CN103799985A - Microwave CT device - Google Patents

Abstract

The invention discloses a microwave CT device. A certain part of a measured object is scanned according to the level with a certain thickness by microwave; a detector receives and detects a permeability value mu and an attenuation value alpha of the microwave passing through the level of an organism; an analogue/digital converter converts the permeability value mu and the attenuation value alpha into numbers, inputs the numbers into a computer system, and performs storage computation and processing on the collected information data obtained by scanning, that is the selected level is divided into a plurality of voxels with the same volume; the dielectric constant epsilon and the conductivity rho of each voxel obtained by calculating are arranged into a matrix, and are stored in a magnetic disk or an optical disk; each number in the number matrix is converted into small blocks with different gray levels from black to white, namely pixels, by a comparison enhancer and a digital/analogue converter, and the blocks are arranged in a matrix manner, namely a number matrix; a microwave CT image is formed after the number matrix is processed. According to the microwave CT device disclosed by the invention, the resolution capacity is high and the image is not damaged; the microwave CT device has high safety, low cost, easiness in popularization and high adaptability, and can be widely applied to medical clinical imaging and other fields.

Description

A kind of microwave CT device

Technical field

The present invention relates to a kind of microwave CT imaging technique, refer to especially a kind of device that can realize to the muscle in soft tissue, fat and so on permeability to microwave and the visibly different tissue of Decay Rate microwave CT low-power detection imaging.

Background technology

At present, medical and clinical imaging field is mainly X ray CT, nuclear magnetic resonance, NMR CT and ultrasound computed tomography.Although these CT have advantages of separately, have obvious shortcoming, as to human body radiation harm, it is found that and use X ray to cause patient's alopecia, skin burn, staff's visual disorder, the problem of the radiohazards such as leukemia; Can manage it expensive etc.This microwave CT device of the present invention has following advantage compared with X ray CT, nuclear magnetic resonance, NMR CT, ultrasound computed tomography: the electrical conductivity that 1, depends primarily on tissue due to the absorption of microwave, for this reason, with x-ray, CT compares, and this microwave CT has more identification ability to the muscle in soft tissue, fat and so on the visibly different tissue of electrical conductivity; 2, because the difference of the Microwave Attenuation Constant of cancerous tissue and normal structure is far longer than the poor of X-ray absorption coefficient, this microwave CT is more easily told cancerous tissue compared with X ray CT; 3,, compared with ultrasound computed tomography, because ultrasound wave decay in the many tissues of air is very large, generally can not obtain lung internal image, and the aerial decay of microwave is very little, easily obtains lung internal image; 4, its technology of microwave imaging comes from mechanics of communication, adopts low-power probe radiation, belongs to Non-ionizing radiation, has stronger damagingly unlike X ray, belongs to noninvasive imaging, has higher safety; 5,, compared with nuclear magnetic resonance, NMR, except having the safety of noninvasive imaging, it cheap, easily promotes.

Summary of the invention

Technical problem solved by the invention is to provide a kind of microwave CT device, to solve the shortcoming in above-mentioned background technology.

Technical problem solved by the invention realizes by the following technical solutions:

A kind of microwave CT device, comprises microwave tube, waveguide, μ detector, alpha detection device, gantry, A/D converter, computer system, contrast booster, D/A converter, display, photographing unit.

Sweep test is made up of microwave tube, waveguide, detector and gantry; Microwave is scanned by certain thickness aspect measured object a part, under selected scan mode (translation/rotation, rotation/rotation, rotation/fixing and spiral).Received the osmotic value μ and the pad value α that detect through the microwave of this aspect of organism by detector.Be converted to numeral through analog/digital converter again, input computer system, the information data that scanning is collected is stored computing; The processing that computer forms image is just like selected aspect is divided into the cuboid that several volumes are identical (voxel).

The DIELECTRIC CONSTANT ε that scanning gained information obtains each voxel as calculated rearranges into matrix with conductivityσ.And be stored in disk or CD.Through contrast booster and digital/analog converter, the each numeral in character matrix is transferred to by the black blockage to the white gray scale such as not, i.e. pixel, and press matrix arrangement, i.e. character matrix.After processing, form microwave CT image.Image is presented on television screen.

In the present invention, the power that microwave tube produces meets microwave CT imaging requirements and is human body firm power density.

In the present invention, described gantry can be freely flexible, and scan mode can be used translation/rotation, rotation/rotation, rotation/fixing and spiral way.

In the present invention, microwave tube generates the microwave frequency of the 8～20GHz scope that is suitable for imaging in biological tissues.

