JP3943353B2 - Flexible ultrasound endoscope device - Google Patents

Description

【００４８】
また、図１３において、二点間のセンサ距離は角度Ｂを用いて算出することができる。二点間の帯状部材２０は円弧Ｌを描いていると見ることができるので、角度ＢはセンサＳ_n とＳ_n+1の接線がなす角度に他ならない。
【００４９】
二点間の空間直線距離Ｄは
Ｄ＝３６０×Ｌ×sin （Ｂ／２）／（π×Ｂ） --（４）
であるから、各センサ対におけるねじりと曲がりの値を内視鏡挿入部基準位置から先端部にかけて積算し、センサ間隔を（４）式を用いて算出し、（３）式の座標変換を連続することによって基準座標系に対する先端部（即ち、超音波プローブ６）の位置座標を算出することができる。
【００５０】
図１４は超音波プローブ６によって得られる二次元の超音波断層像である。Ｐ１，Ｐ２は超音波プローブ６による走査の始点と終点位置に対応し、Ｐ３，Ｐ４は深さに対応しており、画面倍率を設定すると一義的に距離が決まる。即ち、二次元の超音波断層像を表示するグラフィックメモリアドレスと被検体の位置関係は相関性を持って決まる。
【００５１】
内視鏡の挿入基準位置である挿入量／回転角度検出部４０から先端部の座標位置は曲がり検出部２２からの検出値によって知ることができ、超音波プローブ６が走査する画像は二次元座標系で全てのピクセル位置が分かっているので、これを合成することによって一つの平面上の全ての画像は、挿入基準座標系で表現することができる。
【００５２】
それを三次元画像にするためには、挿入量／回転角度検出部４０において挿入部可撓管１の回転角Ｒを検出する。その軸線方向をＺ軸とすると、Ｚ軸を中心としたＲ回転座標系に変換することができる。
【００５３】
仮に手元で回転させた成分が先端部まで正しく伝わらない場合でも、曲がり検出用光ファイバー２１は途中でねじれ角度成分として検出するので先端部の位置座標をほぼ正しく検出することができる。
【００５４】
なお、図８の（Ｂ）に示されるように、一対の曲がり検出部２２，２２′を直交して配置してもよい（第２の実施例）。図１５はそのような帯状部材２０′，２０″が挿入部可撓管１に組み込まれた状態を示している。
【００５５】
この場合、ｎ番目のセンサ対の各曲げ角度と出力電圧の関係は、
Ｘ方向に曲げたときのＸセンサ比例定数を ｅ_n
Ｘ方向に曲げたときのＹセンサ比例定数を ｆ_n
Ｙ方向に曲げたときのＸセンサ比例定数を ｇ_n
Ｙ方向に曲げたときのＹセンサ比例定数を ｈ_n
Ｘ方向の曲げ角度要素を θx
Ｙ方向の曲げ角度要素を θy
Ｘセンサの電圧変化を Ｖｘ_n
Ｙセンサの電圧変化を Ｖｙ_n
とすると、以下の式が成り立つ。
【００５６】
θx ＝ｅ_n ×Ｖｘ_n ＋ ｆ_n ×Ｖｙ_n --（５）
θy ＝ｇ_n ×Ｖｘ_n ＋ ｈ_n ×Ｖｙ_n --（６）
である。
【００５７】
Ｘ，Ｙが完全に直交した理想状態において、Ｘ方向へ曲げたときはＹセンサの電圧変化成分は無視できるはずであるが、実際のセンサ組込み状態ではバラツキが生じることが想定され、Ｘ，Ｙ成分が双方に及ぼす影響を無視できないと考えられる。各比例定数は内視鏡ごとに固有の値となり、予めキャリブレーションにて取得する。
【００５８】
図１６において、内視鏡の挿入方向をｚ軸上にとると、センサＳ_n のベクトルがｙ−ｚ平面となす角度がθxであり、ｘ−ｚ平面となす角度がθyであるので、Ｓ_n の位置座標（ｘ_n ，ｙ_n ，ｚ_n ）は
ｘ_n ＝Ｌ sinθx --（７）
ｙ_n ＝Ｌ sinθy --（８）
ｚ_n ＝Ｌ｛ (cosθx)² −(sinθy)² ｝^1/2
＝Ｌ｛ (cosθy)² −(sinθx)² ｝^1/2 --（９）
となるので超音波プローブ６の位置座標を特定することができる。
【００５９】
