JPH0213476A - Hyper thermier device - Google Patents

Abstract

PURPOSE:To make it possible to heat a deep part locally and heat only a desired part to be cared locally without heating other parts by rotating a cavity resonator to a subject patient about an axis passing a subject part to be cared for a symmetric degree of angle of electric field strength distribution at least at a higher-order resonance mode. CONSTITUTION:For his cavity resonator 1 of a cylindrical form, high frequency power of a predetermined frequency number is supplied from a feed connector 12, and a resonance mode of a desired higher-order mode is produced in the resonator 1 by selecting this feed point and frequency number properly. For example, at TM111 mode, the strength of the electric field is extremely large at a center point O and at points A-D. The resonator 1 is let to repeat reciprocating rotation of 180 deg. about an axis perpendicular to the center axis of the resonator 1 passing the center point O, while a patient 6 is kept fixed. The distribution pattern of the electric field strength rotates, therefore, to the patient 6, and the strength of the electric field is always high at the point O of the patient 6, while at the other points than this point O such as points A, B, C, D, etc., the range of a high strength of the electric field moves corresponding to rotation.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a device for performing hyperthermia therapy for cancer and the like, and particularly relates to a cavity resonator type hyperthermia device.

[Conventional technology]

Hyperthermia is a treatment method that takes advantage of the fact that the tissue of malignant tumors such as cancer is sensitive to heat and treats the tissue by heating the area. Warming only the affected area and avoiding heating other normal tissues as much as possible prevents damage to normal tissues.
This is important in improving the therapeutic effect of the affected area. Dielectric heating methods and microwave heating methods using radiation applicators have been known as methods for heating the human body to about 43 degrees Celsius, but these methods are used when the affected area is deep within the human body. In some cases, there are problems such as insufficient heating or inefficiency in that only the deep part of the body is heated. Therefore, recently, a cavity resonator type hyperthermia device has been proposed. For example, as shown in Fig. 4, a hole for inserting the patient 6 is provided in the side surface of a cylindrical cavity resonator 1, the patient 6 is placed inside the resonator 1, and high-frequency power is supplied to cause resonance. let In this case, the fundamental mode (T M 010 mode) is normally used as the resonance mode.

[Problem to be solved by the invention]

However, in a cylindrical cavity resonant δ-type hyperthermia device as shown in Figure 4, when it resonates in the fundamental mode, the electric field strength distribution will be centered at the center as shown in Figure 5, which shows the pattern in the plane along the diameter. It becomes rotationally symmetrical about the central axis, which becomes stronger and gradually weaker toward the periphery. Therefore, although the vicinity of the central axis of the cylindrical cavity resonator 1 inside the patient 6 is locally heated and deep heating is achieved, the localization is gradual and only the desired treatment area is locally heated. It is insufficient in that it only heats certain parts of the body but not other parts. This invention realizes deep localized heating, and
It is an object of the present invention to provide a cavity resonator type hyperthermia device that can locally heat only a desired treatment area while not heating other areas.

[Means to solve the problem]

In order to achieve the above object, the cavity resonator type hyperthermia device according to the present invention has a cavity resonator into which a treatment target is inserted, and a maximum electric field intensity distribution at a desired treatment site within the inserted treatment target. means for generating a higher-order resonance mode within the cavity resonator, and moving the cavity resonator toward the treatment target by at least an angle of symmetry of the electric field intensity distribution due to the higher-order resonance mode so that the region is located within the cavity resonator; and rotational drive means for rotating the patient about an axis passing through the treatment area.

[For production]

When a higher-order resonance mode is generated within a cavity resonator, a complex pattern of electric field intensity distribution occurs within the cavity. The maximum region of this electric field strength distribution is located at a desired treatment site within the treatment object inserted into the resonator. Then, the cavity resonator is rotated relative to the treatment target around an axis passing through the treatment area. This rotation of the cavity resonator causes the electric field intensity distribution to rotate around the treatment site. Therefore, depending on this rotation, the positional relationship with the electric field intensity distribution will not change for the treatment area that is the center of rotation, and the maximum area will always be located, but in other areas of the treatment target, the electric field intensity distribution will change from rotation to rotation. As it moves, even if a maximum area occurs in other areas, it moves, so in the end, areas other than the treatment area are not heated that much. As a result, only the treatment area within the treatment target is heated more intensively than other areas within the treatment target,
Localized heating of the treatment area located deep within can be achieved. Here, the cavity resonator is not limited to a literal cavity, but may also be one filled with a dielectric material (for example, a liquid such as pure water whose dielectric constant is approximately equivalent to that of the human body).

