FR2585253A1 - Device for treatment using hyperthermia - Google Patents

Abstract

The present invention relates to a device for treatment using hyperthermia, of the type with implantable single-pole probes S1, S2, S3, S4. The said device comprises at least two generators G1, G2, connected to the said implantable probes S1, S2, S3, S4, allowing the distribution of an electric field I1, ..., In to be distributed, which field is used to heat an area 8 to be treated without modifying the position of the said implantable probes.

Description

HYPERTHERMIA TREATMENT DEVICE
The invention relates to a device for treatment by hyperthermia, making it possible to heat a sick region of a patient by the dissipation of electrical energy applied according to an electric field by means of unipolar electrodes arranged in the vicinity of the sick region. . The invention is remarkable in that it makes it possible to considerably reduce the effects, traumatic for the patient, provided by such treatments.

 Hyperthermia is a known process which consists in heating living biological tissues to temperatures appreciably higher than their normal temperature, and which is used in the treatment of various diseases and in particular in cancer therapy.

In the example of this last application, it is desirable to heat the tissues to be treated at temperatures of the order of 440C to 450C, while avoiding as much as possible, a significant rise in the temperature of the surrounding healthy tissue.

 This condition raises a problem which lies in the correct location of the heated area. In certain configurations that the diseased tissues may present, this correct localization of the heating is impossible to obtain with electrodes situated outside the patient's body. Also in many cases, treatment with hyperthermia is carried out using electrodes implanted directly in or around the area to be treated, so as to better circumscribe the heated area.

 Such probes can be either of the bipolar type or of the unipolar type. In the case of bipolar probes, the high frequency electrical energy delivered by a generator, in the form of a voltage, can be applied to a single probe of this type, to heat the region in which it is implanted. In the case of unipolar probes, the high or medium frequency voltage delivered by the generator is applied to two separate unipolar probes, each of the two probes being connected to one of the output poles of the generator, the heated zone then being mainly established between the two unipolar implantable probes.

 The implantation of a bipolar or unipolar probe in a diseased region, represents for a patient an operation which can be accompanied by significant pain, and which is particularly traumatic in that the treatments by hyperthermia for an area to be treated given, must generally be repeated at variable frequencies and over periods of time between a few days and a few tens of days.

 Another painful or at least very unpleasant effect for the patient is linked to the particular sensitivity of the skin tissues to temperature. Indeed, experience shows that it is not generally possible for the comfort of the patient, to maintain, without anesthesia, a temperature of the order of 430 at the level of the skin during periods of order of one hour.

 Another important discomfort for the patient, during the treatment, is linked to the mechanical rigidity of the probes, in particular of the unipolar probes. The latter are generally constituted by metal needles, relatively rigid and which can, even after their positioning, constitute the source of pain or discomfort more particularly when crossing the skin.

 A general aim of the present invention is to provide a structure for implanting the probes, unipolar or bipolar, making it possible to reduce the inconvenience suffered by the patient as much as possible.

 More specifically, one of the aims of the invention is to eliminate the inconvenience due to the repetition of the implantations of the probes.

 Another object of the invention is to suppress overheating of the skin during treatments by hyperthermia of the subcutaneous tissues.

 Finally, another object of the invention is to remove or reduce the discomfort caused to the skin by the rigidity of the probes.

 It should also be noted that during the treatment, certain tissues in the area to be treated may show different temperature rises, which may lead during the treatment to modifying the implantation of the probes. Also, one of the objects of the invention is also to make it possible to modify the configuration of the heated zone, without requiring a modification of the location of the probes.

 According to the invention, a hyperthermia treatment device comprising, at least one generator delivering alternative electrical energy, said electrical energy being applied, according to an electric field, to an area to be treated of a patient by means of unipolar electrodes connected to said generator, at least one of said unipolar electrodes being an implantable unipolar probe, is characterized in that it also comprises at least one vector tube intended to be permanently implanted in the area to be treated by crossing the skin of the patient and containing said unipolar probe during a hyperthermia session, said vector tube comprising at least one tubular end formed of an insulating material and extended by a metal tube, said metal tube being intended to contain at least partially said unipolar probe and to be in contact with said area to be treated, and said tubular end being intended to be located at the level of the skin, said unip probe pole being introduced by said tubular end into said metal tube with which said unipolar probe is in electrical contact.

