JP4625281B2 - Medical diagnostic system - Google Patents

Description

  The present invention relates to a medical diagnostic system, and more particularly to a system combining a nuclear medicine diagnostic apparatus and an ultrasonic diagnostic apparatus.

  In nuclear medicine diagnosis, a medicine containing a tracer as a radioactive element is introduced into a living body, and radiation from the living body is detected. Thereby, it is possible to diagnose the metabolic function, circulatory function, presence or absence of malignant tumor, etc. in the living body. As a nuclear medicine diagnostic apparatus for that purpose, a γ camera, a SPECT (single photon emission computed tomography) apparatus, a PET (positron emission tomography) apparatus, and the like are known. The SPECT apparatus is an apparatus that forms a tomographic image by CT calculation, and one having a plurality of planar detectors, one having a ring-shaped array detector, and the like are known. The PET apparatus is an apparatus that forms a tomographic image or the like by detecting annihilation γ-rays (a pair of 511 kev γ-rays emitted in opposite directions) generated when positrons emitted from positron nuclides combine with free electrons. The PET apparatus has a ring-shaped array detector and forms a tomographic image.

  The image formed by the above nuclear medicine diagnostic apparatus is a “functional image” reflecting the activity of the living body, and in the “morphological image” representing the form of the living body, such as an X-ray CT image, an MRI image, and an ultrasonic image. Absent. Although the tissue structure can be grasped according to the morphological image, it is difficult to specify and identify the property of the tissue, for example, whether it is tumor, malignant or benign, on the image, or skill is required for that. On the other hand, in the case of a functional image, the state of activity in the living body can be imaged by the activity of the drug, but it is difficult to recognize the active site only from the functional image, or skill is required for that. Note that the functional image is generally an image having no real-time property and is not suitable for real-time observation.

  The following Patent Document 1 describes a technology that accurately associates an emission image and an MRI image in an anatomical positional relationship, but does not describe any ultrasonic diagnosis or use of an ultrasonic image. .

JP 2002-214347 A

  As described above, the functional image and the morphological image have an interpolative relationship, and it is desired to form both of these images and use them for diagnosis. Here, as a morphological image, it is desired to use an ultrasonic image from the viewpoints of avoiding unnecessary radiation exposure, real-time measurement, system cost, and the like.

  An object of the present invention is to enable comprehensive diagnosis of a tissue from both a functional aspect and a morphological aspect by using nuclear medicine diagnosis and ultrasonic diagnosis. In particular, the position and distribution of the active site can be accurately recognized in relation to the tissue form in the living body.

(1) A medical diagnostic system according to an embodiment to be described later includes a radiation measurement unit that detects radiation from a three-dimensional space in a living body to which a medicine containing a radioactive substance is administered and acquires three-dimensional volume data, and the volume Storage means for storing data; ultrasonic measurement means for forming a beam scanning plane in the three-dimensional space to obtain a received signal; and an ultrasonic image corresponding to the beam scanning plane based on the received signal On the basis of coordinate information of the beam scanning plane with respect to the three-dimensional space, extraction means for extracting surface data from volume data stored in the storage means, and based on the surface data Te, including a nuclear medicine image forming means for forming a nuclear medicine image, and display processing means for displaying by combining with the nuclear medicine images the ultrasound image.

  According to the above configuration, three-dimensional volume data is acquired by measuring radiation, and the volume data is stored in the storage unit. On the other hand, a beam scanning surface is formed in the three-dimensional space, and an ultrasonic image is formed based on echo data on the beam scanning surface. Based on the coordinate information of the beam scanning plane, plane data is cut out from the volume data, and a nuclear medicine image is formed based on the plane data. It is particularly desirable that the position of the cut surface from which the surface data is cut out is spatially the same as the position of the beam scanning surface. However, as a modification, it is possible to set a cutting surface orthogonal to the beam scanning surface. is there. When a nuclear medicine image and an ultrasound image are displayed at the same time, the ultrasound image and the nuclear medicine image are in a spatial correspondence relationship. Diagnosis becomes possible. For example, even if the presence of a tumor can be recognized on an ultrasound image, it is difficult to recognize whether it is malignant or benign, but by taking into account a nuclear medicine image that is a functional image Recognize the nature of the tumor. Also, even if the active site can be recognized from the nuclear medicine image itself, it is difficult to recognize which part of the organ corresponds to the active site, but an ultrasonic image as a morphological image is used. By considering it together, the form of the active site can be recognized. If a nuclear medicine image and an ultrasound image are displayed in a superimposed manner, for example, the position and spread of the active site can be intuitively and accurately recognized against the background of tissue morphology. If the nuclear medicine image and the ultrasound image are displayed side by side, it can be avoided that the image content of one image is obscured by the image content of one image and the observation of that portion is hindered. It is desirable to be able to select these two display types by the user or automatically.

  The ultrasonic image is preferably formed as a real-time image. In this case, when the probe for transmitting and receiving the ultrasonic wave is moved on the surface of the living body, the content of the ultrasonic image changes accordingly, and at the same time, the volume The position of the surface data cut out from the data also changes, and the content of the nuclear medicine image also changes. As a result, the target tissue is searched from the morphological and functional aspects in the three-dimensional space in the living body, and then the position of the probe is fixed, and comprehensive diagnosis of the target tissue can be performed.

