JP6198097B2 - Abnormal tissue detection device - Google Patents

Description

The present invention relates to abnormal tissue detection device.

  The diagnosis of cancer is generally performed by, for example, capturing an image of a target region with an X-ray mammography or a nuclear magnetic resonance apparatus (MRI (Magnetic Resonance Imaging)) and analyzing the captured image (for example, , See Patent Document 1). However, in X-ray mammography, there are concerns about the adverse effects of X-rays on the living body, and it is difficult to reduce the size of the X-ray mammography apparatus and MRI apparatus. Furthermore, in order to make a diagnosis using these devices, it is essential to have a medical examination at a specialized institution.

  Therefore, an abnormal tissue detection apparatus has been proposed that can easily detect abnormal tissues with a simple configuration without using an X-ray mammography apparatus or an MRI apparatus (see, for example, Patent Document 2). This abnormal tissue detection apparatus is provided with an antenna array arranged in a matrix. This abnormal tissue detection apparatus radiates a microwave (impulse electromagnetic wave) from one antenna of an antenna array to a living body, and receives a reflected wave of the radiated microwave by another antenna of the antenna array. This abnormal tissue detection device transmits and receives microwaves while changing the combination of an antenna that transmits microwaves and an antenna that receives microwaves, and based on a plurality of received signals obtained by the combination of each antenna Detecting abnormal tissues in the living body.

Special table 2007-071873 JP 2010-69158 A

  In order to detect an abnormal tissue in the living body with high accuracy in the abnormal tissue detection device disclosed in Patent Document 1, the relative distance between both antennas is the same even if the combination of antennas for transmission and reception is changed, and If there is no abnormal tissue in the living body, it is necessary to be able to receive the same received signal. This is because, if the received signal changes only by changing the combination of antennas, it is difficult to detect a signal component indicating an abnormal tissue in the living body with extremely small signal fluctuation.

  However, the received signal may differ depending on the combination of antennas that perform transmission and reception. FIG. 22 shows time variation patterns of received signals of combinations of antennas that perform three transmissions / receptions. As shown in FIG. 22, the three received signals are different. This difference in the received signal is caused by a difference in environment around each antenna such as whether the antenna for transmission and reception is on the outer peripheral side or the inner peripheral side of the antenna array. Antennas that are surrounded by other antennas are strongly affected by the bleeding of radio waves from the surrounding antennas, and the antennas at the periphery are less affected by the bleeding of radio waves from the surrounding antennas. For example, it is considered that such a difference in influence appears as a difference in received signals.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a abnormal tissue detection device that can improve the receiving efficiency of the impulse signal of the microwave.

In order to achieve the above object, an abnormal tissue detection device according to a first aspect of the present invention includes an antenna array having an array of a plurality of antennas for transmitting and receiving a microwave impulse signal, and the plurality of antennas. It consists of one antenna that transmits the impulse signal of the microwave and another antenna that receives the impulse signal transmitted from the one antenna, and the relative distance between the one antenna and the other antenna is the same. changing a selection unit for selecting a combination of antennas for transmission and reception Do that, the controls the selection unit, the relative distance of the between one antenna and the other antenna is a combination antenna for the transceiver same preparative ing However, the microwave impulse signal is transmitted and received, and the signal processing for the microwave impulse signal received by the other antenna is performed. And a signal processing unit that performs, by the array of adjuster or antenna, the impulse signal of the microwave in combination antenna for transmitting and receiving the relative distance of the between one antenna and the other antenna are the same The reception environment is the same .

In this case, in the antenna array, a plurality of dummy antennas having impedances equivalent to the antennas are provided as the adjustment unit, and the plurality of dummy antennas are arranged around the plurality of antennas. It is good as well.

  In the antenna array, the antennas may be arranged at a predetermined distance.

  In this case, in the antenna array, the antennas may be arranged in a staggered pattern.

In the antenna array, an absorber that absorbs microwaves may be inserted between the antennas as the adjustment unit .

In this case, an impedance matching layer is provided between the antenna array and the living body,
The effective dielectric constant of the impedance matching layer takes a value between skin tissue and adipose tissue,
The thickness of the impedance matching layer may be smaller than a value obtained by multiplying the width of the impulse signal by an effective phase velocity and larger than a value obtained by multiplying the effective phase velocity by half.

In addition, a microstrip transmission line having an impedance of a predetermined value or more may be provided as the adjustment unit as a line for transmitting transmission / reception signals between the antennas and the selection unit.

The combination of the antenna is also of two pairs of transmit and receive antennas to combine the relative distance between the antennas, the signal processing unit, the impulse signal transmitted from the first set of the one antenna first A signal obtained by receiving the impulse signal transmitted from the second set of transmission antennas by the other antenna of the second set is subtracted from a signal obtained by receiving by the other antenna of the first set. It's good.