 We mean by the expression "placed permanently" with regard to the vector tube, a period of time of, for example, several days, within which several treatment sessions by hyperthermia are provided for which the setting in Place unipolar electrodes or probes by inserting them into a carrier tube.

It should be noted that a very important advantage, brought by the invention, is to be able to easily associate a treatment with brachytherapy with treatment by hyperthermia: the same vector tubes can be used: a) - to introduce radioactive needles (polonium or other) for brachytherapy sessions, b) - to introduce unipolar leads, for hyperthermia sessions,
The invention will be better understood thanks to the description which follows given by way of nonlimiting example, and with the aid of the four appended figures, among which: - Figure 1 illustrates the installation of unipolar probes in an area to treat, with a first version of a hyperthermia treatment device according to the invention; - Figure 2 shows details of a vector tube intended, in the invention, to contain a unipolar probe; - Figure 3 shows schematically a second version, with several generators, of a treatment device according to the invention allowing easily to modify the distribution of the currents in an area to be treated; FIG. 4 schematically illustrates a modification of the distribution of the currents compared to FIG. 3.

 FIG. 1 illustrates a device 1 for treatment by hypothermia according to the invention, and an example of implantation of unipolar probes S1, S2.

The processing device comprises a generator G1 of the type operating at medium or high frequency (of the order of 100 KHZ to several MHZ), and of average power (on the order of a few tens of Watt to a few hundred Watt). The generator G1 delivers, between first and second output terminals 4, 5, an alternating electrical energy intended to be dissipated in the body 6 (partially shown) of a patient, in order to raise the temperature of an area 8 to be treated by hyperthermia. The electrical energy delivered by the generator G1, in the form of a voltage (not shown) for example, is applied to the unipolar probes
S1, S2, the first unipolar probe S1 being for this purpose connected to the first output terminal 4 and the second unipolar probe S2 being connected to the second output terminal 5. In the nonlimiting example described, the unipolar probes S1, S2 are both of the implantable type, that is to say constituted by a metal needle 10, one end of which 11 is connected to a conventional electrical conductor wire 12, by which they are connected to the generator C1, but it is also known in the art. prior art, and this can also be applied in the context of the invention, of using a single implantable probe S1, S2 of the unipolar type cooperating with a unipolar electrode (not shown) intended to be placed outside the body 6 of the patient.

 In the prior art, as explained in the preamble, implantable unipolar probes are implanted directly into the tissues to be treated at each hyperthermia session, contrary to the possibilities offered by the present invention.

 Indeed, according to a characteristic of the invention, the treatment device 1 also comprises vector tubes V1, V2 intended to be implanted in the area 8 to be treated or in its vicinity, as shown in the example non-limiting of Figure 1, and to be left there permanently, that is to say over a period of time containing several sessions of treatment with hyperthermia. The vector tubes Vi, V2 are intended to contain, during each treatment session, a unipolar probe S1, S2 introduced into a vector tube V1, V2 by a first or a second end 17, 18 of the latter, at least one of these ends 17, 18 must for this purpose be outside the body 6 of the patient, that is to say in excess relative to the skin 20 of the patient.

 FIG. 2 shows more clearly, by way of nonlimiting example, a vector tube V1 and a unipolar probe S1. The first and second ends 17, 18 of the vector tube V1, at least one of which is necessary, are made, according to a characteristic of the invention, of an electrically insulating material and, according to another characteristic of the invention, this material must also be flexible; these characteristics each being useful for the comfort of the patient as will be explained in the following description; these conditions being fulfilled by using materials, such as for example a polyamide known under the brand "8nylon", or in polytetrafluoroethylene known under the name "teflon". The first tubular end 17 is extended by a metal tube 23, communicating with the tubular end 17, so that a unipolar probe Si can be introduced in the direction shown by the first arrow 25 for example, into the metal tube 23.

