WO2006091123A1

WO2006091123A1 - Microwave radiothermotomograph

Info

Publication number: WO2006091123A1
Application number: PCT/RU2006/000072
Authority: WO
Inventors: Valerie Eugenievich Hokkanen
Original assignee: Otkrytoe Akzionernoe Obschestvo 'sistema Venture'
Priority date: 2005-02-22
Filing date: 2006-02-20
Publication date: 2006-08-31
Also published as: RU2005104613A

Abstract

The present invention relates generally to a radio engineering and can be used in medicine for diagnostics, in particular, for profile contact measurement of radiothermal radiation of human organs and tissues with the purpose to analysis of their three-dimensional field of temperatures. The entered essential differences allow to realize an operating mode of an active microwave location of deep tissues in a wide spectral range that in turn enables to create three-dimensional temperature fields of deep tissues of an human organism. It is achieved by that microwave radiothermotomograph includes a tunable reference signal generator, a modulator of reference generator, a synchronizer, a tunable band-pass filter, an analog-to-digital converter (ADC) and a digital-to-analog converter (DAC), an operative memory, surface temperature sensors combined with a microwave antenna.

Description

Microwave radiothermotomograph

Technical field

The invention relates generally to radio engineering and can be used in medicine to create three-dimensional temperature fields of human deep tissues.

Background of the invention

There are known single-channel radiothermographs, for example, radiothermometer RTM-Ol-RES (patent RU 2160039 Cl, 1999.06.16), which contains the modulation receiver realizing a zero method of measurement of radiothermal temperature and used for reception integrated (on depth) temperatures of human tissues.

There is known medical radiothermometer (patent RU 2082118 Cl, 1994.07.11), which contains the aerial connected to a first arm of Y-circulator, its second arm is connected to an input of modulation radiometer. The output of reference generator of modulation radiometer is connected to operating input of the modulator. The resistor and the temperature sensor are located with an opportunity of thermal contact. The resistor terminal is connected to an output of modulation radiometer through the decoupling radio frequency entered element and to a third arm of Y-circulator through the entered capacitor. The output of temperature sensor is connected to a temperature indicator.

Disclosure of invention technical problem

Possessing doubtless advantages - reliability of measurements and stability of calibration notices - this radiothermograph has that disadvantages - impossibility in principle to measure deep temperature profiles because only the single-frequency principle of a passive location and one applicator aerial are used, low noise immunity due to the fact that a level of spontaneous thermal radiation of human tissues considerably below available industrial radio noises (computers, mobile phones, illumination lamps and others), that demands special screened room, impossibility to receive a line profile of deep human tissues during one measurement.

The multi-channel radiothermograph (patent RU 2085957 Cl, 1993.01.11) is considered as the most relative known analogue taken as the prototype. This radiothermograph contains a multiple microwave switch, input of which commutes with a number of aerials, circulator and radiometric receiver that consistently connected. Output of temperature sensor is a radiothermograph output. Presence of N aerials allows to perform measurements simultaneously in N points of body surface that is essential difference from the single-channel radiothermograph.

Disadvantage of such radiothermograph is absence of differentiation of temperature on depth that does not allow to receive three-dimensional distributions of temperature fields, and low noise immunity in view of use of passive location principle as well as the useful signal as a rule considerably below the level of industrial radio noises in the used range of wave lengths.

Detailed description of the invention

The present invention provides as technical result an opportunity to receive deep temperature profiles (Fig. 1) due to registration of radiothermal radiation in a wide range of frequencies, increase in depth of definition of temperatures, increase of noise immunity due to use of active location principle.

