JP6557163B2 - Radiation measurement equipment - Google Patents

Description

  The present invention relates to a radiation measurement apparatus, and more particularly to an apparatus for measuring radioactivity of a radioactive sample.

  Devices such as a curie meter and a calibrator are known as ionization chamber type radiation measurement devices for measuring the radioactivity (or radioactivity amount) of a sample (see Patent Document 1). Such an apparatus includes, for example, a detection unit having an ionization chamber, and a main body unit including a calculation unit and a control unit. One or more substrates are provided inside the detection unit. The detection unit is connected to the main unit by a wired method or a wireless method. The detector and the main body may constitute a single unit.

  In a detection unit incorporating an ionization chamber, there are generally a metal part (terminal, wiring, etc.) to which a high voltage is applied and a circuit for processing a weak signal immediately below the ionization chamber. Therefore, it is desirable to prevent moisture from inadvertently entering from there, or to prevent the occurrence of condensation there. For this reason, the lower space of the ionization chamber is an airtight space.

JP 2005-512064

  Due to the convenience of the installation location of the detection unit, it is required to suppress the total height of the ionization chamber unit. For this reason, the height of the lower space directly under the ionization chamber cannot be increased so much, and it is desirable to make the lower space relatively small from the viewpoint of maintaining airtightness.

  As the functionality of the detection unit increases, the number of circuits provided in the detection unit and the scale thereof have increased. Nevertheless, as described above, since the height and volume of the lower space are limited, there is a problem that it is difficult to arrange a plurality of substrates or a large number of substrates there. Even if it is physically possible to arrange all the boards in the lower space, another problem is pointed out that if multiple boards are overly dense, the adjustment of individual circuits becomes difficult. ing.

  An object of the present invention is to secure a necessary substrate arrangement space on the lower side of the ionization chamber and the lower periphery thereof while ensuring the airtightness of the space provided on the lower side of the ionization chamber. Another object is to realize a substrate arrangement that allows easy access to individual substrates after a plurality of substrates are arranged.

  A radiation measurement apparatus according to the present invention includes a housing having a main space that accommodates an ionization chamber, a lower space located below the main space, and an adjacent space adjacent to the lower space, and the main space An ionization chamber having a configuration surrounding the radioactive sample storage chamber, a first substrate provided in the lower space and mounted with a circuit for processing a charge signal from the ionization chamber, and provided in the adjacent space And a second substrate electrically connected to the first substrate, wherein the casing has a partition wall that partitions the lower space and the adjacent space, and the lower space is configured as an airtight space It is characterized by that.

  According to the above configuration, at least the main space, the lower space, and the adjacent space are provided in the housing. An ionization chamber is accommodated in the main space. Desirably, the ionization chamber has a cylindrical shape surrounding a storage chamber for storing a radiation sample. An ionization chamber generally has a collector electrode and a container electrode, and a high voltage is applied between them. When radiation (for example, γ (X) rays) enters the ionization chamber, the gas inside the ionization chamber is ionized to generate electrons and ions. Among them, for example, electrons are collected by the collector electrode, and a charge signal (ionization signal) is output from the collector electrode to the outside.

  A lower space is formed below the main space or the ionization chamber. The lower space is an airtight space, that is, an airtight space. A first substrate is disposed therein. The first substrate is an electronic substrate on which an electrometer circuit is mounted, for example. A plurality of substrates may be arranged in the lower space. The height of the lower space is generally small, and the lower space is a space extending in the horizontal direction. In general, the first substrate is arranged in a horizontal posture, but the first substrate may be arranged in another posture. In order to make the lower space an airtight space, it is desirable that a seal member such as a packing is provided at a mutual joint portion of a plurality of members surrounding the lower space.