In the nonlimiting example described, the metal needle 10 of the unipolar probe Si has a diameter D1 substantially less than an internal diameter D2 of the metal tube 23; this makes it possible to ensure, in a simple manner, an electrical contact between the metal needle 10 and the metal tube 23 when the needle is introduced at least partially into the latter. Assuming that Pugilla 10 has conventionally a diameter D1 of the order of 0.8 mm, and that the internal diameter D2 of the metal tube 23 is of the order of 0.9 to 1 mm for example, in order to allow the passage of the needle 10 and ensure electrical contact , and that on the other hand the wall 24 of the metal tube 23 has a thickness E of the order of 0.1 to 0.15 mm, an outside diameter D3 of the metal tube 23 is of the order of 1.1 to 1.2 mm. The assembly between the metal tube 23 and the tubular ends 17, 18 can be carried out by a person skilled in the art in different ways, as for example shown in FIG. 2, where the metal tube 23 has on the side from its junction J with the tubular ends 17, 18, an end portion 3 where the wall 24 has a thickness El lower, so that the tubular end 17 can be pressed onto this end part 3 without providing any significant excess thickness relative to the outside diameter D3; the end part 3 thus comprising an electrically insulating overcoating 16.

 The implantation of the vector tube V1 in the area 8 to be treated, can be carried out using a hollow needle (not shown) of the type called vector gutter for example, the use in the medical field is common, especially for implantation various probes in living tissue; such a vector gutter also being described in a French patent published under No. 2,421,628. The vector tube V1 can be placed in the vector gutter, which is then introduced into the zone 8 to be treated at the desired location; the vector gutter is then carefully removed by sliding it on the vector tube V1 which remains in place.

Referring again to FIG. 1, the vector tubes VI, V2 being in place, each unipolar probe S1, 52 is introduced into a vector tube V1, V2. The unipolar probes Si, S2 being connected to the generator 7, and the latter being in operation, an electric field represented in FIG. 1 by field lines I1, 12, ..., In is established between the unipolar probes S1, 52 by means of the vector tube V1, V2, in order to bring about a rise in the temperature of the zone to be treated 8 subjected to the electric field. An advantage of this arrangement lies in that it makes it possible to confer on the vector tubes Vi, V2 active lengths L1, L2 respectively between which an electric field is established, independently of the lengths L3 of the unipolar probes S1, S2; this makes it possible to better circumscribe the zone 8 subjected to the electric field. Indeed, for frequencies lower than a few MHz, thicknesses of insulating materials of the order of a tenth of a mm are sufficient to prevent re-establishment of the electric current. In the nonlimiting example described, the active lengths L1, L2 correspond to the length of the metal tubes 23 laid bare, that is to say not arisen by the tubular ends 17, 18 made of insulating material. This makes it possible in particular to give the active lengths L i, L2 possibly different dimensions, compatible with the geometry of the area 8 to be treated, while using unipolar probes
S1, S2 having metal needles 10 of the same length L3.

 The tubular ends 17, 18 also provide a protective role with respect to the skin 20, which is particularly sensitive to temperature rises. Thus, for example, in the case where a unipolar probe, the second unipolar probe S2 for example is located at the level of the skin 20, not being for example fully inserted in the second vector tube V2: the end 11, of the needle 10 connected to the wire 12, then being located outside the body 6 of the patient at a point marked 11 'for example, the presence of the tubular end 17 prevents the establishment of the electric field at the level of the skin 20 and thus avoids the burning sensation felt by the patient in such a case. This possibility of withdrawal of a unipolar probe S1, S2 is all the more important, as it makes it possible to release into the vector tube V1, V2 a zone Z opposite the first end 17, into which can be introduced through the second end 18, a needle of radioactive material (not shown) of a conventional type. This allows simultaneous treatment with hyperthermia and brachytherapy treatment.