In the present invention, A/D converter adopts a ADAS1128,128 passages, 24 digit current numeral analog-digital converters (ADC).Built-in 128 low-power consumption, low noise, low input current integrator, synchronized sampling keep, have two high speeds, the high resolution A/D C of configurable sampling rate and the highest 24 bit resolutions.All ALT-CH alternate channel results are all exported on a LVDS self-clock serial line interface, can reduce external hardware.The compatible serial line interface of SPI can be realized the configuration that ADC adopts SDI to input.SDO output allows several ADC to be connected in a three-wire type bus with daisy chain form.It adopts independent current source VIO, can reduce the digital noise impact on conversion.ADAS1128 adopts the small-sized BGA encapsulation of 10mmx10mm.

In the present invention, computer system processor and infiltration coefficient, attenuation quotient, dielectric constant and the electrical conductivity of calculating each voxel.And be transformed to character matrix.

In the present invention, D/A converter adopts a AD5791 single channel, 20, without buffer voltagc output DAC, adopts the bipolar power supply power supply of the highest 33V.Positive benchmark input voltage range is 5V to VDD-2.5V, and negative reference voltage input range is VSS+2.5V to 0V.Relative accuracy maximum is ± 1LSB, guarantees job note tonality, and DNL (DNL) maximum is ± 1LSB.And adopt multi-functional three-wire type serial line interface, can be with the clock rate work of the highest 35MHz, and with standard SPI, QSPI ^tM, MICROWIRE ^tM, dsp interface standard compatibility.Its built-in electrify restoration circuit, guarantees to export 0V to and keep known output impedance state after DAC powers on, until this device is carried out once to effectively write operation.Output clamp characteristic can be placed in output defined load condition.

In the present invention, display employing model is MYC-2010; Screen size is 408x306mm; Screen diagonal is 20.1 "; Visible angle is 170 ° of H/V; Normal brightness is 300cd/m2; Original resolution is 1600*1200/1200*1600; Pixel is apart from 0.270 (H) * 0.270 (V) mm; Overall dimensions 355x460x65mm and 30bit color, meet the requirement of dicom standard GTG explicit function.

In the present invention, photographing unit adopts the imaging of CT dry laser camera scanning.Print resolution is greater than 508DPI; Output image GTG is greater than 14BIT.

In the present invention, described fixture is screw, nuts and bolt.

Beneficial effect: microwave CT device of the present invention, resolution capability is strong, and noninvasive imaging has higher safety, cheap, easily promotes strong adaptability.

Accompanying drawing explanation

Fig. 1 microwave CT device schematic diagram

Fig. 2 scans aspect voxel and pixel

Fig. 3 character matrix

The CT of Fig. 4 soma value (Hu)

Fig. 5 A/D converter ADAS1128 functional block diagram

Fig. 6 D/A converter AD5791 functional block diagram

Wherein: 1 power power-supply, 2 microwave tubes, 3 waveguides, 4 gantrys, 5 μ detectors, 6 alpha detection devices, 7 A/D converters, 8 computer systems, 9 contrast booster, 10 D/A converters, 11 display, 12 photographing units, 13 scanning aspect voxels, 14 scanning aspect pixels, 15 character matrixs, 16 pixel character matrixs, 17 CT of soma value (Hu) scales, 18 air bodies organize CT value (Hu) 19 fat-bodies to organize CT value (Hu), 20 water bodys are organized CT value (Hu), the 21 source of disease body CT of soma value (Hu) signals, 22 CT of skeleton soma values (Hu).

The specific embodiment

For technological means, creation characteristic that the present invention is realized, reach object and effect is easy to understand, below in conjunction with concrete diagram, further set forth patent of the present invention.

As shown in Figures 1 to 6, microwave CT device is fixed on gantry 4, and gantry, also can translation and rotation except rising fixation.Sweep test is made up of power power-supply 1, microwave tube 2, waveguide 3, μ detector 5, alpha detection device 6; Microwave tube generates the microwave frequency (2 π f=ω) of the 8～20GHz scope that is suitable for imaging in biological tissues.Microwave is scanned by certain thickness aspect measured object a part, and structural design makes scan mode can use translation/rotation, rotation/rotation, rotation/fixing and spiral way.When concrete employing from the easier to the more advanced.Receive and detect osmotic value μ and pad value α through the microwave of this aspect of organism by detector, according to survey need to be designed to 4,6,8,10,12,14,16,18, more than 20 detector set.In figure, drawn 4 detectors and be the schematic diagram of a group, the osmotic value μ and the pad value α that survey change through analog/digital converter again.

A/D converter 7 is completed by ADAS1128 electric current/digital converter chip, take 24 digit currents/digital converter, make high-layer CT system catch real-time mobile picture signal with high accuracy and abundant information amount, and can process a large amount of signals, the dynamic range that tool is vast and the linearity, very high sampling rate, size is little, low in energy consumption.Device provides 128 data ALT-CH alternate channels, and speed is brought up to 20kSPS from 6kSPS (hits per second), and the port number of its support is 4 times (128 to 32) of existing any integrated transducer solution.Under full-speed state, the power (4.5 milliwatts/passage) that ADAS1128 consumes is less than the half of other solution (10 milliwatts/passage).It can also provide superior overall performance specification, as selected and ultra-low noise without loss of charge, more full range.

ADAS1128 electric current/digital converter, by the digital signal converting to.Input computer system 8, stores computing by information data; The processing that computer forms image is just like selected aspect is divided into the cuboid that several volumes are identical (voxel).Solve DIELECTRIC CONSTANT ε and the conductivityσ of each voxel according to two formula below

$\mathrm{\α}=\stackrel{\‾}{\mathrm{\ω}}\sqrt{\frac{\mathrm{\μ\ϵ}}{2}(\sqrt{1+\frac{{\mathrm{\σ}}^2}{{\stackrel{\‾}{\mathrm{\ω}}}^2{\mathrm{\ϵ}}^2}}-1)}---\left(1\right)$

$\mathrm{\λ}=2\mathrm{\π}/\stackrel{\‾}{\mathrm{\ω}}\sqrt{\frac{\mathrm{\μ\ϵ}}{2}(\sqrt{1+\frac{{\mathrm{\σ}}^2}{{\stackrel{\‾}{\mathrm{\ω}}}^2{\mathrm{\ϵ}}^2}}+1)}---\left(2\right)$

The DIELECTRIC CONSTANT ε that scanning gained information obtains each voxel as calculated rearranges into character matrix with conductivityσ.Can be stored in disk or CD.Be sent to digital/analog converter 10 through contrast booster 9.

D/A converter 10 is completed by AD5791, is a single channel, 20, Voltage-output type DAC.For realizing HDR, this device must adopt high power supply voltage work, because supply voltage is higher, more easily away from making an uproar at the end.Therefore, the scope of its supply voltage VDD is 7.5V to 16.5V, and the scope of VCC is-and 7.5V is to-16.5V.The framework of this DAC is made up of the voltage mode R2R ladder network of a calibration.Can provide outstanding matching capacity and degree of stability for the film resistor that builds transducer kernel.For realizing high linearity, R2R resistor ladder is divided into two sections.14 R2R ladder networks produce low 14 (SO to S13).6 of its reinforcements of 20 digit numeric codes are used for driving independently 6 DAC, and it controls the reference voltage of low 14.A multiplication DAC main body that performance is outstanding of the common formation of these two parts.High-performance digital to analog converter (DAC) AD5791 can improve application performance out and out, and the each numeral in character matrix is transferred to by the black blockage to the white gray scale such as not, i.e. pixel, forms microwave CT image after processing.

Microwave CT image is arranged institute by the black pixel to white different gray scales by matrix according to some and is formed.The pixel size of image and number can be different.Size can be 1.0 × 1.0mm, and 0.5 × 0.5mm is not etc.; Number can be 256 × 256, and 65536, or 512 × 512,262144 not etc.Pixel is less, and number is more, and composing images is more careful, and spatial resolution is high.The gray scale of microwave CT image simultaneously, infiltration and the attenuation degree of reflection Organ and tissue to microwave.The black-and-white image of image is expressed as: shadow represents high infiltration low attenuation range, i.e. low density area, as pulmonary; Bai Ying represents the high decay area of hyposmosis, i.e. high density area, as skeleton.In the time describing the density of a certain tissue image, not only can represent by high density or low-density, and available their degree just of CT value explanation density.Unit is Hu (Hounsfield unit).Water is decided to be to 0Hu as standard CT value, the be decided to be+1000Hu of Bone CT value that in human body, density is the highest, and atmospheric density is minimum, is decided to be-1000Hu.In human body between 2000 calibration of the arrive+1000Hu of occupy-1000Hu of CT value of the different and various tissues of density.

So microwave CT image is image reconstruction.Image shows and storage system is presented at the image of machine processing as calculated, reconstruction on television screen.

More than show and described ultimate principle of the present invention and principal character and advantage of the present invention.That in above-described embodiment and description, describes just illustrates principle of the present invention; without departing from the spirit and scope of the present invention; the present invention is not restricted to the described embodiments, and the present invention also has various changes and modifications, and these changes and improvements all fall in the claimed scope of the invention.The claimed scope of the present invention is defined by appending claims and equivalent thereof.

