WO2001003773A1

WO2001003773A1 - High power ultrasound transmitter

Info

Publication number: WO2001003773A1
Application number: PCT/CN1999/000090
Authority: WO
Inventors: Shenxu He; Xiaodong Wu
Original assignee: Shenxu He; Xiaodong Wu
Priority date: 1999-07-13
Filing date: 1999-07-13
Publication date: 2001-01-18
Also published as: AU4894399A

Abstract

The invention provides a high power ultrasound transmitter having a concave inner surface. There are plurality of electroacoustic transducers on the inner surface. The electroacoustic transducers are connected each other in series or in parallel and located on a same spherical surface. The normal of emitting surface of the electroacoustic transducer is perpendicular to the spherical surface. The calibre of the concave is bigger than or equal to 290 mm; the amount of the electroacoustic transducers is bigger than or equal to 201; the diameter of the electroacoustic transducer is less than or equal to 19 mm; the radius of the spherical surface is less than the calibre of the concave. Using this ultrasound transmitter, the temperature at focal spot within human body can reach 70 ∩ 100 °C, while the skin is not seared.

Description

TECHNICAL FIELD The present invention relates to an ultrasonic medical device, and more particularly, to a power ultrasonic transmitter in an external ultrasonic therapeutic machine. Background of the invention

The treatment of cancer has been a difficult medical problem for a long time. Tumor hyperthermia is an effective method for treating tumors that is summarized through scientific exploration and practice. Ultrasound tumor hyperthermia is the main measure of tumor hyperthermia. In order to make this technology For clinical application, people have developed ultrasonic therapy machines.

Ultrasound is a wave that transmits energy. In different media, ultrasonic waves can transmit energy to a certain distance. The biological effects of ultrasound have long been of concern. The biological effects of ultrasound have a lot to do with sound intensity, frequency, and the nature of biological tissues. According to the mechanism of action, it can be divided into: thermal effects, mechanical effects, and so on. The ultrasonic therapy machine can utilize the transmission of ultrasonic energy to concentrate the energy on the lesions in the body and generate enough heat, which can inhibit the growth of tumor cells and further deterioration of the lesions, thereby achieving the purpose of treating tumors and eliminating lesions.

FIG. 1 is a schematic structural diagram of an external ultrasound treatment machine, which mainly includes: a B-ultrasonic positioning device 1 for determining the position of a lesion in the body; an ultrasonic generating device 2 for generating electrical oscillations of a specific frequency and power; a power ultrasonic transmitter 3, The electric oscillation is converted into ultrasonic waves, and the generated ultrasonic waves are focused on a certain focal point; the acoustic wave transmission medium body 4 is used for reducing energy attenuation and spatial refraction in the acoustic wave transmission; and a three-dimensional motion device 5.

Power ultrasound transmitter (hereinafter referred to as transmitter) is the key part of extracorporeal ultrasound treatment machine. It undertakes the task of transmitting high-power ultrasound. Often used is to fix 16 to 24 pieces of electro-acoustic transducers on a spherical substrate, each of which has a diameter of about 20 mm. They are arranged in parallel or in series on the surface of the inner spherical surface in an orderly manner. To form an array of transmitting elements with an inner sphere; the diameter of the transmitter is generally about 200 mm, and the value of the spherical radius R is also about 200 mm.

At present, similar ultrasonic transducers at home and abroad have some common shortcomings, so they cannot be used in clinical practice. These defects include: ① a certain burn rate on the skin during treatment, and the literature reports 7% to 20%; ② pain during treatment General anesthesia or half-body anesthesia is required; ③ there are complications of bleeding and organ perforation when treating abdominal and pelvic organs; and ④ there are limited types of tumors to be treated, which can only treat surface tumors or abdominal cavity. Superficial tumor in the pelvis. Summary of the Invention

An object of the present invention is to provide an ultrasonic power transmitter which can avoid burning a normal part of a human body. The inner surface of the ultrasonic power transmitter is a concave body, and a plurality of electro-acoustic transducers are provided on the inner surface. In parallel or series, the multiple electro-acoustic transducers are located on the same spherical surface, and the normal of the emitting surface of the electro-acoustic transducer is perpendicular to the spherical surface, which is characterized by: the concave shape The diameter of the body (ie, the diameter of the transmitter) is 290 mm or more; the number of the electro-acoustic transducers is 201 or more; the diameter of the electro-acoustic transducers is 19 mm or less; and the spherical surface The radius (ie, the launch radius) is smaller than the caliber of the concave body.

