JP2596887B2 - Radiation image reading method and apparatus - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for reading radiation image information stored in a radiation image conversion panel having a stimulable phosphor, and more particularly to a method for efficiently reading radiation image information. It concerns the device.

[0002]

2. Description of the Related Art Radiation images such as X-ray images are often used for diagnosis of diseases. To obtain this X-ray image,
X-rays transmitted through the subject are irradiated on a phosphor layer (fluorescent screen) to generate visible light, and the visible light is irradiated on a film using a silver salt in the same manner as when a normal photograph is taken. Developed, so-called radiographs are used. However, in recent years, a method has been devised for directly taking out an image from the phosphor layer without using a film coated with a silver salt.

In this method, radiation transmitted through a subject is absorbed by a phosphor, and then the phosphor is excited by, for example, light or heat energy, so that the radiation energy accumulated by the phosphor is absorbed by the phosphor. Then, there is a method in which the fluorescence is detected and imaged. Specifically, for example, US Pat. No. 3,859,527 and JP-A-55-12144 disclose a radiation image conversion method using a stimulable phosphor and using visible light or infrared light as stimulating excitation light. In this method, a radiation image conversion panel having a stimulable phosphor layer formed on a support is used. A latent image is formed by accumulating radiation energy corresponding to the radiation transmittance, and thereafter, the stimulable phosphor layer is scanned with stimulating excitation light to emit the accumulated radiation energy of each part, and this is emitted. It is converted into light, and a radiation image is obtained by an optical signal based on the intensity of the light.

[0004] This radiation image is subjected to image processing as it is or in real time to obtain a silver halide film,
It is output to a CRT or the like and visualized. Further, the radiation image is stored in an image storage device such as a semiconductor storage device, a magnetic storage device, and an optical disk storage device.
It may be output to T or the like and visualized.

The radiation image conversion panel in the above-mentioned radiation image conversion method is generally prepared in several sizes in the same manner as screens and films used in ordinary radiographic methods. The photographer selects and uses it depending on the size of the subject.

However, when there are several types of radiation image conversion panels, there are the following drawbacks.

(1) The manufacturing cost of the radiation image conversion panel increases.

(2) Each time a radiographic image is taken, the photographer must select an appropriate radiographic image conversion panel and set it on the radiographing apparatus, which is troublesome.

(3) It is necessary to manage a large number of radiation image conversion panels having different sizes.

(4) Since the radiographic image capturing device, the reading device, the erasing device, the stock device, and the like must correspond to the radiographic image conversion panels of various sizes, the transport mechanism, the reading mechanism, the erasing mechanism, the stock mechanism, etc. It becomes complicated and the device becomes large.

In general radiography, the subject is sufficiently smaller than the radiation image conversion panel, and the radiographic field (radiation irradiation area) is narrowed down for the purpose of reducing the exposure dose to the subject.

[0012]

However, in the above-described radiation image conversion method, the reading of the radiation image is performed on the entire surface of the radiation image conversion panel, and thus has the following drawbacks.

(1) The required radiation image information is smaller than the read radiation image information, so that not only the utilization efficiency of the image storage device is reduced but also the processing time such as image processing becomes longer.

(2) The resolution of the required part of the radiation image is relatively reduced.

(3) When a radiographic image is output on a silver halide film or a CRT and visualized, a necessary radiographic image and an unnecessary image are mixed to make it extremely difficult to see, and the diagnostic performance is reduced.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described drawbacks in a radiation image reading method using a radiation image conversion panel, and an object of the present invention is to provide a radiation image processing apparatus capable of reducing unnecessary radiation image information. An image reading method and apparatus are provided.

Another object of the present invention is to provide a radiation image reading method and apparatus capable of shortening a radiation image reading time.

Another object of the present invention is to provide a radiation image reading method and apparatus capable of obtaining a plurality of radiation images having different sizes from one radiation image conversion panel.

It is another object of the present invention to provide a radiation image reading method and apparatus capable of miniaturizing and simplifying a radiation image reading apparatus and the like.