このようにして、図１に示される観察像表示装置７０と断層像表示装置８０と三次元像表示装置９０に、図３に示されるように、観察窓５からの光学観察像と、超音波プローブ６による二次元の超音波断層像と、帯状部材２０及び挿入量／回転角度検出部４０からの検出値を組み合わせて二次元の超音波断層像を処理して得られた三次元像とが同時に観察される。
【００６０】
したがって、三次元像によって血管の走行状態を確認しながら、二次元の超音波断層像で処置具１００による穿刺状態をリアルタイムで確認して、血管を突き刺さないように安全に穿刺処置を行うことができる。
【００６１】
【発明の効果】
本発明によれば、超音波プローブから得られる二次元の断層像データを、プローブ位置・姿勢検出手段から得られる超音波プローブの位置と姿勢のデータと組み合わせることにより三次元化して超音波断層像の三次元像を構築する三次元像構築手段を設けたことにより、コンベックスタイプ等の超音波プローブを用いて三次元の超音波断層像を高精度に構築することができ、血管の走行状態等をリアルタイムで確認しながら穿刺処置等を安全に行うことができる。
【図面の簡単な説明】
【図１】本発明の実施例の可撓性超音波内視鏡装置の全体構成図である。
【図２】本発明の実施例の可撓性超音波内視鏡装置の挿入部先端部分の斜視図である。
【図３】本発明の実施例の可撓性超音波内視鏡装置によって同時に得られる表示画面の略示図である。
【図４】本発明の実施例の可撓性超音波内視鏡装置の挿入部可撓管の部分斜視図である。
【図５】本発明の実施例に用いられる曲がり検出用光ファイバーの曲がり検出部の略示断面図である。
【図６】本発明の実施例に用いられる曲がり検出用光ファイバーの曲がり検出部が屈曲した状態の略示断面図である。
【図７】本発明の実施例に用いられる曲がり検出用光ファイバーの曲がり検出部が逆方向に屈曲した状態の略示断面図である。
【図８】本発明の実施例に用いられる曲がり検出用光ファイバーによる三次元の屈曲状態検出の原理を説明するための略示図である。
【図９】本発明の実施例の曲がり検出用光ファイバーが取り付けられた帯状部材の平面図である。
【図１０】本発明の実施例の光信号入出力装置の回路図である。
【図１１】本発明の実施例のコンピュータにおいて行われる演算の内容を説明する座標図である。
【図１２】本発明の実施例のコンピュータにおいて行われる演算の内容を説明する座標図である。
【図１３】本発明の実施例のコンピュータにおいて行われる演算の内容を説明する座標図である。
【図１４】本発明の実施例の二次元の超音波断層像を例示する略示図である。
【図１５】本発明の第２の実施例の挿入部可撓管の部分断面図である。
【図１６】本発明の第２の実施例のコンピュータにおいて行われる演算の内容を説明する座標図である。
【符号の説明】
１ 挿入部可撓管
４ 先端部本体
５ 観察窓
６ 超音波プローブ
９ コンピュータ（三次元像構築手段）
２０ 帯状部材
２１，２１′ 曲がり検出用光ファイバー
２２，２２′ 曲がり検出部
３０ 光信号入出力装置
４０ 挿入量／回転角度検出部
７０ 観察像表示装置
８０ 断層像表示装置
９０ 三次元像表示装置[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a flexible ultrasonic endoscope apparatus that can be inserted into a body to obtain an ultrasonic tomographic image and an optical observation image.
[0002]
[Prior art]
In an ultrasonic endoscope using a so-called convex type ultrasonic probe, an ultrasonic signal transmitted and received from the ultrasonic probe is scanned on a plane including the axis of the distal end of the insertion portion.
[0003]
Therefore, it is easy to project a treatment instrument such as a puncture needle protruding from the distal end portion of the insertion portion along the scanning surface of the ultrasonic signal, and the protruding state of the puncture needle can be detected in real time using an ultrasonic tomographic image. Since the puncture procedure can be performed while confirming with the above, safety is high.
[0004]
[Problems to be solved by the invention]
However, the blood vessel in the vicinity where the puncture needle is passed does not necessarily travel on the ultrasonic scanning surface, and the blood vessel is displayed only in a small granularity on the ultrasonic tomographic screen. It is not possible to confirm the running state of the car.
[0005]
Therefore, for example, as in the invention described in JP-A-6-261900, if a three-dimensional ultrasonic tomographic image is constructed, the running state of the blood vessel can be confirmed three-dimensionally.
[0006]
However, since the ultrasonic endoscope of the invention described in Japanese Patent Laid-Open No. 6-261900 performs so-called radial scanning that emits and receives ultrasonic waves in the direction around the axis of the distal end of the insertion portion, While it is relatively easy to construct an acoustic tomographic image, it is extremely difficult to project the treatment tool from the distal end of the insertion portion onto the ultrasonic scanning surface. For this reason, the protruding state of the treatment tool cannot be confirmed in real time, and there is a risk that a blood vessel may be accidentally pierced to cause a bleeding accident.
[0007]
In addition, the ultrasonic endoscope according to the invention described in Japanese Patent Laid-Open No. 6-261900 detects the position and posture of an ultrasonic probe with a magnetic sensor arranged in the vicinity of the ultrasonic probe, so that posture detection accuracy is high. Low, there is a large error in the directionality of the constructed three-dimensional ultrasonic tomogram.
[0008]
Therefore, the present invention can construct a three-dimensional ultrasonic tomographic image with high accuracy using an ultrasonic probe of a convex type or the like, and puncture while confirming the running state of the blood vessel and the protruding state of the puncture needle in real time. It is an object of the present invention to provide a flexible ultrasonic endoscope apparatus that can safely perform treatment and the like.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, the flexible ultrasonic endoscope apparatus of the present invention includes an ultrasonic probe that transmits and receives an ultrasonic signal for obtaining an ultrasonic tomographic image, and an observation for obtaining an optical observation image. In a flexible ultrasonic endoscope apparatus in which a window is provided at the distal end portion of a flexible insertion portion, a bending detection portion in which the amount of transmitted light changes in accordance with the angle of the bent angle is formed. Probe position / posture detection that detects the position and posture of an ultrasonic probe based on detection values obtained from a plurality of bend detection units, with each bend detection unit of a plurality of flexible bend detection optical fibers being dispersedly arranged in the insertion unit And the two-dimensional ultrasonic tomographic image data obtained from the ultrasonic probe is combined with the ultrasonic probe position and posture data obtained from the probe position / posture detection means to obtain a three-dimensional data. It is provided with a three-dimensional image constructing means for constructing a three-dimensional image of tomographic images.
[0010]
It is preferable that the ultrasonic probe emits and receives an ultrasonic signal on a plane including the axis of the distal end of the insertion portion, and the treatment instrument protrudes from the distal end of the insertion portion on the scanning surface.
[0011]
Also provided are a two-dimensional tomographic image display means for displaying a two-dimensional ultrasonic tomographic image obtained by the ultrasonic probe and a three-dimensional tomographic image display means for displaying a three-dimensional image obtained by the three-dimensional image construction means. It is good to have.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows an overall configuration of a flexible ultrasonic endoscope apparatus, in which a proximal end of an insertion portion flexible tube 1 is connected to one end of an operation portion 2, and a portion near the distal end of the insertion portion flexible tube 1. Is a bending portion 1a that bends in an arbitrary direction by rotating the operation knob 3 disposed in the operation portion 2.
[0013]
The distal end body 4 connected to the distal end of the insertion section flexible tube 1 includes an observation window 5 for obtaining an optical observation image, and an ultrasonic probe 6 for transmitting and receiving an ultrasonic signal for obtaining an ultrasonic tomographic image. Is arranged. V is an observation optical axis directed outward from the observation window 5, and U is an ultrasonic scanning range.
[0014]
FIG. 2 shows the distal end portion main body 4 portion, and the treatment instrument protrusion 4a (the exit of the treatment instrument insertion channel) from which the treatment instrument 100 projects alongside the observation window 5 arranged immediately after the ultrasonic probe 6 is shown. ) Is arranged, and for example, the distal end portion of the treatment instrument 100 such as a puncture needle protrudes obliquely forward.
[0015]
The ultrasonic probe 6 is a convex type that emits and receives an ultrasonic signal sideways so as to scan in a fan shape on a plane including the axis 4x of the tip body 4. U is the ultrasonic scanning range.
[0016]
Then, the position and orientation of the treatment instrument protrusion 4a are set so that the treatment instrument 100 protrudes on the scanning surface of the ultrasonic signal, and the observation optical axis of the observation window 5 is substantially along the scanning surface of the ultrasonic signal. Is set to the position and orientation.
[0017]
By such an ultrasonic probe 6, a two-dimensional ultrasonic tomographic image U2 of a portion located in the ultrasonic scanning range U of the target organ is obtained, and the tip body 4 is rotated around its axis 4x. Since two-dimensional ultrasonic tomographic images U2 at different positions of the organ are sequentially obtained, a three-dimensional image U3 of the ultrasonic tomographic image can be obtained by combining them.
[0018]
The flexible ultrasonic endoscope apparatus of this embodiment is configured so that such a three-dimensional image U3 of the ultrasonic tomographic image can be observed simultaneously with the two-dimensional ultrasonic tomographic image U2 and the optical observation image. There will be described in detail below the configuration and the like.
[0019]
Returning to FIG. 1, an imaging signal of an observation image projected on the imaging surface of the solid-state imaging device by an objective optical system (not shown) arranged in the observation window 5 is sent to an external video processor 7 for imaging. An optical observation image that is signal-processed by the signal processing unit 71, the video signal processing unit 72, the observation image display circuit 73, and the like and obtained through the observation window 5 is displayed on the observation image display device 70 as shown in FIG.
[0020]
An input / output signal to / from the ultrasonic probe 6 is input / output to / from an ultrasonic signal input / output unit 81 of the external ultrasonic signal processing apparatus 8 and is subjected to signal processing by the ultrasonic signal processing unit 82, the tomographic image display circuit 83, and the like. A two-dimensional ultrasonic tomographic image U2 obtained by the ultrasonic probe 6 is displayed on the tomographic image display device 80 as shown in FIG.
[0021]
A flexible synthetic resin strip member 20 in which a plurality of bending detection optical fibers, which will be described later, are arranged on the insertion section flexible tube 1 is, for example, an extension direction of the rear surface of the operation section 2 (that is, a downward direction on the observation screen). The base end portion is connected to the optical signal input / output device 30.
[0022]
As shown in FIG. 4, the plurality of bending detection optical fibers 21 attached to the belt-like member 20 are bent back in a smooth U shape by changing their positions in order. A bend detector 22 is formed in the vicinity of the bent back portion of each bend detection optical fiber 21.
[0023]
For example, about 5 to 30 bending detectors 22 are distributed over the entire length of the insertion section flexible tube 1 with an interval of, for example, several centimeters in the axial direction of the insertion section flexible tube 1.
[0024]
The bending detection unit 22 is formed by forming a light absorption part only in a predetermined direction (for example, upward or downward) in a middle part of the optical fiber 21 for bending detection in which a plastic core is covered with a clad. Since the amount of transmitted light changes corresponding to the degree to which the bending detection unit 22 is bent, the bending angle of the portion where the bending detection unit 22 is arranged can be detected by detecting this.
[0025]
The principle is as described in US Pat. No. 5,633,494, but will be briefly described below.
In FIG. 5, reference numerals 21a and 21b denote a core and a clad of one bending detection optical fiber 21, and the bending detection unit 22 absorbs light that has passed through the core 21a without being totally reflected into the core 21a. The light absorbing portion 22a is formed in a specific direction (here, “downward”) of the clad 21b.
[0026]
Then, as shown in FIG. 6, when the bending detection optical fiber 21 is bent upward, the amount (area) of the light that hits the light absorbing portion 22a out of the light passing through the core 21a increases. 21 light transmission amount decreases.
[0027]
On the contrary, as shown in FIG. 7, when the bending detection optical fiber 21 is bent downward, the amount (area) of the light that hits the light absorbing portion 22a out of the light passing through the core 21a is decreased. The light transmission amount of the optical fiber 21 for use increases.
[0028]
Since the bending amount of the bending detection optical fiber 21 and the light transmission amount in the light absorption unit 22a are in a certain relationship (for example, a linear function relationship), the light transmission amount of the bending detection optical fiber 21 is detected. By this, it is possible to detect the bend angle of the bend detection unit 22 portion where the light absorption unit 22a is formed.
[0029]
Therefore, when a plurality of bending detection units 22 are arranged at intervals in the axial direction of the insertion portion flexible tube 1, the intervals between the bending detection units 22 and the detected bending angles of the respective bending detection units 22. Therefore, the bending state in the vertical direction of the entire insertion portion flexible tube 1 can be detected.
[0030]
Then, as schematically shown in FIG. 8A, the flexible belt-like member 20 is shifted to the left and right with respect to the bending detection unit 22 as described above, and the second bending detection unit 22 ′. When the light transmission amounts of the two bend detection units 22 and 22 'are compared, when there is no twist in the left and right direction, there is no difference in the light transmission amount between the two, and according to the amount of twist in the left and right direction. The difference in the light transmission amount between the two becomes large.
[0031]
As a result, by measuring the light transmission amount of each bending detection unit 22, 22 'and comparing the measured values, the amount of twist in the left-right direction of the portion where the bending detection unit 22, 22' is arranged is detected. Can do.
[0032]
Accordingly, the three-dimensional bending state of the entire belt-shaped member 20 (that is, the bending state of the insertion portion flexible tube 1) can be detected by detecting and comparing the light transmission amount in each of the bending detection units 22 and 22 '. . This principle is as described in US Pat. No. 6,127,672.
[0033]
Further, as shown in FIG. 8B, even if two belt-like members 20 'and 20 "each having a plurality of bending detectors 22 arranged in a row are arranged in a right-angled positional relationship, the same applies. Thus, a three-dimensional bending state can be detected.
[0034]
In the first embodiment of the present invention, a belt-like member 20 as shown in FIG. 8A is attached to the insertion portion flexible tube 1, and the bending detection optical fiber 21 is connected to the insertion portion flexible tube 1. The optical fiber 21 for bending detection may be attached to a built-in object in the insertion portion flexible tube 1 or the like.
[0035]
FIG. 9 shows a state in which the bending detection optical fibers 21 and 21 ′ are attached to the band-shaped member 20, and a plurality of bending detection optical fibers are arranged so that the bending detection portions 22 are positioned at regular intervals in the longitudinal direction of the band-shaped member 20. 21 is attached to the front surface side of the band-shaped member 20, and a second plurality of bending detections are provided on the back surface side of the band-shaped member 20 so that the second bending detection unit 22 ′ is arranged beside each bending detection unit 22 on the front side. An optical fiber 21 'is attached.
[0036]
Further, by arranging at least one simple reference optical fiber 21R in which the light absorbing portion 22a is not formed and comparing the light transmission amount of each bending detection optical fiber 21 with the light transmission amount of the reference optical fiber 21R, The influence of temperature, deterioration with time, etc., on the light transmission amount of the bending detection optical fiber 21 can be eliminated.
[0037]
FIG. 10 shows an optical signal input / output device 30 to which the base end of the belt-like member 20 is connected, and light emitted from one light emitting diode 31 enters all the optical fibers 21, 21 ′, 21 R. Reference numeral 32 denotes a drive circuit for the light emitting diode 31.
[0038]
A photodiode 33 for converting the light intensity level into a voltage level and outputting it is arranged for each emission end of each of the optical fibers 21, 21 ′, 21 R, and the output from each photodiode 33 is output by an amplifier 34. After being amplified, it is converted into a digital signal by the analog / digital converter 35 and sent to the computer 9.
