JP2007020986A - Top board for medical radiological equipment and x-ray ct apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the precision of an image and the function of an apparatus and to reduce the radiation exposed dose of a patient. <P>SOLUTION: This top board 10 for the medical radiological equipment includes an upper face board 12a for mounting a recumbent subject and a lower face board 12b disposed oppositely to the upper face board; and is used by making a driving member and/or a support member contact with the lower face board and being reciprocated in a cantilever state in the subject's height direction. This top board is characterized in that the upper face board and the lower face board are fiber-reinforced resin moldings satisfying a relation expressed by an expression (1), one side in the height direction is a radioscopic part irradiating the radiation for diagnosing the subject, the other side is a fixed non-radioscopic part for achieving the cantilever state, and at least the radioscopic part has an aluminium equivalent weight (an index of X-ray transmission) of 1 mm or less. C<SB>U</SB>/C<SB>L</SB><1 (1). In the expression, C<SB>U</SB>expresses subject's height directional elasticity coefficient EuO/cross-sectional elasticity coefficient Eu90 and C<SB>L</SB>expresses the subject's height directional elasticity coefficient ELO in the lower face board/cross-sectional elasticity coefficient EL90. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

 The present invention relates to a top plate used for moving a patient to be fluoroscopically imaged, for example, in a medical radiation apparatus such as an X-ray CT apparatus or an X-ray imaging apparatus. An X-ray CT apparatus is supplied.

 Image diagnosis of patients using medical radiology equipment such as X-ray CT equipment and X-ray imaging equipment is indispensable in the modern medical field. Higher image accuracy, higher functionality of the device, and radiation exposure to patients Reduction is desired. In order to satisfy these demands, the top plate of medical radiation equipment, which is a bed on which the patient lies, is made longer to capture a wide area at once, and high rigidity and strength to improve patient position accuracy. There is a strong demand for excellent radiation transparency. For example, in the case of an X-ray CT apparatus, the apparatus includes a drive unit that moves the top and bottom and the horizontal direction, a scanning gantry (imaging unit) that collects data necessary for constructing a tomographic image, a control unit, and a power supply unit. However, the patient gets on and off when the top plate is at the lowest position in the both-sided state, and passes through the opening of the scanning gantry in the height direction in the lying state, and X-rays are taken. Accordingly, the top plate at the time of photographing is in a state of protruding from the drive unit, that is, a cantilever state, and a bending moment due to the patient weight acts on the top plate. For this reason, in order to satisfy the above-described requirements for the top plate, it is very important to design the top plate with increased bending rigidity and bending strength in the patient height direction.

 In general, a top plate of a medical radiation device is composed of a sandwich structure using a plastic foam or the like as a core material and using a fiber reinforced resin (hereinafter referred to as FRP) for a skin layer outside the core. In particular, the skin layer is a carbon fiber reinforced resin (hereinafter referred to as CFRP) made of carbon fiber, which has higher specific strength / specific elastic modulus and excellent radiation transmission than general materials such as aluminum, general-purpose resin, and wood. Are often used). In order to increase the bending rigidity and bending strength of the top plate having such a configuration, not only the materials used but also the top plate shape such as an increase in the top plate thickness and an increase in the CFRP skin layer thickness have been studied. However, if the thickness is increased, the radiation transparency of the top plate is deteriorated, so that it is necessary to set the radiation intensity higher in the diagnosis, resulting in a problem of radiation exposure of the patient. Furthermore, handling troubles due to an increase in the weight of the top plate and an increase in the top plate price also occur.

  Therefore, when moving the patient as a means to reduce the thickness of the top plate or skin layer without reducing the bending strength and bending strength of the top plate, that is, when a bending moment acts on the top plate in a cantilevered state. The upper skin with the top plate on the convex side (tensile side) is made of CFRP with carbon fiber capable of expressing high tensile strength and tensile modulus, and the lower skin on the concave side (compression side) with high compressive strength, It has been proposed to use CFRP made of carbon fiber capable of expressing a compression modulus (for example, Patent Document 1). This proposal pays attention to deformation when viewed as the whole top plate, and attempts to achieve high rigidity and high strength efficiently by using carbon fibers suitable for the upper and lower sides of the CFRP skin layer. However, when focusing only on the skin layer, as is apparent from the mechanics, even in the upper surface side skin that is the convex side, compressive stress is generated on the inner layer side. Therefore, selecting the carbon fiber for the upper skin layer by paying attention only to the tensile strength and the tensile modulus cannot always be said to optimize the top plate or skin layer thickness. The same applies to the lower surface side skin layer which is the concave side.

