JP6101549B2 - Shock absorber for optical brain surface measurement, optical measurement probe using the same, and holder for the same - Google Patents

Description

  The present invention relates to a technique for measuring changes in the state of surrounding tissues such as blood vessels distributed on the brain tissue and brain surface using light in an environment where the brain surface or dura mater is exposed by surgical operation.

  As means for noninvasively measuring the internal state of a living body, there are MRI and X-ray CT. For example, in the case of MRI, these apparatuses require a magnet for generating a strong magnetic field and a shield facility for preventing interference with the magnetic field, and become a large measuring apparatus. Therefore, it is not suitable for simple measurement. Since X-ray CT also uses X-rays, sufficient shielding facilities are required. On the other hand, in the method using light, since the light generation mechanism is small and no special shielding equipment is required, simple measurement is possible. In observation, it is necessary to irradiate and detect a region to be examined, but by using an optical fiber, it is possible to flexibly adjust the region of light irradiation and detection. A measuring apparatus using such light is described in, for example, Patent Document 1 and Patent Document 2. The biological light measuring devices described in these documents generate light with a semiconductor laser, guide the generated light through an optical fiber, irradiate the subject, and detect and detect light transmitted or reflected in the living body. Light is guided to a photodiode by an optical fiber, and biological information such as blood circulation, hemodynamics and hemoglobin change is obtained from the detected light quantity.

  Further, in order to realize such biological light measurement, a biological light measurement probe that makes an optical fiber contact with a subject is used. The light irradiating unit for irradiating light, the light detecting unit for detecting light transmitted or reflected in the living body, and the light irradiating unit and the light detecting unit are arranged in a lattice shape or a mesh shape and fixed. It is comprised by the fixing member. In addition, the fixing member is shaped such that the light irradiation unit and the light detection unit are brought into contact with the subject using a band, a rubber string, a hair band, or the like. Patent document 3 etc. are mentioned as an example of this living body light measurement probe. Further, there are usually a plurality of optical fibers, and a biological light measurement probe having a structure in which the plurality of optical fibers are bundled is described in Patent Document 4 and the like. However, the observation methods targeted by these techniques are to observe the internal state from the skin of a living body.

  Meanwhile, in the field of neurosurgery, it is necessary to maximize the resection area of the brain for removing the lesion and to minimize the resection for preserving the function. As information for determining an appropriate resection area, brain activity information actually measured in the patient's brain is used. For example, in determining the focal site of an epileptic patient, an electroencephalogram electrode is placed on the cerebral cortex by surgery, the patient is temporarily awakened, and the excision site is determined based on the electroencephalogram signal at the time of epileptic seizure. However, electrical signals are widely diffused on the brain surface, and there is a problem that the focal position cannot be determined. On the other hand, optical topography, which is a brain function measurement method using near-infrared light, can determine the sensitivity region of the detected signal stochastically, and shortens the distance between the irradiation point and the detection point. High spatial resolution can be obtained.

JP-A-9-98972 JP-A-9-149903 JP-A-8-117209 JP 2001-286449 A

  Normal optical topography measurement assumes that measurement is performed from above the skin and skull. For example, the tip of the optical fiber for observation is kept in contact with the skin at a constant pressure in order to make the contact state with the skin sufficiently stable. This has the advantage that the optical topography measurement method does not hinder the free movement of the observation object, so it is necessary to prevent the contact position of the observation optical fiber from shifting even if the observation object moves during observation. This is a feature that is also provided. Therefore, it has been difficult to apply a conventional optical topography measurement method to a very soft object such as a brain surface.

  The present invention relates to a technique for measuring changes in the state of brain tissue or the like using light in an environment where the brain surface or the dura mater is exposed, and to reduce the impact on the brain surface and enable safe measurement. Objective.

  In order to solve the above problems, for example, the configuration described in the claims is adopted.

  The present application includes a plurality of means for solving the above-described problems. For example, an optical shock absorber for optical brain surface measurement used for optical topography measurement on the brain surface, which is composed of a flexible material. , A sheet portion having a flat surface in contact with the brain surface, and a light irradiation / detection hole for light irradiation or detection provided on the sheet portion, the light irradiation / detection hole of the light irradiation device It is smaller than the irradiation surface or the detection surface of the light detection device.

  As another example, a sheet portion made of a flexible material and having a flat surface in contact with the brain surface, and a light irradiation / detection hole for light irradiation or detection provided in the sheet portion. A holder for holding an optical shock absorber for optical brain surface measurement used for optical topography measurement on the brain surface, comprising three or more support rods holding the shock absorber at one end, and the support A support plate is provided for penetrating and supporting the rod, and the through hole of the support plate is such that each of the support rods is perpendicular to the support plate, and a part of the support rod has a screw structure. It can be fixed to the support plate at an arbitrary position of the support rod.

According to the present invention, in a technique for measuring changes in the state of surrounding tissues such as blood vessels distributed on the brain tissue or brain surface using light in an environment where the brain surface or dura mater is exposed, Impact can be reduced and measurement can be performed safely.

It is a figure which shows schematic structure of the impact buffer of Example 1 of this invention. It is a figure which shows schematic structure of the impact buffer of Example 2 of this invention. It is a figure which shows schematic structure of the impact buffer of Example 3 of this invention. It is a figure which shows schematic structure of the impact buffer of Example 4 of this invention. It is a figure which shows schematic structure of the holder of the impact buffer of Example 5 of this invention. It is a figure which shows schematic structure of the holder of the impact buffer of Example 6 of this invention.

  DESCRIPTION OF EMBODIMENTS Embodiments for carrying out the present invention will be described with reference to the drawings. Note that components having the same function are denoted by the same names and reference symbols throughout the drawings for describing the embodiments for carrying out the invention, and the repetitive description thereof will be omitted.

  FIG. 1 shows an impact buffer for optical brain surface measurement according to a first embodiment of the present invention. FIG. 1 (a) is a plan view thereof, and FIG. 1 (b) is a cross-sectional view taken along line AB. This shock absorber is devised to solve the problem that the observation target is soft and easily damaged. In measurement using light, it is necessary to irradiate the observation target and detect the light reflected from the observation target or propagated through the inside of the observation target, and diffused light. It has been devised to solve the problem of being influenced by.

  In the figure, reference numeral 101 denotes a sheet portion, which is installed between a living tissue, for example, the brain surface and an optical measurement device, for example, an optical fiber for light irradiation or detection, and an impact from the measurement device is transmitted to the brain surface. It is for relieving. The sheet portion is made of a flexible material, and the surface in contact with the brain surface is flat to reduce damage to the brain surface. This is because the brain surface moves slightly in response to heartbeat and respiration, and it is therefore necessary to reduce damage to the brain surface due to friction between the sheet portion 101 fixed to the skull and the brain surface, for example. For the sheet portion 101, for example, a black material having a light shielding property is preferably used in order to prevent light from entering and leaking. The sheet portion 101 is provided with a light irradiation / detection hole 102, and an optical fiber (optical device) for light irradiation or light detection is attached corresponding to the light detection / irradiation hole. In the vicinity of the light detection / irradiation hole 102, a guide / light-shielding portion 103 for guiding the attachment of an optical fiber for light irradiation or light detection is installed. For example, the guide / light-shielding portion 103 has a cylindrical shape having a cross section equal to or larger than that of the optical fiber. The guide / light-shielding unit 103 also functions as a light-shielding mechanism for preventing light leakage from the optical device.

  Here, the light irradiation / detection hole 102 can be a hole having various diameters. However, as an important condition, the surface of the optical device is smaller than the surface of the optical device in order to prevent the surface of the optical device from directly contacting the brain surface. It must be a hole diameter. Regarding the hole diameter, for example, in the measurement using Hitachi Medical Corporation's ETG-100 (trade name), a sheet 101 with a hole diameter of 0.3, 0.5, 1.0 mm was manufactured and used for the experiment. The best observations were obtained when using. This result is in addition to the power of the laser light source for light output, the attenuation characteristics of the optical fiber that guides the output light to the living body, the attenuation characteristics of the optical fiber for light detection, and the detection sensitivity of the photodiode for light detection. This means that there is an influence on the optical characteristics of the brain tissue to be observed and the surrounding biological material, and the optimum hole diameter of the sheet 101 is determined. Therefore, if adjustment of the laser light source output or the detection sensitivity of the light detection device is not simple, prepare a sheet with multiple hole diameters and use several of them to easily obtain the optimum signal. Is possible.