【Example】

Next, an embodiment of a cavity resonator type hyperthermia device according to the present invention will be described with reference to the drawings. FIG. 1 is a sectional view seen from the front, and the cylindrical cavity resonator 1 is arranged so that the axis of the cylinder is in the vertical direction. This cylindrical cavity resonator 1 is fixed to a rotating frame 2, and this rotating frame 2 is rotatably held by a main frame 3. Then, the rotating frame 2 is rotated by at least 180 degrees by the motor 4 and a suitable rotational drive mechanism, and this rotation is repeated back and forth. A hole 11 is provided in the side surface of the cylindrical cavity resonator 1, through which a patient 6 lying on a bed 5 is inserted in a direction perpendicular to the plane of the paper. This bed 5 moves linearly in a direction perpendicular to the plane of the paper, but does not rotate. Therefore, the cylindrical cavity resonator 1 moves toward the patient 6 with an axis parallel to the body axis of the patient 6 as its central axis. It will rotate relative to the A power supply connector 12 is attached to the cylindrical cavity resonator 1 at a position as shown in FIG. 2, for example, and high-frequency power of a predetermined frequency is supplied thereto. By appropriately selecting this feeding point and frequency, a desired higher-order resonance mode can be generated within the cylindrical cavity resonator 1. In this embodiment, TM111 mode is generated. This TM11. mode, the electric field strength distribution on a plane along one diameter is as shown in Figure 2, with the center point O
The electric field strength is at its maximum. In addition, in this pattern, there are also maximum points at points A, B, C, and D. Therefore, if the cross section of the patient 6 is circular as shown by the two-dot chain line in Fig. 2, the electric field strength is high at positions A, B, C, and D on the body surface, It will be heated by the strong electric field strength. However, in this embodiment, an axis (
The cylindrical cavity resonator 1 is caused to repeatedly rotate back and forth through 180° around an axis (which passes through the plane of the paper), while the patient 6 remains stationary. Therefore, the electric field strength distribution in the pattern shown in Fig. 2 rotates with respect to the patient 6, and the electric field strength is always high at point O of the patient 6, but at points A, B, C, and D other than this point O. At other points, such as points, regions with high electric field strength move with rotation. Therefore, as shown in Figure 3, the electric field strength (absolute value) at each point during this rotation remains high and constant at point O, like a straight line A, and for example, at point A, it becomes high like a curved line. It changes by becoming higher or lower. At point A, the average electric field strength is as shown by the dotted line, which is clearly lower than in the case of straight line A. Therefore, only the region near point O is heated relative to other regions, and localized deep heating is achieved. In this case, the rotation angle of the cylindrical cavity resonator 1 needs to be at least the symmetrical angle of the electric field intensity distribution pattern generated therein (180° in the pattern shown in FIG. 2). Therefore, the rotation mechanism of the cylindrical cavity resonator 1 generates a high-order resonance mode with a pattern of electric field intensity distribution in which a maximum area of electric field intensity occurs near the rotation center axis, which is determined mechanically. If the desired affected area of the patient 6 to be treated is located near the axis, only that affected area will be locally heated, and other areas will not be heated. Note that the above TM, 1 mode and its electric field strength distribution pattern (Fig. 2) are just one example, and it is possible to use other higher-order modes and reciprocating rotation angles corresponding to their electric field strength distribution patterns. Of course.

【Effect of the invention】

According to the cavity resonator type hyperthermia device of the present invention, it is possible to locally heat the affected area deep in the patient's body without causing any inconvenience to normal tissues other than the affected area.
It can improve the therapeutic effect.

[Brief explanation of the drawing]

Fig. 1 is a partially sectional front view of a cavity resonator type hyperthermia device according to an embodiment of the present invention, Fig. 2 is a diagram showing the electric field intensity distribution, and Fig. 3 is a diagram showing the change in electric field intensity due to rotation. FIG. 4 is a schematic perspective view of the conventional example, and FIG. 5 is a diagram showing the electric field intensity distribution of the conventional example. DESCRIPTION OF SYMBOLS 1... Cylindrical cavity resonator, 11... Hole, 12... Power supply connector, 2... Rotating frame, 3... Main frame, 4... Motor, 5... Bed, 6 ···patient.

Claims (1)

[Claims] (1) A cavity resonator into which a treatment target is inserted, and a high-order resonance mode within the cavity resonator so that the maximum region of electric field strength distribution is located at the desired treatment site within the inserted treatment target. and rotational drive means for rotating the cavity resonator relative to the treatment target around an axis passing through the treatment area at least by an angle of symmetry of the electric field intensity distribution due to the higher-order resonance mode. A cavity resonator type hyperthermia device characterized by: