JPS63250635A - Image information reader - Google Patents

Abstract

PURPOSE:To improve the optical transfer property without being influenced by the outside, by using a photoconductive body constituted of two kinds of mediums having different refractive indexes, for converging a stimulated phosphorescent light, in an image information reader of a radiant ray. CONSTITUTION:X rays 2 are radiated to an objective to be photographed 1 such as the human body, etc. and an X-ray transmission image is recorded to stimulable phosphor panel 5. Also, a light beam from a light source 6 of a read part is deflected 7, and the stimulable phosphor panel 5 is scanned. The stimulated phosphorescent light generated from its panel 5 is converged by a light converging conduction body 9 and converted to easily handleable wavelength. Light of its wavelength is brought to a photoelectric conversion by a photomultiplier 11, and its electric signal is processed, by which a read image is obtained. In this regard, the light conversion conduction body 9 is formed by a composite constitution by setting its internal core and external clad to a high refractive index and a low refractive index, respectively, and also, mixing a fluorescent substance into the internal core. In such a way, the converging efficiency of the light conversion conduction body 9 becomes large. Accordingly, since the light conversion conduction body is used, the converging efficiency can be improved, and the optical transmission can be executed satisfactorily without being influenced by the outside.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a device for reading image information of a phosphor panel that is recorded by irradiation with radiation.

[Prior art]

This type of image reading device scans and irradiates excitation light onto a photostimulable phosphor panel that has previously recorded image information of a human body, etc. by irradiating it with X-rays to excite the phosphor, thereby causing photostimulated luminescence. The generated fluorescent light is guided to a photoelectric conversion element using a photoconductor.
Devices that read image information are known.

However, this device has a problem in that its performance deteriorates if scratches or dust adhere to the photoconductor.

[Purpose of the invention]

The purpose of the present invention is to improve the light transmission properties and to make them less susceptible to the influence of the external environment.

[Structure of the invention]

To this end, the present invention provides a method for scanning a stimulable phosphor panel for recording radiation image information with excitation light, condensing the stimulated luminescent light from the panel, and performing photoelectric conversion to obtain image information. In the image information reading device, a photoconductor composed of two types of media having different refractive indexes was arranged to collect the exhaustive emitted light.

〔Example〕

Examples of the present invention will be described below. FIG. 1 is a schematic diagram showing the overall structure of an apparatus for carrying out the present invention. In this embodiment, an X-ray irradiator 2 is placed on the back of a subject 1 such as a human body, and a grid 3, a phototimer 4, and a stimulable phosphor panel 5 are arranged in sequence in front of the subject 1. In contrast, an X-ray transmission image of the subject 1 is recorded as fluorescence accumulated energy. The grid 3 shields X-rays incident from other directions than the direction of the X-ray irradiator 2 (reflected or scattered by others) to ensure accurate) 1! The phototimer 4, which is used to obtain images, is used to detect the accumulated amount of X-ray irradiation and control the X-ray irradiator 2.

The above-mentioned X-ray irradiator 2, grid 3, phototimer 4, etc. constitute a recording section.

On the other hand, in the reading section, a light beam from a beam light source 6 using a semiconductor laser or the like is deflected (scanned) by a deflector 7 to scan the stimulable phosphor panel 5 via a mirror 8 or the like. A filter 10 is provided which converts the stimulated luminescence light generated in the light spot portion into a wavelength that is easy to handle using a rond-shaped photoconversion conductor 9, and removes the light generated by the photoconversion conductor 9 from other light. After photoelectric conversion is performed by a PMT (photomultiplier) 11 and amplified by an amplifier 12, the A/D converter 1
3, the digital signal is converted into a digital signal, and the digital signal is sent to an image processing circuit (not shown) to obtain a read image. Reference numeral 14 denotes an erasing lamp, and by lighting this lamp and scanning the exhaustible phosphor panel 5, the energy remaining after the reading and scanning of the panel 5 is released and erased.

FIG. 2 is a block diagram showing the reading section in more detail. The beam light source 6 is equipped with a collimating lens,
The beam shape of these light beams is shaped by a beam shaper 15, passed through a mirror 16 and a filter I7, and then scanned by a galvanometer mirror 18 serving as a deflector 7. and,
This scanned beam passes through the fθ lens 19, has its optical path changed by the mirror 8, and enters the stimulable phosphor panel 5 as excitation light. The above-mentioned photoconversion conductor 9 has a rond shape arranged parallel to the scanning direction of the excitation light so as to cover the scanning line on the tumescent phosphor panel 5, and has both ends thereof. PMTII through filter 10
are combined. 20 is a power supply for PMTll.

