JPH0795189B2 - Image information recording and reading method - Google Patents

Description

The present invention relates to a method of recording an image by, for example, irradiation with radiation and reading the image.

[Prior art]

As an image recording / reading method of this kind, a panel made of a stimulable phosphor or the like is used as a recording medium, and image information of a human body or the like is irradiated therewith by X-rays to be recorded there, and then the recording panel is recorded. There is known a method in which excitation light is scan-irradiated to excite a fluorescent substance, and thereby fluorescent light emitted by stimulated emission is guided to a photoelectric conversion element by an optical transmission member to read image information.

However, this method is not efficient because the stimulated emission light is condensed from the end face of the optical fiber bundle or the like and guided to the photoelectric conversion element. Further, the wavelength of this stimulated emission light is as short as about 200 nm to 500 nm, and the transmission efficiency in the condensing optical system is also low. Further, there is a problem that the conversion efficiency of the photoelectric conversion element is low. Furthermore, in this method, a part of the excitation light, which is extremely strong as compared with the stimulated emission light, is also collected, so the stimulated emission light must be separated from the excitation light and photoelectrically converted. A special filter to cut off was required.

[Object of the Invention]

It is an object of the present invention to provide an image information recording / reading method that eliminates the above-mentioned problems.

[Structure of Invention]

For this reason, the present invention irradiates a recording panel with the first electromagnetic wave to record image information, and relatively scans the panel in the main scanning direction with the second electromagnetic wave in a direction intersecting with the main scanning direction. The sub-scanning to generate a third electromagnetic wave from the recording surface of the panel, and the rod-shaped wavelength conversion medium is arranged along the scanning line formed in the main scanning direction of the panel. In response to the sub-scanning of the electromagnetic wave, the electromagnetic wave is relatively moved in the same direction as the sub-scanning, the third electromagnetic wave is made incident on the wavelength conversion medium and converted into the fourth electromagnetic wave, and the fourth electromagnetic wave is photoelectrically converted. The image information is obtained by processing the electric signal obtained by the conversion.

〔Example〕

Examples of the present invention will be described below. FIG. 1 is a block diagram showing an outline of an entire apparatus for carrying out the present invention. In the present embodiment, an X-ray irradiator 2 is provided on the back of a subject 1 such as a human body, a grid 3, a photo timer 4, and a stimulable phosphor panel 5 are sequentially arranged in front, and the stimulable phosphor panel 5 is arranged. On the other hand, the X-ray transmission image of the subject 1 is recorded as fluorescence accumulated energy. The grid 3 shields X-rays incident from other than the direction of the X-ray irradiator 2 (reflected or scattered by others) to obtain an accurate X-ray image, and the photo timer 4 irradiates X-rays. This is for detecting the accumulated amount and controlling the X-ray irradiator 2. The X-ray irradiator 2, the grid 3, the photo timer 4 and the like described above constitute a recording portion.

On the other hand, the reading portion deflects (scans) the light beam from the beam light source 6 using a semiconductor laser or the like by the deflector 7, scans the stimulable phosphor panel 5 via the mirror 8 or the like, and scans the scanning. A filter that converts the stimulated emission light generated in the light spot portion into a wavelength that can be easily handled by the rod-shaped light conversion conductor 9 and removes the light generated in the light conversion conductor 9 from other light.
Photoelectric conversion is performed by PMT (photomultiplier) 11 via 10, amplified by amplifier 12, then converted to digital signal by A / D converter 13, and the digital signal is sent to an image processing circuit (not shown) to read the image. Trying to get. Reference numeral 14 denotes an erasing lamp, which is turned on and the stimulable phosphor panel 5 is scanned, whereby the energy remaining after the reading and scanning of the panel 5 is released and erased.

FIG. 2 is a structural block diagram showing the reading portion in more detail. The beam light source 6 has a collimator lens,
The light beam from there is shaped into a beam by a beam shaper 15, passes through a mirror 16 and a filter 17, and is scanned by a galvanometer mirror 18 as a deflector 7. Then, the scanned beam passes through the fθ lens 19, the optical path is changed by the mirror 8, and the beam is incident on the stimulable phosphor panel 5 as excitation light. The above-mentioned light conversion conductor 9 has a rod shape arranged in parallel to the scanning line of the stimulable phosphor panel 5 in the direction along the scanning direction of the excitation light,
A PMT 11 is coupled to both ends of the PMT 11 via a filter 10. 20 is a power supply for PMT11. Reference numeral 21 is a current / voltage conversion circuit that converts the current signal obtained by the PMT 11 into voltage, and 22 is an adder that adds the voltage signals obtained by both current / voltage conversion circuits 21. Reference numeral 24 is a logarithmic amplifier for logarithmically amplifying the output of the amplifier 12, 25 is a filter for removing noise components, and 26 is a sampling and holding circuit for sampling the read image signal in pixel units. Further, an optical sensor 27 such as a photodiode for detecting the scanning beam light is arranged at one end of the stimulable phosphor panel 5, and a horizontal synchronizing signal obtained by the optical sensor 27 (one time of excitation light One pulse is output in the main scan.) Is input to the timing signal generation circuit 28 that determines the processing timing. This timing signal generation circuit 28
The signal from is output to the sampling and holding circuit 26, the A / D converter 13, the driver 29 that controls the light beam generator 6, the galvanometer mirror driver 30, and the like.

