CN103860160A - Wireless passive gastrointestinal tract pressure detection system - Google Patents

Abstract

The invention discloses a wireless passive gastrointestinal tract pressure detection system and belongs to the field of medical instruments. The system comprises an internal portion and an external portion. The external portion is composed of a reading coil soft belt sleeving the outside of a body and a portable impedance analyzer. The internal portion is a pressure sensor capsule of an LC oscillation circuit composed of an inductor and a pressure sensitive capacitor. The internal portion and the external portion achieve information transmission and detection in a wireless mode. The internal sensor capsule structure of the system is simple in structure, small in size and low in cost. Cleansing and fasting are not required before examination. A detection result can completely reflect the gastrointestinal tract pressure and the movement state under the physical state. In addition, the capsule can be used for conducting long-term gastrointestinal tract pressure detection without energy supply and provides real-time accurate data for clinical diagnosis and treatment.

Description

A kind of wireless and passive gastrointestinal stress detection system

Technical field

The present invention relates to medical instruments field, relate in particular to a kind of gastrointestinal based on LC oscillation circuit and Mutual Inductance Coupling principle and press detection system.

Background technology

Functional gastrointestinal disorder disease worldwide sickness rate is higher and have a day by day ascendant trend.In daily curative activity, approximately there is nearly 50% patient medical because of the gastrointestinal symptom such as abdominal distention, stomachache, wherein 30～40% be finally diagnosed as gastrointestinal tract dyskinesis disease.Especially in recent years, China people's living standard improves constantly, and dietary structure constantly changes, and operating pressure increases suddenly, and gastrointestinal tract dyskinesis disease is also more and more, becomes one of modal digestive system disease.

Gastrointestinal tract pressure measurement can be understood the Pressure Variation in gastrointestinal tract, and the diagnosis of digestive tract power is had to important reference value.The upper conventional method that records cavity pressure of medical treatment at present mainly contains two kinds, a kind of is pressure transducer capillary tube hydraulic pressure perfusion in vitro, another kind is intracavity micro pressure sensor tremie method, but these two kinds of methods are invasive detection methods, conduit need to be inserted to gastrointestinal tract, patient suffering is large, and compliance is poor.Before patient, need bowel relieving, fasting, therefore testing result can not reflect colonic pressure and the kinestate under physiological status completely, and the insertion of conduit makes detected person in improper physiological status, cannot obtain true and reliable data.In addition, since the fifties in last century, physiological parameter radio pill has been subject to paying attention to widely, become one of focus of current research in the world, the main point both direction of its design, one is to utilize battery for signal emission module energy supply, by the pressure signal modulate emission sensing to receiver module; Another is to utilize power conversion circuits to collect store electricity magnetic wave energy and is transmitter module energy supply.Fig. 1 a and Fig. 1 b show respectively in prior art and utilize battery for signal emission module energy supply, telemetry system illustraton of model and Pressure capsule module map by the pressure signal modulate emission sensing to receiver module, can find out that this system needs special modulate emission and receiving element, and for making the special energy supply module of its job demand (battery or power conversion circuits).

And above-mentioned physiological parameter radio pill, the first utilizes battery for signal emission module energy supply, by the pressure signal modulate emission sensing, to receiver module, its major defect is that application life depends on battery life, and battery can occupy most of volume and have leakage problem.The second utilizes power conversion circuits to collect store electricity magnetic wave energy and is transmitter module energy supply, and its major defect is that the complicated cost of Circuits System is high, and low for energy efficiency.Current most gastrointestinal stress radio pill, still in laboratory stage, only has minority radio pill to put into clinical practice.Put into the gastrointestinal of clinical practice and press radio pill, be mainly still confined to energy consumption and energy supply problem, the high testing time of cost is short, cannot meet the needs of the long-time diagnosis and treatment of gastrointestinal all-digestive tract disease.

Summary of the invention

The present invention addresses the above problem to have proposed a kind of pressure of the gastrointestinal based on LC oscillation circuit and Mutual Inductance Coupling principle detection system, can realize long gastrointestinal stress and monitor continuously.