In order to achieve the specified technical result the microwave thermotomograph includes following basic elements and devices (Fig.2): Al, A2 ... An - N broadband receiving aerials; Bl, B2 ... Bn - N transmitting aerials; Cl, C2... Cn - N temperature surface sensors placed on receiving aerials;

1. Switchboard of receiving aerials;

2. Switchboard of transmitting aerials;

3. Switchboard of surface temperature sensors;

4. Tunable band-pass filter; bandwidth is from 30 to 100 MHz;

5. Modulator of probing signal, depth of modulation is changed from 10 to 100%, modulated signal can be impulse, sinusoidal or has the complex form;

6. Switchboard of square wave by frequency from 1 to 2 KHZ, the current from 10 to 50;

7. Y-circulator;

8. High-frequency broadband amplifier;

9. Amplitude detector, output frequency from 0 up to 10 kHz, a level of the signal not less than 300 mV;

10. Tunable reference signal generator, a power level - equivalent to temperature in the range of 30 - 40° C; 11. Tunable probing signal generator in the range from 500 up to 3000

MHz, which capacity of radiation on aerials mouth does not exceed maximum permissible sanitary norms; 12. Control and synchronizing block; 13. Analog-to-digital converter (ADC);

14. Digital-to-analog converter (DAC) having 4 channels for communication with personal computer;

15. PC - personal computer;

16. Amplifier of low frequency, on output not less than 300 mV, constant of operation time no more 1 sec. Example

Microwave radiothermotomograph works as follows:

The personal computer 15 synthesizes control signals and synchronization signals, then through a first channel DAC 14 transfers them into a block of control and synchronization 12, which starts a tunable probing signal generator 11. Simultaneously the control signals are transferred through a second channel DAC to generator 5, which provides amplitude-phase modulation of the generated signals. The switchboard of transferring aerials 2 connects consistently to each of transferring aerials Bl, B2... Bn, which radiate a probing signal. Synchronously with transferring aerials the switchboard of receiving aerials 1 connects a reception path to each of receiving aerials Al, A2... An consistently, it being that transmit and receive conditions only for transmitting and receiving aerials, which have similar numbers. The received signal is transmitted to personal computer after switchboard 1 further through a third channel DAC, then through a tunable band-pass filter 4, which is operated by a tunable probing signal generator 11. Further the received signal is modulated by six rectangular impulses with frequency from 1 up to 2 kHz, which are generated by the personal computer. The modulated signal is transferred to a first input of circulator 7 and further to a high-frequency broadband amplifier 8. The signals of tunable reference signal generator 10 are transmitted to a second input of circulator 7 and further are used for calibration of reception path according to the temperature. From high-frequency broadband amplifier 8 the signal is transmitted to amplitude detector 9 where it is detected, then it is transmitted to ADC 13, then already in a digital format it is transmitted to personal computer for mathematical processing. Signals from the superficial temperature sensors, which are located on working surfaces of reception aerials Cl, C2... Cn, are transmitted to a second input ADC consecutive through switchboard 3 for the further processing on personal computer. Special software realizes the following stages of processing, which necessary for analysis of deep temperature structures:

- analysis of acting time numbers on presence of artefacts;

- signal sorting and formation of working files;

- synchronous digital detection;

- calibration of the reception path;

- estimation of deep temperature structures by tomography methods;

- graphic visualization of three-dimensional temperature images (thermotomograms).

The offered microwave radiothermotomograph has depth of penetration over 30 % in comparison with the passive variant of reception. Presence of the probing signal increases a noise-stability up to the level when there is no necessity to apply additional protection measures from industrial noises.

Claims

A microwave radiothermotomograph containing N receiving aerials, modulator, circulator, high frequency broadband amplifier, amplitude detector consistently connected comprising that N transmitting aerials are entered into it and probing signals are transmitted to these aerials from a tunable radio frequency generator through both a device of amplitude-phase modulation and a switchboard of transmitting aerials, N temperature surface sensors placed on receiving aerials, signals from which are transmitted to a second input of a analog-digital converter (ADC) through a switchboard and a tunable reference signal generator connected to a second input of Y-circulator with an opportunity to create three-dimensional temperature fields of human deep tissues.