescence is The beam scanning range on the body sheet 10 is changed. That is, the sheet conveying means 11 first conveys the stimulable phosphor sheet 10 at a relatively high speed, and when the sheet 10 reaches a predetermined position, starts conveying the sheet for beam sub-scanning at a predetermined sub-scanning speed. However, the timing of starting this sub-scanning, in other words, the time during which the sheet 10 is conveyed at a relatively high speed as described above, is changed in accordance with the drive control signal S1.

In addition, the optical deflector 1 is synchronized with the timing of starting the sub-scanning.
The beam scanning start timing and the beam deflection range of No. 4 can be changed according to the drive control signal S1. The drive control signal S1 for changing the beam scanning range on the stimulable phosphor sheet 10 as described above is changed depending on the imaging size information S2 inputted to the reading control device 32 using the imaging information input terminal 33, for example. It will be done. That is, when the imaging sizes indicated by the imaging size information S2 are half-cut, large-angle, wide-cut, and important sizes, the beam scanning range specified by the drive control signal S1 is the point P shown in FIG.
I P2, P3, and P4 are used as scanning starting points, and the area is set to the lower right side of the figure from the scanning starting points. In FIG. 4, as an example, a beam scanning range of an important size is shown with diagonal lines. By controlling the beam scanning range in this way, only the recording area that contains a small subject (or the irradiation field area if irradiation field aperture is performed) is subjected to the reading process during radiographic imaging, and the other areas are This prevents the reading processing time from becoming unnecessarily long due to meaningless reading processing of the part.

(Effects of the Invention) As explained in detail above, according to the cassette for stimulable phosphor sheets of the present invention, radiation images can be recorded so that the subject is accurately placed in the partial area to be read on the stimulable phosphor sheet. Therefore, partial recording and partial reading, which are advantageous in shortening the reading processing time, can be performed without failure.

[Brief explanation of the drawing]

Fig. 1 is a perspective view showing a cassette for a stimulable phosphor sheet according to an embodiment of the present invention, Fig. 2 is a plan view showing the setting state of the cassette at the time of photographing, and Fig. 3 is a perspective view showing a cassette for a stimulable phosphor sheet according to an embodiment of the present invention. FIG. 4 is a schematic diagram showing an example of a device for reading radiation image information from a stimulable phosphor sheet on which a radiation image has been photographed. FIG. 4 is a schematic diagram showing a reading area set for the stimulable phosphor sheet. 1... Cassette 2... Cassette top plate 5.
6.7...Reading size display line 10...Stormable phosphor sheet Fig. 1 Fig. 2 Fig. 311 Fig. 4 1, IJ display 1985 Patent Application No. 005.267 2, Invention Name of cassette for stimulable phosphor sheets Representative: Minoru Ohnishi 4, Agent address: 7th floor, 7th floor of Hauraiya Pill, 5-2-1 Roppongi, Minato-ku, Tokyo, subject of amendment [Details of the invention] Explanation j, Column 8, Correction details 1) Mark 11 [@Page 4, line 9, "Often used." j
I am corrected. 2) On page 6, line 3, ``There are many.'' is corrected to ``There are.''

Claims (1)

[Claims] In a cassette for a stimulable phosphor sheet that stores a stimulable phosphor sheet for accumulating and recording radiation image information, a cassette surface plate parallel to the sheet is set to have a size smaller than the sheet size when reading radiation image information from the sheet. 1. A cassette for a stimulable phosphor sheet, the cassette having a display indicating a predetermined reading area.