[0039]
Returning to FIG. 1, an insertion amount / rotation angle detection unit 40 is attached to a so-called mouthpiece or the like at an entrance portion (for example, mouth or anus) in a patient's body where the insertion portion flexible tube 1 is inserted. The flexible tube 1 is passed through the insertion amount / rotation angle detector 40.
[0040]
The insertion amount / rotation angle detection unit 40 is formed from a reflection mark formed on the surface of the insertion portion flexible tube 1 as described in, for example, Japanese Patent Laid-Open Nos. 56-97429 and 60-217326. The insertion length of the insertion portion flexible tube 1 and the rotation angle around the axis line are detected from the change in the reflected light of the light, and the digital detection signal is output from the encoder output device 41.
[0041]
Then, the detection signal of the three-dimensional bending state of the insertion portion flexible tube 1 output from the optical signal input / output device 30 and the insertion length and rotation angle of the insertion portion flexible tube 1 output from the encoder output device 41 are detected. The detection signal is input to the computer 9, the position and orientation of the ultrasonic probe 6 are calculated, and the data and the two-dimensional ultrasonic tomographic image U <b> 2 output from the ultrasonic signal processing unit 82 are combined to obtain the tertiary. An original image U3 is constructed and displayed on the three-dimensional image display device 90 as shown in FIG.
[0042]
Such calculation of the position and orientation of the ultrasonic probe 6 is performed as follows, for example.
The positions of the bending detectors 22 and 22 'are set so that the changes in the output voltage are opposite to each other depending on the direction of the bending of the bending detectors 22 and 22' disposed on the front and back surfaces of the strip member 20. If the state without bending is normalized as zero voltage, the direction of bending can be determined by the sign of the output voltage.
[0043]
The relationship between the bending angle, the twisting angle, and the output voltage of the n-th sensor pair (that is, the bending detection unit 22, 22 ') is as follows.
The proportionality constant when twisted to the right a _n
The proportionality constant when twisted to the left is b _n
The constant of proportionality when bent upward c _n
The proportional constant when bent down is _dn
The output voltage of the sensor pair is V1 _n , V2 _n
The twist angle defined in FIG.
The bending angle defined in FIG.
Then, the following equation holds.
[0044]
(A _n or b _n ) × T + (c _n or d _n ) × B = V 1 _n − (1)
(A _n or b _n ) × T + (c _n or d _n ) × B = V 2 _n − (2)
A _n and b _n in formula (1) (2), whether to use the value of c _n and d _n is the voltage V1 _n, uniquely determined by the change in the sign and voltage value V2 _n.
[0045]
In FIG. 11, (X ₀ , Y ₀ , Z ₀ ) is the original coordinate system, and (X ₁ , Y ₁ , Z ₁ ) is the rotational coordinate system after T rotation. Further, (X ₂ , Y ₂ , Z ₂ ) in FIG. 12 is a rotation coordinate system after B rotation.
[0046]
11 and 12, the (X ₀ , Y ₀ , Z ₀ ) coordinates are rotated about the Y axis by T and then rotated about the X axis by B (X ₂ , Y ₂ , Z ₂ ) can be expressed by the following relational expression.
[0047]
[Expression 1]

[0048]
In FIG. 13, the sensor distance between two points can be calculated using the angle B. Since the belt-like member 20 between the two points can be seen as drawing an arc L, the angle B is nothing but the angle formed by the tangent lines of the sensors _Sn and _{Sn + 1} .
[0049]
The spatial linear distance D between the two points is D = 360 × L × sin (B / 2) / (π × B) — (4)
Therefore, the torsional and bending values in each sensor pair are integrated from the endoscope insertion portion reference position to the distal end portion, the sensor interval is calculated using Equation (4), and the coordinate transformation of Equation (3) is continuously performed. By doing so, it is possible to calculate the position coordinates of the tip (that is, the ultrasonic probe 6) with respect to the reference coordinate system.