The manufacturing principle of the new type of emitter is to avoid the occurrence of burns and pain on the skin under the basic premise of ensuring the heat killing effect. According to analysis, it can be considered that the two complications are caused by the skin in the incident field (the incident area). The energy density is too high, which is caused by exceeding the skin's pain area and cumulative heating threshold. Figure 2 is a schematic diagram of increasing the aperture of the transmitter to reduce the incident energy density. After a simple analysis, it can be found that with the same emission radius R, the diameter D of the transmitter is doubled, and the energy density of the incident field will be reduced to one quarter of the original. This increase in the aperture D of the transmitter can effectively reduce the energy density of the incident field. Therefore, the emission radius R should be smaller than the caliber of the concave body. The present invention has been confirmed by a large number of experiments. In the case where the diameter of the ultrasonic power transmitter is greater than 290 mm, the energy density of the incident field can be reduced below the pain threshold of the human body, and a painless treatment effect can be obtained, which is further combined with other parameter selection. To achieve the design objective of the present invention.

The principle of focusing each electro-acoustic transducer is shown in Figure 3. d is the diameter of the electro-acoustic transducer, A and B are the two ends of the diameter, the focal point is F, and the center of the surface of the electro-acoustic transducer is the focal point. The high vertical distance is F0, and Z AFB is the included angle of the focused beam 2 α. Then it can be clearly seen that the smaller the Z AFB is, the smaller the offsetting effect is, and the more the synergistic enhancement effect is more obvious.

The principle when selecting the number of electro-acoustic transducers is: The denser the array of electro-acoustic transducers, the better the uniformity of the transmitted energy density. The smaller the average transmission power of each electroacoustic transducer (rated power / actual transmission power), the longer the service life.

In the working state, when a set of continuous electric pulses with the same phase or the same basic phase is applied to these electro-acoustic transducers, the electro-acoustic transducers emit several beams of ultrasound, the beams of which are directed toward the center of the sphere, and the focus is spot-shaped (sphere Center position) to form a high-energy-density region (focal region), with a temperature of 70 ~ 100 ° C. Tumor cells quickly die at this high temperature, thus forming an ideal treatment for killing cancerous tissues without surgery.

The ultrasonic transmitter of the present invention has a simple structure, convenient use, and reliable performance; and can give full play to the efficiency of focusing, so that the temperature of the focal point in the human body reaches 70 to 100 ° C, but avoids skin burns, and does not require anesthesia during treatment. There are no complications in the treatment of cavity organs, and the adaptive diseases have been greatly expanded, and excellent treatment results can be obtained. Brief description of the drawings

In order to make the present invention easier to understand, the embodiments are described below with reference to the accompanying drawings to further describe the present invention in detail, wherein FIG. 1 is a schematic structural diagram of an ultrasonic treatment machine in the prior art; FIG. 2 is a schematic diagram of expanding an aperture of a transmitter to reduce incident energy density;

Figure 3 is a schematic diagram of the phase difference comparison principle of a small-diameter electro-acoustic transducer unit;

FIG. 4 is a side view of a preferred embodiment of a power ultrasonic transmitter of the present invention; a way of implementing the present invention

Choice of transmitter caliber:

The manufacturing principle of the new type of emitter is to avoid skin burns and pain under the basic premise of ensuring heat killing effect. According to analysis, it can be considered that the two complications are caused by the high energy density of the skin in the incident field. Exceeded skin pain threshold and cumulative warming threshold.

Figure 2 is a schematic diagram of increasing the aperture of the transmitter to reduce the incident energy density. After a simple analysis, it can be found that with the same emission radius R, the diameter D of the transmitter is doubled to the original, and the incident field energy density will be reduced to one quarter of the original.