  The radiation measuring means is preferably configured as a nuclear medicine diagnostic apparatus. In that case, it is desirable to use a PET apparatus as the nuclear medicine diagnostic apparatus, but it is also possible to use a SPECT apparatus or the like. In any case, an apparatus that can acquire three-dimensional volume data is used. In general, slice data (corresponding to a tomographic image as a nuclear medicine diagnosis image) is acquired at each scanning position on a living body, and volume data is configured as a set of the slice data. The storage means may be provided inside the nuclear medicine diagnostic apparatus or the ultrasonic diagnostic apparatus, or may be provided outside them. A nuclear medicine diagnostic apparatus, an ultrasonic diagnostic apparatus, an image data server, or the like may be connected to the network to exchange data between them. The ultrasonic measuring means preferably includes the probe, and preferably, the ultrasonic measuring apparatus and the ultrasonic image forming means constitute an ultrasonic diagnostic apparatus. The display processing means may be provided in the ultrasonic diagnostic apparatus. Alternatively, the display processing unit may be configured as a computer including a display processing program and a processor (CPU) that executes the display processing program.

  It should be noted that the ultrasonic diagnosis may be performed as it is without moving the living body (patient) after the volume data is acquired by the nuclear medicine diagnosis, or the living body is separated after the volume data is acquired by the nuclear medicine diagnosis. The ultrasonic diagnosis may be performed by moving to the location. It is desirable that the spatial relationship between the coordinate system in the nuclear medicine diagnosis and the coordinate system in the ultrasonic diagnosis is known or fixed. If necessary, a calibration device described later is provided or the calibration process is executed. Is done.

(2) In the above configuration, preferably, the extracting unit specifies a cutting plane specifying unit that specifies a cutting plane at the same position as the beam scanning plane in the three-dimensional space based on the coordinate information, and the volume data. And surface data cutout means for cutting out data on the cut surface as the surface data. The cut surface is a surface corresponding to the beam scanning surface, and the surface data cut out from the volume data may be data having a thickness of one pixel or data having a thickness of a plurality of pixels. Also good. Interpolation processing is applied to the surface data as necessary.

  Preferably, the cutting plane specifying means recognizes the coordinate information of the beam scanning plane in real time and dynamically specifies the cutting plane, and the plane data cutout means is configured for the dynamically specified cutting plane. The surface data is cut out in real time, and the ultrasonic image is a real time image. According to this configuration, since an ultrasonic image is displayed in real time and a nuclear medicine image spatially corresponding to the ultrasonic image is displayed, a search for a target tissue or a search for the entire three-dimensional space can be easily performed.

  Preferably, the display processing unit superimposes the nuclear medicine image and the ultrasonic image to form a composite image. According to this configuration, the evaluation can be performed by directly associating the organizational function and the organizational form. Preferably, the display processing unit forms the composite image by arranging the nuclear medicine image and the ultrasound image. According to this configuration, the entire contents of each image can be clearly recognized without being hidden.

  Preferably, the nuclear medicine image is a color two-dimensional tomographic image representing a tissue function, and the ultrasonic image is a black and white two-dimensional tomographic image representing a tissue form.

  Preferably, a robot for positioning and holding the probe forming the beam scanning surface is provided. It is desirable that a position sensor such as an encoder is provided at each joint portion in the robot so as to detect the position and posture of the probe (or beam scanning plane). Instead of using a robot, a user may hold a portable probe, and the user may move or position the probe. In that case, it is desirable to detect the position and orientation of the probe using a magnetic sensor or the like.

  Preferably, calibration is performed to calibrate the coordinate information of the cut surface with respect to the three-dimensional space by obtaining a spatial relationship between the first coordinate system in radiation measurement and the second coordinate system in ultrasonic measurement. A device is provided. According to this configuration, since the positional relationship between the first coordinate system and the second coordinate system can be recognized, the cut surface corresponding to the beam scanning surface can be accurately specified. In the calibration, one coordinate system may be matched with the other coordinate system, or coordinate correction may be performed when calculating the coordinates of the cut surface.

  Preferably, the calibration device specifies a first spatial relationship between the living body and the first coordinate system in the radiation measurement, and the living body and the second coordinate in the ultrasonic measurement. Means for specifying a spatial relationship with the system, and the first coordinate system and the second coordinate system are spatially related with respect to the living body as a reference. According to this configuration, since each coordinate system is defined or calibrated with respect to the living body, even if the nuclear medicine diagnosis and the ultrasonic diagnosis are performed in different places, that is, the nuclear medicine diagnosis apparatus and the ultrasonic diagnosis apparatus Even if the positional relationship is unknown, it is possible to accurately calculate the coordinates of the cutting plane. That is, the nuclear medicine image can be accurately positioned with respect to the ultrasonic image.

  Preferably, the means for specifying the spatial relationship detects at least one position marker provided at at least one site in the living body, and coordinates of the position marker at the time of the radiation measurement and the ultrasonic measurement. A marker coordinate detector. According to this configuration, the coordinate system can be defined based on the coordinates of the position marker. If the posture or orientation cannot be detected in addition to the position of the position marker, a plurality of position markers are provided on the living body, and the reference coordinate system of the living body can be recognized from their positional relationship. In this case, it is desirable that the three orthogonal axes are defined by three or more position markers, but one or two position markers can also be provided when a condition such as a living body lying horizontally is satisfied. . Further, more position markers may be provided to detect the position of each part of the living body. The coordinates of the position marker are specified by techniques such as magnetic detection, electrical detection, and mechanical detection. It should be noted that a difference in posture of the living body may be determined from a mutual comparison between the coordinate patterns of the plurality of position markers at the time of nuclear medicine diagnosis and the coordinate patterns of the plurality of position markers at the time of ultrasonic diagnosis.

  Preferably, the calibration device spatially matches the beam scanning plane and the cut plane based on the coordinates of the position marker in the radiation measurement and the coordinates of the position marker in the ultrasonic measurement. The correction means for executing the coordinate correction process is included.

(3) A medical diagnosis system according to an embodiment to be described later includes a medical diagnosis apparatus including a nuclear medicine diagnosis apparatus and an ultrasonic diagnosis apparatus for comprehensively diagnosing a living body to which a medicine containing a radioactive substance is administered in terms of function and form. The nuclear medicine diagnosis apparatus includes radiation measurement means for detecting radiation from a three-dimensional space in the living body and acquiring three-dimensional volume data, and the ultrasonic diagnosis apparatus is in the three-dimensional space. An ultrasonic measurement unit that forms a beam scanning surface to obtain a reception signal, and an ultrasonic image formation unit that forms an ultrasonic image as a morphological image representing a tissue form based on the reception signal. The medical diagnostic system further includes extraction means for extracting surface data of a cut surface at the same position as the beam scanning surface from the volume data, and based on the surface data A nuclear medicine image forming means for forming a nuclear medicine image as a functional image expressing a tissue function, and a display processing means for combining the nuclear medicine image and the ultrasound image to display a composite image, When moving the beam scanning plane with respect to the living body, the content of the ultrasound image is changed, with it, the contents of the nuclear medicine image you change.

(4) An image processing apparatus according to an embodiment to be described later detects a radiation from a three-dimensional space in a living body to which a medicine containing a radioactive substance is administered, and acquires three-dimensional volume data. An image processing apparatus for use in a medical diagnostic system, comprising: an ultrasonic diagnostic apparatus that forms a beam scanning plane in a three-dimensional space and forms an ultrasonic image corresponding to the beam scanning plane; Extraction means for extracting surface data from the volume data based on surface coordinate information, and display processing for displaying a combined image by combining the nuclear medicine image formed based on the surface data and the ultrasound image and means, the including.

  As described above, the display processing means is incorporated in the nuclear medicine diagnostic apparatus or the ultrasonic diagnostic apparatus, or is configured as an independent image processing apparatus such as a computer.

  As described above, according to the present invention, a tissue can be comprehensively diagnosed from both functional and morphological aspects by using nuclear medicine diagnosis and ultrasonic diagnosis. In particular, the position and distribution of the active site can be accurately recognized in relation to the tissue form in the living body.

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

  FIG. 1 shows a preferred embodiment of a medical diagnosis system according to the present invention, and FIG. 1 is a perspective view showing the entire configuration thereof. This medical diagnostic system includes a nuclear medicine diagnostic apparatus 10 configured as a PET apparatus, an ultrasonic diagnostic apparatus 12, and a robot 90 as a probe positioning mechanism.

  The nuclear medicine diagnosis apparatus 10 has a bed 35 that is moved and scanned in the x direction in the figure. A living body as a patient to which a medicine having a radioactive substance is administered is placed on the bed 35. The radioactive material is a radioisotope that emits positrons. As is well known, a positron combines with surrounding electrons to generate a pair of annihilation gamma rays (511 keV). The pair of annihilation gamma rays emerges in opposite directions with an angle of 180 degrees.

  The gantry 37 has a ring-shaped radiation detection unit, and detects the radiation by the radiation detection unit at each position while sequentially moving the living body in the x direction. Image information can be acquired. Specifically, the bed 35 is inserted into the cavity 37A of the gantry 37, the radiation incident position is obtained from each detector of the ring-shaped radiation detection unit, and the nuclear medicine image is acquired.

  The ultrasonic diagnostic apparatus 12 includes a main body 14 and a probe 16. The probe 16 is connected to the main body 14 by a probe cable, and the probe 16 is held by a robot 90 described later. The main body 12 is provided with a display unit 18 and an input unit 20. The input unit 20 is configured by an operation panel.

  As described above, the robot 90 functions as a probe positioning mechanism and has a plurality of arms 26, 27, and 28 coupled to the support column 24. A probe holder 29 is provided at the tip of the arm 30, and the probe 16 is held by the probe holder 29. As illustrated in FIG. 1, each arm can be moved in a desired direction, whereby the probe 16 can be brought into contact with the living body at an arbitrary position and posture. Various types of mechanisms can be employed as the robot 90. The user grasps the probe 16 and abuts on the living body, and detects the position and posture of the probe using a magnetic field generator and a magnetic sensor. May be.

  In FIG. 1, the nuclear medicine diagnostic apparatus 10 and the ultrasonic diagnostic apparatus 12 are arranged close to each other, but each apparatus may be provided in a separate room. That is, after the nuclear medicine diagnosis is performed, the patient may be moved to another location and the patient may be subjected to ultrasonic diagnosis at that location.

  FIG. 2 is a block diagram showing each configuration in the medical diagnosis system of the present embodiment.

  In the nuclear medicine diagnostic apparatus 10, the ring-shaped detection unit 34 detects a pair of annihilation γ rays emitted from the living body 36 as indicated by reference numerals 38A and 38B. Data regarding the position of the incident γ rays is obtained from the arrangement of the sensors of the detection unit 34. The obtained data group can be reconstructed to generate nuclear medicine image data as described below. Therefore, the signal processing unit 50 performs processing such as timing processing or signal amplification, and the image forming unit 52 forms a tomographic image as a nuclear medicine image based on the signal output from the signal processing unit 50. Data corresponding to the cross section is sent to the control unit 54. The control unit 54 arranges the tomographic image data (slice data) acquired at each position side by side, thereby constructing three-dimensional volume data. The volume data is transferred from the control unit 54 to the data storage device 31 via the network 30.

  The bed driving mechanism 42 is a mechanism for moving the bed described above, and slice data is acquired as described above while sequentially transporting a living body, and the volume data is configured by collecting slice data at each position. Is done. The control unit 54 gives a control signal 48 to the gantry driving mechanism 40 and gives a control signal 44 to the bed driving mechanism 42. Also, coordinate information 46 is output from the bed driving mechanism 42 to the control unit 40. This is information for specifying the position of each slice data.

  Connected to the network 30 are a nuclear medicine diagnostic apparatus 10, an ultrasonic diagnostic apparatus 12, a data storage device 31, and a calibration apparatus 32. Of course, necessary signals may be exchanged between the devices without using the network 30. The data storage device 31 functions as an image data server that accumulates volume data. The data storage device 31 includes a storage medium 82 that stores volume data and a data management unit 80. The data management unit 80 manages volume data stored on the storage medium 82.

  The ultrasonic diagnostic apparatus 12 includes a probe 16 that functions as a transducer. An ultrasonic beam is formed by the probe 16, and a scanning plane is formed by electronically scanning the ultrasonic beam. Of course, this probe 16 may have a 2D array transducer and form a three-dimensional data capture space.

  The transmission / reception unit 56 functions as a transmission beam former and a reception beam former. A plurality of transmission signals are supplied from the transmission unit 56 to the array transducer provided in the probe 16. Further, the plurality of reception signals output from the array transducer are subjected to phasing addition processing in the transmission / reception unit 56, whereby the reception signals after phasing addition are output to the image forming unit 58. The image forming unit 58 includes a digital scan converter (DSC) or the like, and forms a B-mode image as a two-dimensional tomographic image based on echo data. The image data is output to the display processing unit 60.

  The control unit 62 performs operation control of each component in the ultrasonic diagnostic apparatus 12. Further, the position and orientation of the probe or scanning plane are recognized based on the coordinate information 70 output from the robot 90. The control unit 62 includes a surface data acquisition unit 64 in the present embodiment. The surface data acquisition unit 64 specifies a cut surface in a three-dimensional space corresponding to the current position of the scan surface, and acquires the surface data corresponding to the cut surface by cutting it out from the volume data. Therefore, information specifying the address of the surface data is sent from the control unit 62 to the data storage device 31, and the data management unit 80 cuts out the surface data from the volume data based on the information and sends it to the ultrasonic diagnostic apparatus 12 side. Send. The acquired surface data is output to the display processing unit 60 via the surface data acquisition unit 64.

  In this embodiment, the robot 90 is driven manually. That is, the position and posture of the probe are freely set by the user. On the other hand, an actuator or a motor may be provided at each joint portion of the robot 90, and the movement of the robot 90 may be controlled by the control of the control unit 62. The control signal in that case is indicated by reference numeral 72. The graphic image forming unit 66 generates a graphic image to be combined with the ultrasonic image or the nuclear medicine diagnosis image based on the information passed from the control unit 62, and outputs the data to the display processing unit 60. The input unit 20 includes the operation panel as described above, and information input by the user is passed to the control unit 62. In the present embodiment, the display processing unit 60 has a function of forming a color nuclear medicine image based on the surface data acquired by the surface data acquisition unit 64, the monochrome ultrasound image formed by the image forming unit 58, and the above-mentioned And a function of synthesizing with a color nuclear medicine image to form a composite image. The image data of the composite image is sent to the display unit 18, and the composite image is displayed on the display unit 18. The composite image includes a graphic image as necessary.