As another means for reducing the thickness of the top plate or the skin layer, in the skin layer composed of a plurality of FRP layers, when the bending moment is applied, the FRP layer located on the most core side in the upper side skin layer serving as the tension side In addition, an FRP layer having higher compressive strength than the FRP layer positioned next to the FRP layer is disposed. In the lower skin layer on the compression side, the FRP layer positioned closest to the core side is placed next to the FRP layer. It has been proposed to dispose an FRP layer having a higher tensile strength than the positioned FRP layer (for example, Patent Document 2). This proposal takes into account the deformation of the upper and lower skin layers when a bending moment acts on the top plate in a cantilever state, and depending on the position relative to the core, the compressive strength and tensile strength of the FRP layer constituting the skin layer The strength is determined, which is very effective for reducing the thickness of the top plate or skin layer. However, when the thickness of the lower surface side shell is smaller than that of the upper surface side shell and the rigidity in the patient's height direction is low, the lower surface side shell and the core are locally bent at the position of the drive member and the support member in contact with the lower surface side shell. Therefore, repeated reciprocation may cause fatigue failure due to out-of-plane shearing of the lower shell and core compression. This proposal also optimizes the total thickness of the skin layer because it is necessary to increase the thickness of the lower shell in order to prevent fatigue failure and to satisfy the mechanical requirements of the top plate in long-term repeated X-ray photography. It's hard to say.
Japanese Utility Model Publication No. 5-62208 Japanese Patent Laid-Open No. 2004-216021

  The present invention has been made in view of the above-mentioned problems of the conventional top plate, and in image diagnosis of a patient using a medical radiological device, higher accuracy of the image, higher functionality of the device, and reduction of the radiation exposure amount of the patient. Therefore, it is to provide a medical radiation equipment top plate and an X-ray CT apparatus with uniform and good radiation transmission.

  In order to solve the above-mentioned problems, the medical radiation device top plate of the present invention includes an upper surface plate on which a subject in a lying position is placed, and a lower surface plate disposed opposite to the upper surface plate, and a driving member and / or a supporting member. In contact with the lower surface plate and can be reciprocated in a cantilevered state in the height direction of the subject, the upper surface plate and the lower surface plate being a fiber reinforced resin that satisfies the relationship represented by the formula (1) A molded article, and one side in the height direction is a radioscopic part that emits radiation for diagnosis of the subject, and the other side is a non-fluoroscopic part that is fixed to realize the cantilever state, at least The radiation fluoroscopic portion is characterized in that an aluminum equivalent which is an index of X-ray transmission is 1 mm or less.

C _U / C _L <1 (1)
In the formula, C _U : the height elastic modulus Eu0 / cross-sectional elastic modulus Eu90 of the subject on the top plate
C _L : Height elastic modulus EL0 / cross-sectional elastic modulus EL90 of the subject on the bottom plate
In order to improve the radiation transmittance of the top plate, the upper surface plate and the lower surface plate are each preferably a fiber reinforced resin molded product using continuous carbon fibers as reinforcing fibers.

Further, in order to reduce the thickness of the top plate and the top plate skin layer, the relationship expressed by the formula (2) to the elastic modulus ratios C _U and C _L of the subject in the height direction and the cross-sectional direction of the upper surface plate and the lower surface plate, respectively. Is preferably satisfied.

C _U / C _L <0.8 (2)
In the above-described top plate of the present invention, the length of the top plate in the height direction is 2.0 m or more and 3.5 m or less, and the cantilever span is 70% of the top plate length. The thickness of the top plate and the skin layer can be effectively reduced when the breaking load when the evenly distributed load is applied to 9800 N or more.

  Further, as the most preferable form for minimizing the aluminum equivalent, it is desirable that the upper surface plate and the lower surface plate are connected at both ends in each cross-sectional direction, and at least the radioscopic portion has a hollow structure.

 When the radiation see-through part of the top plate has a hollow structure, it is preferable that a reinforcing member is disposed in the non-see-through part.

 In addition, it is preferable that at least a part of the reinforcing member is connected to both the upper plate and the lower plate, and the weight of the subject lying on the upper plate is transmitted to the lower plate through the reinforcing member.

  In addition, when used in a cantilevered state in the cantilever direction of the subject, if there is a large difference in the bending rigidity between the radioscopic part and the non-fluoroscopic part, the boundary between the radioscopic part and the non-fluoroscopic part is driven. When passing through a member or a support member, there is a possibility that a rapid change occurs in the deflection of the top plate. A sudden change in the deflection not only changes the vertical position of the subject and lowers the image quality of the diagnostic image, but also causes a deterioration in the ride comfort, giving the subject anxiety. Therefore, in order to realize a gradual change in the top plate deflection, the bending stiffness of the reinforcing member in the height direction of the subject is constant or decreased from the top plate end of the non-transparent part toward the radioscopic part. Preferably it is.

  Moreover, in order to improve the assembly / maintenance property to the medical radiation equipment by reducing the total weight of the top plate, it is preferable to use aluminum as the material of the reinforcing member. As another material, a fiber reinforced resin may be used as the material of the reinforcing member.