  The light shielding unit 103 is a mechanism that prevents light from leaking from an optical fiber for light irradiation, for example, and reaching directly to the optical fiber for light detection. In the observation using light, the light that diffuses in the living tissue and is detected after that is weak, so that it is necessary to sufficiently block the direct leakage light from the optical fiber. Therefore, the light shielding unit 103 covers the optical device and prevents leakage light. For example, a black rubber material is used. In addition, the sheet part 101 and the light-shielding part 103 can be attached separately for ease of processing, and a processing method in which both are attached can be considered. For example, in a transparent instantaneous adhesive, light leaks from there. There is a possibility that. Therefore, it is desirable to use an adhesive that does not transmit light, or to integrally form the sheet portion 101 and the light shielding portion 103. Further, since the sheet portion 101 is made of a flexible material that follows the shape of the brain surface, the light irradiation / detection hole 102 and the surface of the optical device are not always parallel. Therefore, in order to prevent the optical device from being detached from the guide / light-shielding portion 103, the guide / light-shielding portion 103 needs to have a sufficient height. For example, it is desirable to have a height that is 1/3 or more of the cross-sectional length of the optical device. However, if the height of the guide / light-shielding portion 103 is too high, the flexibility of the sheet portion 101 is impaired. Therefore, it is desirable that the height be such that the flexibility of the sheet is not impaired.

  In order to expose the brain surface to be observed, it is necessary to incise the skin, remove the skull, and incise the dura mater if necessary. Therefore, there are problems of bleeding from the cut surface and cerebrospinal fluid entering the measurement area. If the environment of the measurement area changes, it will adversely affect the noise of the observation signal. Therefore, the observation area protective film 104 having no permeability is provided for the purpose of preventing blood or the like from entering the brain surface as an observation area from the surrounding area. As a method of using this observation area protective film, for example, it is installed so as to slide between the brain surface outside the observation area and the dura mater. As a result, it is possible to prevent blood or the like from entering the observation region and causing noise.

  According to the shock absorber for optical brain surface measurement of the present embodiment, by including a sheet portion that is composed of a flexible material between the brain tissue and the optical device, and the surface that contacts the brain surface is a flat surface. The impact on the brain surface can be reduced and optical measurement can be performed safely. In addition, by making the light irradiation / detection hole smaller in diameter than the surface of the optical device, it is possible to prevent the surface of the optical device from coming into direct contact with the brain surface.

  2A to 2C show an impact buffer for optical brain surface measurement according to Example 2 of the present invention.

  As described in Example 1, the brain surface moves slightly in response to heartbeat and respiration. Therefore, for example, it is necessary to reduce damage due to friction between the sheet portion 101 fixed to the skull and the brain surface. In the shock absorber shown in FIG. 2A, chamfering is performed on the corner of the surface of the sheet portion 101 that contacts the brain surface, that is, the corner of the light irradiation / detection hole to provide a chamfered portion 201 having an appropriate curvature. . By performing chamfering, damage due to friction with the brain surface can be further reduced.

  FIG. 2B is provided with an optical device detachment prevention mechanism 202. For example, the guide / light-shielding portion 103 is provided with a convex portion and a concave portion is provided on the optical device (optical fiber) side so that the convex portion of the guide / light-shielding portion 103 fits into the concave portion on the optical device side when the optical device is attached. To do. Thereby, it is possible to prevent the optical device from being detached from the guide / light-shielding unit 103 during optical measurement.

  FIG. 2C shows a state in which an optical device (optical fiber) 203 is attached to an optical brain surface measurement shock absorber provided with a chamfered portion 201 and a detachment preventing mechanism 202. By fitting the convex portion of the guide / light-shielding portion into the concave portion on the optical device side, it is possible to prevent the optical device from coming off. In addition, as the detachment prevention mechanism 202, a convex portion may be provided on the optical device side and a concave portion may be provided on the guide and light shielding portion side.

  As shown in FIG. 2C, the optical measurement probe of the present invention includes an optical shock absorber for measuring the brain surface and an optical device for light irradiation and light detection.

  FIG. 3 shows an impact buffer for optical brain surface measurement according to Embodiment 3 of the present invention.

  As described in Example 1, there are problems of bleeding from the cut surface and cerebrospinal fluid entering the measurement region. In the present embodiment, the sponge portion 301 is disposed so as to surround the periphery of the sheet portion 101 for the purpose of preventing blood and the like from entering the brain surface as an observation region from the surrounding region. By using the sheet portion 101 having the sponge portion 301, the observation region can be protected and interference with blood or the like can be prevented. For example, the protection effect can be further enhanced by using a material that gels by touching the sponge with liquid.

  The optical measurement probe shown in FIG. 1 includes 2 vertical × 4 horizontal optical fibers for irradiation or detection. The optical device needs to have a constant distance between the irradiation device and the detection device, but the distance between the irradiation devices or the detection devices is not limited. Therefore, by reducing these distances, higher density measurement is possible.

  In FIG. 4, the example of the buffer sheet for the high-density measurement of Example 4 of this invention is shown. In the figure, for example, an optical fiber 402 for irradiation is arranged in the center row, and an optical fiber 401 for detection is arranged in the upper row and the lower row. Although the distance between the irradiation optical fiber and the detection optical fiber is constant, high-density measurement can be performed by bringing the irradiation devices and the detection devices closer to each other.

  In actual measurement, it is necessary to fix the optical device and the shock absorber of the present invention to the observation target. This is because even minute movements and positional deviations affect the signal as noise. However, since brain tissue is soft and easily damaged, it is not suitable as a fixed part. Therefore, a skull having sufficient strength is used as the fixing portion.

  FIG. 5 shows a holder for fixing the optical device and the shock absorber according to the fifth embodiment of the present invention. The mounting rod 501 has a screw-like tip, and can be fixed to the skull with a screw. In order to keep parallel to the measurement surface, it is desirable that there are three or more mounting rods 501. Further, it is desirable that the support plate 502 has a hole portion in which the three attachment rods 501 are parallel to each other, and has a mechanism for fixing the attachment rod 501 to the front surface or the back surface. For example, a fixing tool using a screw. Further, the support plate 502 has a hole for fixing the support rod 503 that supports the buffer sheet 506 (which is a schematic diagram of the buffer sheet shown in FIG. 1). The holes are provided so that each support bar 503 is perpendicular to the support plate 502. The support bar 503 has the purpose of holding the buffer sheet 506 and adjusting the parallelism between the buffer sheet 506 and the observation surface. Therefore, three or more support bars are provided. Then, for example, an end portion of the support bar 503 is threaded to provide a screw structure 504, and the vertical position of the support bar 503 is finely adjusted by turning a screw attached to the support bar 503. Since the support bar 503 needs to support the buffer sheet 506, it needs to have a certain hardness. On the other hand, since the brain surface to be observed is soft and easily damaged, the buffer sheet 506 needs to be supported flexibly. Therefore, it is desirable that a spring mechanism 505 or a sponge-like member is provided at the tip of the support bar 503 so that the buffer sheet 506 and the support bar 503 are flexibly coupled.

  The optical device is assumed to be an optical fiber in this embodiment. Alternatively, an LED light emitting element or a photodiode element may be used directly. In that case, a cable for power supply and information transmission is provided. In order to prevent optical fibers and cables from damaging the brain surface or obstructing the measurement during measurement, it is desirable that the support plate 502 includes a hole mechanism 507 through which these cables pass. In the figure, one hole mechanism is provided. It is considered that the stability at the time of measurement is increased by providing the hole mechanism 507 at the center. On the other hand, since it becomes difficult to route the cables if they are combined in one place, hole mechanisms may be provided in about three different places. In addition, it is desirable that the hole mechanism has a stopper mechanism in order to prevent the optical fiber and cables from unexpectedly shifting toward the brain surface and damaging the brain surface. For example, a mechanism for bundling optical fibers with a clip-like instrument and screwing them.

  FIG. 6 shows a shock absorber holder according to Embodiment 6 of the present invention.

  In this embodiment, a distance meter is provided in the holder described in Embodiment 5 of FIG. A distance meter 601 is installed on each of the support rods 503 of the shock absorbing sheet 506, and the distance to the brain surface to be measured can be measured. Since it is desirable that the seat surface and the brain surface be as parallel as possible, the vertical position of the seat support bar 503 is adjusted based on the measurement result of the distance meter 601 so that the seat surface and the brain surface are kept parallel. Furthermore, a mechanism for notifying by light or sound may be provided when the difference in distance between the three points observed by the distance meter is within or outside the predetermined range. For example, it may be notified when the sum of the deviation between the average value of the observation results of three distance meters and the respective observation results is a set value, for example, 2 mm or more.

DESCRIPTION OF SYMBOLS 101 Sheet | seat part 102 Light irradiation / detection hole 103 Guide / light-shielding part 104 Observation area protective film 201 Chamfering part 202 Detachment prevention mechanism 203 Optical apparatus 301 Sponge part 401 Optical fiber 402 for detection Optical fiber 501 for mounting Mounting rod 502 Support plate 503 Sheet Support bar 504 Sheet support bar screw structure 505 Sheet support bar spring mechanism 506 Impact buffer sheet 507 Hole 601 Distance meter

Claims (15)

An impact buffer for optical brain surface measurement used for optical topography measurement on the brain surface,
A sheet part made of a flexible material and having a flat surface in contact with the brain surface;
Provided in the sheet portion, and provided with light irradiation / detection holes for light irradiation or detection,
An impact buffer for optical brain surface measurement, wherein the light irradiation / detection hole is smaller than an irradiation surface of a light irradiation device or a detection surface of a light detection device. The impact buffer for optical brain surface measurement according to claim 1, further comprising:
An impact buffer for optical brain surface measurement, which has a guide / light-shielding portion for preventing leakage light while guiding the attachment of the light detection device or the light irradiation device on the surface on which the light detection device or the light irradiation device is arranged. The impact buffer for optical brain surface measurement according to claim 1, further comprising:
An impact buffer for optical brain surface measurement, having a non-permeable observation area protective film that can be placed under the dura mater outside the sheet portion. The impact buffer for optical brain surface measurement according to claim 1, further comprising:
An impact buffer for optical brain surface measurement having a sponge part for absorbing cerebrospinal fluid and blood on the outer periphery of the sheet part. The shock absorber for optical brain surface measurement according to claim 1,
An impact buffer for optical brain surface measurement in which corners of the light irradiation / detection holes are chamfered. The impact buffer for optical brain surface measurement according to claim 2,
An impact buffer for optical brain surface measurement, wherein the guide / shading part includes a mechanism for preventing the light irradiation device or the light detection device from coming off. The shock absorber for optical brain surface measurement according to claim 1,
An impact buffer for optical brain surface measurement, wherein the light irradiation device or the light detection device is an optical fiber. The impact buffer for optical brain surface measurement according to any one of claims 1 to 7,
An optical measurement probe comprising a light irradiation device and a light detection device. Optical topography measurement on the brain surface, which is composed of a flexible material and has a flat surface that contacts the brain surface, and a light irradiation / detection hole for light irradiation or detection provided on the sheet portion. A holder for holding an impact buffer for optical brain surface measurement used in
Three or more support rods that hold the shock absorber at one end, and a support plate that penetrates and supports the support rods,
The through holes of the support plate are such that each of the support bars is perpendicular to the support plate;
A shock absorber retainer having a screw structure in a part of the support rod and capable of being fixed to the support plate at an arbitrary position of the support rod. The shock absorber holder according to claim 9, further comprising:
A shock absorber holder having attachment means for attaching the support plate to a subject. The impact buffer holder according to claim 9,
A shock absorber holder in which a plurality of the support rods have the screw structure, and the distance between the support plate and the shock absorber can be arbitrarily changed at three or more points. The shock absorber holder according to claim 9,
A shock absorber holder having a spring or a sponge mechanism at a joint between the support bar and the shock absorber. The shock absorber holder according to claim 9,
A shock absorber holder having a distance meter for observing a distance between a region surface to be measured and the shock absorber at three or more points. In the shock absorber holder according to claim 13,
A shock absorber retainer having a mechanism for notifying by light or sound when the observed difference in distance between three points is within or outside a predetermined range. The shock absorber holder according to claim 9,
A holding device for an impact buffer, wherein the support plate has a hole portion through which a cable connected to the light irradiation device and the light detection device passes, and a fixing mechanism that fixes the penetrated cable to the hole portion.

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