[0020]

The object of the present invention is to irradiate a part of a radiation image conversion panel having a stimulable phosphor layer with radiation from a radiation source to accumulate and record radiation image information. In a radiation image reading method for reading information including radiation image information stored and recorded on a panel to obtain a read signal including a radiation image signal, a radiation irradiation area of the radiation image conversion panel is obtained from radiation stop information of the radiation source. A radiation image reading method, comprising detecting and outputting only a radiation image signal from the radiation irradiation area among the read signals based on the radiation irradiation area, and radiation having a radiation diaphragm. A radiation image conversion panel having a source and a stimulable phosphor layer which is partially irradiated with radiation to accumulate and record radiation image information; An excitation light scanning unit that scans the image conversion panel with stimulating excitation light to convert the accumulated and recorded radiation image information into stimulating emission, and a photodetector that photoelectrically reads the radiation image conversion panel and obtains a signal. In the radiation image reading device having, based on the radiation aperture information of the radiation source, an area calculation means for assessing the radiation irradiation area,
Reading means for receiving radiation irradiation area information from the area calculating means and selecting and outputting only a radiation image signal from the radiation irradiation area among the read signals. Achieved by the device.

[0021]

According to this configuration, necessary radiation image information can be reduced, the utilization efficiency of the image storage device can be increased, and the processing time for image processing and the like can be shortened.

Further, when the image is output on a silver halide film or a CRT and visualized, unnecessary images are not mixed, so that diagnostic performance is improved.

In the present invention, the radiation-irradiated region is narrower only to a portion where radiation is truly irradiated, and is broader to a true radiation-irradiated portion and its peripheral portion. However, the area of the peripheral part is preferably 50% or less of the area of the true radiation irradiated part.

In the present invention, in order to select and output only an image signal from the radiation irradiation area of the radiation image conversion panel, the radiation irradiation area is detected in advance, and the radiation image reading apparatus is adapted to the radiation irradiation area. It is necessary to specify the reading area. In the present application, radiation stop information of a radiation source is used as a method of detecting the radiation irradiation area.

[0025]

Next, the present invention will be described with reference to examples.

FIG. 1 is a schematic view of a radiation image reading apparatus according to one embodiment of the present invention.

In FIG. 1, reference numeral 1 denotes an imaging unit, 101 denotes a radiation source, 102 denotes a subject, and 103 denotes a radiation image conversion panel according to the present invention. Reference numeral 2 denotes a pre-reading unit, 201 is a pre-reading stimulating excitation light source, 203 to 205 are optical scanning systems, 207 is a stimulating light-emitting condensing body, and 208 is a photoelectric converter. Reference numeral 3 denotes a book reader.
Reference numeral 01 denotes a stimulating light source for book reading, reference numerals 303 to 307 denote an optical scanning system, reference numeral 309 denotes a stimulating light emitting condensate, and reference numeral 310 denotes a photoelectric converter. Reference numeral 4 denotes a radiation image reproducing unit.

In 1, the radiation emitted from the radiation source 101 is converged by a radiation diaphragm (not shown), passes through the subject 102, and is absorbed by a partial area of the radiation image conversion panel 103. As a result, part of the energy is accumulated in the stimulable phosphor, part is emitted as instantaneous light emission, and part is as afterglow of instantaneous light emission even after radiation irradiation from the radiation source 101 stops. Released. The radiation image conversion panel 103 irradiated with the radiation in 1 is sent to the pre-reading unit 2.

In step 2, the radiation image conversion panel 103 is entirely read by stimulating excitation light 202 from a stimulating excitation light source 201 for pre-reading. Next, the radiation image conversion panel 103 is fully read in the main reading unit 3, and the reading control unit 312 controls the analog / digital converter 311 based on the radiation aperture information (not shown) from the radiation source 101 to perform sampling. The reading area is specified by changing the start position and the end position. Next, the signal that has passed through the analog / digital converter 311 is sent to the radiation image reproducing unit 4.

In the above example, the reading area is specified by controlling the analog / digital converter to change the sampling start position and the end position.
This may be performed in combination with a method of giving a signal to the sub-scanning mechanism 308 to specify a reading area in the sub-scanning direction.

In the above example, the pre-reading unit and the main reading unit have separate mechanisms, but the main reading unit may also serve as the pre-reading unit, or the photographing unit, the pre-reading unit, and the book reading unit. The reading unit may be integral.

In the present invention, the stimulable phosphor refers to a stimulus such as optical, thermal, mechanical, optical, or electrical (stimulated excitation) after irradiation with light or high-energy radiation.
By means of the phosphor which shows stimulated emission corresponding to the dose of the first light or high-energy radiation, but from a practical point of view, preferably a phosphor which shows stimulated emission by stimulated excitation light of 500 nm or more. is there.