21 is a current/voltage conversion circuit that converts the current signal obtained by PMTll into a voltage, and 22 is an adder that adds the voltage signals obtained by both current/voltage conversion circuits 21. 24
2 is a logarithmic amplifier that logarithmically amplifies the output of the amplifier 12, 25 is a filter for removing noise components, and 26 is a sampling hold circuit that samples the read image signal pixel by pixel. Further, at one end of the volatile phosphor panel 5, an optical sensor 27 such as a photodiode that detects the scanning beam light is arranged, and a horizontal synchronization signal (one time of excitation light One pulse is emitted during main scanning.)
Timing signal generation circuit 2 that determines the processing timing
8 is entered. The signal from this timing signal generation circuit 28 is sent to the sampling hold circuit f126, the A/D
A driver 29 that controls the converter 13 and the light beam generator 6
, is output to a galvanometer mirror driver 30, etc.

As shown in FIG. 3, the above-mentioned light conversion conductor 9 has the property of generating light of a different wavelength from inside toward the end face when light enters from the side, and is a volatile phosphor panel. By arranging the panel 5 facing the panel 5, the three-dimensional light reception angle from the stimulated luminescence point of the panel 5 becomes extremely large, and the light collection efficiency becomes high.

This light conversion conductor 9 is a fluorescent opto-collector (product name)
It is also called a transparent plastic such as acrylite, polycarbonate, or polystyrene under certain conditions, in which a special fluorescent substance is dispersed and mixed.

The majority (80%) of the fluorescence generated inside due to the incidence of light from the outside is guided to both end face portions according to the law of total internal reflection, and is emitted in a concentrated state. In this example, the excitation light λ2 (-500 nm ~ 2.00 nm
nm, 700 nm to 800 nm for semiconductor laser light
) is excited by the stimulable phosphor panel 5 and is emitted from the stimulable phosphor panel 5. The stimulated luminescent light λ3 (=200 nm to 500 nm) is received from the side to generate a different wavelength λ4 (=400 nm to 2,000 nm).
nm), exits from both end faces, and enters the PMT II via the filter 10. FIG. 4 is a diagram showing the wavelength conversion characteristics of this light conversion conductor 9. When this photoconversion conductor 9 is placed facing the panel 5, the excitation light component passes through the photoconversion conductor 9 and does not enter the PMTII, resulting in a good S/N ratio.

As shown in FIG. 5, if a mirror 31 is formed by silver plating or the like on one end surface of the light conversion conductor 9, the case shown in FIG. The output light λ4 converted there can be focused with the same efficiency.

As shown in FIG. 6, this light conversion conductor 9 has a core 9a with a high refractive index inside, a crand 9b with a low refractive index outside, and a fluorescent substance mixed into the inner core 9a side. If it is a composite configuration of different types of media, the cladding 9b
As shown in FIG. 7, the converted output light λ4 can be guided to both ends without suffering from dirt or scratches on the outer cover, and the light collection efficiency is significantly improved. In Figure 7, 9c
is a fluorescent substance.

In this case, if the refractive index of the core 9a is nl and the refractive index of the cladding 9b is 02, the numerical aperture N, A, and the light reception and emission angles are N, A, = (nl ``nz'') ``''light reception and emission Angle = 2 sin (N, 8,).

Further, as shown in FIG. 8, this light conversion conductor 9 has a straight portion disposed along the scanning direction of the excitation light of the stimulable phosphor panel 5, and one conductor at each end thereof. P of
It can be bent to lead to the MTII, or it can be similarly arranged as a convergent light conversion conductor 9', which is a bundle of a plurality of small diameter light conversion conductors, as shown in FIG.

On the other hand, the method of incidence of the excitation light λ2 is shown in Fig. 10 (al
In addition to the method of making the light incident from an oblique direction as shown in ~(d+), there is also a method of making the light incident directly from above as shown in the same group (el~(h).In the former case, a light conversion conductor may be used as necessary. 9
．． A gear for passing the excitation light λ2 is formed in a part of 9'. In the latter case, the excitation light is made to pass between two adjacent light conversion conductors 9 or 9' directly above each other.