Further, the signal processing unit, for all combinations of antenna for transmitting and receiving the relative distance that Do the same with the other antenna and the one antenna, a plurality of acquired by the antenna array system of the microwave An average signal pattern of the impulse signal is calculated as a reference signal, and the abnormal tissue in the living body is calculated based on a difference between the reference signal and the impulse signal of the microwave received by each antenna of the antenna array of the antenna array device. May be detected.

  According to the present invention, in the combination of an antenna for transmission and reception in which the relative distance between one antenna that transmits a microwave impulse signal and the other antenna that receives the impulse signal is the same, the reception environment of the microwave impulse signal Are formed to be the same. Thereby, since the received signal in each antenna can be made the same, the abnormal tissue in the living body can be accurately detected based on the plurality of received signals received. As a result, the reception efficiency of the microwave impulse signal can be improved.

It is a figure for demonstrating the method of detecting a cancer tissue. 1 is a perspective view of a cancer detection device according to Embodiment 1 of the present invention. It is a schematic diagram which shows the internal structure of the cancer detection apparatus of FIG. It is a figure which shows the arrangement | sequence of each antenna in the antenna array of FIG. It is a figure which shows a mode that the antenna array of FIG. 3 was set to the biological body. It is a graph which shows the frequency characteristic of a scattering parameter. It is a graph which shows the frequency characteristic of a scattering parameter. It is a figure which shows the internal structure of the cancer detection apparatus with which the dielectric film is 2 layer structure. It is a figure which shows an example of the frequency characteristic of the scattering parameter in case a dielectric film is 2 layer structure. It is a figure which shows an example of the frequency characteristic of the scattering parameter in case a dielectric film is 2 layer structure. It is a graph which shows an example of the received signal received with the combination of several antennas. It is a figure which shows the matrix coordinate of an antenna array. FIG. 11A is a graph showing a signal received by the receiving antenna. FIG. 11B is a graph showing a differential signal of signals received by the receiving antenna. FIG. 12 (A) is a diagram showing a configuration of a cancer detection apparatus according to Embodiment 3 of the present invention. FIG. 12B is a diagram for explaining a detection method by the cancer detection apparatus. It is a figure which shows the arrangement | sequence of each antenna in the antenna array of the cancer detection apparatus which concerns on Embodiment 4 of this invention. It is a graph which shows an example of the received signal received with the combination of several antennas. It is a figure which shows the arrangement | sequence of each antenna in the antenna array of the cancer detection apparatus which concerns on Embodiment 5 of this invention. It is a circuit diagram which connects the antenna of the cancer detection apparatus which concerns on Embodiment 6 of this invention, and the switch connected to the antenna. It is sectional drawing of the main body of the cancer detection apparatus which concerns on Embodiment 7 of this invention. It is a flowchart of the process of the signal processing part of the cancer detection apparatus which concerns on Embodiment 8 of this invention. It is a figure for demonstrating the positional relationship of the combination of an antenna and abnormal tissue. FIG. 20A and FIG. 20B are diagrams for explaining another method for creating a reference signal for detecting breast cancer in actual clinical practice. FIG. 21A and FIG. 21B are graphs for explaining another method of creating a reference signal for detecting breast cancer in actual clinical practice. It is a graph which shows an example of the received signal in the combination from which the antenna differs in the conventional abnormal tissue detection apparatus.

  Hereinafter, an antenna array apparatus and an abnormal tissue detection apparatus according to embodiments of the present invention will be described in detail with reference to the drawings, taking a breast cancer sensor for detecting breast cancer as an example.

(Embodiment 1)
Embodiment 1 of the present invention will be described.

  First, a method for detecting cancer tissue will be described with reference to FIG.

First, as schematically shown in FIG. 1, a plurality of antennas A _{1 to} A ₄ are arranged at regular intervals on the surface of a living body.

Subsequently, it emits an impulse signal of the microwave from the antenna A _1. Part of the emitted microwave propagates into the living body. In general, cancer tissue CA is known to have a dielectric constant about 5 to 10 times higher than that of normal living tissue. Therefore, when the cancer tissue CA exists, the microwave is reflected at the interface of the regions having different dielectric constants, that is, the surface of the cancer tissue CA, and is received by the antennas A _{2 to} A ₄ .

Here, if the time from when the microwave impulse signal is emitted until the antenna A ₂ receives the reflected wave is T ₁₂ [s], T ₁₂ · c (c: speed of light in the living body) is This is the stroke distance of the microwave impulse signal.

Accordingly, the cancer tissue CA is the antenna _{A 1} and _{A 2} is the focus, the sum of the distance from the antenna _{A 1} and _{A 2} will be located on an ellipse _{E 12} as a _{T 12} · c.

The same processing is performed on the microwaves received by the antennas A _{3 to} A ₄ , and the position of the cancer tissue CA can be obtained by obtaining the intersections of the plurality of ellipses E _{12 to} E ₁₄ .