  An adjacent space is provided adjacent to the lower space. A partition is provided between the lower space and the adjacent space. The partition preferably forms part of the housing, which functions as a partition to maintain the airtightness of the lower space. The lower space and the adjacent space may be slightly separated from each other, but desirably these spaces are adjacent to each other through one partition wall. The adjacent space is particularly preferably formed on the back side (that is, the back side) of the lower space, but it may be formed on the right side, the left side, or the front side of the lower space. The adjacent space is usually configured as an unsealed space. You may provide the air hole and slit for heat dissipation etc. in the member surrounding adjacent space. In the adjacent space, the second substrate is desirably arranged in a vertical posture, that is, in a standing posture, but may be arranged in another posture. In addition to the second substrate, one or more other substrates may be disposed in the adjacent space.

  According to the above configuration, since the adjacent space which is the expansion space can be used in addition to the lower space for the arrangement of the board group (or the electronic component group), a sufficient space for the board group arrangement is provided. It can be secured. In addition, an increase in the height of the lower space can be avoided and at the same time an increase in the volume can be avoided, so that the airtightness can be improved. The plurality of circuits include a circuit to be installed in the hermetic space and a circuit that is not required so far, and it is desirable to use the lower space and the adjacent space properly according to such a circuit type.

  The radiation measuring apparatus is preferably an apparatus for measuring the radioactivity of a radiation sample (sample). The radioactive sample may be a liquid that is injected and administered to a living body. It is desirable that a jig for holding a vial or syringe containing a radioactive sample is provided in the sample storage chamber. On the first substrate, for example, an integral type or linear type electrometer circuit for processing a weak signal is mounted. On the second substrate, for example, a power source (high voltage source for ionization chamber), a count circuit, a communication circuit, a relay control circuit, and the like may be provided. The radiation measurement apparatus may be configured by a unit having an ionization chamber and a main body that processes a signal therefrom.

  Preferably, the lower space is a space extending in a first horizontal direction and a second horizontal direction, in which the first substrate is disposed in a horizontal posture, and the adjacent space is in the first horizontal direction and the vertical direction. A space extending in a direction, in which the second substrate is arranged in a vertical posture. According to this configuration, the height of the lower space can be suppressed, the width of the adjacent space (the width in the direction perpendicular to the substrate surface) can be suppressed, or the installation space in the horizontal direction can be increased. Can be suppressed.

  Preferably, the first horizontal direction is a front-rear direction, the second horizontal direction is a left-right direction, the casing has a columnar shape standing up as a whole, and the casing has a lower portion and a rear side. A box-like enlarged portion is provided on the side, and the adjacent space is provided in the enlarged portion. If a box-shaped enlarged part (part having an adjacent space) is formed on the back side of the housing, specifically on the back side of the cylindrical part, it accommodates a plurality of substrates while reducing the installation area. Can be placed.

  Preferably, the housing includes a removable bottom plate that closes a bottom surface of the lower space, and a removable back plate that closes a back surface of the adjacent space. According to this configuration, a desired space can be easily accessed individually.

  Preferably, a plurality of signal lines are provided between the first substrate and the second substrate, and the partition structure has a sealing structure through which the plurality of signal lines are inserted while maintaining airtightness of the lower space. Provided. According to this configuration, the sealing property, that is, the air tightness can be enhanced at the insertion portion of the plurality of signal lines.

  Preferably, the seal structure includes a screw hole opened on the adjacent space side, an annular seal member disposed in the screw hole, and a screw that is screwed into the screw hole. In the forward state, the seal member is in a state of being crushed so as to clamp the plurality of signal lines passing therethrough,

  According to the present invention, it is possible to secure a necessary substrate arrangement space on the lower side of the ionization chamber and the lower periphery thereof while ensuring the airtightness of the space provided on the lower side of the ionization chamber. Alternatively, it is possible to realize a substrate arrangement that allows easy access to individual substrates after the arrangement of a plurality of substrates.

