JP2002006049A - X-ray digital imaging device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make a cassette single body small and lightweight by a method wherein a stationary-type cooling unit is installed separately from a portable- type cassette and both are connected by a flexible tube. SOLUTION: The X-ray digital imaging device of a portable type is composed of a photoelectric conversion element in which a phosphor emits light by irradiation with X-rays so as to be converted into an electric signal as a pixel (sensor) sensitive to its visible light. The imaging device is composed of an electronic circuit component which processes the electric signal of the conversion element. The imaging device is composed of a support structure which supports them. The imaging device is composed of an enclosure which houses them. The imaging device records an image as a digital signal. The enclosure and the cooling unit which is installed separately from it are connected by the flexible tube. An air current which is generated by a blower inside the cooling unit is introduced into the enclosure so as to cool the conversion element and the circuit component.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an X-ray digital radiography apparatus using a portable digital cassette for radiography.

[0002]

2. Description of the Related Art For a long time, X-ray photography has been carried out by a method in which a silver halide film and an intensifying screen are brought into close contact with each other, stored in a cassette, irradiated with X-rays, and then developed. . In recent years, with the development of large-area two-dimensional photoelectric conversion elements and digital image processing technology, computerization of X-ray photography has been rapidly performed.

[0003] Such computerization has been compared with the conventional film shooting methods, such as quick display of shooting results, easy transmission of images, easy storage of image data, easy search, and saving of consumables such as films. (See, for example, an electronic cassette for recording an X-ray image and an X-ray radiogram imaging method in JP-A-6-342099).

On the other hand, photoelectric conversion mainly requires a photoelectric conversion element formed in a two-dimensional array on a glass plate and an electronic circuit for signal processing thereof, which is disadvantageous in reducing the size and weight of the device. There was a side. This will be described below with reference to FIG.

FIG. 4 is a cross-sectional view showing an example of a conventional portable digital cassette. The housing 4 is made of an opaque metal or plastic, and a part or all of the housing 4 is a protective panel 4b (housing lid) made of an X-ray permeable member (for example, CFRP = carbon fiber reinforced plastic). .

A fluorescent plate 2 provided with a phosphor for converting X-rays into fluorescent light (visible light) is provided inside the housing 4 from the side near the protective panel 4b, and converts the fluorescent light (visible light) into an electric signal. Two-dimensionally arranged photoelectric conversion elements 1, a support plate 3 for fixing them, a flexible circuit board 5a for extracting electric signals of the photoelectric conversion elements 1, an electronic circuit for processing electric signals, and an electronic circuit on which a power supply unit and the like are mounted The substrate 5 and the like are stored.

[0007] Then, the subject 11 to be X-ray photographed is placed on the protective cover 4b and then irradiated with X-rays 10,
At the same time, by supplying power to the photoelectric conversion element 1 and the electronic circuit board 5 and driving the same, an image (digital image) obtained by X-ray photography can be obtained.

In order to repeat such an operation, the housing 4
, An electronic circuit board or the like consumes power every time X-ray imaging is performed, and as a result, heat is generated. Also, such as the power supply
Some circuits keep the time required for radiography short,
During the period of use, it is necessary to always supply power and to be in a standby state. During that period, the temperature inside the housing 4 gradually increases.

Generally, the photoelectric conversion element 1 and the circuit boards 5, 5a
Since the above electronic components are composed of semiconductors such as amorphous silicon and crystalline silicon, the rise in ambient temperature may cause deterioration of the performance of the X-ray imaging apparatus, such as image deterioration due to increase in thermal noise, fluctuation of signal amplification factor , Fluctuations and the like.

[0010] Further, the rise in the internal temperature of the casing 4 also heats the protection panel 4b, and the temperature of the surface to which the subject 11 touches also rises. In a stationary type conventional medical X-ray imaging apparatus, the surface temperature is 41 ° C. according to Japanese Industrial Standard JIS T1001 (general rules for safety of medical electrical equipment) 11.1 (2).
(Allowable temperature for human body contact), an exhaust fan 6 is provided in the housing 4 to forcibly exhaust the internal air, thereby suppressing a rise in temperature. Have been.

[0011]

However, when the above conventional example is used as it is in a portable manner, there are the following problems. 1. Since the exhaust fan 6 is built-in, the size of the housing 4 is increased, and the weight of the entire apparatus is increased. Therefore, the portability of the device is impaired. 2. The housing needs to be provided with a vent 4a. The ventilation holes are provided with the photoelectric conversion element 1, the circuit boards 5, 5
In order to protect “a” from liquids such as foreign matter, light leakage, and disinfectant, it is necessary to configure a complicated ventilation path, which causes an increase in size, weight, and cost. Furthermore, because of the complicated path, the resistance of the ventilation flow 22 and the exhaust air 23 is significantly increased, so that the exhaust air volume of the exhaust fan 6 also has to be increased, which leads to further increase in size and weight.

The present invention has been made for the purpose of solving such a problem, and a feature thereof is that a stationary cooling unit is provided separately from a portable cassette, and both of them are flexible. The purpose is to reduce the size and weight of the cassette unit by connecting with a flexible tube.

[0013]

Therefore, in the present invention,
A photoelectric conversion element that emits a phosphor by X-ray irradiation and converts it into an electric signal as a pixel (sensor) responsive to the visible light, an electronic circuit component that processes the electric output of the photoelectric conversion element, and supports these In a portable X-ray digital imaging apparatus for recording an image as a digital signal, the housing and a cooling unit separately provided are provided. A connection is made with a flexible tube, and an airflow generated by a blower in the cooling unit is introduced into the housing to cool the photoelectric conversion element and the electronic circuit component.