Furthermore, an antenna for transmitting Te switched to _{A 2,} radiating microwaves from an antenna _{A 2,} which was received by the antenna _{A 1, A 3, A 4} , the same processing. Thereafter, while switching the transmitting antenna to A ₃ and A ₄ in sequence, the microwave is radiated, the reflected wave is received by the other antenna, and the same processing is performed, whereby the position of the cancer tissue CA is specified more accurately. It becomes possible.

Hereinafter, each antenna A _k, the selected antenna for transmission and A _m, a selected antenna for the reception and A _n.

  In the above-described example, the description has been given in two dimensions for easy understanding, but in reality, the above-described processing is performed in three dimensions.

  Next, the cancer detection apparatus 10 that determines the presence and position of cancer tissue using such a method will be described.

  As shown in FIG. 2, the cancer detection device 10 includes a main body 11 and a display device 12.

  As shown in FIG. 3, an antenna array 13, a switch circuit 14, and a signal processing unit 15 are stacked on the main body 11.

In the antenna array 13, a plurality of antennas A _k (k = 1 to 16) are arranged in a 4 × 4 matrix as shown in FIG. FIG. 4 shows the antenna array 13 viewed from the living body side. The antennas A _{1 to} A _{16 of the} antenna array 13 transmit and receive microwave impulse signals.

Antenna array 13, one antenna A _m and another antenna A _n and antenna combination (A _{m, A n)} for transmission and reception relative distance is equal microwave impulse signal of the reception environment in the same with It is formed to become.

More specifically, the antenna array 13 further includes a plurality of dummy antennas B _{1 to} B ₂₀ . The plurality of dummy antennas B _{1 to} B ₂₀ are equivalent in impedance to the antennas A _{1 to} A ₁₆ . For example, if the impedance of the entire circuit including the CMOS circuits of the antennas A _{1 to} A ₁₆ and the switch circuit 14 connected to the antennas is 50Ω, the impedance of the entire circuit including the antennas B _{1 to} B ₂₀ is also 50Ω. Set to

The plurality of dummy antennas B _{1 to} B ₂₀ are arranged so as to surround the plurality of antennas A _{1 to} A ₁₆ . With the dummy antennas B _{1 to} B ₂₀ , the antennas A _{1 to} A ₄ , A ₅ , A ₈ , A ₉ , A ₁₂ , A _{13 to} A ₁₆ are also connected to the antennas A ₆ , A ₇ , A ₁₀ , A ₁₁ and the like. Similarly, the four sides are surrounded by the antenna.

Returning to FIG. 3, the switch circuit 14 as a selection unit is a semiconductor switch circuit using a semiconductor switching element. The switch circuit 14 is provided between the antenna array 13 and the signal processing unit 15. The switch circuit 14 switches antennas (A _m , A _n ) that perform transmission and reception under the control of the signal processing unit 15. More specifically, the switch circuit 14, receives the one antenna A _m which transmits an impulse signal of the microwave of the plurality of antennas A ₁ to A _16, an impulse signal transmitted from one antenna A _m the combination of an antenna for transmitting and receiving comprising a further antenna _{a n} to _(a m, _{a n)} to select a.

  The signal processing unit 15 is a computer. The computer has a CPU (Central Processing Unit) and a memory. The function of the signal processing unit 15 is realized by the CPU executing a program stored in the memory.

The signal processing unit 15 performs signal processing for determining the presence or absence of cancer tissue CA in the living body based on the received microwave electrical signal. The signal processing unit 15 outputs a microwave transmission signal to the antenna array 13 and inputs the microwave reception signal from the antenna array 13. Further, the signal processing unit 15 outputs a control signal for controlling the switch circuit 14 to the switch circuit 14. Transmission signal of the microwave, and input and output of the received signal, by the output of the control signal, the signal processing unit 15 outputs the microwave electric signal sent from either antenna A _m of the antenna array 13, inputting the electrical signals of the received microwave with either antenna a _n of the antenna array 13.

The signal processing unit 15 controls the switch circuit 14, while changing the combination of the antenna A _k for transmission and reception, and transmitting and receiving an impulse signal of the microwave, for microwave impulse signal received by the other antenna A _n Perform signal processing.

  FIG. 5A shows a state where the antenna array 13 is set on the living body 30. As shown in FIG. 5A, in the cancer detection device 10, a dielectric film 20 as an impedance matching layer is inserted between the antenna array 13 and the living body 30. The antenna array 13 is in contact with the fat layer 32 of the living body 30 through the dielectric film 20 and the skin 31 of the living body 30.

From transmission line theory, dielectric layer 1 with dielectric constant and intrinsic impedance ε ₁ and η ₁ respectively, dielectric layer 2 with dielectric constant and intrinsic impedance ε ₂ and η ₂ respectively, dielectric constant and intrinsic impedance respectively When there is a multilayer structure composed of the dielectric layer ₃ having ε ₃ and η ₃ , the effective radio wave reflection coefficient is λ ₂ and the propagation constant is β ₂ in the dielectric layer 2 of thickness d. Γ _eff is expressed by the following equation.