The skin pain threshold I is derived below based on empirical data. The two data of the ultrasonic frequency and focal sound intensity of the hyperthermia machine are very similar to those of the lithotripsy machine. The skin incident energy density of the lithotripsy machine can be used as the important reference data of the hyperthermia machine. Successful experience at home and abroad believes that when the caliber of the lithotripter's emitter is greater than or equal to Φ 200 μm, the shock wave with a frequency of 1 MHz and a focal sound intensity of 1 KW / cm ² has these two technical features that are not painful and do not hurt the skin. As shown, when the diameter of the emission Crushing D = O) 1 20cm, from the focal plane on the transmitter height H = 16cm, transmit radius ^{^{^{R 2 = 16 2 + 10 2}}} , R «18. 7cm 0 when When the incident field skin is 6 cm away from the focal point, the incident field radius r = 10 x 6/16 = 3. 75 cm, and the skin incident field area S = π r ² 44. lcm ² , then the pain threshold I = 1000/44 can be obtained. . 1 «22. 6W / cm ² .

Analyze the current domestic and foreign hyperthermia machines, the caliber D is generally around O 20cm, the emission radius R is 30cm, then r = 2.12cm, S = 14.1cm ² , then the incident field skin (target skin distance 6cm), the energy density of the download is 1 = 1000 / 14.1 «70.8W / cm ² , this value exceeds the pain threshold by 213%, so it should be improved.

Because the ultrasound used by the hyperthermia is a sine wave, it is more severe than tissue damage caused by a unidirectional pressure pulse. Therefore, a value exceeding 11% of the pain threshold will cause skin pain to be more obvious and should be re-examined. The experimental data of the caliber of the transmitter is explained in detail below.

Example 1:

When the diameter of the transmitter is D = Φ50 η and the emission radius is R = 36cm, when the target skin distance is 6cm and the focal sound intensity is 1KW / cm ² , the energy density of the incident field skin is 1 = 9.49W / cm ² , this value is only Corresponds to 2/5 of the pain threshold, so theoretically there should be no pain. When the prototype used this transmitter for many animal experiments, the animal did not generate any hot response during ultrasonic emission, and when it was launched with a Φ22 transmitter with the same radius, the animal had a significant struggling hot response, which proved that the design was successful. The measured maximum temperature of this emitter in a target area 6 to 8 cm deep from the skin is 87 ° C, which has far exceeded the basic temperature of hyperthermia (> 60 ° C), which can meet the therapeutic application.

Example 2:

When the diameter of the transmitter is D = Φ29 (, the emission radius is R = 27cm, it is theoretically deduced that when the target skin distance is 6cm and the focal sound intensity is 1KW / cm ² , the power density of the incident field skin is 22.6W / cm ² . A similar painless effect was obtained in animal simulation experiments using this transmitter, proving that this design is also successful. However, strictly speaking, the R value of a D29cm transmitter should not be greater than 27cm, and the focal sound intensity should be stable and fixed at 1000W / _C m ² or so.

Example 3:

When the diameter of the transmitter is D = (I 5cm, the radius of the launch is 30cm, it is a better value for the transmitter. Through similar design calculations, the transmitter has a skin sound intensity of 1000W / cm ² and a target skin distance of 6cm. The incident sound power density is 1 = 6.85W / cm ² , this value is only equal to 30% of the pain experience threshold, and has the potential to further increase the focal sound intensity without pain and no anesthesia. Designed to carry out more than 600 actual treatments in the clinic, no case of pain occurred, no case required anesthesia, the focus temperature in the deep abdomen reached 70 ~ 107 ° C, and the malignant tumors of the abdomen and pelvic organs were effectively treated separately. Excellent results were achieved, and no bleeding or perforation complications occurred.

When the diameter of the transmitter is further enlarged, the structure density of the whole machine will be too large, and the imbalance and treatment inconvenience will be inconvenient. No further research is necessary. Choice of Electroacoustic Transducer Radius:

The basic requirement of a thermotherapy machine is that the focusing temperature is greater than 60 ° C. Technically, it is necessary to ensure the focusing effect. Under the premise that the whole machine has the effect of no pain and no skin burns, each beam must reach the focus. The ultrasound beam has as large a focusing effect as possible. For the purpose of deep focus hyperthermia for depth of 3 cm or more, the ultrasound frequency should be about 1 MHz. At this time, the wavelength of ultrasound in the human body is only about 1.5 mm. Obviously, the geometric accuracy of the wave source has high requirements. Therefore, it is necessary to fully consider that the microbeams constituting each beam have the smallest angle cancellation and the largest synergy effect.