  The present invention relates to a top plate used for moving a subject in a medical radiology apparatus such as an X-ray CT apparatus and an X-ray imaging apparatus, for example. A plate and an X-ray CT apparatus are supplied. By using the top plate and the X-ray CT apparatus of the present invention, it is possible to perform diagnosis with high accuracy images, safe diagnosis with a small amount of X-ray exposure of the subject, and the like.

 The medical radiation device top plate (hereinafter abbreviated as “top plate”) of the present invention is used by placing a subject in a lying state and reciprocating it in a cantilever state in the height direction of the subject. Here, the recumbent state refers not only to a recumbent in a narrow sense but also to the entire lying state including the supine, prone and the like. In order to provide such a use, the cross section of the top plate has a crescent shape or a shape based on a rectangle or a trapezoid.

 In order to keep the posture of the subject in a stable state, the upper surface plate preferably has a concave curved surface on the subject side. Note that a belt or the like for forcibly fixing the posture of the subject may be attached to the upper surface plate.

 The lower surface plate is disposed to face the upper surface plate and has a function of contacting and supporting the driving member and / or the supporting member when reciprocating in a cantilever state in the height direction. The lower surface plate and the upper surface plate may be directly connected or may be connected via another member. As a shape, it is a curved surface plate that is directly connected to the upper surface plate with a curved surface whose cross section is an arc or a parabola, or a composite surface shape in which a flat plate having side plates connected to the upper surface plate at both ends of the flat plate is connected. Although it can be mentioned, from the viewpoint of simplification of the shape of the drive member and the support member and stabilization of the vertical position at the attachment portion and the contact portion, it is a composite surface shape having side plates connected to the upper surface plate at both ends of the plane. It is preferable. In the case where the lower surface plate has a composite surface shape, it is preferable in terms of improving the degree of freedom in molding conditions when the thickness and the laminated structure of the flat plate and the side plate arranged opposite to the upper surface plate are the same. When the thickness and the laminated structure of the flat plate and the side plate arranged opposite to each other are designed separately, it is preferable because it can cope with the uniform reaction force received from the drive member and the support member.

Upper plate and the lower plate is high performance of high precision and medical radiographic equipment image, for combine strength and rigidity and radiolucent capable of satisfying demands such as radiation exposure dose reduction the patient, C _U / C _L is 1 It is necessary to be a fiber reinforced resin molded product (hereinafter referred to as FRP) which is less than the above.

Here, C _U is the upper plate, the height direction modulus Eu0 of the subject, the value obtained by dividing the cross-sectional direction modulus Eu90, C _L is the lower plate, the subject's height direction modulus EL0 Is a value obtained by dividing by the modulus of elasticity in the cross-section direction EL90. When C _U / C _L is 1 or more, the upper surface plate is easily deformed in the cross-sectional direction, and deformation (collapse) of the cross-section of the top plate due to the body weight of the subject becomes a problem. From this viewpoint, it is more preferable that C _U / C _L is less than 0.8. Here, the elastic modulus is measured in accordance with JIS by cutting a sample having a length of 200 mm and a width of 25 mm from a top plate and a bottom plate to produce a test piece. In the case of carbon fiber reinforced resin, the tensile test method conforms to JIS K7073 and the bending test method conforms to JIS K7074. However, the specimen thickness is the thickness of each of the upper surface plate and the lower surface plate. Moreover, when the upper surface plate and the lower surface plate are curved surfaces, the test piece size conforms to JIS. The sample is cut out from the center in the cross-section direction for the top plate, from the center in the cross-section if the bottom plate is curved, or from the plane plate facing the top plate in the case of a composite surface shape including a plane plate and side plates. The central part in the cross-sectional direction.

 Further, when the top plate is considered in the height direction of the subject, it can be divided into two regions, a radioscopic portion and a non-fluoroscopic portion. The radioscopic part is a region that emits radiation for diagnosis, and depending on the application, it often occupies 50 to 70% of the total length of the top plate from one end of the top plate. The length of the top plate has been increased for the purpose of expanding the fluoroscopic range, and recently, there is a top plate having a radioscopic portion length of 1.5 m or more. The non-transparent portion is a top plate area other than the radioscopic portion, and the top plate is fixed to a driving member of a medical radiation device on the top plate end side of the non-fluoroscopic portion.

 In addition, the top plate of the present invention needs to have an aluminum equivalent of 1 mm or less, which is an index of X-ray transmission, at least in the radioscopic part from the viewpoint of reducing the radiation exposure dose of the patient. The aluminum equivalent is an index indicating how many mm of the aluminum plate corresponds to the X-ray permeability compared with the aluminum permeability.

  FRP is characterized in that the physical properties can be designed by reinforcing fibers and matrix resin simultaneously with the anisotropic design, but in the present invention, in order to obtain good radiation transmission as well as strength and rigidity, Each face plate preferably uses continuous carbon fibers as reinforcing fibers.

