JP5487008B2 - Ultrasound bone evaluation device - Google Patents

Description

  The present invention relates to an ultrasonic bone evaluation apparatus that evaluates a bone state using ultrasonic waves.

  An ultrasonic bone evaluation device that evaluates the state of bone tissue by radiating ultrasonic waves to bones such as ribs and measuring the speed of sound and the degree of attenuation of ultrasonic waves propagating in bone tissue has been put to practical use. ing. This type of ultrasonic bone evaluation apparatus has a pair of ultrasonic transducers arranged facing each other. The bone to be evaluated is positioned between these ultrasonic transducers, ultrasonic waves are transmitted from one ultrasonic transducer in the pair, and ultrasonic waves that have passed through the bone tissue are received by the other ultrasonic transducer. Then, based on this transmission / reception signal, the state of the target bone tissue is evaluated.

  Patent Document 1 below describes an ultrasonic bone evaluation apparatus in which two deformable matching material storage portions are mounted on two opposing ultrasonic transducers. The matching material storage unit stores an acoustic matching material such as water. The mutually opposing surfaces of the two alignment material storage portions are freely deformable, and are deformed following the shape of the surface of the living body when abutting against the living body. In this state, ultrasonic waves are transmitted and received.

JP-A-7-204205

  When a member positioned close to a living body, for example, a member on which a living body is placed is a member having a high sound velocity that propagates through the member, ultrasonic waves that bypass the member propagate in the living body. May be received before the ultrasound. When the speed of sound is used as a drawing parameter, the ultrasonic wave that propagates through the proximity member while bypassing the living body has an object that is hard like bone (high speed of sound) in a portion that does not have bone or the like. Create artifacts on the image.

  An object of this invention is to suppress generation | occurrence | production of the artifact produced by the member adjacent to the biological body.

The ultrasonic bone evaluation apparatus of the present invention includes a mounting table having a mounting surface on which a living body is placed in contact, and a pair of ultrasonic transducers disposed so as to sandwich the living body placed on the mounting table. And a deformable acoustic matching unit that is located between the ultrasonic transducer and the living body and that achieves acoustic matching between the ultrasonic transducer and the living body. Mounting table are at least partially adjacent to or scanning range within a scan range of ultrasonic transducers exists, contacts the Re matching unit child. A structure for restricting the propagation of ultrasonic waves is provided in a portion of the mounting table located within the scanning range of the ultrasonic transducer or a portion adjacent to the scanning range.

  The structure for limiting the propagation of ultrasonic waves can be, for example, a groove in a direction perpendicular to the propagation direction of ultrasonic waves. Moreover, this groove | channel shall be provided in the mounting surface of a mounting base.

  Moreover, the structure which restrict | limits propagation of an ultrasonic wave can be made into the absorber of the ultrasonic wave embedded in the mounting base, for example.

  By restricting the propagation of ultrasonic waves that try to bypass the mounting table, the occurrence of artifacts is suppressed.

It is a perspective view which shows the external appearance of the ultrasonic bone evaluation apparatus of this embodiment. It is a perspective view which shows the external appearance of the ultrasonic bone evaluation apparatus of this embodiment. It is an expansion perspective view which shows the external appearance of a footrest and a vibrator unit. It is an expanded sectional view which shows the positional relationship of a footrest, a vibrator | oscillator unit, and a leg. It is a schematic sectional drawing of a vibrator | oscillator unit. It is a perspective view which shows the shape of the front side member of a matching material bag. It is a perspective view which shows the shape of the front side member of a matching material bag. It is a perspective view which shows the shape of the front side member of a matching material bag. It is a perspective view which shows the outline of the mechanism for moving an ultrasonic transducer | vibrator. It is a figure which shows the scanning range of an ultrasonic beam. It is a figure for demonstrating the propagation path | route of a cocoon and the surrounding ultrasonic wave. It is a figure which shows an example of a footrest. It is a figure which shows the other example of a footrest. It is a figure which shows the further another example of a footrest. It is explanatory drawing in the case of measuring small feet, such as a child. It is a figure for demonstrating the propagation path of an ultrasonic wave at the time of using a spacer for the measurement of a small leg. It is a figure which shows an example of a spacer. It is a figure which shows the other example of a spacer. It is a figure which shows the further another example of a spacer. It is a figure which shows the further another example of a spacer. It is a figure which shows the further another example of a spacer. It is a figure which shows the further another example of a spacer. It is a figure which shows the further another example of a spacer. It is a figure which shows the further another example of a spacer.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following, an ultrasonic bone evaluation apparatus that evaluates the ribs will be described, but the bone to be evaluated is not limited to this. It is easily conceivable by those skilled in the art to achieve the gist of the present invention by appropriately changing the configuration of the device for bones other than the ribs in accordance with the shape and characteristics of the bone and its surroundings. is there.