Gastrointestinal based on LC oscillation circuit and Mutual Inductance Coupling principle disclosed by the invention is pressed detection system, and it comprises:

LC tank pressure sensor capsule in body, changes for sensing gastrointestinal stress;

The soft band of external read coil, for described body in the LC oscillation circuit of LC tank pressure sensor capsule produce Mutual Inductance Coupling signal;

Portable electric impedance analyzer, it is worn on external, for generation of swept-frequency signal to read the impedance of the soft band of described external read coil after Mutual Inductance Coupling, and after being analyzed, this impedance obtains the frequency at impedance phase minima place, set up the relation of presser sensor electric capacity pressure in this frequency and LC oscillation circuit capsule, for reflecting gastrointestinal stress monitoring result

The above-mentioned gastrointestinal based on LC oscillation circuit and Mutual Inductance Coupling principle disclosed in this invention presses detection system to have the following advantages:

A, this scheme application LC oscillation circuit and Mutual Inductance Coupling principle, without special signal emission module, simplified system structure.

B, LC tank pressure sensor capsule structure are simple, only comprise presser sensor electric capacity and inductance, and Non-energy-consumption, does not need the supply modules such as battery, and cost is low, can realize long-time continuous monitoring.

C, the simple volume of pressure transducer capsule structure are little, without lead-out wire, have realized patient's no pain, without wound, without the monitoring to gastrointestinal pressure and kinestate under the normal physiological state of bowel relieving and fasting.

The induction coupling that the Helmholtz coil principle of utilizing d, the soft band of read coil has realized in coil distance situation far away in vivo and in vitro strengthens.

E, portable electric impedance analyzer are simple small and exquisite easy to operate, are convenient to wear, and utilize frequency sweep control and data processing algorithm to realize the meticulous searching of Frequency point, shown and pressure record in real time.

Accompanying drawing explanation

Fig. 1 a and 1b are the structural representations of battery class physiological parameter telemetry system and capsule in prior art;

Fig. 2 is the structural representation of the gastrointestinal stress detection system based on LC oscillation circuit and Mutual Inductance Coupling principle in the present invention;

Fig. 3 is the fundamental diagram based on LC oscillation circuit and Mutual Inductance Coupling in the present invention.

The specific embodiment

For making the object, technical solutions and advantages of the present invention clearer, below in conjunction with specific embodiment, and with reference to accompanying drawing, the present invention is described in more detail.

The present invention is a kind of gastrointestinal stress detection system based on LC oscillation circuit and Mutual Inductance Coupling principle, and as shown in Figure 2, this system comprises and is positioned at the LC oscillation circuit capsule of body, the soft band of external read coil and portable electric impedance analyzer.Wherein, in body, LC tank pressure sensor capsule changes for sensing gastrointestinal stress; The soft band of external read coil is for LC oscillation circuit signal in Mutual Inductance Coupling body; Portable electric impedance analyzer is worn on external, produce swept-frequency signal for reading the soft band impedance of external read coil after Mutual Inductance Coupling, portable electric impedance analyzer receives, stores the frequency that obtains impedance phase minima place after this impedance treated analysis, set up the relation of presser sensor electric capacity pressure in this frequency and LC oscillation circuit capsule, for reflecting gastrointestinal stress monitoring result; Body pressure sensor capsule and vitro detection part realize the wireless transmission of information by Mutual Inductance Coupling.

The operation principle of native system as shown in Figure 3, based on LC oscillation circuit and Mutual Inductance Coupling principle, the inductive sensor L in the LC oscillation circuit sensor capsule in body _s, presser sensor capacitor C _stime in parallel, produce a natural resonance frequency f _s, wherein capsule internal resistance is R _s,

When $R_S^2<<\frac{L_S}{C_S}$ Time, $f_S=\frac{1}{2\mathrm{\&pi;}}\sqrt{\frac{1}{L_S{C}_S}-\frac{R_S^2}{L_S^2}}\&cong;\frac{1}{2\mathrm{\&pi;}\sqrt{L_S{C}_S}}.---\left(1\right)$

Gastrointestinal stress changes the capacitance C that causes described sensor capsule internal pressure sensitization capacitance _schange, and then cause the natural resonance frequency f of LC oscillation circuit _schange.The soft band of external read coil L _rinductive sensor L with LC oscillation circuit sensor capsule _smutual Inductance Coupling occurs, and the LC oscillation circuit natural resonance frequency of sensor capsule changes the impedance Z that causes the soft band of external read coil _ichange,