In the present invention, the stimulating light is light capable of efficiently emitting radiation energy accumulated in the stimulable phosphor as stimulating light, and is preferably an Ar laser or a He-Ne laser. , Kr laser, YAG laser, He-Cd laser, semiconductor laser and the like.

FIG. 2 is a schematic view of a radiation image reading apparatus according to another embodiment of the present invention, in which a radiation irradiation area is designated in advance during radiation irradiation.

In FIG. 2, reference numeral 71 denotes an imaging device; 72, a radiation source; 73, a radiation image conversion panel according to the present invention; 74, a plurality of frames drawn on the imaging device for designating a radiation irradiation area in advance; Is a radiation image reading unit that can read the area of the radiation image conversion panel 73 corresponding to the area specified by the plurality of frames, 76 is a controller for moving the system, 77 is a keyboard for manually performing input, Reference numeral 78 denotes a radiation image reproducing device.

The radiation from the radiation source 72 is narrowed down by a radiation stop (not shown) and is applied to an area specified in advance by a frame 74. The information on the designated area is transmitted as the aperture stop information S1, the aperture value of the radiation aperture of the radiation source 72 to an area calculation unit (not shown) of the controller 76, and the radiation irradiation area is determined. The radiation irradiation area information S2 is input to a reading control unit (not shown) of the image reading unit 75, and the radiation image information read by the reading unit 75 is visualized by the radiation image reproducing device 78. In this embodiment, the means for transmitting the information on the designated radiation irradiation area is not limited to the above. Further, the portions 71 to 78 may be integrated or separate.

[0037]

As described above, according to the present invention, since the unnecessary radiographic image information is small, the utilization efficiency of the image storage device is improved.

Further, according to the present invention, since unnecessary radiographic image information is small in the obtained radiographic image information, the processing time such as image processing is reduced.

According to the present invention, when a radiographic image is visualized, unnecessary images are not mixed, so that the image is easy to see and the diagnostic performance is improved.

Further, according to the present invention, it is not necessary to select the size of the radiation image conversion panel according to the size of the subject and the like, and the complexity is eliminated.

Further, according to the present invention, it is not necessary to select the size of the radiation image conversion panel according to the size of the subject or the like, so that the size of the radiation image conversion panel becomes one type and the radiation image photographing apparatus and the reading apparatus are used. The erasing device, the stocking device, etc. are simplified and downsized.

The present invention has the above effects and is very useful industrially.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a radiation image reading method and apparatus of the present invention.

FIG. 2 is an explanatory diagram of another radiation image reading method and apparatus of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 imaging unit 2 pre-reading unit 3 main reading unit 4 radiation image reproducing unit 101, 72 radiation source 102 subject 103, 73 radiation image conversion panel 201 pre-reading stimulating excitation light source 301 main-reading stimulating excitation light source 311 analog / digital Transducer 312 Read control unit 202, 302 Stimulated excitation light 203, 204, 205; 303, 304, 305, 306, 307 Optical scanning system 206, 308 Sub-scanning mechanism 207, 309 Stimulated emission concentrator 208, 209 Converter 71 Imaging device 75 Image reading unit 76 Controller 77 Keyboard 78 Radiation image reproducing device

Claims (2)

(57) [Claims] 1. A radiation image information accumulated and recorded by irradiating the radiation from the radiation source in a part of the radiation image conversion panel having a stimulable phosphor layer, it is accumulated and recorded before Symbol radiation image conversion panel read the information including radiation image information about the radiation image reading method for obtaining a read signal comprises a radiation image signal, the radiation area of the radiation image conversion panel, detects the radiation aperture information of the radiation source, the <br / > A radiation image reading method, wherein only a radiation image from the radiation irradiation area is selected and output from the read signals based on the radiation irradiation area. 2. A radiation image conversion panel having a radiation source having a radiation stop, a stimulable phosphor layer partially irradiated with radiation and accumulating and recording radiation image information, and a radiation image conversion panel provided with a radiation image conversion panel. excitation light scanning means for converting the accumulated recorded radiation image information to the stimulated emission was scanned with尽励Okoshiko, Shin reading read-the radiographic image conversion panel photoelectrically
A radiation image reading device having a photodetector that obtains a signal, based on radiation stop information of the radiation source, a region calculation unit that scans a radiation irradiation region, and receiving radiation irradiation region information from the region calculation unit. And a reading control means for selecting and outputting only a radiation image from the radiation irradiation area among the reading signals .