  FIG. 1 and FIG. 2 are perspective views showing an appearance of an ultrasonic bone evaluation apparatus 10 that uses a rib as an evaluation target. A footrest 14 is disposed on the upper part of the apparatus main body 12. The footrest 14 is a base having a substantially L-shaped placement surface, and places the foot F as shown by the chain line in FIG. 2 for positioning. The foot is positioned by aligning the heel with the L-shaped corner of the footrest 14. Two transducer units 16A and 16B including ultrasonic transducers are arranged on the left and right sides of the footrest 14 so as to sandwich the heel portion. The left and right vibrator units 16A and 16B have a symmetric structure, and when it is not particularly necessary to distinguish between left and right, they are simply referred to as the vibrator unit 16 and will be described below. In addition, regarding the elements constituting the left and right vibrator units 16A and 16B, A and B are added to the reference signs when it is necessary to distinguish between the left and right, and only the numerical signs are used when the distinction is not necessary. It explains using. The transducer unit 16 has an acoustic matching unit in order to achieve acoustic matching between the heel portion and the ultrasonic transducer. The acoustic matching portion is deformable and deforms to adhere to the heel portion, eliminating the air layer therebetween. In this ultrasonic bone evaluation apparatus 10, the acoustic matching unit includes an acoustic matching material such as water and a matching material bag 18 containing the water and the like. When the foot is placed on the footrest 14, the matching material bag 18 is brought into contact with the heel portion of the foot, thereby matching the acoustic impedance between the ultrasonic transducer and the heel portion.

  3 and 4 are enlarged views of the footrest 14 and the vibrator unit 16. In FIGS. 3 and 4, one side, that is, a portion on the right side for the subject when the subject puts his / her foot on the footrest 14 is shown by being broken at the median surface of the footrest 14. Yes. The footrest 14 is substantially L-shaped, and the angle formed between the bottom surface 20 constituting the two sides of the L-shape and the contact surface 22 is substantially a right angle. The subject places the sole of the foot on the bottom surface 20 with the rear end surface of the footpad contacting the contact surface 22. At this time, the alignment material bag 18 is disposed so as to abut on the position of the foot heel, particularly the position of the rib and the surrounding position. The flange portion of the matching material bag 18 and the surface in contact with the periphery thereof have a shape of a substantially spherical surface surrounded by a surface orthogonal to one diameter and two surfaces parallel to this diameter and orthogonal to each other. ing. When the foot is placed on the footrest 14, the alignment material bag 18 comes into contact with the heel portion and the left and right sides around the heel portion, and the alignment material bag 18 is deformed so as to follow the surface of the heel portion, thereby eliminating the presence of an air layer. .

  FIG. 5 is a cross-sectional view of the vibrator unit 16. The matching material bag 18 is formed by fixing a back side member 26 opposite to the front side member 24 on the foot side, which is a target living body, to an annular ring frame 28. The front side member 24 is sandwiched between the ring frame 28 and a first fixing ring 30 located inside the ring frame 28, and is fixed to the ring frame 28. Further, the rear side member 26 is sandwiched between the first fixing ring 30 and the second fixing ring 32 and indirectly fixed to the ring frame 28. The back side member 26 is bent in a bellows shape, and the central portion is coupled to the outer peripheral portion of the ultrasonic transducer 34. On the further back side of the back side member 26, a support plate 36 that restricts and supports the back side member 26 so as not to bulge to the back side is disposed. The support plate 36 includes a plurality of annular plate-like support plates 38a, 38b, 38c, and 38d, and the outermost support plate 38a further has a cylindrical portion at the outer peripheral edge portion. It is fixed to. The innermost support plate 38 d is fixed to the outer periphery of the ultrasonic transducer 34. The back side member 26 is fixed to the ultrasonic transducer 34 by being sandwiched between a flange 40 provided on the outer peripheral portion of the ultrasonic transducer 34 and a support plate 36d on the innermost periphery. The support plates 36a, 36b, 36c, and 36d are slidable with each other, and allow movement in a direction perpendicular to the probe axis of the ultrasonic probe 34 described later.

  FIGS. 6-8 is a perspective view which shows the shape of the front side member 24 of a matching material bag. The front member 24 has a circular base portion 41, and a bulging portion 42 that bulges toward the heel portion on the footrest 14 and each of the pair of vibrator units 16 </ b> A and 16 </ b> B. The communication pipes 44A and 44B communicating with the internal spaces of the matching material bags 18A and 18B, and a calibration block pocket 46 for arranging a calibration block are provided. The left and right communication pipes 44A and 44B are connected at the center, and the internal spaces of the left and right alignment material bags are communicated. By moving the two ultrasonic transducers 34A and 34B to the positions of the communication tubes 44A and 44B and making them face each other, the speed of sound in the alignment material can be measured.

  The shape of the bulging portion 42 is a shape obtained by cutting a spherical surface with a first plane orthogonal to one diameter and second and third planes parallel to the diameter and orthogonal to each other. The diameter is orthogonal to the base portion 41, and the plane formed by the base portion 41 corresponds to the first plane. The second and third planes are surfaces formed by the bottom surface 20 and the contact surface 22 of the footrest 14. The cut surface formed by the second and third planes becomes the first side surface 48 and the second side surface 50. Further, a part of the spherical surface cut out by these first to third planes becomes the living body contact surface 51 that contacts the foot, which is the target portion. Therefore, the first side surface 48 of the bulging portion 42 is along the bottom surface 20 of the footrest and the second side surface 50 is along the contact surface 22. And the side surface of the bulging part 42 formed from the 1st and 2nd side surfaces 48 and 50 is formed in an L shape along the surface which puts the leg of an L-shaped footrest as a whole. In other words, the bulging portion can be seen as a partial dome shape obtained by cutting a dome with a low height by two intersecting planes.

  FIG. 9 is a diagram showing a moving mechanism 52 that moves the ultrasonic transducer 34. The vibrator unit 16 is shown with the support plate 36 omitted, and the bellows-shaped portion of the back member 26 of the alignment material bag 18 appears. The two ultrasonic transducers 34A and 34B are fixed to the tip of a U-shaped or U-shaped support frame 54. The support frame 54 is moved by a drive mechanism 56 in a plane orthogonal to the direction in which the two ultrasonic transducers 34A and 34B face each other (that is, the axial direction of the ultrasonic transducer). Accordingly, the two ultrasonic transducers 34A and 34B do not move in the direction in which they face each other, and the distance from each other does not change. However, the two ultrasonic transducers 34A and 34B can move in either direction in the direction orthogonal to the facing direction. It has become. In order to allow the movement of the ultrasonic transducer 34, the back member 26 of the alignment material bag has a bellows structure, and the support board 36 has a configuration having multiple support plates 38a to 38d. The respective support plates 38a to 38d slide on each other to allow the ultrasonic transducer 34 to move.

  FIG. 10 is a diagram showing the footrest 14 and the foot F placed thereon. A meandering arrow Y indicates a scanning path of the ultrasonic transducer 34. A range R surrounding the locus of the arrow Y is an ultrasonic beam scanning range. The ultrasonic transducer 34 is scanned in a range R including the rib C to obtain transmitted ultrasonic data. Based on this received data, bones, particularly ribs are evaluated.

  As shown in FIG. 10, a part of the footrest 14 is included in the scanning range R. In addition, the sole portion and the rear portion of the heel are in contact with the footrest 14 and are located close to the footrest 14. For this reason, the ultrasonic wave propagated through the footrest 14 may be received before the ultrasonic wave propagated through the heel portion.