  The calibration device 32 identifies the spatial relationship between the first coordinate system in nuclear medicine diagnosis, that is, radiation measurement, and the second coordinate system in ultrasonic diagnosis, that is, ultrasonic measurement, and determines the two coordinate systems. Thus, it functions to accurately calculate the cutting plane corresponding to the scanning plane. As will be described later, the first coordinate system and the second coordinate system are defined or calibrated with respect to the living body as a reference, so that the movement of the living body can be changed between the nuclear medicine diagnosis and the ultrasonic diagnosis. Even if there is a change in posture, it is possible to accurately extract surface data corresponding to the scanning surface.

  FIG. 3 shows a more specific configuration example of the robot 90 shown in FIG. The robot 90A shown in FIG. 3 will be described below.

  As described above, the robot 90A has a plurality of arms 100, 102, 104, and the like. Further, joint portions 106, 108, 110 are provided between the arms 100, 102, 104 and between the arm 104 and the probe holder 98. Each joint 106, 108, 110 is provided with an encoder 114, 116, 118, 120, and the probe holder 98 also detects an angle of rotation of two axes with respect to the joint 112 that drives the probe 96 to rotate. 122 and 124 are provided. Thus, by providing an encoder for each movable part in the robot 90A, it is possible to detect the spatial position and orientation of the probe 96 as a result, that is, to specify the position and orientation of the scanning plane. It becomes possible. The configuration shown in FIG. 3 is, of course, an example, and other configurations may be adopted.

  FIG. 4 conceptually shows the processing contents of the display processing unit 60. The coordinate information at the time of acquiring the nuclear medicine image, the coordinate information of the probe at the time of ultrasonic diagnosis, and the spatial relationship between them are managed. Based on such information, the volume data 200 is indicated by reference numeral 201. It is possible to calculate the cut surface in FIG. In this case, calibration information is taken into account as will be described later. When the cut surface is specified in the volume data 200, that is, when the cut surface 202 at the position matching the scan surface is specified, the data on the cut surface 202 is sent to the display processing unit 60 as the surface data 204. In the display processing unit 60, a processing process 206 is executed on the surface data 204, thereby forming a functional image 208. Examples of the processing 206 include color conversion. In this case, the color conversion table 210 is referred to. The function of the living tissue is associated with the hue, and the functional image 208 is configured as a color nuclear medicine image.

  On the other hand, a morphological image 212 is generated as a two-dimensional tomographic image by ultrasonic diagnosis. A composite image 214 is formed by combining the functional image 208 and the morphological image 212 side by side. On the other hand, the composite image 216 is formed by superimposing the functional image 208 and the morphological image 212 on each other. In this case, a graphic image 218 may be further combined with the combined images 214 and 216.

  FIG. 5 shows a composite image 220 formed by superimposing a color functional image 224 on a black and white morphological image 222. When the probe is moved, the position of the scanning surface in the living body changes, so the content of the morphological image 222 also changes. Following this, the cutting plane corresponding to the scanning plane is updated in real time, and plane data 204 corresponding to the cutting plane is acquired in real time, and as a result, synthesized with the morphological image 222. The contents of the function image 224 will also change. Therefore, the activity of the tissue on a certain scanning plane can be evaluated together with its form. Reference numeral 226 represents a guidance display, which schematically represents the positional relationship between the three-dimensional space and the cut surface. When the probe is moved, the cut surface also changes, and the content of the guidance display also changes.

  FIG. 6 shows a composite image 228 in which the function image 230 and the morphological image 232 are arranged. In the case of the composite image 220 as shown in FIG. 5, even if the contents of the morphological image existing as the background cannot always be clearly recognized, by displaying in parallel as shown in FIG. Both organization forms can be recognized accurately. However, according to the embodiment shown in FIG. 5, it is possible to directly recognize the organization function with the form as a background, and in that sense, the correspondence can be recognized more accurately than the display content shown in FIG. 6.

  Hereinafter, for reference, a method for specifying the scanning plane position (corresponding to the cutting plane position) in the three-dimensional space will be described with reference to FIG. The methods described below are examples, and various other methods can be used.

In (A) of FIG. 7, the origin P _e is an origin of the xyz space, corresponds to the start point of the arm sequence comprising a plurality of arms. Within xyz space, as identified through a first arm of a length L ₁ from the origin P _e is a point P _1. Also, the point through a second arm having a length of a length L ₂ from P ₁ that is identified a point P _2. Actually, there are more arms, but in this calculation, two arms are targeted. Incidentally, the first arm having the origin _Pe and the point P ₁ as both ends can rotate around the z axis. The rotation angle is defined as θ ₁ . The second arm having both ends of the points P ₁ and P ₂ rotates on the xz plane when θ ₁ = 0. The rotation angle is θ ₂ .

The coordinates of the point P ₁ are as follows from the above conditions.