[0014] In this case, as an embodiment of the present invention, a heat exchanger is provided in the cooling unit, and the cooling air is sent to the inside of the housing by the action of the heat exchange air. Providing a dust-proof filter in one or both of the ventilation paths of the intake and exhaust air, wherein the flexible tube has two systems for sending and returning the cooling unit with respect to the housing; The body is
It is effective to use an airtight structure other than the connection port with the tube.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be specifically described below with reference to FIGS. FIG.
The first embodiment is shown in FIGS. 2 and 3,
The second and third embodiments are shown in schematic schematic cross sections, respectively.

(First Embodiment) In the embodiment of the present invention shown in FIG. 1, a stationary cooling unit 21 is prepared separately from a portable housing 4, and air is blown inside the cooling unit 21. 22
Fan 21a is provided. Then, from the cooling unit 21, through the flexible tube 20,
After the cool air is introduced into the inside and cools the inside, it is discharged to the outside of the housing 4 through the vent 4a.

During use, since the inside of the housing 4 is kept higher than the atmospheric pressure, there is little fear of foreign matter entering from the vent 4a.
Intrusion of liquid splash etc. is also prevented. Therefore, the vent 4a
In the structure, only the light shielding that affects the photographing need be considered.
Further, by providing a dustproof filter (not shown) at the intake port of the fan 21a, dust can be prevented from entering. The other configuration is the same as the conventional one.

In use, the cooling unit 21 is connected to the housing 4 via the flexible tube 20, and the subject 11 to be X-rayed is protected by the protective cover 4.
b) to irradiate X-rays 10 and simultaneously supply and drive power to the photoelectric conversion element 1 and the electronic circuit board 5 to obtain an image (digital image) by X-ray photography Can be.

In order to repeat such an operation, the housing 4
, An electronic circuit board or the like consumes power every time X-ray imaging is performed, and as a result, heat is generated. Also, such as the power supply
Some circuits keep the time required for radiography short,
During the period of use, it is necessary to keep the power on at all times and to be in a standby state. However, heat can be released to the outside by the operation of the cooling unit 21 described above.

In addition, since the housing 4 itself is not provided with a cooling means, the size and weight can be sufficiently reduced.

(Second Embodiment) FIG. 2 shows a cross section of a second embodiment according to the present invention. Here, the flexible tube 20a has two reciprocating flow paths, i.e., flow and return, and the blow 22 and the exhaust 23 are circulated in the housing 4 and the cooling unit 21. Therefore, a heat exchanger 21 b is provided inside the cooling unit 21 to absorb heat from the exhaust gas 23.

Thus, unlike the first embodiment, there is no need to provide a vent for exhausting air in the housing 4 itself, and a more complete sealed structure can be achieved.
Therefore, if necessary, the cooling medium sealed in the housing 4 can be an inert gas other than air or an electrically insulating liquid.

(Third Embodiment) Normally, in a medical X-ray imaging apparatus, a portion that touches a human body, that is, an imaging apparatus (housing 4) is waterproofed with vinyl or the like in order to prevent infection by bacteria or the like. Covering is performed.

In the third embodiment according to the present invention, as shown in FIG. 3, in the configuration of the second embodiment, the entire housing 4 and a part of the flexible tube 20a are covered with a waterproof cover. 24, which can provide a more hygienic and safer device.

[0025]

As described above, according to the present invention,
Since the cooling unit is separated from the housing, a small and lightweight portable X-ray digital imaging apparatus can be easily realized.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a first embodiment according to the present invention.

FIG. 2 is a cross-sectional view showing a second embodiment.

FIG. 3 is a cross-sectional view showing a third embodiment.

FIG. 4 is a cross-sectional view of a conventional X-ray digital cassette.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Two-dimensional photoelectric conversion element 2 Fluorescent plate 3 Support plate 4 Case 4a Vent 4b Protective cover 5 Circuit board 5a Flexible circuit board 6 Exhaust fan 10 X-ray 11 Subject 20 and 20a Flexible tube 21 Cooling unit 21a Fan 21b Heat exchanger

Claims (5)

[Claims] 1. A photoelectric conversion element which emits a phosphor by X-ray irradiation and converts it into an electric signal as a pixel (sensor) responsive to the visible light, and an electronic circuit component for processing an electric output of the photoelectric conversion element And a supporting structure for supporting them, and a housing for accommodating them. In a portable X-ray digital imaging apparatus that records an image as a digital signal, the housing and a cooling unit provided separately from the housing are provided. X-rays, wherein the X-rays are connected to a unit by a flexible tube, an airflow generated by a blower in the cooling unit is introduced into the housing, and the photoelectric conversion element and electronic circuit components are cooled. Digital photography device. 2. The X-ray digital imaging apparatus according to claim 1, wherein a heat exchanger is provided in the cooling unit, and cool air having a temperature equal to or lower than room temperature is sent into the housing by the action of the heat exchange air. 3. The X-ray digital imaging apparatus according to claim 1, wherein a dust-proof filter is provided in one or both of ventilation paths of the cooling unit and the casing. . 4. The flexible tube is provided with two systems for sending and returning the cooling unit with respect to the housing, and the housing has an airtight structure except for a connection port with the tube. The X-ray digital imaging apparatus according to claim 1, wherein: 5. The cooling unit is provided with a heat exchanger, and the cooling unit is provided with two systems of sending and returning to the casing, and the casing is airtight except for a connection port with the tube. The X-ray digital imaging apparatus according to claim 1, wherein the X-ray imaging apparatus has a structure.