JPH03258251A - Apparatus for measuring temperature distribution - Google Patents

Abstract

PURPOSE:To obtain the title apparatus capable of easily knowing the change of heating with the elapse of time by displaying the temp. data from the starting time of heating on a display in matching relation to time data. CONSTITUTION:The heating of an examinee (living body) 16 is started by a heater. A timer is preliminarily operated at this time or before heating. The driving of an ultrasonic converter 1 is stopped during heating and, during this period, the signal stored in a waveform memory part 5 receives predetermined signal processing in a frequency analyzing part 8 and a signal processing part 9 to be accumulated in the signal processing part as acoustic characteristic distribution. The signal processing is completed about one min after the start of heating and, next, temp. distribution measuring operation is performed in order to calculate the max. temp. region of heating distribution. The data after heating is accumulated in the signal processing part 9 by the transmission and reception of an ultrasonic pulse, the memory of a waveform, the analysis of frequency and signal processing. A temp. operation part 10 compares the acoustic characteristic distribution before heating and that after heating with respect to the same region and, from a difference between both distributions, the change quantity of acoustic characteristics due to heating is calculated and converted to temp. change quantity on reference to the signal of a data reference part 11. The output of the temp. operation part 10 is subjected to scanning conversion in matching relation to the format of a display part 14 by a scanning conversion part 13 to be displayed as the color data corresponding to temp. change quantity.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a temperature distribution measuring device for non-invasively measuring a temperature distribution image of a heated area, for example, when performing thermotherapy for cancer.

Conventional technology When performing thermal treatment for cancer, the temperature of the heated area is measured,
It is necessary to heat the body to around 43°C, which is effective for thermotherapeutic treatment, and to control the temperature so as not to damage surrounding normal cells. Conventionally, a plurality of temperature sensors such as thermocouples and thermistors are inserted into a living body to estimate temperature distribution and perform heating control. In this way, inserting a temperature sensor into a living body may cause pain to the patient, may induce cancer metastasis, complicate preparations for heating treatment, and require accurate treatment. There are problems such as the inability to measure temperature distribution.

Recently, in order to solve such problems, research and development have been conducted on non-invasive temperature distribution measuring devices that do not harm living organisms. Most of these methods use a relative temperature measurement method that detects the amount of temperature change in some physical property of living tissue and converts it into temperature information. As this temperature measurement method,
For example, a configuration described in Japanese Patent Application No. 128214/1988 is known.

The configuration will be described below with reference to the drawings.

FIG. 3 is a functional block diagram showing the basic configuration of a conventional temperature distribution measuring device. In Fig. 3, 1 is an ultrasonic converter composed of two types of ultrasonic transducers that transmit pump wave pulses and probe wave pulses, and 2 is a pump wave converter for ultrasonic converter 1. 3 is a pulse driver that applies driving pulses for probe waves to the ultrasonic converter 1; 4 is an amplifier that amplifies the received output of the ultrasonic converter 1; 5 is an amplifier 4 is a waveform storage unit that stores the output of 4, 6 is a timing control unit that controls the operation timing of the pulse driver 2.3 and the waveform storage unit 5, and 7 is a clock generator that supplies clocks to the waveform storage unit 5 and the timing control unit 6. 8 is a frequency analysis unit that performs Fourier transform on the waveform stored in the waveform storage unit 5; 9 is a signal processing unit that performs signal processing on the output of the frequency analysis unit 8 to obtain acoustic characteristics; 10 is a signal processing unit 11 is a data reference unit that outputs temperature dependence information of acoustic characteristics to the temperature calculation unit 10; 12 is a reception detection unit that detects the output of the amplifier 4; 13 creates an acoustic characteristic distribution image based on the output of the signal processing section 9, and the temperature calculation section 1
A scan conversion unit creates a temperature distribution image using the output of 0, and a B-mode tomographic image using the output of the reception detection unit 12, 14 is a display unit that displays the output of the scan conversion unit 13, and 16 is a subject (living body). .

The operation of the above configuration will be described below.

By driving the pulse driver 2.3, two types of ultrasound pulses, a pump wave and a probe wave, travel from the ultrasound converter 1 to the living body 16 while being superimposed with their phases controlled. Reflected waves are generated at different depths within the living body 16 and are received again by the ultrasound converter 1 as a continuous signal. This received signal is amplified by an amplifier 4, A/D converted at high speed, and stored in a waveform storage section 5. Then, by scanning the ultrasonic converter 1 with a scanner (not shown), the two inside the living body 16 are
Reflected waves from each dimensional portion are sequentially stored in the waveform storage unit 5. When the reflected waves before heating are accumulated in this way, the living body 16 begins to be heated by a heater (not shown). It takes about 10 minutes to warm up to a therapeutically effective temperature. During this time, the output from the waveform storage unit 5 is sequentially divided into signal lengths corresponding to a predetermined distance within the living body 16 for each scanning line, and analyzed into a spectrum by the frequency analysis unit 8. Here, the ultrasonic pulse traveling inside the living body 16 is affected by nonlinear phenomena and ultrasound absorption within the living body 16, and the frequency component of the transmitted wave has changed. In the signal processing unit 9, acoustic characteristics related to nonlinear phenomena and ultrasonic absorption are calculated from the frequency variation distribution corresponding to a predetermined distance, and a two-dimensional acoustic characteristic distribution signal is accumulated. When the operation in the signal processing section 9 is completed, the ultrasonic wave is sent out again from the ultrasonic conversion section 1 as described above, and according to the above operation,
The acoustic characteristic distribution within the living body 16 is measured. Since this acoustic characteristic varies depending on the temperature, the temperature calculation section 10 compares the acoustic characteristic of the same place before and after heating, and calculates the temperature dependence of the acoustic characteristic of each tissue prepared in advance in the data reference section 11. Determine the temperature change due to heating by referring to the characteristic data. By performing this for the entire area, a two-dimensional temperature distribution can be obtained. The obtained two-dimensional temperature distribution information is displayed by the scan converter 13 in a state matching the display format of the display unit 14. On the other hand, the output from the amplifier 4 is detected by the reception detection section 12 and subjected to necessary signal processing, and then converted to an ultrasonic tomographic image signal by the scan conversion section 13 and displayed on the display section 14. On the display unit 14, for example, an ultrasonic tomographic image of the temperature measurement area can be displayed at the same time as a temperature distribution image after heating.

Problems to be Solved by the Invention However, in the conventional temperature distribution measuring device as described above,
In order to obtain a signal with less noise, it is necessary to interrupt heating for a few seconds when measuring temperature, and approximately 1 minute is required for signal processing. Become. However, since the state of temperature rise must be judged from the temperature distribution image, there are still problems such as difficulty in controlling heating.

The present invention solves the problems of the prior art as described above, and when measuring temperature distribution non-invasively, it is possible to easily know the change in heating over time. Provides a temperature distribution measuring device that can be easily controlled, and also allows you to select a desired area and measure the temperature in that area faster than obtaining a two-dimensional temperature distribution. The object of the present invention is to provide a temperature distribution measuring device.

Means for Solving the Problem The technical solution of the present invention for achieving the above object is as follows:
A thermometer that non-invasively measures a two-dimensional temperature distribution image inside a subject from outside the subject; a display that displays the temperature distribution image; It is equipped with a location selector and a means for intermittently measuring the temperature of the selected area, and is configured to display the temperature data from the start of heating on the display unit along with time information. .

The temperature measuring device can measure the relative temperature distribution based on changes in the characteristics of the specimen before and after heating the inside of the specimen, and the selected position of the location selector is displayed above. It can be displayed superimposed on the temperature distribution image displayed on the device, and an ultrasonic device can be used as the temperature measuring device. In addition, the above display displays the ultrasonic tomographic images of the temperature measurement area before and after heating, as well as the temperature distribution image after heating and the time-lapse data from the start of heating of the area selected by the location selector. Temperature changes can be graphed and displayed at the same time.

Furthermore, the interval at which the temperature of the area selected by the location selector is measured can be made shorter than the interval at which the two-dimensional temperature distribution is measured.

Therefore, according to the present invention, the two-dimensional temperature distribution of the subject is non-invasively measured using the thermometer and displayed on the display, and the required location is selected using the location selector and the temperature distribution of that part is selected. The temperature can be measured intermittently and the obtained temperature information from the start of heating can be displayed on the display over time.

Furthermore, by limiting the scanning to a selected area, the amount of signal is reduced, and the signal processing time is shortened, so temperature information can be obtained in a shorter time than when measuring the entire area.

Embodiments Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a functional block diagram showing the basic configuration of a temperature distribution measuring device in an embodiment of the present invention.

This embodiment differs from the conventional example shown in FIG. 1 in that it includes a location selector 17, a scanner 18, and a timer 19.

In FIG. 1, reference numeral 1 denotes an ultrasonic transducer composed of two types of ultrasonic transducers that transmit pump wave pulses and transmit and receive probe wave pulses, and 18 a scanner that scans the ultrasonic transducer 1. , 2 is a pulse driver that applies drive pulses for pump waves to the ultrasonic converter 1; 3 is a pulse driver that applies drive pulses for globbing to the ultrasonic converter l;
4 is an amplifier that amplifies the received output of the ultrasonic converter 1; 5 is a waveform storage unit that stores the output of the amplifier 4; and 6 is a control unit that controls the operation timing of the pulse driver 2.3, the waveform storage unit 5, and the scanner 18. 7 is a clock generation section that supplies clocks to the waveform storage section 5, the timing control section 6, and a timer described later; 8 is a frequency analysis section that performs Fourier transform on the waveform stored in the waveform storage section 5. , 9 is a signal processing unit that performs signal processing on the output of the frequency analysis unit 8 to obtain acoustic characteristics; 10 is a temperature calculation unit that calculates the temperature based on the output of the signal processing unit 9; ] 1 is a temperature calculation unit 10; a data reference unit that outputs temperature-dependent information on acoustic characteristics;
Reference numeral 2 denotes a reception detection unit that detects the output of the amplifier 4, and 13, the output of the signal processing unit 9 is used to create an acoustic characteristic distribution image, and the output of the temperature calculation unit 10 is used to generate a temperature distribution image and the start of heating, etc. over time from a predetermined time. a scan conversion unit that creates a temperature change line graph image and creates a B-mode tomographic image based on the output of the reception detection unit 12; 14 is a display unit that displays the output of the scan conversion unit 13;
1 is a location selector for selecting a predetermined area from the displayed temperature distribution image; 19 is a timer for measuring time; and 16 is a subject (living body).

The operation of the above configuration will be described below.

Since the basic operation of this embodiment is almost the same as that of the conventional example, the explanation will mainly be given to the operation that is different from that of the conventional example.

The procedure for transmitting an ultrasonic signal into the living body 16 before heating and measuring the acoustic characteristics inside the living body 16 based on the received signal reflected from within the living body 16 is exactly the same as in the conventional example. Then, the scanner 18 scans the ultrasound converter 1 to detect the living body 16.
The reflected waves from each two-dimensional part of the heating element are stored in the waveform storage section 5, and the reflected waves before heating are stored. Next, the living body 16 begins to be heated by a warmer (not shown). At this time or before heating, the timer 19 is operated. During heating, the drive of the ultrasonic transducer 1 is stopped, and during that time,
The signal stored in the waveform storage section 5 undergoes predetermined signal processing in the frequency analysis section 8 and the signal processing section 9, and is stored in the signal processing section 9 as an acoustic characteristic distribution. Signal processing is completed in about one minute after the start of heating, and then a temperature distribution measurement operation is performed to find the highest temperature region of the heating distribution. This procedure is also the same as that of the conventional example described above, and the ultrasonic pulse is transmitted and received, waveform storage, frequency analysis, and signal processing are performed, and the data is stored in the signal processing section 9 as data after heating. The temperature calculation section 1o compares the same region with the acoustic characteristic distribution before heating, calculates the amount of change in acoustic characteristics due to heating from the difference, and converts it into the amount of temperature change with reference to the signal from the data reference section 11.

Output of temperature calculation section 10. The power is displayed on the display section 14 by the scan conversion section 13.
The image is scan-converted in accordance with the format of , and displayed in color as color information corresponding to the amount of temperature change. It is easy to check the area with the highest temperature, and by operating the location selector 17, such as a track bowl, while displaying this selection position on the display unit 14, you can easily select the required area, such as the highest temperature point. can do. The temperature information of the selected area is sent to the scan converter 1 along with the time at which it was measured intermittently.
3 is output. The scan conversion unit 13 arranges storage units in the scan conversion unit 13, writes data to the storage unit, and reads data so as to obtain a predetermined format.

Figure 2 (a, l, tb+ shows an example, the figure (a)
The display format shown in is the pre-warming ultrasound tomographic image 20,
Ultrasonic tomographic image after heating 21, temperature change graph after heating 22
Temperature distribution image 23 including symbols 24 indicating selected areas
Consisting of By displaying in this way, it is possible to detect a positional shift between the temperature measurement locations before and after heating. This display format may be changed to the arrangement shown in fb) of the same figure. However, by simultaneously displaying the color par 25 showing the correspondence between the amount of temperature change and the color, the gray scale 26 showing the gradation of the ultrasonic tomographic image, etc., it is possible to make the temperature information and the like even easier to understand.

Next, the ultrasonic signals are transmitted and received by limiting the selected locations. This is based on the output of the location selector 17, and by driving the scanner 18, the ultrasound converter 1 selects only that part.
Alternatively, ultrasonic signal scanning is performed only in a limited area centered on that part. The reflected signal is amplified by the amplifier 4 in the same manner as described above, and the waveform is stored in the waveform storage section 5. in this case,
Since the amount of waveform memory is about 1/10 compared to full area scanning, the time required for next frequency analysis in the frequency analysis section 8 and signal processing in the signal processing section 9 is also shortened to about 10 seconds. be done. Next, the temperature calculation unit 10 performs similar processing, and compares it with the acoustic characteristic distribution before heating or used for location selection to determine the temperature increase during that period. At this time, it is possible to compare the acoustic characteristics of only the selected area, but in order to improve the temperature measurement accuracy, the temperature changes in the areas before, after, to the left and right of the selected area are also calculated, and averaging, smoothing, etc. You can go. The amount of temperature change in the area selected in this manner is output to the scan converter 13 together with the time at which it was measured. The scan converter 13 plots the current measurement value on a temperature change graph. Measurement of such a limited area is performed multiple times and temperature changes are plotted, and the temperature of the entire area is also measured. In the case of temperature measurement in the entire area, the ultrasonic tomographic image after heating, the temperature distribution image, and the plot of temperature change over time are all updated. As a result, a temperature distribution image can be obtained, and the temperature change in an arbitrarily selected area can be measured in a shorter time than it would take to obtain a temperature distribution image, and by graphing the change over time, the degree of temperature rise can be determined. This makes it possible to easily control heating.

In this example, the case where ultrasonic waves were used as a non-invasive temperature measuring device was explained, but it is also possible to use other non-invasive temperature measuring devices such as XICT, MRI, microwave, etc. can also be implemented in the same way. Also,
Although the selection of the temperature measurement location has been described for one area, it is also possible to set a plurality of points and graph the temperature changes in those areas by changing the colors.

Effects of the Invention As described above, according to the present invention, the temperature distribution inside the subject is measured non-invasively, the temperature distribution image is displayed on the display, and the temperature distribution in an area arbitrarily selected by the location selector is measured. Since the change over time is displayed on the display, the degree of temperature rise can be easily known, and heating can be easily controlled.

However, by scanning a limited selected area, the signal processing time can be shorter than by scanning the entire area, so short-term temperature changes can be accurately determined.

[Brief explanation of drawings]

FIG. 1 is a functional block diagram showing the basic configuration of a temperature distribution measuring device in an embodiment of the present invention, and FIGS. 2(a) and (b)
FIG. 3 is a diagram showing an example of displaying the temperature distribution in the above embodiment, and FIG. 3 is a functional block diagram showing the basic configuration of a conventional temperature distribution measuring device. 1... Ultrasonic transducer, 2, 3... Pulse driver, 5...
... Waveform storage section, 6... Timing control section, 8...
Frequency analyzer, 9... Signal processing section, 10... Temperature calculation section, 13... Scan conversion section, 14... Display section, 17.
...Place selector, 18...Scanner, 19 Timer

Claims (6)

[Claims] (1) A thermometer that non-invasively measures a two-dimensional temperature distribution image inside the object from outside the object, a display that displays the temperature distribution image, and an arbitrary temperature distribution image that is displayed. The apparatus is equipped with a place selector for selecting an area, and a means for intermittently measuring the temperature of the selected area, and is configured so that temperature data from the start of heating is displayed on the display together with time information. Temperature distribution measuring device. (2) Claim 1 in which the thermometer relatively measures the temperature distribution based on changes in characteristics of the subject before and after heating the inside of the subject.
The temperature distribution measuring device described. (3) The temperature distribution measuring device according to claim 1, wherein the selected position of the location selector is displayed superimposed on the temperature distribution image displayed on the display. (4) The temperature distribution measuring device according to claim 2, wherein the temperature measuring device is an ultrasonic device. (5) Ultrasonic tomographic images of the measurement area before and after heating are displayed on the display, as well as a temperature distribution image after heating and the time-lapse data from the start of heating of the area selected by the location selector. 2. The temperature distribution measuring device according to claim 1, wherein the temperature distribution measuring device is configured to simultaneously display temperature changes in a graph. (6) The temperature distribution measuring device according to claim 1, wherein the interval at which the temperature of the area selected by the location selector is measured is shorter than the interval at which the two-dimensional temperature distribution is measured.