It is a perspective view which shows suitable embodiment of the radioactivity measuring apparatus (Curie meter) as a radiation measuring apparatus which concerns on this invention. It is a block diagram which shows the electrical structure of a radioactivity measuring apparatus. It is a front view of a detection unit. It is a perspective view which shows a mode that the detection unit was seen from diagonally upward. It is a perspective view which shows a mode that the detection unit was seen from diagonally downward. It is a figure which shows the AA sectional view. It is a perspective view which shows a mode that the lower part of the housing | casing was seen from diagonally upward. It is a perspective view which shows a mode that the lower part of the housing | casing was seen from diagonally downward. It is a figure which shows the skeleton structure of the lower part of a housing | casing. It is a figure which shows an example of the seal structure provided in the partition.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described with reference to the drawings.

  FIG. 1 shows a Curie meter as a radiation (radioactivity) measuring apparatus. This apparatus is an apparatus for measuring radioactivity of a radiopharmaceutical as a tracer administered to a living body, for example. Other samples may be measured. The curie meter is configured by a detection unit 10 and a main unit 12 in the present embodiment. They are connected to each other by a communication cable.

  The detection unit 10 has a cylindrical portion 14 having a standing cylindrical shape. The lower portion 16 of the cylindrical portion 14 swells in the radial direction with a certain radial thickness. Further, an enlarged portion 18 is provided on the back side (back side) of the cylindrical portion 14. The enlarged portion 18 has a box-like shape enlarged in the left-right direction and the up-down direction. The enlarged portion 18 has a certain thickness in the front-rear direction. A sample storage portion is formed along the central axis of the detection unit 10, and in FIG. 1, a holder 19 is stored in the sample storage portion. The inside is a sample accommodation hole 18A. The holder 19 is made of a resin or the like, and includes a cylindrical portion and a hook-like portion that protrudes in the horizontal direction from the upper end edge thereof. The former cylindrical part is inserted into the sample storage part. A well-type ionization chamber is accommodated in the cylindrical portion 14.

  The main unit 12 functions as a calculation unit and a display unit. A substrate on which a processor is mounted is housed inside. The main unit 12 is provided with a liquid crystal display 22 with a touch panel. It functions as a display and an input device. The main unit 12 is supported by a stand 20. The tilt angle of the main unit 12 can be switched. It is also possible to hang the main unit 12 on a wall. The main unit 12 and the detection unit 10 may be connected by a wireless communication method.

  FIG. 2 is a block diagram showing the electrical configuration of the Curie meter according to this embodiment. The detection unit 10 has three spaces, that is, a main space 24, a lower space 26, and an adjacent space 28. An ionization chamber 30 is disposed in the main space 24. The ionization chamber 30 includes a collecting electrode 32 and a container electrode 34, and a high voltage of, for example, several hundred volts is applied between them. A sample accommodation hole 18A is formed along the central axis of the ionization chamber 30. In the example shown in FIG. 2, the sample 36 is arranged there. Radiation (γ rays) emitted from the ionization ionizes the gas inside the ionization chamber 30, and one of the electrons and ions generated thereby is collected by the collector electrode 32, whereby a charge signal (ionization signal) is generated. Arise. The charge signal is sent to electrometer circuit 42 via signal path 38.

  The lower space 26 is a space provided immediately below the main space, and is an airtight space. A first substrate 40 on which an electrometer circuit 42 is mounted is disposed in the lower space 26. In this embodiment, the electrometer circuit is an integrating electrometer circuit, which includes a capacitor for accumulating electric charge, a relay for releasing electric charge charged in the capacitor, and the like. Another electronic component such as a relay may be provided to change the operating conditions. In the present embodiment, a comparator that compares the voltage of the capacitor with a threshold value is provided, and the signal level is switched from low to high when the voltage of the capacitor becomes larger than the threshold value. The amount of charge is obtained by measuring the time required from the start of charge to the level fluctuation, and the radioactivity (radioactivity amount) is calculated backward. On the first substrate 40, electronic circuits up to the comparator are mounted. The output signal of the comparator is sent to the electronic circuit 50 via the signal path 44. A high voltage is applied to the ionization chamber 30 via the first substrate in the lower space 26 or via a different route. It is conceivable to use other types of electrometer circuits.

  In the lower space, electrons and wiring to which a high voltage is applied exist, and a circuit for processing a weak signal exists, so that the lower space is configured as an airtight space. That is, it is configured so that moisture does not freely enter the lower space, and is configured so that condensation does not easily occur in the lower space. This will be described in more detail later.

  The adjacent space 28 is an extended space formed on the back side of the lower space, and the substrate placement space is increased by forming the adjacent space 28. The adjacent space 28 is a non-sealed space in this embodiment. It is a normal substrate housing space. A plurality of air cooling openings communicating with the adjacent space may be provided for heat dissipation and other reasons. A second substrate 46 is disposed inside. The second substrate has a power source (high voltage source) 48 for the ionization chamber 30 and an electronic circuit 50. The electronic circuit 50 includes a circuit (such as a counter) that generates a signal indicating the amount of radioactivity, a circuit that performs communication with the main unit 12, and the like. In the present embodiment, a controller circuit that controls the operation of one or a plurality of relays is also mounted. Each component in the detection unit 10 is operated by the power supplied from the main unit 12.

  In the main unit 12, an arithmetic control unit 54 constituted by a microcomputer or the like is provided, and a liquid crystal display 22 with a touch screen panel is provided. The display 22 displays a measurement result and an operation screen. The amount of radioactivity is calculated from the count value by the calculation control unit 54. The measurement nuclide is specified by the user using the operation screen.

  FIG. 3 shows the front of the detection unit 10. The X direction is the first horizontal direction, that is, the left-right direction, and the Z direction is the vertical direction, that is, the up-down direction. The direction orthogonal to the X direction and the Z direction is the Y direction, which is the second horizontal direction, that is, the depth direction (front-rear direction). A cross section taken along line AA shown in FIG. 3 is shown later in FIG. The detection unit 10 has a lower portion 16, and an enlarged portion 18 is provided on the back side, that is, the back side.

  FIG. 4 is a perspective view showing the detection unit 10 as viewed from above. Inside the detection unit 10, an adjacent space 28 is provided in addition to the main space 24 and the lower space 26. The adjacent space 28 is an internal space of the enlarged portion 18, and the back side opening is covered with the back plate 58. The enlarged portion 18 is a portion protruding from the tubular portion 14 to the back side thereof. It is enlarged in the left-right direction and the up-down direction, and has a box-like form. It has a certain thickness in the depth direction. A back plate 58 is attached to the back frame 60 in the enlarged portion 18 with four screws. A connector on the cable side is connected to the connector 56. The back plate 58 is formed with slit rows 59 for heat dissipation.

  FIG. 5 is a perspective view showing the detection unit as viewed from below. A lower space is formed in the lower frame 64 of the lower portion 16, and a bottom plate 62 is attached to the lower space. The bottom plate 62 is detachably joined to the opening edge of the lower frame 64 with airtightness.

  FIG. 6 shows a longitudinal section of the detection unit. In the cylindrical part 14, the outermost member is a case 70 having a cylindrical shape, which is made of, for example, an aluminum material. Inside the case 70 is the main space 24, in which the ionization chamber 30 is arranged. The ionization chamber 30 has a collector electrode 32 and a container electrode 34. The container electrode 34 has a cylindrical shape, and a cylindrical insulating material 72 is disposed between the container electrode 34 and the case 70. The bottom plate 68 is a part of the container electrode 34. The inside 66 of the ionization chamber 30 is filled with an inert gas as an ionization gas. A well-shaped sample storage portion is formed along the central axis of the ionization chamber 30, and a holder 19 is provided there. The inside of the holder 19 is a sample accommodation hole 18A. An electrode structure 74 is provided below the collector electrode 32. It consists of an extraction electrode connected to the collector electrode 32, an extraction electrode connected to the container electrode 34, an insulating member between them, etc. (FIG. 6 shows the electrode structure 74 in a simplified manner). .

  A lower end portion of the case 70 is inserted into the lower frame 64. A lower space 26 is provided in the lower frame 64. The lower space 26 is located immediately below the main space 24, that is, immediately below the ionization chamber 30. It is a sealed space, that is, an airtight space into which external air cannot naturally enter. For this reason, the sealing member is arrange | positioned in the junction part between members. The lower frame 64 has a downward opening, and the opening is covered with a bottom plate 62. The bottom plate 62 is detachable, and an annular or circular seal member 76 is provided between the bottom plate 62 and the opening edge of the lower frame 64.

  A first substrate 40 is disposed in the lower space 26 with a horizontal posture. It is a substrate on which an electrometer circuit or the like is mounted as described above. An electrode structure 74 is electrically connected to the first substrate 40. That is, the charge signal from the collector electrode 32 is sent to the electrometer circuit on the first substrate 40. The power supply voltage may be supplied to the ionization chamber 30 via the first substrate 40, or the power supply voltage may be supplied to the ionization chamber 30 via another system (for example, a cable) that does not pass through the first substrate 40. It may be supplied. In the present embodiment, one substrate is disposed in the lower space 26, but a plurality of substrates may be disposed there. According to the configuration of the present embodiment, when the bottom plate 62 is removed, the entire back surface of the first substrate 40 is exposed, so that access to the first substrate 40 is good and workability is improved.

  A back frame 60 is provided on the back side of the lower frame 64. The lower frame 64 and the back frame 60 are integrated to form a lower housing. Like the case 70, the lower housing is made of an aluminum material or the like. Case 70 constitutes an upper housing. The entire casing of the detection unit is configured by the lower casing and the upper casing.

  The back frame 60 has a box shape, that is, has a certain thickness in the Y direction, which is the front-rear direction, and has a form that spreads in the X direction, which is the left-right direction, and the Z direction, which is the vertical direction. Inside, an adjacent space 28 having a box shape is provided. The adjacent space 28 can also be referred to as a back space. The back frame 60 and the lower frame 64 share the partition wall 60A or are connected to each other by the partition wall 60A. The partition wall 60 </ b> A is a partition for ensuring the airtightness of the lower space 26, in other words, a partition between the lower space 26 and the adjacent space 28.

  In the adjacent space 28, the second substrate 46 is arranged with a vertical posture, that is, a standing posture. As described above, the power supply, the signal processing circuit, the control circuit, the communication circuit, and the like are provided on the second substrate 46. In the present embodiment, one substrate is disposed in the adjacent space 28, but a plurality of substrates may be disposed there. Various substrates can be arranged in the adjacent space 28 as necessary. The back frame 60 has an opening facing the back side, and a back plate 58 is attached thereto. Access to the second substrate 46 is easy with the back plate removed. Therefore, workability can be improved. When the second substrate 46 is arranged in a horizontal posture, a relatively large installation space is required on the back side of the cylindrical portion 14, but in the present embodiment, the second substrate 46 is arranged in a vertical posture. Since the back frame 60 is configured to accommodate the second substrate 46 in such a posture, an increase in the installation area on the back side of the cylindrical portion 14 can be suppressed. Since the enlarged portion is located on the back side of the cylindrical portion, when the detection unit is observed from the front side, the enlarged portion is not obtrusive and has an advantage of good appearance.

  A seal structure 78 is provided at the lower center of the partition wall 60A. The seal structure 78 is a structure through which a plurality of signal lines are inserted, and maintains airtightness during the insertion. In FIG. 6, the details of the plurality of signal lines and the seal structure 78 are omitted for simplification of the drawing. This will be described in detail later with reference to FIG.