Here, when d = λ _2/4,
When,

Thus, reflection is minimum and transmission is maximum. At this time
Because

Thus, when the intrinsic impedances of the dielectric layer 3 and the dielectric layer 1 are equal, the reflection disappears.

Here, two examples 1 and 2 are considered. In Example 1, the dielectric layer 1, the dielectric layer 2, and the dielectric layer 3 are an antenna substrate (ε ₁ = 10), an impedance matching layer, and skin (ε ₃ = 28), respectively. When the frequency is 10 GHz and the wavelength is 3 cm, the wavelength λ ₂ in the dielectric layer ₂ is 3 cm / √ (ε ₂ ). The dielectric constant of the impedance matching layer is
Thus, ε ₂ = 19 is obtained.

In Example 2, the dielectric layer 1, the dielectric layer 2, and the dielectric layer 3 are an impedance matching layer (e ₁ ), skin (e ₂ = 28), and fat (e ₃ = 5.2), respectively. When the frequency is 10 GHz and the wavelength is 3 cm, the wavelength λ ₂ in the dielectric layer ₂ is 3 cm / √ (ε ₂ ). The dielectric constant of the skin is
Thus, ε ₁ = 150 is obtained.

Thus, the value varies depending on the structure of the dielectric. The result of obtaining the optimum value using the three-dimensional electromagnetic field simulation is shown in FIG. 5B. FIG. 5B shows the frequency characteristics of the scattering parameters (reflection coefficient S ₁₁ and transmission coefficient S ₂₁ ), the upper curve shows the reflection coefficient S ₁₁ , and the lower curve shows the transmission coefficient S ₂₁ . Show. Depending on the dielectric constant of the dielectric film 20, the frequency characteristic of the scattering parameter (reflection coefficient S ₁₁ and transmission coefficient S ₂₁₎ varies greatly. Thus, by inserting the dielectric film 20 between the antenna and the skin, S ₁₁ can be reduced to −10 dB or less. This indicates that the intensity of the radio wave reflected at the interface of the dielectric film 20 can be suppressed to -10 dB or less, that is, the maximum / minimum ratio of standing waves caused by reflection can be suppressed to 2 or less. On the other hand, the transmission coefficient S ₂₁ of the high-frequency side, radio waves indicates the degree to transmit dielectric film 20, since S ₂₁ decreases when increasing the dielectric, over a band wider scattering parameter S ₁₁ to minimize reflections, The optimum dielectric constant of the impedance matching layer that becomes −10 dB or less is ε ₂ = 20. At this time, the thickness of the impedance matching layer is 1 mm. However, at this time, the dielectric constant of the skin is calculated with ε ₂ = 35.

From this, it can be seen that the effective dielectric constant of the dielectric film 20 takes a value between the skin tissue and the fat tissue. This improves the transmission efficiency of the microwave impulse signal emitted from the antenna A _m. If the dielectric constant of the skin is about 28 and the dielectric constant of the fat tissue is 5.2, the effective dielectric constant of the dielectric film 20 can be 10 to 20, for example.

In addition, the thickness of the impedance matching layer, that is, the dielectric film 20 allows a scattered wave from the tumor target to arrive after a direct wave is received, and eliminates interference between received signals. For this purpose, assuming that the thickness of the impedance matching layer is t, the distance d between the transmitting and receiving antennas, the pulse width is T, and the effective phase velocity is ν _eff , from Pythagorean theorem,

T is satisfied. That is, it is appropriate that the thickness t of the impedance matching layer is larger than ½ of the value obtained by multiplying the width of the impulse signal by the effective phase velocity and smaller than twice. If it is too large, the measurement time becomes longer, which is not appropriate.

As an example, for example, if T = 100 ps, the speed of light is c = 3 × 10 ⁸ m / s, the dielectric constant of the dielectric film 20 is 28, and the effective phase velocity is 5.7 × 10 ⁷ m / s, The thickness t of the impedance matching layer is suitably in the range of 3 to 6 mm.

FIG. 6 shows the frequency characteristics of the scattering parameters (reflection coefficient S ₁₁ and transmission coefficient S ₂₁ ). In the graph of FIG. 6, the upper curve shows the reflection coefficient S _11, the lower curve indicates the transmission coefficient S _21. As shown in FIG. 6, the frequency characteristics of the scattering parameters (reflection coefficient S ₁₁ and transmission coefficient S ₂₁ ) vary greatly depending on the thickness of the dielectric film 20.

S _11, since a parameter indicating the degree of reflection, it is as small as possible. As a guide, a standing wave ratio of 2 or less, which is the magnitude of a standing wave that occurs due to reflection, is used as a reference. If this is displayed in decibels, it will be -10 dB, and if it is less than this, it can be said that reflection is small. From this point of view, when viewing the upper data in FIG. 6, when d = 1 mm, it is −10 dB or less in all the bands of 3 to 10 GHz.

On the other hand, the curve of the bottom of FIG. 6 represents the transmission coefficient S _21, when the film thickness increases, S ₂₁ is increased. This indicates that the attenuation is small and the signal is easily transmitted, and although it is preferable, since the above-described S ₁₁ is deteriorated and almost no signal is transmitted, a thick film cannot be adopted. Also from this, it is determined that d = 1 mm is optimal.

Thus, the dielectric film 20 transmission coefficient S ₂₁ of the high-frequency side by inserting between the antenna and the skin but has been improved, the thickness d of the dielectric film 20 is equal to or greater than 5 mm, for most frequency ranges You can see that it is reflected.

As shown in FIG. 7, the dielectric film 20 may have a two-layer structure of a dielectric film 20A and a dielectric film 20B. When the dielectric film has two layers, the frequency characteristics of the scattering parameters (reflection coefficient S ₁₁ and transmission coefficient S ₂₁ ) are further improved.

  Here, as Example 1, a case where an impedance matching layer is formed using a dielectric film 20A having a dielectric constant of 10.2 and a dielectric film 20B having a dielectric constant of 38 is considered. In this case, since the dielectric constant of the antenna array 13 is 10.2, the dielectric constant of the dielectric film 20A is adjusted to this. Moreover, since the dielectric constant of the skin 31 is 28, the dielectric constant of 38 of the substance close to it is selected. At this time, the matching condition is found by optimizing the film thickness.

As shown in FIG. 8A, when the film thickness of the dielectric film 20A is 1 mm and the film thickness of the dielectric film 20B is 4 mm, a condition with less reflection is obtained in which S ₁₁ is −10 dB or less in the band of 3.9 to ₁₁ GHz. be able to. At this time, the transmission coefficient S ₂₁ also secures a band.

By making the impedance matching layer into two layers, the degree of freedom of optimization can be improved, and the structure at that time has a dielectric constant ε _A on the side in contact with the antenna substrate, a value close to the antenna substrate, on the side in contact with the skin As the dielectric constant ε _B , a dielectric constant close to that of the skin is selected. The average value at this time is

Thus, the effective dielectric constant of the impedance matching layer is between the skin and fat values.

As Example 2, FIG. 8B shows a simulation result in the case where the total film thickness of the two-layer structure is 10 mm. When the film thickness of the dielectric film 20A is 1 mm and the film thickness of the dielectric film 20B is 9 mm, it is possible to obtain a low reflection condition where S ₁₁ is −10 dB or less in the band of 4 to ₁₁ GHz.

FIG. 9 shows an example of a received signal received by a combination of several antennas. This graph, the antenna _{A 1} and the antenna _{A m} for transmission, the received signal Tx1_Rx5 the case of the antenna _{A n} for receiving an antenna _{A 5,} the antenna _{A m} for transmission antenna _{A 7,} the antenna A ₁₁ and the received signal Tx7_Rx11 the case of the antenna _{a n} for receiving and an antenna _{a 11} and the antenna _{a m} for transmission, the received signal Tx11_Rx15 the case of the antenna _{a n} for receiving an antenna _{a 15,} but shows Has been. As shown in FIG. 9, the received signal Tx1_Rx5, the received signal Tx7_Rx11, and the received signal Tx11_Rx15 have the same signal waveforms because of the structural symmetry.

As described above in detail, according to the present embodiment, for transmission and reception relative distance between the other antenna A _n for receiving an antenna A _m and the impulse signal for transmitting an impulse signal of the microwave is the same In the antenna combination (A _m , A _n ), the microwave impulse signal reception environment is the same. Thus, as shown in FIG. 9, since the received signal at each antenna A _n can be the same, based on the received plurality of received signals, possible to accurately detect cancer tissue CA in vivo Can do. As a result, the reception efficiency of the microwave impulse signal can be improved.

(Embodiment 2)
Next, a second embodiment of the present invention will be described.

In the present embodiment, the arrangement of each antenna Ak _and dummy antennas B _{1 to} B _{20 in} the antenna array 13 is the same as that in the first embodiment.

In this embodiment, the combination of transmission and reception antennas is a combination of two sets of transmission antennas and reception antennas having the same relative distance between the antennas. For example, the matrix coordinates of the antenna A _k, as shown in FIG. 10, and (1,1) to (4,4).

  Here, for a plurality of antennas arranged in a matrix of rows and columns at regular intervals on the surface of the living body, for example, a combination of transmission and reception antennas corresponding to matrix coordinates (1, 1) and (3, 1) is Assume that a pair of transmission and reception antennas corresponding to matrix coordinates (1, 2) and (3, 2) is a second group.

The signal processing unit 15 is obtained by receiving the impulse signal transmitted from the first set of transmission antennas (A ₁ (1, 1)) by the first set of reception antennas (A ₉ (3, 1)). The signal obtained by receiving the impulse signal transmitted from the second set of transmission antennas (A ₂ (1,2)) by the second set of reception antennas (A ₁₀ (3,2)) is subtracted from the signal. To do.

As shown in FIG. 11A, the direct wave from the transmitting antenna (A ₁ (1,1)) to the receiving antenna (A ₉ (3,1)) is transmitted to the transmitting antenna (A ₂ (1,2)). To the receiving antenna (A ₁₀ (3, 2)). For this reason, the signal obtained by subtraction is a signal (see FIG. 11B) consisting only of components scattered by the tumor target. The signal processing unit 15 performs confocal image processing using this to calculate the target position.

(Embodiment 3)
Next, a third embodiment of the present invention will be described.

  FIG. 12A shows the internal structure of the main body 11 of the cancer detection apparatus 10 according to the second embodiment. As shown in FIG. 12A, the cancer detection device 10 further includes an acceleration sensor 17. A plane on which the antenna array 13 is formed is an XY plane.

As shown in FIG. 12 (B), in the cancer detection apparatus 10, detection is performed a plurality of times by contacting the body 11 on the skin while shifting the main body 11 by ΔX and ΔY in the X-axis direction and the Y-axis direction. As a result, it is possible to increase the resolution by apparently increasing the number of draft difficulties. The acceleration sensor 17 is used as a sensor for detecting the position of each antenna _Ak . The signal processing unit 15, the output of the acceleration sensor 17, calculates the position of each antenna A _k at the time of detection. In this way, the number of measurement points can be substantially increased by changing the positional relationship between the target TA and each antenna for each detection. Thereby, detection accuracy can be improved.

In the present embodiment, not only the acceleration sensor 17 but also any sensor can be used as long as it is a sensor for detecting the position of each antenna _Ak .

(Embodiment 4)
Next, a fourth embodiment of the present invention will be described.

In this embodiment, the sequence of each antenna A _k of the antenna array 13 is different from the first embodiment. The antenna array 13 is not provided with dummy antennas B _{1 to} B ₂₀ .

FIG. 13 shows an arrangement of antennas A _k (k = 1 to 16) in the antenna array 13. As shown in FIG. 13, in this antenna array 13, the antennas _Ak are spaced apart by a predetermined distance. Interval of each antenna _{A k} is vertical is amm (for example, about 10 mm), although horizontal is b mm (for example, about 6 mm), the present invention is not limited to this interval.

More specifically, in the antenna array 13, each antenna A _k are arranged in staggered. Thus, further increasing spacing of each antenna A _k of the antenna array 13, it is possible to minimize the effects of radio waves oozing from adjacent antenna A _k.

FIG. 14 shows an example of a received signal received by a combination of several antennas. In this graph, the antenna A ₁ and the transmitting antenna, the received signal Tx1_Rx5 in the case where the antenna A ₅ and the receiving antenna, the antenna A ₇ and the transmitting antenna, receiving in the case where the antenna A ₁₁ and the receiving antenna a signal Tx7_Rx11, the antenna _{a 11} and the transmitting antenna, the received signal Tx11_Rx15 in the case where the antenna _{a 15} and the receiving antenna are the shown. As shown in FIG. 14, the received signal Tx1_Rx5, the received signal Tx7_Rx11, and the received signal Tx11_Rx15 are in good agreement.

Thus, also in this embodiment, one which transmits an impulse signal of a microwave antenna A _m and combinations of other relative distance between the antenna A _n is for the same transmitting and receiving antenna for receiving an impulse signal (A _m, A in _n), by separating the adjacent antenna a _k, the reception environment of the impulse signal of the microwave is formed to be the same. Thus, as shown in FIG. 8, since the received signal at each antenna A _k in the absence of cancer tissue CA may be the same, from the received signal, accurately cancer tissue CA in vivo 30 Can be detected. As a result, the reception efficiency of the microwave impulse signal can be improved.

(Embodiment 5)
Next, a fifth embodiment of the present invention will be described.

In this embodiment, the sequence of each antenna A _k of the antenna array 13 is different from the first embodiment. The antenna array 13 is not provided with dummy antennas B _{1 to} B ₂₀ .

As shown in FIG. 15, in the antenna array 13, the absorber 40 is inserted between the antennas A _{1 to} A ₁₆ . As such an absorber 40, for example, a ferrite thin film can be used. By this way, the radio wave exudation of from each antenna A _k is absorbed by the absorber 40, the effect on the received signal received by each antenna can be minimized.

Thus, also in this embodiment, one which transmits an impulse signal of a microwave antenna A _m and combinations of other antennas An of the relative distances for the same transmitting and receiving antenna for receiving an impulse signal (A _m, A _n in), by inserting an absorber 40 between adjacent antenna a _k, the reception environment of the impulse signal of the microwave is formed to be the same. Thus, it is possible to equalize the received signal at each antenna A _k in the absence of cancer tissue CA, can be from the received signal, to accurately detect cancerous tissue CA in vivo 30. As a result, the reception efficiency of the microwave impulse signal can be improved.