  FIG. 11 is a diagram showing a state of propagation of ultrasonic waves in the vicinity of the contact point between the rear portion of the heel and the footrest 14. The figure shows the footrest 14 and shows a cross section of the foot F as viewed from above along the contact surface 22. The ultrasonic wave transmitted from one ultrasonic transducer 34B is transmitted from the matching material bag 18B to the foot F and further to the matching material bag 18 on the opposite side, and is received by the ultrasonic transducer 34A. The ultrasonic wave propagation path D1 is indicated by a broken line. This ultrasonic wave propagates through the soft tissue of the living body between the rib C and the body surface. Further, a part of the ultrasonic waves enters the footrest 14 from the alignment material bag 18B contacting the contact surface 22, and further enters the alignment material bag 18A on the opposite side, and reaches the ultrasonic transducer 34A. This propagation path D2 is indicated by a broken line in the figure. The speed of sound in the footrest 14 is faster than the speed of sound in the soft tissue of the living body. Therefore, even if the propagation path D2 is longer than the propagation path D1, the ultrasonic wave transmitted through the propagation path D2 is super early. The sound wave transducer 34A may be reached. In this case, it is recognized as if there is a hard, bone-like object in the soft tissue (so-called artifact generation). Even if the footrest 14 does not exist within the ultrasonic scanning range R, the same problem occurs if it is disposed adjacent to the range R.

  The footrest 14 of the ultrasonic bone evaluation apparatus 10 of the present embodiment has a structure for blocking or limiting the ultrasonic wave propagating through the footrest 14 described above.

  FIG. 12 shows an example of the footrest 14. A groove 58 is provided on the bottom surface 20 and the contact surface 22 that are in contact with the foot F of the footrest 14. The groove 58 is provided on the surface of the footrest 14 where the foot is in contact, and is provided so as to extend in a direction crossing the direction in which the ultrasonic wave propagates. Moreover, although the illustrated groove is provided over the entire length of the footrest 14, it may be provided so as to block only the ultrasonic wave propagation path passing through the portion in contact with the heel and the periphery thereof. The depth of the groove 58 is sufficiently longer than the path of the ultrasonic wave that propagates around the groove to pass through the living body, that is, when the groove bypasses the groove, the ultrasonic wave propagates to the ultrasonic vibrator faster than the ultrasonic wave that propagates in the living body. The depth should not be reached. The groove 58 limits the propagation of the ultrasonic wave and blocks the ultrasonic wave, thereby suppressing the generation of the artifact.

  FIG. 13 shows another example of the footrest. An ultrasonic absorber 62 is embedded in the footrest 60 so as to cross the ultrasonic wave propagation path that passes through the portion in contact with the heel and the periphery thereof. The ultrasonic absorber 62 may be disposed over the entire length of the footrest, or may be disposed on only a part of the entire length of the footrest as illustrated. The ultrasonic absorber 62 is, for example, a soft material such as rubber or sponge. In order to adjust the amount of ultrasonic absorption, the size and number of ultrasonic absorbers 62 in the ultrasonic propagation path direction can be adjusted. The ultrasonic absorber 62 reduces the number of ultrasonic waves that reach the ultrasonic vibrator earlier, and suppresses the generation of artifacts.

  FIG. 14 shows another example of the footrest. In the footrest 64, a plurality of holes 66 are arranged on a portion where the heel contacts and an ultrasonic wave propagation path passing through the portion. The holes 66 may be arranged at a uniform density throughout the footrest 64, or the density may be changed depending on the location. Moreover, you may arrange | position only in the part which a heel contacts, and its circumference | surroundings. Each hole 66 may be provided so as to penetrate the plate thickness of the plate-like footrest, and may have a bottom dug down to a predetermined depth from the surface on which the foot is placed. In addition, at least one hole 66 is disposed on a straight line connecting the ultrasonic transducers 34A and 34B forming a pair. With this arrangement, the ultrasonic path in the footrest 64 is prevented from being a straight line, and is prevented from being received earlier than the ultrasonic wave propagating through the living body. The degree of overlap of the holes 66 is set so that the propagation path of the ultrasonic wave becomes sufficiently long. Further, the ultrasonic waves are diffused and attenuated by the peripheral surface of the hole 66, and the reception intensity of the ultrasonic transducer on the reception side is lowered. This also has the effect of suppressing the occurrence of artifacts.

  FIG. 15 is a diagram for explaining a foot support method when measurement is performed on a foot E smaller than a normal adult such as a child. In order to put the rib C in the middle of the scanning range R of the ultrasonic transducer, the spacer 68 is placed on the footrest 14 and the foot E is further placed thereon. Therefore, in this case, the spacer 68 functions as a mounting table having a mounting surface on which the living body is mounted in a contact state. 16 is a cross-sectional view taken along the line H-H shown in FIG. The bulging portions 42A and 42B of the left and right alignment material bags 18A and 18B are in contact with the side surface of the spacer 68 together with the foot E. The ultrasonic wave propagation time D may be shorter in the path D4 that bypasses the foot E and propagates in the spacer 68 than in the ultrasonic wave propagation path D3 that passes through the foot E, which causes artifacts.

  The spacer 68 is also provided with a structure for blocking or limiting the ultrasonic wave propagating through the spacer 68.

  FIG. 17 shows the spacer 68. The entire spacer 68 can be made of a material that absorbs ultrasonic waves. Specific materials include rubber and closed-cell sponge having a hardness of about 50. In addition, spacers 70 and 72 shown in FIGS. 18 and 19 are parts (ultrasonic absorbers) 76, made of a material that absorbs ultrasonic waves, on an ultrasonic wave propagation path that passes around the part where the heel contacts. 78. FIG. 18 shows an example in which an ultrasonic absorber 76 is arranged on the end face of the spacer 70, and FIG. 19 shows an example in which an ultrasonic absorber 78 is arranged inside the spacer. The dimension of the ultrasonic absorbing material 78 in the direction in which the ultrasonic wave passes is determined from the necessary absorption amount of the ultrasonic wave. The ultrasonic absorbing material restricts the propagation of ultrasonic waves in the spacers 68, 70, and 72, and suppresses the generation of artifacts.

  FIG. 20 shows another example of the spacer. The spacer 80 has a groove 82 on the surface on which the foot E is placed. The groove 82 is provided so as to extend in a direction crossing the direction in which the ultrasonic wave propagates. Moreover, although the illustrated groove is provided over the entire length of the spacer 80, it may be provided so as to cross only the ultrasonic wave propagation path that passes through the portion in contact with the flange and the periphery thereof. The depth of the groove 82 is sufficiently longer than the path of the ultrasonic wave that propagates around the groove to pass through the living body, that is, when the groove bypasses the groove, the ultrasonic transducer is earlier than the ultrasonic wave that propagates in the living body. The depth is such that it does not reach. Similar to the groove 58 of the footrest 14 shown in FIG. 12, the groove 82 restricts the propagation of ultrasonic waves and blocks the ultrasonic waves to suppress the generation of artifacts.

  FIG. 21 shows still another example of the spacer. The spacer 84 has a groove 86 on the surface on which the foot E is placed. The spacer 84 has such a shape that a plate having a certain thickness is bent. However, it is not necessary to bend the plate in actual production. A groove 86 is formed by a portion bent into a U-shape. The groove 86 is also provided so as to extend in a direction crossing the direction in which the ultrasonic wave propagates. There are two grooves 86, that is, portions bent into a U-shape, whereby the spacer 84 can be stably placed on the footrest 14. The number of grooves may be more than two. The groove 86 limits the propagation of the ultrasonic wave and blocks the ultrasonic wave, thereby suppressing the generation of the artifact.

  FIG. 22 shows another example of the spacer. In the spacer 88, a plurality of holes 90 are disposed on the ultrasonic wave propagation path passing through and around the portion in contact with the heel. The holes 66 may be arranged at a uniform density throughout the footrest 64, or the density may be changed depending on the location. Moreover, you may arrange | position only in the part which a heel contacts, and its circumference | surroundings. Each hole 90 may be provided so as to penetrate the plate thickness of the plate-like spacer 88, and may have a bottom dug down to a predetermined depth from the surface on which the foot is placed. In addition, at least one hole 90 is arranged on a straight line connecting the pair of ultrasonic transducers 34A and 34B. This arrangement prevents the ultrasonic path in the footrest 64 from becoming a straight line, and prevents the ultrasonic wave propagating through the spacer 88 from being received earlier than the ultrasonic wave propagating through the foot E. Further, the degree of overlapping of the holes 90 is set so that the propagation path of the ultrasonic wave is sufficiently long.