  Further, the top plate of the present invention has a height direction length of the upper surface plate of 2.0 m or more and 3.5 m or less, and the span of the cantilever state is 70% of the length of the upper surface plate. When the breaking load when the uniformly distributed load is applied is 9800 N or more, the thickness of the top plate and the skin layer can be effectively reduced. In order to minimize the aluminum equivalent, It is most preferable that the bottom plate is connected at both ends in each cross-sectional direction, and at least the radioscopic portion has a hollow structure.

 Hereinafter, an embodiment of the present invention will be specifically described with reference to the drawings. Each figure represents a representative example, and the present invention is not limited to these.

  FIG. 1 is a schematic view showing an operation example of the top plate of the present invention in a medical radiation apparatus, FIG. 2 is a perspective view of the top plate according to an embodiment of the present invention, having a partially broken portion, and FIGS. Sectional drawing which cut | disconnected the top plate in the height direction and the cross-sectional direction to 11 is shown, and the schematic for the process and equipment for manufacturing the top plate of this invention to FIGS. 12-14 is shown.

  As shown in FIG. 1, the top plate 10 of the present invention is a subject in a cantilever state in which an end portion is fixed to a moving member 21 of a driving unit 20 of a medical radiation device with a bolt or the like, and lying on the upper surface side. 30 is used by reciprocating in the height direction X of the subject. For this reason, a downward bending moment in the vertical direction Z acts on the top plate 10, but in order to reduce the top plate deflection in the vertical direction Z and stabilize the reciprocation in the height direction X, the lower surface side of the top plate 10 is It is often supported by the support member 22. Generally, a metal or resin roll is used for the support member 22.

  In addition, the top plate 10 occupies about 50 to 70% of the total length of the top plate from one side end portion, and a radioscopic portion 10a that irradiates radiation to diagnose the subject 30 and an end portion other than the radiographic portion 10a. It can be divided into two regions of the non-transparent part 10b fixed to the moving member 21 of the drive part 20 on the side. In recent years, radiography has been required to have a wide range of imaging with higher functionality, and the top plate 10 has a length of 2.0 m to 3.5 m and the radioscopic portion 10a has a length of 1.5 m or more. It has become mainstream.

 In order to cope with such use, the top plate 10 has a thickness of about 20 to 70 mm, a width of about 300 to 600 mm, and has a breaking strength of 9800 N or more, which is four times or more the weight of the subject 30. Even when the strength safety factor is adopted, it is possible to cope with a subject having a weight of 250 kg, and it is possible to cope with subjects having virtually any weight.

  As shown in FIG. 2, the top plate 10 is generally a sandwich structure that includes a core 11 and a skin layer 12 that is positioned outside the core 11 and has higher rigidity than the core 11. The skin layer 12 preferably includes the entire core 11 with two side plates 12c and 12d as shown in FIG. 3 as well as the upper plate 12a and the lower plate 12b. Although the side plates 12c and 12d are not necessarily required, the cross-sectional direction Y of the top plate 10 is used in order to prevent the core 11 from being locally deformed or compressed and broken by a local load due to the body weight of the subject 30. In this case, the upper surface plate 12a and the lower surface plate 12b are preferably connected by the two side surface plates 12c and 12d.

 The cross-section in the Y direction of the top plate 10 is a shape based on a rectangle or a trapezoid, but in order to keep the posture of the subject 30 lying down in a stable state, as shown in FIG. Often curved. If the surface plate other than the upper surface plate 12a is also curved, the cross section has a crescent shape. In the case of the composite surface shape shown in FIG. 3, the lower surface plate 12b and the side surface plates 12c and 12d are combined to be interpreted as a lower surface plate having a concave cross section.

 The core 11 is preferably as low in density as possible within a range that satisfies the required values of high rigidity and high strength. The material of the core 11 is polyurethane foam, polystyrene foam, polyvinyl chloride foam, acrylic foam, Plastic foams such as polymethacrylimide foam, cellulose acetate foam, epoxy foam, and phenol foam can be used.

  As described above, a bending moment downward in the vertical direction Z acts on the top plate 10, but considering the anxiety of the subject 30 due to interference with other parts of the medical radiological device and deflection of the tip, The “top plate that does not flex” is ideal. However, if the thickness of the top plate 10 and the thickness of the skin layer 12 are increased only for the purpose of reducing the deflection of the top plate, the radiation transmittance of the top plate 10 is deteriorated. For this reason, it is necessary to set the radiation intensity higher in the diagnosis, and an increase in the radiation exposure amount of the subject 30 becomes a problem.

 The top plate 10 of the present invention is characterized in that the aluminum equivalent is 1 mm or less. However, in designing, both rigidity / strength and radiation transparency are considered, that is, on the side of the radioscopic portion 10a ( It is very important to minimize the thickness of the top plate 10 and the thickness of the skin layer 12 within the design range of the deflection of the top plate end on the free end side. For this reason, it is preferable that the upper surface plate 12a, the lower surface plate 12b, and the side surface plates 12c and 12d which are the skin layers 12 are FRP in which an anisotropic design is possible.

  The FRP includes a reinforced fiber and a matrix resin. As the reinforced fiber, at least one of carbon fiber (including graphite fiber), aramid fiber, high-strength polyethylene fiber, glass fiber, and boron fiber is used. be able to. Among these, it is preferable to use carbon fibers that are excellent in radiolucency. These reinforcing fibers can be used in the form of woven fabric such as plain weave, satin weave, twill weave, weave weave, or strand.

  As matrix resin, thermosetting resin such as epoxy resin, unsaturated polyester resin, vinyl ester resin, phenol resin, polyimide resin, and thermoplastic resin such as ABS resin, nylon resin, polyether ether ketone resin, polyolefin resin, etc. Can be used. Among these, it is preferable to use an epoxy resin or a vinyl ester resin in view of the adhesiveness and moldability with the carbon fiber.

  The elastic modulus of FRP can be designed according to the type, characteristics, and form of the reinforcing fiber, the ratio of the reinforcing fiber and the matrix resin, etc. In order to minimize the thickness of the skin layer 12, the height direction X of the top board 10 It is effective to increase the rigidity (bending rigidity). Therefore, it is preferable that the upper surface plate 12a and the lower surface plate 12b have a design in which the elastic modulus in the height direction X is increased.

In the case of CFRP, although it depends on the carbon fiber content, in order to achieve an aluminum equivalent of 1 mm or less of the top plate 10, it is a standard to design the top plate with the skin layer 12 thickness within the range of 1 to 8 mm. However, as shown in FIG. 4, when the thickness of the lower surface plate 12 b is small and the bending rigidity is low, the lower surface plate 12 b and the core 11 are locally deformed at the position of the support member 22. In this state, when the top plate 10 repeats reciprocating movement, the lower surface plate 12b is fatigued by the out-of-plane shearing force and the core 11 is fatigued by the compression force, and the mechanical requirement specifications of the top plate 10 cannot be satisfied for a long time. Therefore, as shown in FIG. 5, it is preferable that the lower surface plate 12b is designed so as to increase the thickness and bear more than half of the bending rigidity of the entire skin layer 12. Increasing the bending rigidity of the lower surface plate 12b not only prevents fatigue breakage, but also reduces local bending deformation at the position of the support member 22, and the smooth reciprocation of the top plate 10 is obtained. 30 anxiety can also be reduced.

  However, if the thickness of the lower surface plate 12b is increased and the thickness of the upper surface plate 12a is decreased too much, as shown in FIG. 6, the upper surface plate 12a is locally deformed by the local load due to the body weight of the subject 30, The top plate 10 may be deformed in cross section in the direction of the middle black arrow.

 Therefore, in order to optimize the thickness of the skin layer 12, first, the top plate 10 is regarded as one structure, and the deflection of the top plate end portion on the side of the radioscopic portion 10a (free end side) is within the design range. Thus, the elastic modulus and thickness of the skin layer 12 are designed in each of the height direction X and the cross-sectional direction Y, and then the lower surface plate 12b is designed to bear more than half of the bending rigidity of the entire skin layer 12. . And it is important for the upper surface plate 12a to increase the rigidity in the cross-sectional direction Y compared to the lower surface plate 12b. That is, it is important that the relationship of the formula (1), preferably the relationship of the formula (2) is established between the upper surface plate 12a and the lower surface plate 12b.

C _U / C _L <1 (1)
C _U / C _L <0.8 (2)
Here, symbols in the formula are as follows.
C _U : Elastic modulus Eu0 in the height direction X / elastic modulus Eu90 in the cross-sectional direction Y in the upper surface plate 12a
C _L : Elastic modulus EL0 in the height direction X / elastic modulus EL90 in the cross-sectional direction Y in the bottom plate 12b
By satisfying the above relationship, the thickness of the skin layer 12 can be optimized, but the aluminum equivalent of the top plate 10 is affected not only by the skin layer 12 but also by the core 11. In order to satisfy the required values of rigidity and strength of the top plate 10, the thickness of the top plate 10 is about 20 to 70 mm, but the core 11 occupies most of the thickness. Therefore, it is preferable that the core 11 has as low a density as possible and has excellent radiation transparency. Therefore, in order to minimize the aluminum equivalent, the upper surface plate 12a and the lower surface plate 12b are connected at both ends in each cross-sectional direction, or are connected at both ends via the side plates 12c and 12d, and at least the radioscopic portion It is the most preferable form that 10a has a hollow structure.

 As shown in FIG. 7, the top plate 10 is subjected to a maximum bending moment when it protrudes most from its usage, that is, when the support member 22 is in the non-transparent portion 10b. Therefore, the non-perspective portion 10b not related to the image diagnosis, that is, the aluminum equivalent, has the reinforcing member 13 disposed therein to increase the rigidity of the top plate 10, and the cantilever span is short even when the support member 22 is positioned, and the bending moment The skin layer 12 of the radioscopic part 10a having a small thickness is preferably made thin.

 However, when the top plate 10 has a hollow structure, as shown in FIG. 8, the weight of the subject 30 is transmitted from the top plate 12a to the bottom plate 12b via the side plates 12c and 12d. And the peeling force acts on the reinforcing member 13. Since the reinforcing effect cannot be obtained if the lower surface plate 12b and the reinforcing member 13 are separated while the top plate 10 repeatedly moves back and forth, the bending rigidity of the top plate 10 is remarkably lowered. For this reason, it is preferable that at least a part of the reinforcing member 13 is connected to both the upper surface plate 12a and the lower surface plate 12b.

  In the example shown in FIG. 9, the reinforcing member 13 fills all the space formed by the skin layer 12, but in this case, the weight of the subject 30 is transmitted to the upper surface plate 12a, the reinforcing member 13, and the lower surface plate 12b. The peeling force does not act between the bottom plate 12b and the reinforcing member 13. What is important is the propagation of force from the upper surface plate 12a to the lower surface plate 12b, and the reinforcing member 13 may have a plate-like protrusion as shown in FIG.

 Furthermore, the reinforcing member 13 has a constant bending rigidity in the height direction X of the subject 30 from the end of the non-perspective portion 10b of the top 10 toward the radioscopic portion 10a as in the example shown in FIG. Preferably it is present or reduced. When the top plate 10 is used while being reciprocated in a cantilevered state, if there is a large difference in bending rigidity between the radiation see-through portion 10a and the non-see-through portion 10b, when the driving member 22 passes through these boundaries, Abrupt changes in the deflection of the plate 10 can occur. That is, not only does the position of the subject 30 in the vertical direction Z fluctuate and the image quality of the diagnostic image is deteriorated, but also the riding comfort is prevented from deteriorating and giving the subject 30 anxiety.

 The reinforcing member 13 may be made of any material as long as the bending rigidity can be improved. However, considering the weight and elastic modulus of the top plate 10, it is preferable to design aluminum or fiber reinforced resin.

 The top plate 10 of the present invention described above can be manufactured using a molding method such as pultrusion molding, autoclave molding, press molding, hand lay-up molding, RTM molding and the like generally used in FRP. For example, as shown in FIG. 12, the first step of machining the core 11 into a predetermined shape and the necessary number of reinforcing fiber prepregs to be the upper surface plate 12 a, the lower surface plate 12 b, the side surface plates 12 c and 12 d are wound around the core 11. After forming from the second step, and finally from the third step of prepreg curing while heating and pressurizing in the mold 40, finishing can be performed and manufactured. At the time of the above molding, the upper surface plate 12a, the lower surface plate 12b, and the side surface plates 12c and 12d can be obtained by integrally molding with both ends in the width direction being connected at the same time. This is preferable because there are advantages in terms of mechanical characteristics by reducing the number of parts and advantages from the viewpoint of productivity because the number of steps can be reduced.

 In the case of a hollow structure that does not require the core 11, first, a pipe-shaped skin layer 12 is formed, and a reinforcing member 13 manufactured in a separate process is attached to the non-perspective portion 10b with an adhesive or the like. The top plate 10 can be manufactured by attaching separate parts to both ends. In this case, since the machining process of the core 11 can be omitted, the machining cost at the time of manufacture is often not cheap compared to the case where the core 11 is present.

 The skin layer 12 is made of FRP, but if the reinforcing fiber is bent or wavy, the strength rigidity is lowered and the design value cannot be satisfied. For this reason, pultrusion molding is the most preferable method for forming the pipe-shaped skin layer 12. In the case of pultrusion molding, molding can be performed while applying a certain tension to the reinforcing fiber and its woven fabric. Therefore, compared to other molding methods, the bending and undulation of the reinforcing fiber is small, and the skin layer 12 having the same physical properties as the design value is formed. Obtainable. Furthermore, pultrusion molding is highly mass-productive and effective in reducing processing costs.

 FIG. 13 shows a schematic facility when a pipe-shaped FRP molded product is formed by pultrusion molding. The roll-shaped reinforcing fiber fabric 41 is pulled out while the position is regulated by the guide 42, the resin is impregnated into the fabric 41 through the resin bath 43, and the resin is heated and cured by the mold 46. In addition, by controlling the gripping force, the propulsive force, and the moving timing of the clamps 47a and 47b of the pulling device 47, the pipe-shaped skin layer 12 is continuously formed and cut into a predetermined length by the cutter 48. Can be obtained. As shown in FIG. 14, the mold 46 is composed of an upper mold 46a and a lower mold 46b, the temperature of which can be controlled by a heater 49, and a core 45 supported by a cylinder 44 is disposed in a portion corresponding to the internal space. ing.