(Embodiment 6)
Next, a sixth embodiment of the present invention will be described.

FIG. 16 shows a circuit configuration for connecting the antenna A _k and the switch 70 of the switch circuit 14 connected to the antenna A _k . As shown in FIG. 16, a transmission line 60 for transmitting a signal between each antenna _Ak and the switch 70 is provided. The transmission line 60 has an impedance of a predetermined value or more. The transmission line 60 has a sufficiently high impedance. Thereby, it can be considered that the impedance in the antenna Ak is substantially constant _regardless of whether the switch 70 is on or off.

Thus, also in this embodiment, one which transmits an impulse signal of a microwave antenna A _m and combinations of other relative distance between the antenna A _n is for the same transmitting and receiving antenna for receiving an impulse signal (A _m, A in _n), between the antenna a _k and the switch 70 are connected by a high impedance transmission line 60, by stabilizing the impedance of the antenna a _k, the reception environment of the impulse signal of the microwave by each antenna a _k It is formed to be the same. Thus, it is possible to equalize the received signal at each antenna A _k in the absence of cancer tissue CA, can be from the received signal, to accurately detect cancerous tissue CA in vivo 30. As a result, the reception efficiency of the microwave impulse signal can be improved.

(Embodiment 7)
Next, a seventh embodiment of the present invention will be described.

  FIG. 17 shows a cross section of the main body 11 according to the present embodiment. As shown in FIG. 17, in the present embodiment, an absorber film 16 that covers the antenna array 13 is further formed between the antenna array 13 and the switch circuit 14. The absorber film 16 is, for example, ferrite.

The absorber film 16 can prevent the microwaves emitted from the antenna _Ak from being mixed into the signal flowing through the switch circuit 14.

(Embodiment 8)
Next, an eighth embodiment of the present invention will be described.

  In the present embodiment, a method for detecting a cancer tissue CA of a living body in the signal processing unit 15 will be described.

FIG. 18 shows a flow of processing of the signal processing unit 15. As shown in FIG. 18, first, the signal processing unit 15 transmits / receives microwave impulse signals with all combinations (A _m , A _n ) of transmission / reception antennas having the same relative distance, and acquires reception signals, respectively. (Step S1).

  Subsequently, the signal processing unit 15 calculates an average signal pattern of the acquired plurality of received signals as a reference signal (step S2).

As shown in FIG. 19, combinations (A _m , A _n ) of transmission / reception antennas having the same relative distance (A ₁ , A ₅ ), (A ₆ , A ₁₀ ), (A ₅ , A ₉ ), etc. And the combination of the antennas A _k having the same relative distance (A _m , A _n ), the pattern of the received signal is the same if there is no cancer tissue CA.

In addition, the living body 30 may include a cancer tissue CA that changes a received signal. When cancer tissue CA is present, the signal pattern of the received signal received by each antenna _Ak changes. How the received signal received by each antenna _Ak varies depending on the cancer tissue CA depends on the positional relationship between the antenna _Ak and the cancer tissue CA. For example, when the antenna A ₅ is for transmission and the antenna A ₉ is for reception, the appearance position of the component of the cancer tissue CA in the received signal, and when the antenna A ₆ is for transmission and the antenna A ₁₀ is for reception The appearance positions of the components of the cancer tissue CA in the received signal are different from each other.

Thus, since the appearance positions of the components of the cancer tissue CA in the reception signals received by the respective antennas A _k are different from each other, if the average of the reception signals received by the respective antennas A _{k is taken} , CA components can be suppressed. In the present embodiment, the component of the cancer tissue CA is detected using the received signal actually measured using the living body 30 as a reference signal.

Returning to FIG. 18, subsequently, the signal processing unit 15 detects the cancer tissue CA in the living body 30 based on the difference between the reference signal and the impulse signal of the microwave received by each antenna _Ak of the antenna array 13. (Step S3). After step S3 ends, the signal processing unit 15 ends the process.

Thus, according to this embodiment, the basis of the average pattern of a received signal relative distance is received respectively by the same combination of the antenna A _k. In this way, regardless of the presence or absence of the cancer tissue CA in the living body 30, there is no cancer tissue CA observed in the living body 30, and the signal pattern of the received signal along the characteristics of the living body 30 is set. Can be substantially obtained. As a result, cancer tissue CA can be detected with high accuracy.

(Embodiment 9)
Next, a ninth embodiment of the present invention will be described.