$Z_i=j2\mathrm{\&pi;f}{L}_R[1+k^2\frac{{\left(\frac{f}{f_S}\right)}^2}{1-{\left(\frac{f}{f_S}\right)}^2+\frac{1}{Q_S}j\frac{f}{f_S}}]---\left(2\right)$

Wherein f is the frequency sweep frequency of the swept-frequency signal of described portable electric impedance analyzer generation, L _rself inductance of the soft band of external read coil,

be the quality factor of LC oscillation circuit sensor capsule, k is the coefficient of coup of Mutual Inductance Coupling.By the known Z of formula (2) _iphase place at natural resonance frequency f _sthere is a minima in place, analyzes Z by portable electric impedance analyzer _iphase minimum point obtain the natural resonance frequency of body inner sensor capsule, by the anti-capacitance C that can draw presser sensor electric capacity that pushes away in this natural frequency substitution formula (1) _s, the capacitance C of rear presser sensor electric capacity is demarcated in contrast _swith the relation of impressed pressure P, thereby draw gastrointestinal stress size.

Further, above-mentioned LC tank pressure sensor capsule structure simply only comprises presser sensor electric capacity and inductance, does not need the supply modules such as battery, and Non-energy-consumption, can realize long-time monitoring.Wherein presser sensor standardize solution is the silicon capacitive pressure transducer that MEMS processing technique is made, and inductance is the inductance coil that the inductance that processes of MEMS or traditional method coiling form.The application of MEMS technique makes this capsule volume little, and diameter is less than or equal to 9mm, and length is less than or equal to 20mm, and its shell is biocompatible material, can directly take, with low cost, is convenient to make disposable Orally taken product.Before taking this capsule, do not need bowel relieving, fasting, therefore testing result can reflect colonic pressure and the kinestate under physiological status completely simultaneously.

The soft band of described external read coil is only one group of tubbiness spiral winding, material is copper cash or other low resistance metal wires, this tubbiness spiral winding receives the swept-frequency signal of portable electric impedance analyzer output, and be created in gastrointestinal part basic uniformly time Electromagnetic Field for Mutual Inductance Coupling.

Described portable electric impedance analyzer comprises master controller, Direct Digital Frequency Synthesizers (DDS), high-speed AD converter (ADC), read coil drive circuit and liquid crystal display.Main controller controls DDS produces swept-frequency signal, and read coil drive circuit is realized the power amplification of swept-frequency signal, and gathers feedback signal.In the time that swept-frequency signal output frequency is the resonant frequency of LC oscillation circuit, changes because Mutual Inductance Coupling causes the soft band impedance of external read coil, and then cause the feedback signal amplitude, the phase change that collect.The impedance of the soft band of external read coil after this signal calculates variation by discrete Fourier transform after ADC conversion, master controller completes the impedance spectrum figure that can obtain the soft band of external read coil after frequency sweep, by the noise in finite impulse response (FIR) filtering impedance spectrum, determine the position of resonant frequency, final conversion Calculation is gastrointestinal stress.The program of master controller is first carried out coarse scanning and is determined resonance peak point roughly, carries out afterwards close scanning and realizes accurately location and make portable electric impedance analyzer can complete a stomach every 1s to press and read.

The present invention compared with prior art, has realized patient's no pain, without wound, without the monitoring continuously for a long time to gastrointestinal pressure and kinestate under the normal physiological state of bowel relieving and fasting.The induction coupling that simultaneously the present invention has realized in coil distance situation far away in vivo and in vitro strengthens, and utilizes frequency sweep control and the data processing algorithm to have realized the meticulous searching of Frequency point and have shown in real time.

Above-described specific embodiment; object of the present invention, technical scheme and beneficial effect are further described; institute is understood that; the foregoing is only specific embodiments of the invention; be not limited to the present invention; within the spirit and principles in the present invention all, any modification of making, be equal to replacement, improvement etc., within all should being included in protection scope of the present invention.