Claims (10)

1. a microwave CT device, is characterized in that: adopt microwave property, utilize computer system and relevant the information data that scanning is collected is set stores computing, after processing, form microwave CT image.Image is presented on display screen.

2. microwave CT device according to claim 1, is characterized in that: propped up by gantry 4, gantry, also can translation and rotation except rising fixation.Make scan mode can use translation/rotation, rotation/rotation, rotation/fixing and spiral way.

3. microwave CT device according to claim 1, is characterized in that: comprise microwave tube, waveguide, μ detector, alpha detection device, gantry, A/D converter, computer system, contrast booster, D/A converter, display, photographing unit; Its model, specification, size except this patent clear and definite, can adjust arbitrarily according to the needs of development.

4. sweep test according to claim 3, is characterized in that: be fixed on gantry 4 by power power-supply 1, microwave tube 2, waveguide 3, μ detector 5, alpha detection device 6; Microwave tube generates the microwave frequency of the 8～20GHz scope that is suitable for imaging in biological tissues, receive and detect osmotic value μ and pad value α through the microwave of this aspect of organism by detector, according to the needs of surveying can have 4,6,8,10,12,14,16,18, more than 20 detector set.

5. scan according to claim 4 gained information, it is characterized in that: the DIELECTRIC CONSTANT ε that obtains as calculated each voxel rearranges into matrix with conductivityσ.And be stored in disk or CD.Through contrast booster and digital/analog converter, the each numeral in character matrix is transferred to by the black blockage to the white gray scale such as not, i.e. pixel, and press matrix arrangement, i.e. character matrix.

6. A/D converter according to claim 3, it is characterized in that: A/D converter 7 is completed by ADAS1128 electric current/digital converter chip, take 24 digit currents/digital converter, make high-layer CT system catch real-time mobile picture signal with high accuracy and abundant information amount, and can process a large amount of signals, the dynamic range that tool is vast and the linearity, very high sampling rate, size is little, low in energy consumption.Device provides 128 data ALT-CH alternate channels, speed 20kSPS, and under full-speed state, the power that ADAS1128 consumes is 4.5 milliwatts/passage.

7. computer processing system according to claim 3, is characterized in that: the processing that image is formed is just like selected aspect is divided into the cuboid that several volumes are identical (voxel).Solve DIELECTRIC CONSTANT ε and the conductivityσ of each voxel according to two formula.And the DIELECTRIC CONSTANT ε of each voxel is rearranged into character matrix with conductivityσ.Can be stored in disk or CD.Be sent to digital/analog converter 10 through contrast booster 9.

8. D/A converter according to claim 3, is characterized in that: D/A converter 10 is completed by AD5791, is single channel, 20, Voltage-output type DAC.This device adopts high power supply voltage work and solves away from making an uproar at the end.The scope that is supply voltage VDD is 7.5V to 16.5V, and the scope of VCC is-and 7.5V is to-16.5V.

According to claim 3,4,5,6,7,8, described in, it is characterized in that: microwave CT image according to some by the black pixel to white different gray scales by matrix arrange institute form.The pixel size of image can be 1.0 × 1.0mm, and 0.5 × 0.5mm is not etc.; Number can be 256 × 256, and 65536, or 512 × 512,262144 not etc.Pixel is less, and number is more, and composing images is more careful, and spatial resolution is high.The gray scale of microwave CT image simultaneously, infiltration and the attenuation degree of reflection Organ and tissue to microwave.The black-and-white image of image is expressed as: shadow represents high infiltration low attenuation range, i.e. low density area, as pulmonary; Bai Ying represents the high decay area of hyposmosis, i.e. high density area, as skeleton.In the time describing the density of a certain tissue image, not only can represent by high density or low-density, and available their degree just of CT value explanation density.2000 calibration of arrive+1000Hu of be divided into-1000Hu, unit is Hu (Hounsfield unit).Water is decided to be to 0Hu as standard CT value, be decided to be+1000Hu of Bone CT value, be decided to be-1000Hu of air.

10. display according to claim 3, is characterized in that: it is MYC-2010 that display adopts model; Screen size is 408x306mm; Screen diagonal is 20.1 "; Visible angle is 170 ° of H/V; Normal brightness is 300cd/m2; Original resolution is 1600*1200/1200*1600; Pixel is apart from 0.270 (H) * 0.270 (V) mm; Overall dimensions 355x460x65mm and 30bit color.Photographing unit adopts the imaging of CT dry laser camera scanning.Print resolution is greater than 508DPI; Output image GTG is greater than 14BIT.

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