A calibration method for a transducer device of an ultrasonic surgical cutting instrument

Abstract

The present invention proposes a calibration method for a transducer device of an ultrasonic surgical cutting instrument. The method measures the current amplitude of a transducer handle before leaving the factory, calculates the amplitude difference, and compares the amplitude difference with the amplitude tolerance. When the amplitude difference is less than the amplitude tolerance, the current value at this time is the calibrated current value, and the calibrated current value is written into a chip in the transducer handle. The calibrated current value is read by a power supply host and energy is output according to the current value. This calibration method is implemented before the instrument leaves the factory, and can also be actively adopted after the instrument has been used for a long time, so that the consistency of the energy output by the transducer handle is guaranteed.

Description

Technical Field

[0001] The invention relates to the field of medical device energy surgery, and in particular to a calibration method for a transducer device of an ultrasonic surgical cutting instrument. Background Art

[0002] Ultrasonic surgical cutting instruments, hereinafter referred to as ultrasonic scalpels. The main function of ultrasonic scalpels is to achieve minimal thermal damage and vascular closure while cutting soft tissue. The entire system is mainly composed of a power supply host, a transducer handle, and a scalpel head. The following figure shows the various systems of ultrasonic scalpels.

[0003] The transducer device for ultrasonic surgical cutting instruments, hereinafter referred to as the transducer handle, is based on the principle of using the inverse piezoelectric effect of piezoelectric ceramics to convert the electrical energy applied to the piezoelectric ceramic crystal stack into kinetic energy (ultrasonic vibration) on the horn. Common Langevin transducer handles mainly include: pre-tightening bolts, rear cover plate, front cover plate, flange, horn, such as Figure 1 shown.

[0004] Most of the existing power ultrasonic transducer handles use Langevin transducers, which have a simple structure and a high front-to-back amplitude ratio, and are therefore widely used. The core component of the transducer handle is the piezoelectric ceramic sheet, which has a complex and time-consuming production process and needs to go through the following processes: batching - mixing and grinding - pre-firing - secondary grinding - granulation - molding - plastic removal - sintering into porcelain - shape processing - electrode - high-voltage polarization - aging test, etc. It is difficult to ensure the consistent performance of each piezoelectric ceramic, which leads to differences in the output mechanical vibration performance of the transducer handle. After the ultrasonic blade is connected to the transducer handle, this difference will be magnified several times (generally 3 to 5 times), and the energy level output to the patient's lesion position on the action head will be uneven, which will also trouble doctors, that is, the ultrasonic blades of the same manufacturer will have a fast and slow cutting speed when used in the same gear, which is difficult to control, and thus causes unnecessary impact on patients and doctors. In addition, the unstable assembly process of the transducer handle and the degradation of performance after long-term use can lead to adverse effects. Summary of the invention

[0005] In view of the above defects, the present invention proposes a method for calibrating a transducer handle. This calibration method is implemented before the device leaves the factory, and can also be actively adopted after the device is used for a long time, so that the consistency of the energy output by the transducer handle is guaranteed.

[0006] A calibration method for a transducer device of an ultrasonic surgical cutting instrument, comprising:

[0007] Step 1, measure the current amplitude A0 of the transducer handle before leaving the factory;

[0008] Step 2, calculating the amplitude difference T, where the amplitude difference T is equal to the absolute value of the difference between the target amplitude Ast and the current amplitude A0;

[0009] Step 3, compare the amplitude difference T with the amplitude tolerance Adet; if the amplitude difference T is less than the amplitude tolerance Adet, the current value I0 initially set for the transducer handle is the final current value Is after the transducer handle is calibrated; if the amplitude difference T is greater than the amplitude tolerance Adet, proceed to step 4;

[0010] Step 4, recalculate the new current value;

[0011] Determine the magnitude relationship between the current amplitude A0 and the target amplitude Ast. If the current amplitude A0 is greater than the target amplitude Ast, reduce the default output current I0 and calculate the calibration current value IS. If the current amplitude A0 is less than the target amplitude Ast, increase the default output current I0 and calculate the calibration current value IS.

[0012] Step 5, re-measure the current amplitude A0 of the output of the current transducer handle according to the calculated calibration current value Is, and return to step 2 to calculate the amplitude difference T until the amplitude difference T is less than the amplitude tolerance Adet. When the amplitude difference T is less than the amplitude tolerance Adet, the current value at this time is the calibrated current value;

[0013] Step 6, writing the calibrated current value into the chip in the transducer handle.