  FIG. 8 is a perspective view showing the lower housing (lower frame 64, rear frame 60) as viewed from below. The bottom plate and the back plate are removed, and the lower space 26 and the adjacent space 28 can be observed simultaneously. FIG. 9 shows a longitudinal section of the lower housing. The lower frame 64 and the back frame 60 in which the bottom wall 80 exists as a part of the lower frame 64 are connected via a partition wall 60A. The sealing structure 78 is provided on the partition wall 60A.

  FIG. 10 shows a cross section of the seal structure 78. A screw hole 86 is formed in the partition wall 60A. It is a hole opened on the adjacent space side. An O-ring 90 is disposed in the screw hole 86 and a screw 88 is disposed. The O-ring 90 is tightened by screwing of the screw hole 86 and the screw 88, and is crushed and deformed. A cable group 92 is passed through the O-ring 90. It is a bundle of several cables. Among them, a portion that passes through the seal structure 78 is covered with a heat shrinkable tube 94. The O-ring 90 holds the cable group 92 via the heat shrinkable tube 94. That is, the O-ring 90 is crushed and deformed by the advancement of the screw 88, the inner diameter thereof is reduced, and the O-ring 90 is sealed so that there is no gap with the cable group. Thereby, airtightness in the insertion portion is secured while protecting the individual cables. The seal structure 78 shown in FIG. 10 is an example, and other configurations can be adopted. From the viewpoint of workability, it is better to tighten the screw on the adjacent space side. It is possible to arrange a plurality of sealing members such as O-rings as necessary.

  According to the above embodiment, the adjacent space as the expansion space is provided in the casing of the detection unit in addition to the main space and the lower space. The adjacent space can be used as a substrate placement space. As a result, it is possible to expand the substrate accommodation space while avoiding an increase in the height of the detection unit and maintaining the airtightness of the lower space.

DESCRIPTION OF SYMBOLS 10 Detection unit, 12 Main body unit, 14 Cylindrical part, 16 Lower part, 18 Hypertrophied part, 24 Main space, 26 Lower space, 28 Adjacent space (back space), 30 Ionization chamber, 40 First board, 46 Second board, 60A partition wall, 78 seal structure.

Claims (6)

A housing having a main space for accommodating an ionization chamber, a lower space located below the main space, and an adjacent space adjacent to the lower space;
An ionization chamber provided in the main space and having a form surrounding the radioactive sample storage chamber;
A first substrate mounted in the lower space and mounted with a circuit for processing a charge signal from the ionization chamber;
A second substrate provided in the adjacent space and electrically connected to the first substrate;
Including
The housing has a partition wall that partitions the lower space and the adjacent space,
The lower space is configured as an airtight space,
A radiation measuring apparatus characterized by that. The apparatus of claim 1.
The lower space is a space extending in a first horizontal direction and a second horizontal direction, in which the first substrate is disposed in a horizontal posture,
The adjacent space is a space extending in the first horizontal direction and the vertical direction, in which the second substrate is arranged in a vertical posture.
A radiation measuring apparatus characterized by that. The apparatus of claim 2.
The first horizontal direction is a front-rear direction, and the second horizontal direction is a left-right direction;
The casing has a cylindrical shape standing up as a whole,
The housing has a box-shaped enlarged portion at the bottom and back side,
The adjacent space is provided in the enlarged portion,
A radiation measuring apparatus characterized by that. The apparatus of claim 3.
The housing is
A removable bottom plate for closing the bottom surface of the lower space;
A removable back plate for closing the back of the adjacent space;
A radiation measurement apparatus comprising: The apparatus of claim 1.
A plurality of signal lines are provided between the first substrate and the second substrate,
The partition wall is provided with a seal structure for inserting the plurality of signal lines while maintaining the airtightness of the lower space.
A radiation measuring apparatus characterized by that. The apparatus of claim 5.
The seal structure includes a screw hole opened on the adjacent space side, an annular seal member disposed in the screw hole, and a screw that is screwed into the screw hole.
The seal member is in a state of being crushed so as to clamp the plurality of signal lines passing through the seal member in a forward state of the screw,
A radiation measuring apparatus characterized by that.

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