 Another very important advantage for the comfort of the patient is provided by the flexibility of the tubular ends 17, 18, which allows them relative movements relative to a longitudinal axis 28 of the unipolar probes S1, S2, this flexibility allowing them to follow movements of the skin due for example to slight movements of the patient, thus making it possible for the latter to feel painful tightness.

 In the nonlimiting example of FIG. 1, - two vector tubes V1, V2 have been shown, but a greater number n of these vector tubes V1, V2, ..., Vn can be permanently installed, in the case for example, or a greater number of unipolar probes S1, S2 are used with, for example, several generators (not shown in FIG. 1) or even in the case where the practitioner wishes to modify the configuration of the heating of a zone 8 treated. Such a modification may be desirable from one treatment session for hyperthermia to a next session, or even during the same session, in cases for example where tissues (not shown) of an area to be treated 8 have different sensitivities. electric field.

 FIG. 3 schematically illustrates a second version of the treatment device 1 according to the invention, which makes it possible to carry out modifications of the heated zone as mentioned above, without requiring the modification of the position of implantation of vector tubes V1, V2 , ... already installed (not shown in Figure 3 for clarity). It should be noted that this version of the invention is also applicable in the case of a conventional use of implantable unipolar probes, that is to say without using the vector tubes V1, V2, ..., V3.

In this second version, the processing device 1 must comprise, in addition to the first generator C1, at least one additional generator G2, that is to say at least two generators
G1, G2 synchronized in frequency.

Also, in the nonlimiting example described, the processing device 1 comprises, in addition to the first generator G1, a second and a third generator G2, G3, substantially of the same type as the first generator Gl; a number N of generator, greater than 3 which can also be used. In the nonlimiting example described, the processing device 1 also comprises a main oscillator 30 connected by links 31 to each of the generators G1,
G2, G3 so that the latter operate at the same frequency F1 and according to the same phase.

The area to be treated 8 is represented in FIG. 3 by a sectional view along a plane perpendicular to the longitudinal axis 28 shown in FIG. 1. In the example described, six unipolar probes S1, S2, ..., S6 are either implanted directly in the area to be treated 8, or are each placed, as in the previous example, in a vector tube previously implanted; unipolar probes Si, ...,
S6 being shown according to their section, they are represented in FIG. 3 according to circles. In the nonlimiting example described, the unipolar probes SI,..., 56 are arranged in the zone 8 to be treated in substantially a circle 16 having a center O, through which three axes 33, 34, 35 pass between them forming an angle t of about 300 two unipolar probes SI, ..., S6 connected to the same generator G1,
G2, G3 being, in the nonlimiting example described, arranged on the same axis 33, 34, 35, but opposite to the center
O. Each of the probes S1, ..., S6 is connected by an electrical conductor 12 to one of the output terminals BI, Ef2, ..., B6 of a generator Gl, G2, G3 - the first and second probes S1 , S2, arranged on the first axis 33 are connected respectively to the first and to the second terminal
B1, B2 of the first generator Gl - the third and fourth probes 53, S4 arranged along the second axis 34, are respectively connected to a third and fourth output terminals B3, B4 of the second generator G2; - The fifth and sixth probes S5, S6 arranged on the third axis 35, are respectively connected to a fifth and a sixth output terminal BS, B6 of the third generator G3.

 The three generators G1, G2, G3 operating at the same frequency F1, if the polarities +, - (for a given instant) of the output terminals B1, B2, and B3, B4 and BS, B6 corresponding to each of the generators are identified G1, G2, G3, it is possible to place the unipolar probes Si -to S6 corresponding to a desired position in the zone 8 to be treated, as for example shown in FIG. 3, so as to establish the electric field between these unipolar probes S1 to S6 according to a desired configuration; this positioning of the probes can be done by direct implantation or by placing each probe in a vector tube as it was previously explained.