[0014] Furthermore, if the current amplitude A0 is greater than the target amplitude Ast, the default output current I0 is reduced, and the formula for calculating the calibrated current value IS is:

[0015] IS = Io - (A0 - Ast) / C1;

[0016] If the current amplitude A0 is less than the target amplitude Ast, the default output current I0 is increased, and the formula for calculating the calibrated current value IS is:

[0017] IS=Io+(Ast-A0) / C2;

[0018] Among them, C1 and C2 are calibration constants.

[0019] Furthermore, the amplitude tolerance Aset is a constant, and its value range is 0 to 10 micrometers.

[0020] Furthermore, the target amplitude Ast is a constant, representing a performance benchmark of the transducer handle, and is obtained through experimental measurement and market data collection.

[0021] Furthermore, in step 6, the calibrated current value is written into the chip in the transducer handle, and the calibrated current value is read by the power supply host and energy is output according to the current value, thereby ensuring that the energy output by each transducer handle is consistent.

[0022] Furthermore, in step 1, a hydrophone method or a calorimeter method is used to measure the current amplitude A0 of the transducer handle.

[0023] Furthermore, in step 1, the amplitude of the energy output by the transducer handle is controlled by changing the magnitude of the output current of the power supply host.

[0024] Furthermore, the calibration constants C1=0.1 and C2=0.2.

[0025] Terminology explanation:

[0026] Amplitude tolerance Adet: According to standard YY-0644 "Measurement distribution of basic output characteristics of ultrasonic surgical systems", the general measurement methods of amplitude include optical microscopy, laser vibrometer, and feedback voltage. Among them, the laser vibrometer method has high accuracy but expensive equipment, and the optical microscopy method is simple to measure but has poor measurement accuracy. The present invention recommends the use of laser vibrometer for measurement. Generally, advanced foreign manufacturers can achieve an accuracy of 0.1 to 0.5 microns, and domestic manufacturers can also achieve an accuracy of less than 1 micron. With high-precision amplitude measurement equipment, the accuracy of the measured amplitude is guaranteed. On this basis, through a large number of experimental measurements and clinical effect feedback, a reliable and robust amplitude tolerance value is set. If the amplitude difference before and after calibration is less than this amplitude tolerance Adet, it can be determined that the transducer handle is within the standard range, that is, this amplitude tolerance Adet controls the consistency and internal quality of the output energy of the transducer handle.

[0027] Target amplitude Ast: The setting of target amplitude Ast is not arbitrary. First, according to the principle of ultrasonic cutting, if the mechanical vibration of the particle is accelerated to 5000g (g is the acceleration of gravity, approximately 10m / s2) and acts on biological tissue, the affected part will be quickly cut without damaging the surrounding tissue.

[0028] According to the formula: acceleration C = 〖(2πf)〗^2·A, where f is the frequency and A is the amplitude, the amplitude of the ultrasonic knife head reflects its cutting ability under the same frequency. Manufacturers set the target amplitude Ast through a large number of experimental measurements and clinical effect feedback. Currently, the amplitude of ultrasonic cutting surgical instruments is mostly within 40-120 microns.

[0029] Compared with the prior art, the present invention has the following beneficial technical effects:

[0030] This patent achieves the consistency of the output energy of the transducer handle through a method of transducer handle calibration. Manufacturers can set the amplitude tolerance Adet and the target amplitude Ast according to the situation so that the energy sold at the active end of the ultrasonic blade head is consistent. It should be noted that the ultrasonic blade head will amplify this difference several times (generally 3 to 5 times) after connecting the transducer handle. If the transducer handle is not calibrated, the amplitude difference caused by the transducer handle will be amplified at the active end of the blade head, making it difficult for doctors to grasp the amount of energy when using it, thereby affecting the patient's personal safety. In addition, the transducer handle is a reusable device, and its performance may decline after multiple uses. If it is not calibrated, the output energy capacity will decrease at best, and the transducer will work in a high-load and low-output state at worst, causing damage to the device and endangering the patient. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following is a brief introduction to the drawings required for the specific embodiments or the description of the prior art. In all the drawings, similar elements or components are generally identified by similar reference numerals. In the drawings, the elements or components are not necessarily drawn according to the actual scale.