In addition, in order to improve the incidence efficiency of the stimulated luminescent light generated from the photostimulable phosphor panel 5 into the photoconversion conductor, the first
As shown in FIG. 1, a stimulable luminescence light reflecting member 32 is attached to the back surface of the photoconversion conductor (the side opposite to the side facing the stimulable phosphor panel 5), either in close contact with it or separated from it. If this reflecting member 32 is brought into close contact with a plurality of small-diameter focused light converting conductors 9', it will also function as a bundle of the conductors 9'.

In addition, this reflective member 32 is made of a material that has the ability to transmit excitation light, and prevents the excitation light from being reflected there and returning to the stimulable phosphor panel 5, so that the quality of the read image is affected by interference with the excitation light. to prevent it from deteriorating. FIG. 12 is a diagram showing an example of a light conversion conductor to which such a reflecting member 32 is attached.

FIG. 13 is a diagram showing an example in which light conversion conductors 9 or 9' are arranged on both the front and back surfaces of the stimulable phosphor panel 5. The volatile phosphor panel 5 has not only the side irradiated with excitation light, but also
Since stimulated luminescence light is also generated from the opposite side, by arranging the light conversion conductor also on the opposite side, the light collection efficiency can be greatly improved.

〔Effect of the invention〕

As described above, in the present invention, the photoconductor that condenses stimulated luminescence light is composed of two types of media with different refractive indexes, so the inner side is a high refractive index medium and the outer side is a low refractive index medium. This allows optical transmission to be performed without being affected by external influences.

Moreover, if this photoconductor is arranged so that the stimulated luminescent light is incident on its side surface, the three-dimensional light receiving angle from the stimulated luminescent point becomes extremely large, and the light collection efficiency is improved.

[Brief explanation of drawings]

Fig. 1 is a schematic configuration diagram of an image information recording/reading device showing the principle of the present invention, Fig. 2 is a more detailed block diagram of the reading device portion, Fig. 3 is an explanatory diagram of the light conversion conductor, and Fig. 4 ( al, (
bl is a characteristic diagram of the light conversion, Fig. 5 is an explanatory diagram of another method of focusing light from the photoconversion conductor, Fig. 6 is an explanatory diagram of a composite structure of the photoconversion conductor, and Fig. 7 is an explanatory diagram of the light conversion conductor. FIG. 6 is an explanatory diagram of the action of the photoconversion conductor shown in FIG.
- (h) are explanatory diagrams of excitation light irradiation, Fig. 11 (al, (b)
l is an explanatory diagram showing a reflection member attached to a light conversion transmitter to improve the condensing efficiency of stimulated luminescence light, and Fig. 12 (al~(hl)
13 is an explanatory diagram of each case, and FIG. 13 is an explanatory diagram of light conversion conductors arranged on the upper and lower surfaces of a stimulable phosphor panel. ■...Subject, 2...X-ray generator, 3...Grid, 4...Phototimer, 5...Stimulable phosphor panel, 6...Light beam generator, 7... ...Deflector, 8...
- Mirror, 9... Photoconversion conductor, 10... Filter, 11... PMT, I2... Amplifier, 13... A
/D converter, 14... Erasing lamp, 15... Beam shaper, 16... Mirror, 17... Filter, 18
...Galvano mirror-119...fO lens, 20.
...PMT power supply, 21...Current/voltage conversion circuit, 2
2... Adder, 24... Logarithmic amplifier, 25... Filter, 26... Sampling hold circuit, 27...
・・Horizontal opening)■Signal sensor, 28...Timing generation circuit, 29...Light beam generator driver, 3o...
Galvano mirror driver, 31...Mirror, 32
...Light reflecting member. Agent Patent Attorney Tsuneaki Nagao Figure 1 ■ Figure 5 Figure 7 Figure 10 (e) (f) (g)
(h) Figure 11 (a) (b) 9'32 Figure 12 (a) (b) (c)
(d) (e) (f)
(q> (h) (a>
(b) Q no

Claims (3)

[Claims] (1) An image information reading device that scans a photostimulable phosphor panel on which radiation image information is recorded with excitation light, collects the stimulated luminescent light from there, and performs photoelectric conversion to obtain image information. In this case, two materials having different refractive indexes are used for condensing the stimulated luminescence light.
An image information recording/reading device characterized in that a photoconductor made of a seed medium is arranged. (2) The image information reading device according to claim 1, wherein the photoconductor has a structure in which a low refractive index medium is filled around a high refractive index medium. (3) The image information reading device according to claim 2, wherein the high refractive index medium has a fluorescent substance dispersed therein.