With reference to FIGS. 20 and 21, another reference signal generation method for detecting breast cancer in actual clinical practice will be described. In FIG. 19 or FIG. 10, as a combination of transmitting and receiving antennas having the same relative distance, the relative distance is (A ₅ , A ₉ ), (A ₆ , A ₁₀ ), (A ₇ , A ₁₁ ), and the like. It is assumed that there is a combination (A _m , A _n ) of the same antenna A _k . For example, in the combination of (A ₅ , A ₉ ) and (A ₆ , A ₁₀ ), as shown in FIGS. 20 (A) and 20 (B), one combination has the breast cancer target in the middle, When one of the combinations is separated by d _m = 11.6 mm, the direct wave disappears because the difference between the received waveforms (see FIG. 21A) is equal because of the structural symmetry. Therefore, only the signal delayed by being scattered by the breast cancer target remains as a differential signal (see FIG. 21B) due to the difference in positional relationship. As a result, only the scattered signal can be created by the difference between the two sets of received signals without averaging. In this method, since the reference signal is formed by a difference instead of an average, common noise can be suppressed and a signal-to-noise ratio can be improved. By performing a combination of two sets of four transmission / reception antennas on the antenna array and using the difference signal to perform a confocal image, imaging can be performed with a relatively simple algorithm.

  In each of the above embodiments, the number of antennas is 16. However, the present invention is not limited to this, and the number of antennas may be arbitrary.

  Various embodiments and modifications can be made to the present invention without departing from the broad spirit and scope of the present invention. The above-described embodiments are for explaining the present invention and do not limit the scope of the present invention. In other words, the scope of the present invention is shown not by the embodiments but by the claims. Various modifications within the scope of the claims and within the scope of the equivalent invention are considered to be within the scope of the present invention.

  The present invention is suitable for an antenna array device used for a breast cancer sensor or the like. The present invention is not limited to breast cancer sensors, and can be applied to detection and discrimination of regions with different dielectric constants in the living body such as other tumors.

DESCRIPTION OF SYMBOLS 10 Cancer detection apparatus 11 Main body 12 Display apparatus 13 Antenna array 14 Switch circuit 15 Signal processing part 16 Absorber film | membrane 17 Acceleration sensor 20, 20A, 20B Dielectric film | membrane 30 Living body 31 Skin 32 Fat layer 40 Absorber 60 Transmission line 70 Switch

Claims (9)

An antenna array having an array of a plurality of antennas for transmitting and receiving microwave impulse signals;
The antenna includes one antenna that transmits the microwave impulse signal and another antenna that receives the impulse signal transmitted from the one antenna. The one antenna and the other antenna a selection unit relative distance between the antenna selecting a combination of antennas for transmission and reception that Do the same,
Wherein by controlling the selection unit, while changing a combination of the antenna for the transmission and reception relative distance equal bets ing said as one of the antenna and the other antenna transmits and receives an impulse signal of the microwave, of the other A signal processing unit that performs signal processing on the microwave impulse signal received by the antenna;
Equipped with a,
Depending on the arrangement of the adjustment unit or antenna, the reception environment for the microwave impulse signal is the same for the combination of transmitting and receiving antennas having the same relative distance between the one antenna and the other antenna. ing,
Abnormal tissue detection device. In the antenna array,
A plurality of dummy antennas having an impedance equivalent to each of the antennas is provided as the adjustment unit,
The plurality of dummy antennas are arranged around the plurality of antennas,
The abnormal tissue detection apparatus according to claim 1. In the antenna array,
The antennas are arranged at a predetermined distance apart from each other.
The abnormal tissue detection apparatus according to claim 1. In the antenna array,
The antennas are arranged in a staggered pattern,
The abnormal tissue detection device according to claim 3. In the antenna array,
An absorber that absorbs microwaves is inserted as the adjustment unit between the antennas.
The abnormal tissue detection apparatus according to claim 1. Between the antenna array and the living body, there is an impedance matching layer,
The effective dielectric constant of the impedance matching layer takes a value between skin tissue and adipose tissue,
A thickness of the impedance matching layer is smaller than a value obtained by multiplying the width of the impulse signal by an effective phase velocity, and larger than a value obtained by multiplying a half of the effective phase velocity;
The abnormal tissue detection apparatus according to any one of claims 1 to 5. As a line for transmitting a signal for transmission and reception between each antenna and the selection unit, a microstrip transmission line having an impedance of a predetermined value or more is provided as the adjustment unit.
The abnormal tissue detection apparatus according to any one of claims 1 to 6. The combination of the antenna is also of two pairs of transmit and receive antennas to combine the relative distance between the antennas, the signal processing unit, the impulse signal transmitted from the first set of the one antenna first A signal obtained by receiving the impulse signal transmitted from the second set of transmission antennas by the other antenna of the second set is subtracted from a signal obtained by receiving by the other antenna of the first set. ,
The abnormal tissue detection apparatus according to any one of claims 1 to 7. The signal processing unit
For all combinations of antenna for transmitting and receiving the relative distance that Do the same with the one antenna and the other antenna, the reference average signal pattern of a plurality of impulse signal of the microwave obtained by the antenna array system As a signal,
Detecting abnormal tissue in the living body based on the difference between the reference signal and the impulse signal of the microwave received by each antenna of the antenna array of the antenna array device;
The abnormal tissue detection apparatus according to any one of claims 1 to 8.