  FIG. 23 shows another example of the spacer. A guard 94 that prevents the alignment material bag 18 from approaching is provided on the side surface of the spacer 92 so that the alignment material bag 18 does not directly contact the main body of the spacer 92. The guard 94 is fixed, for example, by bending both ends of a round bar and bringing both ends into contact with the side surface of the spacer 92. The guard 94 may be provided in the peripheral portion of the heel, and the alignment material bag 18 is allowed to come into contact with the spacer 68 in a portion other than the target heel periphery, for example, a portion corresponding to the toe. A portion of the guard 94 extending along the side surface of the spacer 92 is spaced from the spacer 68 and prevents the ultrasonic wave propagated from the alignment material bag 18 to the guard 94 from being directly transmitted to the side surface of the spacer. The ultrasonic wave transmitted to the guard 94 may be transmitted from both ends of the guard 94 to the spacer 68, but in this case, the path length becomes long, so that no artifact is generated.

  FIG. 24 shows another example of the spacer. The spacer 96 has a guard 98 similar to the spacer 92 described above on its side surface. The difference from the spacer 92 described above is that a portion of the side surface of the spacer 96 where the guard is provided is a side surface advance / retreat portion 100 that advances and retracts with respect to the main body of the spacer 96. When the guard 98 is pushed by the alignment material bag 18, the guard 98 and the side surface advancing / retreating portion 100 are retracted together so that the side surface of the spacer 96 is not in contact with the alignment material bag 18. In this spacer 96 as well, the occurrence of artifacts can be suppressed as in the case of the spacer 92 described above.

  In the ultrasonic bone evaluation apparatus 10 of the present embodiment, the alignment material bag 18 comes into contact with the surfaces (the bottom surface 20 and the contact surface 22) that contact the feet of the footrest on the side surfaces 48 and 50 thereof. However, an apparatus configuration in which the surface of the matching material bag 18 that contacts the living body contacts the side surface of the footrest together with the foot is also assumed. In this apparatus configuration, the example of each spacer described above can be applied to a footrest.

  DESCRIPTION OF SYMBOLS 10 Ultrasonic bone evaluation apparatus, 14 Footrest, 16 vibrator unit, 18 alignment material bag, 20 bottom face, 22 contact surface, 34 ultrasonic vibrator, 42 bulging part, 48, 50 side face of bulging part, 51 biological contact surface, 58 grooves, 60, 64 footrest, 62 ultrasonic absorber, 64 footrest, 68, 70, 72, 80, 84, 88, 92, 96 spacer, 76, 78 ultrasonic absorption Material, 82,86 groove.

Claims (5)

An ultrasonic bone evaluation apparatus that transmits and receives ultrasonic waves to a living body to evaluate bones in the living body,
A mounting table having a mounting surface on which a living body is placed in contact;
A pair of ultrasonic transducers arranged so as to sandwich the living body placed on the mounting table;
A deformable acoustic matching portion located between the ultrasonic transducer and the living body, for achieving acoustic matching between the ultrasonic transducer and the living body;
Have
The mounting table has at least a part thereof within the scanning range of the ultrasonic transducer or adjacent to the scanning range, and the acoustic matching unit is in contact with the mounting table , and the portion positioned within the scanning range of the mounting table or The part adjacent to the scanning range is provided with a structure that limits the propagation of ultrasonic waves.
Ultrasound bone evaluation device.   The ultrasonic bone evaluation apparatus according to claim 1, wherein the structure for limiting the propagation of ultrasonic waves is a groove in a direction orthogonal to the propagation direction of the ultrasonic wave, and the groove is provided on the mounting surface of the mounting table. An ultrasonic bone evaluation device.   The ultrasonic bone evaluation apparatus according to claim 1, wherein the structure that limits the propagation of ultrasonic waves is an ultrasonic absorber embedded in the mounting table. The ultrasonic bone evaluation apparatus according to any one of claims 1 to 3,
The alignment portion includes a bulging portion that bulges toward the living body on the side facing the living body, and the bulging portion is in contact with the living body contact surface that contacts the living body and the mounting surface of the mounting table. And having side surfaces,
Ultrasound bone evaluation device. The ultrasonic bone evaluation apparatus according to claim 4,
The mounting surface of the mounting table is configured by arranging two planes in an L shape,
The living body contact surface is a part of a spherical surface, the side surface is composed of two flat surfaces arranged in an L shape along the placement surface, and the bulging portion is formed by the living body contact surface and the side surface. The
Ultrasound bone evaluation device.