P ₁ (x ₁ , y ₁ , z ₁ ) = P ₁ (0, 0, L ₁ ) (1)

Next, P ₂ (x ₂ , y ₂ , z ₂ ) which is the coordinate of P ₂ is obtained. If the mapping of the length L ₂ to the xz plane is L ₂ ′, the values of x ₂ and z ₂ are derived as follows.

x ₂ = x ₁ + L ₂ 'sin θ ₂ (2)

z ₂ = z ₁ + L ₂ 'cos θ ₂ (3)

here,
L ₂ '= L ₂ cos θ ₁ (4)
Therefore, from x ₁ = 0 and z ₁ = L ₁ , the following is obtained.

x ₂ = L ₂ cos θ ₁ sin θ ₂ (5)

z ₂ = L ₁ + L ₂ cos θ ₁ cos θ ₂ (6)

When a mapping L ₂ to the xy plane and L ₂ ", y ₂ is derived as follows.

y ₂ = y ₁ + L ₂ ”sin θ ₁ (7)

here,
L ₂ ″ = L ₂ sin θ ₂ (8)
Therefore, from y ₁ = 0, the following is obtained.

y ₂ = L ₂ sin θ ₁ sin θ ₂ (9)

  In summary, the coordinates of P2 are as follows.

P ₂ (x ₂ , y ₂ , z ₂ ) =
P ₂ (L ₂ cos θ ₁ sin θ ₂ ,
L ₂ sin θ ₁ sin θ ₂ ,
L ₁ + L ₂ cos θ ₁ cos θ ₂ ) (10)

Therefore, the coordinates of the end points (end points far from the origin) of each arm can be calculated by sequentially using the arm length and angle for each arm. Thereby, even if three or more arms are connected, the coordinates of the end point P _n of the last arm can be easily obtained. The end point P _n is an origin or a reference point when defining a probe or a scanning plane.

In FIG. 7B, two orthogonal axes 234 and 236 correspond to two axes among the x axis, the y axis, and the z axis. The intersection of these axes 234 and 236 is the probe origin P _n described above. Here, the rotation angle of the probe around the axis 234 is α. The shaft 236 ′ is obtained by rotating the shaft 236 by α. Let β be the rotation angle of the probe around its axis 236 ′. _{Let the} point defined by α be P _a and the point defined by β be P _d .

  Each point has a component on each axis as follows.

P _n (x _n , y _n , z _n )
P _a (x _a , y _a , z _a )
P _d (x _d , y _d , z _d )

  Since the scanning plane can be defined as a plane passing through the above three points, it can be replaced as follows.

ax _n × by _n × cz _n + D = 0 (11)

ax _a × by _a × cz _a + D = 0 (12)

ax _d × by _d × cz _d + D = 0 (13)

_Given P _n , P _a , and P _d, there are three mathematical formulas for the unknowns a, b, c, and D. Therefore, the unknowns a, b, and c are expressed as follows using D, respectively. be able to.

a = t ₁ D (14)

b = t ₂ D (15)

c = t ₃ D (16)

  Using the above, the formula defining the scan plane is:

t ₁ x + t ₂ y + t ₃ z + 1 = 0 (17)

  As described above, the coordinates of the scanning plane, that is, the coordinates of the cutting plane with respect to the volume data can be calculated in the three-dimensional space based on the definition of the probe origin and the scanning plane.

  FIG. 8 shows three-dimensional volume data 200. The volume data corresponds to a data storage space. The volume data covers the whole or the main part of the living body 36 in the illustrated example, but the volume data may be acquired for a part of the living body. As described above, when the coordinates of the cut surface are calculated, as shown in FIG. 9, the cut surface is specified as the plane specified by the above three points, and the data (surface data) on the cut surface is determined. A nuclear medicine image can be formed by reading. That is, an arbitrary tomographic image can be constructed. In addition, about the coordinate calculation method of a cut surface, it is not restricted above, Various methods can be used.

  Next, calibration will be described.

  Even when the ultrasound diagnosis is performed while maintaining the position and posture of the living body at the time of the nuclear medicine diagnosis (“in the case of no change in the living body”), the first coordinate system in the nuclear medicine diagnosis and the second in the ultrasound diagnosis. Unless the relationship with the coordinate system is known or fixed, the coordinates of the cutting plane with respect to the volume data cannot be specified accurately. Therefore, as shown in FIG. 10, the nuclear medicine diagnosis apparatus 10 and the robot 90 may be connected by a connecting mechanism 240 so that the two have a predetermined positional relationship. Here, the coupling mechanism 240 includes an engaging portion 240A provided on the nuclear medicine diagnosis apparatus 10 side and an engaging portion 240B provided on the robot 90 side. Moreover, as shown in FIG. 11, the nuclear medicine diagnostic apparatus 10 and the robot 90 may be mounted on a common base 242 and both may be physically integrated. According to this configuration, two coordinate systems or origins can be spatially related or always matched.

  On the other hand, when the position of the living body fluctuates ("in the case of living body fluctuation"), for example, when the nuclear medicine diagnosis and the ultrasonic diagnosis are performed in separate rooms, or after the nuclear medicine diagnosis, In the case of making an ultrasonic diagnosis by lying on the bed again after leaving, the position and posture of the living body itself are not maintained, so the coordinates of the cut surface cannot be specified, or the part to be originally displayed There is a problem that a nuclear medicine image of a part different from the nuclear medicine image is displayed.