  Examples of the present invention will be specifically described below. However, the top plate of the present invention is not limited to this embodiment.

  It has a crescent-shaped cross section with a length of 2 m, a width of 0.47 m, and a maximum height of 0.034 m, a breaking load of 9800 N or more (equally distributed load on the top surface of the top plate), repeated reciprocating durability of 40000 times, aluminum equivalent of 1 mm The top plate was manufactured as follows in order to satisfy the following design specifications.

A carbon fiber was used as the reinforcing fiber, and a CFRP hollow structure (skin layer) having a crescent cross section was formed by pultrusion using a woven fabric having the following specifications. As the matrix resin, a vinyl ester resin (Neopol 8250H manufactured by Nippon Ipica) was used.
<Textile base material A>
Warp: Carbon fiber
Tensile strength 4900Mpa, tensile elastic modulus 230Gpa, 24,000 filaments Weft: Polyester fiber Tensile strength 1000Mpa
Weight per unit area 742g / m ²
Weave weave <woven fabric base B>
Warp: Carbon fiber
Tensile strength 4900 Mpa, tensile elastic modulus 230 Gpa, number of filaments 24000 Weft: carbon fiber Tensile strength 3530 Mpa, tensile elastic modulus 230 Gpa, number of filaments 12000 per unit weight 596 g / m ²
Satin weave <woven fabric base C>
Warp: Carbon fiber
Tensile strength 3530 Mpa, tensile elastic modulus 230 Gpa, 6,000 filaments Weft: carbon fiber Tensile strength 3530 Mpa, tensile elastic modulus 230 Gpa, 6,000 filaments per unit weight 317 g / m ²
Plain weave <woven fabric substrate D>
Warp: Carbon fiber Tensile strength: 3530 Mpa, tensile elastic modulus: 230 Gpa, number of filaments: 3000 Weft: Carbon fiber: Tensile strength: 3530 Mpa, tensile modulus of elasticity: 230 Gpa, number of filaments: 3000 per unit weight: 317 g / m ²
The satin weave In addition, the top plate uses a base material A: 1 base material, a base material B: 1 base material, and a base material D: 4 sheets, a thickness of 2.9 mm, a height direction elastic modulus of 68.2 GPa, and a cross-sectional direction elastic modulus of 62. The layer was designed in consideration of moldability and appearance so as to be .9 Gpa.

In addition, the bottom plate is composed of two base materials A, two base materials B, one base material C, and one base material D, and has a thickness of 3.7 mm, a height direction elastic modulus of 89.1 GPa, Laminate design was performed in consideration of formability and appearance so that the cross-sectional elastic modulus was 43.2 Gpa.
Therefore,
Total thickness of skin layer 6.6mm
Elastic modulus ratio C _U = 1.084 of the top plate, Elastic modulus ratio C _L = 2.063 of the bottom plate
C _U / C _L = 0.525 <0.8
It has become.

  The reinforcing member had a length of 850 mm and was a CFRP molded product having a crescent cross section (bending elastic modulus of about 7000 MPa) so that the entire space of the skin layer could be filled. Further, the front end portion on the boundary side with the radioscopic portion was obliquely cut at 30 °, and the thickness in the top plate direction, that is, the bending elastic modulus decreased in the patient height direction at the oblique cut portion.

After a reinforcing member is bonded to the CFRP hollow structure (skin layer) using an epoxy adhesive, an injection molded thermoplastic resin molded product is bonded to both ends of the CFRP hollow structure, and finish processing is performed. Manufactured.
[Evaluation results]
a) Strength of the top plate The top plate is bolted at a position where it is attached to the moving member of the drive unit of the medical radiation device, and the cantilever state is obtained with the support member disposed at a position of 1400 mm corresponding to the state where the top plate protrudes most. It was realized. When the equally distributed load acting on the entire length of the top plate was increased, the lower surface plate contacting the support member at 12817N was destroyed, but it was confirmed that the design specification value 9800N was sufficiently exceeded.
b) Endurance of reciprocating movement When the patient weight of 205 kg was set, the top board was loaded at a rate according to IEC (International Electrotechnical Commission) 60601-1, and the top board was reciprocated. Destruction was not observed and it was confirmed that there was no problem with the top plate performance.
c) Aluminum equivalent In general, the X-ray transmission is often indicated by the thickness of the plate, which is comparable to that of aluminum, and is similar to JESRA (Japan Engineering Standards of Radiation Apparatus). Measurements were performed at 80 kV, 2 mA, 40 sec.

  The aluminum equivalent of the radioscopic part was 0.82 mm, and it was confirmed that the design specification value of 1 mm or less was satisfied.

 When the present invention is used, the top plate used for moving a patient at the time of image diagnosis by a medical radiological device satisfies the required specification of strength and rigidity, and the aluminum equivalent which is an index of X-ray permeability is 1 mm or less. Can be. Since the radiation transparency is better than that of a conventional top plate, it is possible to perform a diagnosis with high accuracy and a safe diagnosis with a small amount of radiation exposure of a patient.

Schematic which shows the operation example of the top plate of this invention in medical radiology equipment The perspective view of the top plate which is one Embodiment of this invention which has a partially broken part Sectional drawing of the top plate obtained in the Example of this invention Sectional drawing which cut | disconnected the top plate obtained in the Example of this invention in the moving direction Sectional drawing which cut | disconnected the other top plate obtained in the Example of this invention in the moving direction Sectional view of hollow structure top plate obtained in Example of the present invention and deformation model diagram under load Sectional drawing which cut | disconnected the hollow structure top plate obtained in the Example of this invention in the moving direction Non-transparent section view and load transmission model diagram of hollow structure top plate obtained in an embodiment of the present invention Sectional view and load transmission model diagram of non-transparent part of hollow structure top plate obtained in another embodiment of the present invention Non-transparent part sectional view of a hollow structure top plate obtained in another embodiment of the present invention Sectional drawing which cut | disconnected the hollow structure top plate obtained in the other Example of this invention in the moving direction Process drawing which shows one method of manufacturing the top plate of this invention Schematic of pultrusion equipment for manufacturing the top plate of the present invention Schematic of pultrusion mold for manufacturing the top plate of the present invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 10: Top plate 10a: Radioscopic part 10b: Non-permeable part 11: Core 12: Skin layer 12a: Upper surface plate 12b: Lower surface plate 12c: Side surface plate (right)
12d: Side plate (left)
13: Reinforcing member 20: Drive unit 21: Moving member 22: Support member 30: Subject (patient)
40: Press molding die 41: Reinforcing fiber fabric 42: Guide 43: Resin bath 44: Cylinder 45: Core 46: Pull-out molding die 46a: Upper die of the drawing mold 46b: Lower die 47 : Pulling device 47a: Clamp (upstream)
47b: Clamp (downstream)
48: Cutter 49: Heater

Claims (11)

A top plate for placing a subject lying in a recumbent state, and a bottom plate placed opposite to the top plate; and a drive member and / or a support member in contact with the bottom plate in a cantilever state in the height direction of the subject A medical radiation device top plate used by reciprocating movement, wherein the upper surface plate and the lower surface plate are fiber-reinforced resin molded products that satisfy the relationship represented by the formula (1), and one side in the height direction is covered A radioscopic part that emits radiation for examiner diagnosis, and the other side is a non-fluoroscopic part that is fixed to realize the cantilever state, and at least the radioscopic part is an aluminum that is an index of X-ray permeability A medical radiation device top plate, wherein an equivalent is 1 mm or less.
C _U / C _L <1 (1)
In the formula, C _U : the height elastic modulus Eu0 / cross-sectional elastic modulus Eu90 of the subject on the top plate
C _L : Height elastic modulus EL0 / cross-sectional elastic modulus EL90 of the subject on the bottom plate   The medical radiation equipment top plate according to claim 1, wherein each of the upper surface plate and the lower surface plate is a fiber-reinforced resin molded product using continuous carbon fibers as reinforcing fibers. The medical radiation according to any one of claims 1 and 2, wherein the relationship represented by the formula (2) is established between the elastic modulus ratios C _U and C _L in the height direction and the cross-sectional direction of the subject on each of the upper surface plate and the lower surface plate. Equipment top plate.
C _U / C _L <0.8 (2)   When the length in the height direction of the upper surface plate is 2.0 m or more and 3.5 m or less and the span in the cantilever state is 70% of the length of the upper surface plate, an evenly distributed load is applied to the entire upper surface plate. The medical radiation equipment top plate according to any one of claims 1 to 3, wherein a breaking load when it is applied is 9800 N or more.  The medical radiation equipment top plate according to any one of claims 1 to 4, wherein the upper surface plate and the lower surface plate are connected at both end portions in each cross-sectional direction, and at least the radiation fluoroscopic portion has a hollow structure.  The medical radiation apparatus top plate according to any one of claims 1 to 5, wherein a reinforcing member is disposed in the non-transparent part.   The medical radiation apparatus top plate according to claim 6, wherein at least a part of the reinforcing member is connected to both the upper surface plate and the lower surface plate.  The bending rigidity in the height direction of the subject of the reinforcing member is constant or decreased from the top plate end of the non-transparent part toward the radiologically transparent part. Medical radiation equipment top plate.   The medical radiation apparatus top plate according to any one of claims 6 to 8, wherein aluminum is used as a material of the reinforcing member.   The medical radiation equipment top plate according to any one of claims 6 to 8, wherein a fiber reinforced resin is used as a material of the reinforcing member.   The X-ray CT apparatus using the medical radiation equipment top plate in any one of Claims 1-10.

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