As shown in FIG. 3, the above-mentioned light conversion conductor 9 has a property of generating light of another wavelength from the inside in the end face direction by the light incident from the side surface, and is a stimulable phosphor panel. By arranging the panel 5 so as to face it, the stereoscopic light receiving angle from the stimulated emission point of the panel 5 becomes extremely large, and the light collection efficiency becomes large. The light conversion conductor 9 is also called a fluorescent optocollector (trade name), and is made by mixing and mixing a special fluorescent substance in a transparent plastic such as acrylite, polycarbonate, polystyrene under specific conditions. Most (80%) of the fluorescence generated inside due to light incident from the outside is guided to both end face portions according to the law of total internal reflection, and is emitted in a dense state. In this embodiment, the excitation light lambda ₂ emitted light lambda ₃ generated from the stimulable phosphor panel 5 is excited by _{(= 500nm~2,000nm, 700nm~800nm} in light of the semiconductor laser) ₍₌ 200 nm to 500 nm ) Is received from the side surface, converted into light of another wavelength λ ₄ (= 400 nm to 2,000 nm), emitted from both end surfaces, and passed through the filter 10.
It is incident on PMT11. FIG. 4 is a diagram showing wavelength conversion characteristics of the light conversion conductor 9, FIG. 4 (a) is an example of the spectrum of incident light, and FIG. 4 (b) is an example of the spectrum of emitted light. Facing the photostimulable phosphor panel 5, this light conversion conductor 9
, The excitation light component passes through the light conversion conductor 9, so that it does not enter the PMT 11 and the S / N is improved.

As shown in FIG. 5, if a mirror 31 is formed on one end surface of the light conversion conductor 9 by silver plating or the like, only one PMT 11 attached to the other end side can be used as shown in FIG. It is possible to collect the emitted light λ ₄ converted there with the same efficiency as.

As shown in FIG. 6, the light converting conductor 9 has a high-refractive index core 9a inside and a low-refractive index clad 9b provided outside the inner core 9a. With the composite structure of the different media, the output light λ ₄ after conversion can be led out to both ends without being affected by dirt or scratches on the outer cover of the cladding 9b, as shown in FIG. ,
The light collection efficiency is significantly improved. In FIG. 7, 9c is a fluorescent substance.

In this case, the refractive index of the core 9a is n ₁ and the refractive index of the clad 9b is
Assuming n ₂ , the numerical aperture NA and the light receiving and emitting angles are NA = (n ₁ ² −n ₂ ² ) ^1/2 light receiving and emitting angles = 2 sin ⁻¹ (NA).

In addition, as shown in FIG. 8, the light conversion conductor 9 has a linear portion at a position along the scanning direction of the excitation light of the stimulable phosphor panel 5, and has one end at each end. PM
It may be bent so as to lead to T11, or, as shown in FIG. 9, it may be similarly arranged as a focused light conversion conductor 9'in which a plurality of small diameter light conversion conductors are bundled.

On the other hand, as an incident method of the excitation light λ ₂ , there are
In addition to the method of obliquely entering the light as shown in (d), there is a method of making the light incident directly from above as shown in the parts (e) to (h). In the former case, a gap for passing the excitation light λ ₂ is formed in a part of the light conversion conductors 9 and 9 ′, if necessary. In the latter case, two light conversion conductors 9 are arranged.
Alternatively, the excitation light is allowed to pass between the adjacent portions immediately above 9 '.

In addition, in order to improve the incidence efficiency of the photostimulated luminescent light generated from the stimulable phosphor panel 5 to the light conversion conductor,
As shown in the figure, the photostimulable luminescent light reflecting member 32 is attached to the back surface (the side opposite to the side facing the stimulable phosphor panel 5) of the photoconversion conductor so as to be in close contact with or away from it. This reflective member 32
When brought into close contact with a plurality of small-diameter focused light conversion conductors 9 ', they also function as a bundle of the conductors 9'.
The reflecting member 32 is made of a material having a transmissivity for the excitation light, and prevents the excitation light from being reflected there and returning to the stimulable phosphor panel 5 to prevent the read image quality from disturbing the excitation light. So that it will not be deteriorated. 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 view showing an example in which the photoconversion conductors 9 or 9'are arranged on both front and back surfaces of the stimulable phosphor panel 5. Since the stimulable phosphor panel 5 generates stimulated emission light not only from the side irradiated with the excitation light but also from the opposite side, the light conversion conductor is also arranged on the opposite side to collect light. Will be greatly improved.

〔The invention's effect〕

As described above, the present invention performs wavelength conversion. Therefore, by converting the wavelength into a wavelength that can be easily handled by the condensing optical system, cost reduction of the optical system, optimizing photoelectric conversion elements, and facilitating selection of filters are possible. Etc. can be realized.

[Brief description 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 a reading device portion, FIG. 3 is an explanatory view of a light conversion conductor, and FIG. a),
(B) is a characteristic diagram of the light conversion, FIG. 5 is an explanatory diagram of another method of condensing light from the light conversion conductor, FIG. 6 is an explanatory diagram of a composite structure of the light conversion conductor, and FIG. The figure is an explanatory view of the operation of the light conversion conductor shown in FIG. 6, and FIGS. 8 and 9 are illustrations of connecting both ends of the light conversion conductor to one PMT, and FIGS.
11 (a) and 11 (b) are explanatory views of the excitation light irradiation, FIG. 11 (a) and FIG. 11 (b) are explanatory views in which a reflection member is attached to the light conversion conductor for improving the efficiency of concentrating stimulated emission light, and FIG. (A) to (h) are explanatory views in each case, and FIG. 13 is an explanatory view in which a photoconversion conductor is arranged on the upper and lower surfaces of the stimulable phosphor panel. 1 ... Subject, 2 ... X-ray generator, 3 ... grid, 4 ... photo timer, 5 ... stimulable phosphor panel, 6 ... light beam generator, 7 ... deflector, 8 ... mirror, 9 ... light conversion conduction Body, 10 ...
Filter, 11 ... PMT, 12 ... Amplifier, 13 ... A / D converter, 14 ...
Erase lamp, 15 ... Beam shaper, 16 ... Mirror, 17 ... Filter, 18 ... Galvano mirror, 19 ... f.theta. Lens, 20 ... PMT
Power supply, 21 ... Current / voltage conversion circuit, 22 ... Adder, 24 ... Logarithmic amplifier, 25 ... Filter, 26 ... Sampling hold circuit, 27 ... Horizontal sync signal sensor, 28 ... Timing generation circuit, 29 ... Optical beam generator Driver, 30 ... Galvano mirror driver, 31 ... Mirror, 32 ... Light reflecting member.

Claims (6)

[Claims] 1. A recording panel is irradiated with a first electromagnetic wave to record image information, and a second electromagnetic wave is used to perform main scanning in the main scanning direction while relatively scanning the panel in a direction intersecting the main scanning direction. A sub-scanning is performed to generate a third electromagnetic wave from the recording surface of the panel, and a rod-shaped wavelength conversion medium arranged along a scanning line formed in the main scanning direction of the panel is used to generate a second electromagnetic wave. In response to the sub-scanning, it is relatively moved in the same direction as the sub-scanning, the third electromagnetic wave is made incident on the wavelength conversion medium to be converted into a fourth electromagnetic wave, and the fourth electromagnetic wave is photoelectrically converted. An image information recording / reading method, characterized in that the image information is obtained by processing an electric signal obtained as described above. 2. The image information recording / reading method according to claim 1, wherein the first electromagnetic wave is radiation such as X-rays. 3. The image information recording according to claim 1 or 2, wherein the second electromagnetic wave is excitation light having a wavelength of 500 nm to 2,000 nm that excites the recording panel. How to read. 4. The image information recording / reading according to claim 1, wherein the second electromagnetic wave is excitation light having a wavelength of 700 nm to 800 nm that excites the recording panel. Method. 5. The third electromagnetic wave is applied to the recording panel 20.
5. The image information recording / reading method according to claim 1, wherein the stimulated emission light has a wavelength of 0 nm to 500 nm. 6. The image information recording / reading method according to any one of claims 1 to 5, wherein the fourth electromagnetic wave has a wavelength of 400 nm to 2,000 nm.