 Thus supposing that the first, third and fifth output terminals B1, B3, BS have a positive polarity +, the second, fourth and sixth output terminals B2, B4, B6 will have a negative polarity -, these polarities +, - are found respectively at the level of the unipolar probes S1, S3, S5 and S2, S4, S6.

 The electric field represented by the field lines 11 to Ins will in these conditions be established throughout the area 8 to be treated.

As already mentioned, it may be desirable to modify the distribution of the electric field, that is to say the configuration of the heated zone. This is possible in the invention, without causing additional inconvenience to the patient, either by substituting the unipolar probes 51, ..., S6 with each other, relative to the vector tubes, in the case where these are used, or by modifying the +, - respective polarity of the probes S1, to S6, by acting on the generators G1, G2, G3, both in the case where the unipolar probes S1 to S6 are located directly in the area 8 to be treated, as in in the case where they are arranged in vector tubes. To this end, each of the generators G1, G2, G3 comprises an reversing device 41, 42, 43 respectively, making it possible to reverse the polarity between two output terminals B1, B2 and B3 , B4 and B5,
B6 of the same generator G1, G2, G3. The switching devices 41, 42, 43 may consist of conventional switching means allowing for example for the first generator G1, to reverse connections (not shown) established between the output terminals B1, B2 and amplifiers (not shown ) that conventionally comprises each generator G1, G2, G3; such an inversion of the polarities being achievable in different ways, all within the reach of those skilled in the art, and may also consist in an inversion of the conducting wires 12 connected to the output terminals B1, B2.

 It is thus possible, by modifying the polarity of the probes Si to S6, to obtain a modification of the distribution of the electric field, such as for example represented in FIG. 4.

 FIG. 4 represents the area 8 to be treated according to a view similar to that of FIG. 3, that is to say along a plane perpendicular to the longitudinal axis 28 shown in FIG. 1; the unipolar probes Si to 56 occupy the same position as in FIG. 3, but have different +, - polarities, so that these polarities are successively positive + and negative -. The electric field, represented by the field lines I1, ..., In established between adjacent probes of opposite polarity +, - then corresponds substantially to a circular distribution along the circle 16, that is to say around of the center O which in this configuration is not subjected to the electric field.

 Other configurations of the heating of the zone 8 to be treated can be obtained, by modifying either the distribution of the probes SI, ..., S6 in the vector tubes V1, V2, ..., or by modifying the positive polarity + or negative - given to each of the probes.

 This description constitutes a nonlimiting example of a hyperthermia treatment device 1 according to the invention, in which n vector tubes VI, V2, ..., Vn capable of being permanently implanted make it possible to eliminate the causes of the discomfort felt by a patient with prior art treatment devices; a treatment device 1 according to the invention also making it possible to produce heating suitable for the area 8 to be treated, with much more flexibility than in the prior art.

Claims (4)

 1. Hyperthermia treatment device, comprising a generator (Gl) delivering an alternative electrical energy, said electrical energy being applied, according to an electrical field (I1, ..., In), to a zone (8) to be treated with a patient thanks to two unipolar probes (S1, S2) of the implantable probe type, connected to said generator (G1), characterized in that it also comprises at least a second generator (G2), synchronized in frequency with the first generator ( G1), and connected to a third and fourth unipolar probe (S3, S4) cooperating with the first two probes (S1, 52) to heat said area (8) to be treated.  2. Treatment device according to claim 1, characterized in that it comprises means (41, 42) for modifying the distribution of said electric field (it, ..., In) without modifying the setting of said probes (SI, S2, S3, S4).  3. Treatment device according to claim 2, characterized in that each of said generators (G1, G2) comprises switching means (41, 42) for reversing the polarity (+, -) applied to the two unipolar probes (S1-S2 , S3-S4) to which it is connected, in order to modify the distribution of the electric field to which said zone (g) to be treated is subjected.  4. Treatment device according to one of claims 1 to 3, characterized in that it further comprises a main oscillator (30) connected to said first and second generators (G1, G2) to operate them at the same frequency.