JPS62152476A - Hyperthermia apparatus using liquid - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a hyperthermia device using a liquid, particularly a liquid that can effectively heat the inside of a living body by irradiating microwaves to affected tissue within the living body. A hyperthermia device using

[Prior art] By irradiating high frequency waves, particularly microwaves, to affected tissue such as cancerous tissue in a living body to heat the tissue to a temperature of about 42 to 45°C, and performing this continuously or intermittently, Hyper-Mia devices are well known for treating affected tissue. This hyperthermia device utilizes the fact that when a living body is exposed to an alternating electric field in a predetermined frequency range, the living body is heated by microwave energy, and this microwave energy can be used to non-invasively heat the affected tissue. It is carried out according to

Cancer tissues have poor blood flow compared to other normal tissues, so the cold PL effect is low, so irradiating microwaves at a predetermined frequency into a living body can selectively target only cancer tissues without damaging normal tissues. It can be cured by heating.

By the way, when irradiating microwaves into a living body, a matching layer is provided between the applicator and the surface of the living body to achieve impedance matching, and the microwaves emitted from the applicator are applied to the living body. efforts are being made to make it work efficiently.

[Problem to be Solved by the Invention 1 Problems with the Prior Art However, in the past, the matching layer itself was formed from a solid, and solid matching layers have poor adhesion to the surface of the living body, resulting in uneven heating. There was a problem in that the surface of the living body could not be heated uniformly.

Furthermore, the matching layer acts to insulate the surface of the living body, thereby heating the normal surface of the living body, making it impossible to efficiently heat only the affected tissue.

The present invention has been made in view of the above-mentioned conventional problems.
The purpose is to provide a hyperthermia device using a liquid that has a cooling effect on the matching layer and can adjust the temperature of the surface of the living body.

[Means for Solving the Problems] In order to achieve the above object, the present invention forms a matching layer bag that performs impedance matching using a liquid instead of a conventional matching layer made of a solid material, and It is characterized by having a senna device and a circulation device installed.

The temperature sensor device then detects the temperature of the liquid, and the circulation device circulates the liquid into the matching layer bag to maintain a constant 4 degrees based on the output of the temperature sensor device.

When choosing a material for the matching layer, for example, the dielectric constant ε of the matching layer
is required from the relationship between Therefore, microwave (2°45
0MHz>, if the space is 1. Since the dielectric constant of a living body is 47, the relative dielectric constant of the matching layer is about 7, and the dielectric constant of water is 80 as a liquid.
As such, the applicant proposes to use castor oil, silicone oil or the like as a matching layer.

[Function] According to the above configuration, the microwave irradiated toward the living body heats the matching layer bag and the inside of the living body, but at this time, the temperature of the liquid in the matching layer bag is constantly detected. The liquid is circulated in a circulation device so that this temperature becomes a predetermined temperature.

Therefore, even if the temperature of the living body surface increases, it can be cooled down by the matching layer bag, and the living body surface can be maintained at a desired temperature.

[Example 1 Preferred embodiments of the present invention will be described below based on the drawings.

FIG. 1 shows a hyperthermia device, in which a matching layer bag 14 is provided between an applicator 10 that irradiates microwaves and a living body 12 in close contact with the surface of the living body.

A temperature sensor 16 and a circulation duplex 18 are installed in the matching layer bag 14, and a constant temperature bath 20 and a circulation pump 22 are provided in the circulation duplex 18. Further, a thermometer 24 is connected to the temperature sensor 16, and the output of this temperature 8124 is supplied to the constant temperature oven 20.

In the example, castor oil is used as the liquid, and assuming that the thickness of the castor oil in the matching layer bag 14 is 15 mm, experiments have shown that a thickness of 15 to 20 mm is the most efficient for heating. This was confirmed.

That is, as shown in FIG. 2, castor oil 28 is placed on a phantom 26 equivalent to a muscle, and the applicator 10 is placed 15 cm away from the phantom 26.

Then, in the phantom 26, 30
2.450MHz by placing 30 thermocouples up to IR111
irradiate with microwave. In this case, the thickness of the castor oil 28 is increased to 5+nti, and each time, the temperature before and after heating is measured at each measurement point in the phantom 2G. In addition,
The microwave irradiation time is set to 20 seconds.

The experimental results obtained in this way are evaluated as follows.

B. Let the humidity difference at each point before and after heating be the temperature increase at the depth of that point.

The relationship between the depth and the upper limit temperature T is fitted using the following exponential function.

Upper limit temperature T=To-exp[-α×(depth) Therefore, To and α can be determined from the figure.

C. Let PO be the microwave output during irradiation, and evaluate the heating efficiency using the following formula.

Heating efficiency-1/Pof To-e-(xldzThe change in humidification efficiency determined according to this evaluation method with respect to the thickness of the castor oil layer is shown in FIG. Maximum efficiency was achieved when the height was 15 to 20 mm.

The present invention has the above configuration, and its operation will be explained below.

First, microwaves are irradiated from the applicator 10 into the living body 12 via the matching layer bag 14 to warm the affected tissue, and at the same time as the affected tissue is warmed, the surface of the living body and the matching layer bag are also warmed.

In this case, the castor oil is circulated within the matching layer bag 14 by the circulation device 22, and the temperature of the castor oil is maintained at a predetermined temperature. Therefore, the temperature of the surface of the living body can be maintained at a predetermined temperature despite being heated by microwaves.

As a result, overheating of the matching layer can be prevented and the temperature of the surface of the living body can be freely controlled fII, making it possible to perform good heating treatment. In other words, the temperature of the affected tissue is 42°C to 45°C.
If heated to a certain temperature, it will become necrotic and heal, but it is better to keep normal tissue at a temperature as low as possible, and maintaining the temperature of normal tissue on the surface of a living body at a normal temperature will avoid causing pain to the patient. It also disappears.

In addition, although castor oil is used as the matching layer in the example,
Silicone oil or a liquid having an impedance equivalent to these can be applied.

[Effects of the Invention] As explained above, according to the present invention, a matching layer bag is formed using a liquid and this liquid is circulated, so that the surface of a living body is cooled and its temperature is controlled. This makes it possible to perform good heating treatment.

[Brief explanation of drawings]

Figure 1 is an explanatory diagram showing an example of the hyperthermia device using the liquid of the present invention, Figure 2 is an explanatory diagram showing an experimental method using castor oil, and Figure 3 is the experimental result of Figure 2. FIG. 10... Applicator 12... Living body 14... Matching layer bag 16... Temperature sensor 22... Circulation pump

Claims (2)

[Claims] (1) A hyperthermia device that heats the inside of a living body by irradiating microwaves includes a matching layer bag that performs impedance matching using a liquid, a temperature sensor device that detects the temperature of the liquid, and an output of this temperature sensor device. 1. A hyperthermia device using a liquid, comprising: a circulation device that circulates the liquid within a matching layer bag so that the temperature of the liquid is kept constant. (2) The apparatus according to claim (1), wherein castor oil is used as the liquid, and the thickness of the castor oil in the matching layer bag is 15 to 20 mm. Device.