[0050]
FIG. 14 is a two-dimensional ultrasonic tomographic image obtained by the ultrasonic probe 6. P1 and P2 correspond to the start point and end point position of scanning by the ultrasonic probe 6, and P3 and P4 correspond to the depth. When the screen magnification is set, the distance is uniquely determined. That is, the positional relationship between the graphic memory address for displaying the two-dimensional ultrasonic tomogram and the subject is determined with correlation.
[0051]
The coordinate position of the distal end from the insertion amount / rotation angle detection unit 40, which is the insertion reference position of the endoscope, can be known from the detection value from the bending detection unit 22, and the image scanned by the ultrasonic probe 6 is a two-dimensional coordinate. Since all pixel positions are known in the system, all images on one plane can be expressed in the insertion reference coordinate system by combining them.
[0052]
In order to make it a three-dimensional image, the insertion amount / rotation angle detection unit 40 detects the rotation angle R of the insertion portion flexible tube 1. If the axial direction is the Z axis, it can be converted into an R rotation coordinate system centered on the Z axis.
[0053]
Even if the component rotated at hand is not correctly transmitted to the tip, the bending detection optical fiber 21 detects the twist angle component on the way, so that the position coordinate of the tip can be detected almost correctly.
[0054]
As shown in FIG. 8B, the pair of bending detection units 22 and 22 'may be arranged orthogonally (second embodiment). FIG. 15 shows a state in which such belt-like members 20 ′ and 20 ″ are incorporated in the insertion portion flexible tube 1.
[0055]
In this case, the relationship between each bending angle of the nth sensor pair and the output voltage is
The X sensor proportionality constant when bent in the X direction e _n
Y sensor proportional constant when bent in the X direction is f _n
X sensor proportional constant when bent in the Y direction g _n
Y sensor proportional constant when bent in the Y direction h _n
The bending angle element in the X direction is θx
The bending angle element in the Y direction is θy
X sensor voltage change Vx _n
The voltage change of the Y sensor Vy _n
Then, the following equation holds.
[0056]
_{θx = e n × Vx n +} f n × Vy n - (5)
_{θy = g n × Vx n +} h n × Vy n - (6)
It is.
[0057]
In an ideal state in which X and Y are completely orthogonal, the voltage change component of the Y sensor should be negligible when bent in the X direction, but it is assumed that variations will occur in the actual sensor built-in state. It is thought that the influence which an ingredient has on both cannot be ignored. Each proportionality constant is a unique value for each endoscope and is acquired in advance by calibration.
[0058]
16, when taking the insertion direction of the endoscope on the z-axis, the angle of the vector of the sensor S _n makes with the y-z plane is [theta] x, since the angle between the x-z plane is [theta] y, S _n position coordinates _{(x n, y n, z} n) is _{x n = L sinθx - (7} )
y _n = L sinθy-(8)
z _n = L {(cosθx) ² − (sinθy) ² } ^1/2
= L {(cosθy) ² − (sinθx) ² } ^1/ 2-(9)
Therefore, the position coordinates of the ultrasonic probe 6 can be specified.
[0059]
In this manner, the observation image display device 70, the tomographic image display device 80, and the three-dimensional image display device 90 shown in FIG. A two-dimensional ultrasonic tomographic image obtained by the probe 6 and a three-dimensional image obtained by processing the two-dimensional ultrasonic tomographic image by combining the detection values from the band-shaped member 20 and the insertion amount / rotation angle detection unit 40. Observed at the same time.
[0060]
Therefore, it is possible to confirm the puncture state of the treatment tool 100 in real time with a two-dimensional ultrasonic tomographic image while confirming the running state of the blood vessel with a three-dimensional image, and perform a puncture treatment safely so as not to pierce the blood vessel. it can.
[0061]
【The invention's effect】
According to the present invention, the two-dimensional tomographic image data obtained from the ultrasonic probe is three-dimensionalized by combining the ultrasonic probe position and posture data obtained from the probe position / orientation detecting means, and the ultrasonic tomographic image is obtained. By providing 3D image construction means for constructing 3D images, it is possible to construct 3D ultrasound tomograms with high accuracy using a convex type ultrasonic probe, etc. A puncture treatment or the like can be performed safely while confirming in real time.
[Brief description of the drawings]
FIG. 1 is an overall configuration diagram of a flexible ultrasonic endoscope apparatus according to an embodiment of the present invention.
FIG. 2 is a perspective view of a distal end portion of an insertion portion of the flexible ultrasonic endoscope apparatus according to the embodiment of the present invention.
FIG. 3 is a schematic view of a display screen simultaneously obtained by the flexible ultrasonic endoscope apparatus according to the embodiment of the present invention.
FIG. 4 is a partial perspective view of an insertion portion flexible tube of the flexible ultrasonic endoscope apparatus according to the embodiment of the present invention.
FIG. 5 is a schematic cross-sectional view of a bending detection unit of a bending detection optical fiber used in an embodiment of the present invention.
FIG. 6 is a schematic cross-sectional view showing a bent state of a bending detection portion of a bending detection optical fiber used in the embodiment of the present invention.
FIG. 7 is a schematic cross-sectional view showing a state in which a bend detection portion of a bend detection optical fiber used in an embodiment of the present invention is bent in a reverse direction.
FIG. 8 is a schematic diagram for explaining the principle of three-dimensional bending state detection by a bending detection optical fiber used in an embodiment of the present invention.
FIG. 9 is a plan view of a belt-like member to which a bending detection optical fiber according to an embodiment of the present invention is attached.
FIG. 10 is a circuit diagram of an optical signal input / output device according to an embodiment of the present invention.
FIG. 11 is a coordinate diagram for explaining the contents of calculation performed in the computer according to the embodiment of the present invention.
FIG. 12 is a coordinate diagram for explaining the contents of calculation performed in the computer according to the embodiment of the present invention.
FIG. 13 is a coordinate diagram for explaining the contents of calculation performed in the computer according to the embodiment of the present invention.
FIG. 14 is a schematic view illustrating a two-dimensional ultrasonic tomographic image of an embodiment of the present invention.
FIG. 15 is a partial cross-sectional view of an insertion portion flexible tube according to a second embodiment of the present invention.
FIG. 16 is a coordinate diagram for explaining the contents of calculation performed in the computer according to the second embodiment of the present invention;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Insertion part flexible tube 4 Tip part main body 5 Observation window 6 Ultrasonic probe 9 Computer (three-dimensional image construction means)
20 Band-shaped members 21, 21 ′ Optical fibers for detecting bending 22, 22 ′ Bending detector 30 Optical signal input / output device 40 Insertion / rotation angle detector 70 Observation image display device 80 Tomographic image display device 90 Three-dimensional image display device

Claims (3)

A flexible ultrasonic endoscope in which an ultrasonic probe for transmitting and receiving an ultrasonic signal for obtaining an ultrasonic tomographic image and an observation window for obtaining an optical observation image are provided at the distal end portion of the flexible insertion portion. In the mirror device,
A plurality of flexible bending detection optical fibers are arranged in a distributed manner. A light source that is embedded in the outer shell of the insertion portion flexible tube that forms the insertion portion, and that detects the intensity of the emitted light for each of the optical fibers, and a single light source for allowing light to enter all the optical fibers. A probe position / posture detection unit that is disposed outside the insertion portion flexible tube and detects the position and posture of the ultrasonic probe based on a detection value obtained by the light intensity detection unit;
The two-dimensional ultrasonic tomographic image data obtained from the ultrasonic probe is combined with the ultrasonic probe position and posture data obtained from the probe position / posture detection means to form a three-dimensional image to obtain the ultrasonic tomographic image. A flexible ultrasonic endoscope apparatus comprising a three-dimensional image construction means for constructing a three-dimensional image. 2. The apparatus according to claim 1, wherein the ultrasonic probe transmits and receives an ultrasonic signal on a plane including an axis of the distal end of the insertion portion, and treatment instruments protrude from the distal end of the insertion portion on the scanning surface. Flexible ultrasound endoscope device. Two-dimensional tomographic image display means for displaying a two-dimensional ultrasonic tomographic image obtained by the ultrasonic probe and three-dimensional tomographic image display means for displaying a three-dimensional image obtained by the three-dimensional image construction means are provided. The flexible ultrasonic endoscope apparatus according to claim 1 or 2.

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