Figure 3 is a schematic diagram of the phase difference comparison principle of a small-diameter electro-acoustic transducer unit. As shown in Fig. 3, d is the diameter of the electro-acoustic transducer, A and B are the two ends of the diameter, and the focal point is F. The electro-acoustic transducer The vertical distance from the center of the surface of the energy container to the focal point is F0, and ZAFB is the included angle of the focused beam 2cc. Then it can be clearly seen that the smaller the ZAFB, the smaller the offset effect, and the more obvious the synergy enhancement effect.

When making this design, it is assumed that the new design of the AF value is the same as the traditional design value. When traditional design

When the AB value is 2cm and the AF value is 30cm, it can be known through calculation that H = 29.98cm, sina = l / 30, and a = 1.91. . When the new design is AB = 19mm, the calculation is equivalent, and cc = 1.81. This calculation is implemented and technically feasible; when the new design is AB = 15, the same calculation is performed, a = l. ⁴ 3 °, when this calculation is implemented and technically feasible, the maximum temperature at point F is 87 ° C; when the new design is AB = 12mm , Equivalent calculation, cx = 1.15. This calculation was implemented, the technology is feasible, and the maximum temperature at point F is 10 ⁷ ° C; When the new design is AB = lmm, the same calculation, ct = 0.095 °, this calculation is implemented, the technology is feasible, and the maximum temperature of point F is 111 ° C. When the AB value is too small, it should have the best focusing effect, but AB is too small. Although technically feasible, the assembly and wiring workload of each piece will be increased by dozens of times, which is disadvantageous for the implementation of industrial production.

Then, a better value that guarantees the focusing effect and is convenient for industrial production is selected as 12 hidden. Selection of the number of electroacoustic transducers:

From the points 1 and 2 mentioned above, it can be confirmed that the aperture selection value of the new transmitter is 290-500mm, and the diameter of each electro-acoustic transducer is selected from 1 to 19mm. Corresponding to this, the power ultrasound of the present invention The number of the electro-acoustic transducers used is 201 or more. The smaller the number of electro-acoustic transducers, the higher the power emitted by a single electro-acoustic transducer. In this way, near the focal point, it is easy to form a high-temperature region and cause burns to the human body. Especially in the case of increasing the ultrasonic transmission power, it is very easy to cause burns to the human body. Increasing the number of electro-acoustic transducers can correspondingly reduce the transmission power of a single electro-acoustic transducer. Therefore, when selecting the number of electroacoustic transducers, the principle is: The denser the array of electroacoustic transducers, the better the uniformity of the emitted energy density. The smaller the average transmit power (rated power / actual transmit power) of each electroacoustic transducer, the larger the value and the longer the service life.

Example 4:

According to the principle above, when the diameter of the transmitter is Φ 290 and the R value is 270mm, the maximum number = effective installation area ÷ actual installation area per piece, and the maximum number of Φ 1 hidden launch arrays that can be installed.

①Total installation area = 2 π r · h = 6. 28 χ 270 χ h = 98344. 8mm ²

②Effective installation area = total area-Φ 808 area of the ultra-sport bar-waterproof empty belt 1 0 hidden width (edge area) = 98344. 8— 3. 14 X 40 ² — 285 X 1 0

= 90470. 8mm ² ③ The actual installation area of each electro-acoustic transducer = 9mm ²

④Total number of installations = 90470.8 ÷ 9-10000 (units)

That is, in this embodiment, the diameter of the transmitter is C> 290mm, the value of R is 270mm, the diameter of the electro-acoustic transducer is ΦΙΙΙ, and the number of electro-acoustic transducers is 10,000. In animal experiments, when the focus sound intensity = 1KW, the animal has neither painful struggling nor skin burns, and the target zone can be monitored at 108 ° C in the pig. However, the installation process of this transmitter is very tedious, and the processing accuracy is too strict.

Example 5:

According to the transmitters mentioned above (Φ value 290, R value 70, h value 58), in the case of using a 015mm electroacoustic transducer, the actual installation area of each electroacoustic transducer needs 289mm ² , the maximum installation Quantity = 90470 ÷ 289 = 313, but in the actual installation process, only 201 pieces are installed when the effective area occupied by the unnecessary shielding tape is reduced. With this launcher, the same animal experiment effect as that of the previous experiment is achieved. At the same time, when a normal human forearm probes into the launching field, it also has no pain and no heat. The temperature rise in animals is 89 ° C.