  Thus, the use of a calibration device 32 as shown in FIG. In FIG. 12, the patient as the living body 36 is placed on a bed 246. Although the bed 246 is shown here as being used at the time of ultrasonic diagnosis, the same mechanism is also mounted on the bed 35 used at the time of nuclear medicine diagnosis. The bed 246 is provided with a detection unit 250 including a plurality of detection elements 250a arranged two-dimensionally on a horizontal plane. On the other hand, in the patient, position markers 252a to 252d are attached to one or a plurality of predetermined locations. For example, position markers are provided on the top of the head, wrist, thigh, ankle, and the like. In this case, it is desirable to attach a position marker at a position where no trouble occurs in nuclear medicine diagnosis and ultrasonic diagnosis. For example, in the case of abdominal diagnosis, it is desirable to provide in the neck and ankle, and in the case of diagnosing the neck, it is desirable to provide in the abdomen and ankle.

  Each position marker 252a to 252d has a resonance circuit including a coil and a capacitor. It is desirable that the resonance frequency is different for each position marker so that each position marker can be identified. On the other hand, each detection element 250a includes a coil that generates an alternating magnetic field. An oscillation circuit 254 and a rectifier circuit 258 are connected to the detection unit 250 via a switch 256, the detection elements 250 are selected one by one, and an oscillation signal is supplied to the selected detection element 250a. Is output to the rectifier circuit 258. The rectified signal is input to the signal processing circuit 262. The signal processing circuit compares the magnitudes of the detection values for the respective detection elements 250a, and has a specific resonance frequency to be searched based on the coordinates of the specific detection element that has obtained the largest detection value. Specifies the horizontal coordinate of the position marker. The control circuit 260 controls the operation of the switch 256 and the oscillation frequency, and communicates with an external device. Further, it is determined that the patient position at the time of nuclear medicine diagnosis and the patient position at the time of ultrasonic diagnosis do not coincide with each other, and a coordinate correction amount (calibration data) is calculated. Of course, the first coordinate system and the second coordinate system may be individually calibrated with the patient as a reference.

  The operation of the configuration shown in FIG. 12 will be described. An oscillation signal having a certain frequency is sequentially supplied to a plurality of detection elements 250a, and a detection value is obtained for each detection element 250a. Specifically, an alternating magnetic field is generated in the detection element supplied with the oscillation signal, and induced energy is induced in the resonance circuit in the position marker to accumulate electromagnetic energy. Then, the induced voltage induced in the coil of the detection element is rectified by the rectifier circuit by the magnetic field generated by the resonance current flowing through the resonance circuit and sent to the signal processing circuit. The signal processing circuit 262 identifies the horizontal coordinate of the position marker having the frequency as the resonance frequency from the magnitude of the detection value of each detection element. If this process is repeatedly executed while switching the frequency, the horizontal coordinate of each position marker can be finally specified. That is, the position of the patient can be specified, and information related to the posture of the patient can be acquired.

  The control circuit 260 matches the coordinate information of the position marker at the time of nuclear medicine diagnosis with the coordinate information of the position marker at the time of ultrasonic diagnosis, so that the position of the cut surface coincides with the position of the scanning surface. Calculate calibration data. The calibration data is used for the coordinate calculation of the cut surface. For example, when the calibration data represents a horizontal offset amount, it is used as a correction value to specify the exact position of the cut surface. The control circuit 260 has a function of determining an inconsistency between the posture of the living body at the time of nuclear medicine diagnosis and the posture of the living body at the time of ultrasonic diagnosis and outputting an alarm. That is, if the posture changes to an unacceptable level, the reliability of the calibration data may be reduced. In such a case, a warning is issued to the user. With such an alarm, it is possible to prompt the patient to correct the posture of the patient to the same one as at the time of the nuclear medicine diagnosis.

  In the configuration described above, the horizontal coordinate for the living body is specified under the precondition that the bed height at the time of nuclear medicine diagnosis and the bed height at the time of ultrasonic diagnosis are the same. You may make it obtain the coordinate about a biological body also about a direction.

  FIG. 13 conceptually shows a calibration method. Reference numeral 270 represents a reference coordinate system based on a living body. That is, this reference coordinate system is defined by the living body itself, and does not change even when the living body moves. On the other hand, there is a first coordinate system 272 at the time of radiation measurement and a second coordinate system 274 at the time of ultrasonic measurement. If such a first coordinate system 272 and the second coordinate system 274 are completely coincident with each other, the cutting plane specification 284 is accurate, but the coordinate systems 272 and 274 are configured independently. If so, calibration is required. That is, when specifying the cut surface as indicated by reference numeral 284 from the position 282 of the scanning surface defined on the second coordinate system 274, it is indicated by C3 or C4 in order to specify the cut surface more accurately. It is desirable to perform such calibration. Incidentally, reference numeral 280 represents volume data acquired in the first coordinate system 272, and surface data is acquired by specifying a cut surface 284 on the volume data 280. On the other hand, the echo data on the scanning plane is acquired for the scanning plane.