Claims (9)

1. the gastrointestinal stress detection system based on LC oscillation circuit and Mutual Inductance Coupling, it comprises:

LC tank pressure sensor capsule in body, changes for sensing gastrointestinal stress;

The soft band of external read coil, for described body in the LC oscillation circuit of LC tank pressure sensor capsule produce Mutual Inductance Coupling signal;

Portable electric impedance analyzer, it is worn on external, for generation of swept-frequency signal to read the impedance of the soft band of described external read coil after Mutual Inductance Coupling, and after being analyzed, this impedance obtains the frequency at impedance phase minima place, set up the relation of presser sensor electric capacity pressure in this frequency and LC oscillation circuit capsule, for reflecting gastrointestinal stress monitoring result.

2. gastrointestinal stress detection system according to claim 1, is characterized in that: in described body, LC tank pressure sensor capsule is made up of presser sensor electric capacity and inductance.

3. gastrointestinal stress detection system according to claim 1, is characterized in that: in described body, the shell of LC tank pressure sensor capsule is biocompatible material, and diameter is less than or equal to 9mm, and length is less than or equal to 20mm.

4. gastrointestinal stress detection system according to claim 1, it is characterized in that: the soft band of described external read coil is one group of tubbiness spiral winding, material is copper cash or other low resistance metal wires, its produce in vivo gastrointestinal part basic uniformly time Electromagnetic Field for Mutual Inductance Coupling.

5. gastrointestinal stress detection system according to claim 1, is characterized in that: described portable electric impedance analyzer comprises master controller, Direct Digital Frequency Synthesizers (DDS), high-speed AD converter (ADC), read coil drive circuit and LCDs; Described in described main controller controls, Direct Digital Frequency Synthesizers produces swept-frequency signal, described read coil drive circuit is realized the power amplification of swept-frequency signal, and gathering the Mutual Inductance Coupling signal that in the soft band of described external read coil and described body, the LC oscillation circuit in LC tank pressure sensor capsule produces, this Mutual Inductance Coupling signal calculates the impedance of the soft band of external read coil after described high-speed AD converter conversion by discrete Fourier transform.

6. gastrointestinal stress detection system according to claim 2, it is characterized in that: the presser sensor electric capacity in described body in LC tank pressure sensor capsule is the silicon capacitive pressure transducer that MEMS processing technique is made, inductance is the inductance coil that the inductance that processes of MEMS or traditional method coiling form.

7. gastrointestinal stress detection system according to claim 1, is characterized in that, gastrointestinal stress changes the capacitance C that causes LC tank pressure sensor capsule internal pressure sensitization capacitance in described body _schange, and then cause the natural resonance frequency f of LC oscillation circuit _schange, wherein said natural resonance frequency calculates as follows:

When $R_S^2<<\frac{L_S}{C_S}$ Time, $f_S=\frac{1}{2\mathrm{\&pi;}}\sqrt{\frac{1}{L_S{C}_S}-\frac{R_S^2}{L_S^2}}\&cong;\frac{1}{2\mathrm{\&pi;}\sqrt{L_S{C}_S}}$

Wherein, L _sfor the inductive sensor value in LC oscillation circuit sensor capsule in body, R _sfor the resistance value in LC oscillation circuit sensor capsule in body.

8. gastrointestinal stress detection system according to claim 7, is characterized in that, described natural resonance frequency f _svariation cause the impedance Z of the soft band of external read coil _ichange, wherein said impedance is expressed as follows:

$Z_i=j2\mathrm{\&pi;f}{L}_R[1+k^2\frac{{\left(\frac{f}{f_S}\right)}^2}{1-{\left(\frac{f}{f_S}\right)}^2+\frac{1}{Q_S}j\frac{f}{f_S}}]$

Wherein, f is the frequency sweep frequency of the swept-frequency signal of described portable electric impedance analyzer generation, L _rself inductance of the soft band of external read coil,

be the quality factor of LC oscillation circuit sensor capsule in described body, k is Mutual Inductance Coupling coefficient.

9. gastrointestinal stress detection system according to claim 8, is characterized in that, described portable electric impedance analyzer is by analyzing Z _iphase minimum point, obtain the natural resonance frequency f of body inner sensor capsule _s, and according to described natural resonance frequency f _scalculate the capacitance C of described presser sensor electric capacity _s,and according to the capacitance C of described presser sensor electric capacity _swith the relation of impressed pressure P, and then draw gastrointestinal stress size.

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