Example 6:

Considering that in order to simplify the mechanical design of human body treatment, it is necessary to position the B ultrasound probe above the center of the transmitter to ensure that the treatment adjustment distance is greater than 17cm, so the transmitter parameters with R value of 300 hidden, Φ value of 450mm, and h value of 198mm are better parameters. , The effective installation area of this transmitter = 2 π rh-B ultrasound probe footprint area-probe shield area-waterproof area = 135253 Sa ² . When the electro-acoustic mounted D12mm on this area of the transducers, each electro-acoustic transducer actual installation area to be occupied 14 χ 14 = 256 wake ^2, so the actual installation electroacoustic transducer Number of transducer = 135 253 + 256 = 528 (sheet). This example has been tested in more than 400 clinical trials. Under the premise that the treatment interval is guaranteed, the treatment has no skin pain and no skin burns. The focus temperature is up to 108 ° C, which proves to be a better choice. Choice of launch radius:

In the laboratory phase, researchers designed transmitter data of different calibers and different radii. Listing 1 is as follows:

(Table 1 )

From Table 1, it can be analyzed that in order to ensure that the sound intensity of the skin's human shooting field does not exceed the threshold of pain, on the one hand, the diameter of the transmitter must be increased. With the increase of the diameter of the transmitter, the emission radius determines the skin incidence area. Decisive factor of sound intensity value. It is confirmed by a large number of experiments that: the radius of the spherical surface should be smaller than the diameter of the concave body, and the radius of the spherical surface can be selected to be 270 mm or more and 360 mm or less to obtain better results. Example 7

FIG. 4 is a side view of Embodiment 7 of the power ultrasonic transmitter of the present invention; in the preferred embodiment, the inner surface of the power ultrasonic transmitter is a concave body, and the view in the direction of the K direction is circular, except for the bottom of the pot, The other parts of the inner surface are located on the same spherical surface, and a plurality of piezoelectric sheets are laid on the spherical part of the inner surface, and the plurality of piezoelectric sheets are tangent to the inner surface, wherein: the diameter of the concave body is equal to 290 mm; the number of said piezoelectric sheets is 201; The diameter of the piezoelectric sheet is 15 mm.

The efficiency of focusing can be brought into full play, so that the temperature of the focal point in the human body reaches 70 to 100 ° C, but skin burns are avoided, and no anesthesia is required during treatment. There are no complications in the treatment of cavity organs, and the adaptive disease species has been greatly expanded, and excellent therapeutic effects can be obtained. All the features disclosed in the present invention (including any related claims, abstract and drawings) can be at least certain features and / or steps can be mutually inclusive.

All features disclosed in this invention (including any related claims, abstract and drawings) may be replaced by features having the same or similar purpose, unless otherwise indicated. In this way, unless otherwise indicated, each feature disclosed in the present invention is taken as an example for general introduction.

The invention is not limited to the specific introduction of the above embodiments. The present invention may be further updated or new combinations of the features disclosed in the present invention (including any related claims and new combinations may be made).

Claims

Claim

1. A power ultrasonic transmitter, the inner surface of which is a concave body, and a plurality of electro-acoustic transducers are provided on the inner surface. The plurality of electro-acoustic transducers are connected in parallel or in series. The electro-acoustic transducers are located on the same spherical surface, and the normal of the emission surface of the electro-acoustic transducer is perpendicular to the spherical surface, which is characterized by:

The caliber of the concave body is 290 mm or more;

The number of said electro-acoustic transducers is 201 or more;

The diameter of the electro-acoustic transducer is 19 mm or less;

The radius' j of the spherical surface is equal to the caliber of the concave body.

2. The power ultrasonic transmitter according to claim 1, wherein: the radius of the spherical surface is 270 mm or more and 360 mm or less.

3. The power ultrasonic transmitter according to claim 1 or 2, wherein: the caliber of the concave body is 500 mm or less.

4. The power ultrasonic transmitter according to claim 1 or 2, characterized in that: the number of said electro-acoustic transducers is 10,000 or less.

5. The power ultrasonic transmitter according to claim 3, wherein the number of said electro-acoustic transducers is 10,000 or less.

6. The power ultrasonic transmitter according to claim 1, 2 or 5, wherein the diameter of the electro-acoustic transducer is 1 mm or more.

7. The power ultrasonic transmitter according to claim 3, wherein the diameter of the electro-acoustic transducer is 1 mm or more.

8. The power ultrasonic transmitter according to claim 4, wherein the diameter of the electro-acoustic transducer is 1 mm or more.