  If the calibration apparatus as shown in FIG. 12 is used, the first spatial relationship 276 between the living body and the first coordinate system can be specified using the living body as a reference. Then, using the first spatial relationship 276, the first coordinate system 272 may be corrected as indicated by C1, or when the cutting plane is specified 284 as indicated by C3. Reference data may be used. The same applies to the second coordinate system 274, and the second spatial relationship 278 between the living body and the second coordinate system 274 is specified with the living body as a reference, and the second spatial relationship 278 is indicated by C2. The correction data of the coordinate system 274 may be used, or may be used for specifying the cut surface 284 as indicated by C4.

  According to the method shown in FIG. 13, each coordinate system is defined with reference to the patient itself even when the patient moves, so that a cutting plane that completely matches the actual position of the scanning plane is calculated. And accurate surface data can be obtained. Note that the image composition processing shown in FIG. 4 may be performed by a computer or the like existing on the network. The data storage device 31 shown in FIG. 2 may be provided in the nuclear medicine diagnostic apparatus 10 or may be provided in the ultrasonic diagnostic apparatus 12. In any case, it is desirable that when an ultrasonic image is displayed, a nuclear medicine image having the same positional relationship is displayed together with or on the ultrasonic image.

It is a perspective view showing the whole medical diagnostic system composition concerning the present invention. 1 is a block diagram showing an overall configuration of a medical diagnosis system according to the present invention. It is a perspective view for demonstrating the mechanism of a robot. It is a figure for demonstrating the content of a display process. It is a figure for demonstrating the display which superposed | stacked the function image and the form image. It is a figure which shows the case where a function image and a form image are displayed side by side. It is a figure which shows the coordinate system for calculating the position of a scanning surface. It is a figure which shows volume data. It is a figure which shows the cut surface set on volume data. It is a figure explaining the connection between apparatuses by a connection mechanism. It is a figure which shows the case where each apparatus is installed on a common base. It is a figure which shows notionally the structural example of a calibration apparatus. It is a figure which shows notionally the content of the calibration process.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 Nuclear medicine diagnostic apparatus, 12 Ultrasonic diagnostic apparatus, 31 Data storage apparatus, 32 Calibration apparatus, 60 Display processing part, 64 plane data acquisition part, 90 Robot (probe positioning mechanism).

Claims (7)

Radiation measuring means for detecting radiation from a three-dimensional space in a living body to which a drug containing a radioactive substance is administered, and acquiring three-dimensional volume data;
Storage means for storing the volume data;
Ultrasonic measurement means for obtaining a received signal by forming a beam scanning plane in the three-dimensional space;
Ultrasonic image forming means for forming an ultrasonic image corresponding to the beam scanning surface based on the received signal;
Means for extracting surface data from volume data stored in the storage means based on coordinate information of the beam scanning surface with respect to the three-dimensional space, the beam scanning in the three-dimensional space based on the coordinate information; An extraction means comprising: a cutting surface specifying means for specifying a cutting surface at the same position as the surface; and a surface data cutting means for cutting out data on the cutting surface as the surface data from the volume data ;
A nuclear medicine image forming means for forming a nuclear medicine image based on the surface data;
Display processing means for combining and displaying the nuclear medicine image and the ultrasound image;
Including
A calibration device that calibrates the coordinate information of the cut surface with respect to the three-dimensional space by obtaining a spatial relationship between a first coordinate system in radiation measurement and a second coordinate system in ultrasonic measurement. The calibration apparatus is provided, wherein the calibration device specifies a first spatial relationship between the living body and the first coordinate system in the radiation measurement, and the living body and the second coordinate in the ultrasonic measurement. Means for identifying a second spatial relationship with a system, wherein the first coordinate system and the second coordinate system are spatially related with respect to the living body,
The means for specifying the first and second spatial relationships includes at least one position marker provided at at least one site in the living body, and coordinates of the position marker at the time of the radiation measurement and the ultrasonic measurement. And a marker coordinate detector for detecting the medical diagnostic system. The system of claim 1 , wherein
The cutting plane specifying means dynamically identifies the cutting plane by recognizing the coordinate information of the beam scanning plane in real time,
The surface data cutout means cuts out the surface data in real time for the dynamically specified cutting surface,
The medical diagnostic system, wherein the ultrasonic image is a real-time image. The system of claim 1, wherein
The medical diagnostic system, wherein the display processing unit forms a composite image by superimposing the nuclear medicine image and the ultrasonic image. The system of claim 1, wherein
The medical processing system, wherein the display processing unit forms a composite image by arranging the nuclear medicine image and the ultrasound image. The system according to claim 3 or 4 ,
The medical diagnosis system, wherein the nuclear medicine image is a color two-dimensional tomographic image representing a tissue function, and the ultrasonic image is a black and white two-dimensional tomographic image representing a tissue form. The system of claim 1, wherein
A medical diagnostic system comprising a robot for positioning and holding a probe forming the beam scanning plane. The system of claim 1 , wherein
The calibration apparatus performs coordinate correction for spatially matching the beam scanning plane and the cut plane based on the coordinates of the position marker in the radiation measurement and the coordinates of the position marker in the ultrasonic measurement. A medical diagnostic system comprising correction means for executing processing.

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