[0032] Attached Figure 1 It is a schematic diagram of the structure of the Langevin type transducer handle in the prior art;

[0033] Attached Figure 2 This is a schematic diagram of the components of each system of the ultrasonic scalpel;

[0034] Attached Figure 3 A flow chart of a method for calibrating a transducer device. DETAILED DESCRIPTION

[0035] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0036] In the drawings of the specific embodiments of the present invention, in order to better and more clearly describe the working principles of the various components in the system, the connection relationship of the various parts in the device is shown, which only clearly distinguishes the relative position relationship between the various components, and cannot constitute a limitation on the signal transmission direction, connection sequence and size, dimensions and shape of the components or structures.

[0037] The ultrasonic surgical cutting instrument transducer device of the present invention is used for an ultrasonic surgical cutting instrument, which is hereinafter referred to as an ultrasonic scalpel. The main function of the ultrasonic scalpel is to achieve minimal thermal damage and blood vessel closure while cutting soft tissue, such as Figure 2 As shown, the entire ultrasonic knife system is mainly composed of three parts: a power supply, a transducer handle, and a knife head.

[0038] The energy output by the transducer handle is mainly reflected in the amplitude indicator, which can be measured by energy measurement equipment. In the standard YY-0644 "Measurement distribution of basic output characteristics of ultrasonic surgical systems", there are several methods to measure the output energy of the transducer handle:

[0039] Hydrophone method: This method uses a calibrated hydrophone to measure the sound pressure at a certain distance from the ultrasonic blade, and then calculates the output energy value;

[0040] Calorimeter method: This method is to insert the active end of the ultrasonic blade into a calorimeter containing a sound-absorbing liquid to determine the rate of temperature rise of the liquid, thereby indirectly calculating the output energy of the transducer handle.

[0041] The power host divides the energy output by the transducer handle into several levels, generally 5 levels, through an inherent program. The power host is an energy supply device that provides alternating current, including signal control and human-computer interaction. The amplitude of the energy output by the transducer handle is controlled by changing the output current of the power host. Both current and amplitude are variables that can be processed digitally, and the key parameter of the power host's control end to control the energy output by the transducer handle is current.

[0042] Based on this, the present invention proposes a calibration method for a transducer device of an ultrasonic surgical cutting instrument, such as Figure 3 The flowchart of the transducer device calibration method is shown, which includes the following steps:

[0043] Step 1, measure the current amplitude A0 of the transducer handle before leaving the factory;

[0044] Step 2, calculate the amplitude difference T; the amplitude difference T is equal to the absolute value of the difference between the target amplitude Ast and the current amplitude A0.

[0045] It should be pointed out here that the target amplitude Ast is a constant, representing a performance benchmark parameter of the transducer handle, which can be obtained through experimental measurement and market data collection.

[0046] Step 3: Compare the amplitude difference T with the amplitude tolerance Adet.

[0047] If the amplitude difference T is less than the amplitude tolerance Adet, the current value I0 initially set for the transducer handle is the final current value Is after the transducer handle is calibrated; if the amplitude difference T is greater than the amplitude tolerance Adet, the default output current needs to be adjusted and the process goes to step 4.

[0048] It should be pointed out that the amplitude tolerance Aset is a constant, usually 0 to 10 microns, and its size depends on the manufacturer's production test conditions and quality requirements.

[0049] Step 4: Adjust the default output current and calculate the rated current value.

[0050] Determine the relationship between the current amplitude A0 and the target amplitude Ast. If the current amplitude A0 is greater than the target amplitude Ast, it means that the energy output by the transducer handle is too large and the default output current I0 needs to be reduced. The formula for calculating the calibration current value IS is:

[0051] IS = Io - (A0 - Ast) / C1;

[0052] Among them, C1 is the calibration constant, and C1 is calculated by statistics of a large number of experimental measurement results.

[0053] On the contrary, if the current amplitude A0 is less than the target amplitude Ast, it means that the energy output by the transducer handle is too small, and the default output current I0 needs to be increased. The formula for calculating the calibration current value IS is:

[0054] IS=Io+(Ast-A0) / C2;

[0055] Among them, C2 is the calibration constant, and C2 is calculated by statistics of a large number of experimental measurement results.

[0056] Step 5: re-measure the current amplitude A0 of the output of the current transducer handle according to the calculated calibrated current value Is, and return to step 2 to calculate the amplitude difference T until the amplitude difference T is less than the amplitude tolerance Adet. When the amplitude difference T is less than the amplitude tolerance Adet, the current value at this time is the calibrated current value Is.

[0057] Step 6, finally write the calibrated current value Is into the chip in the transducer handle, that is, each transducer handle has its own "customized" current value, which will be read by the power supply host and output energy according to this current value, thereby ensuring that the energy output by each transducer handle is consistent. It should be noted that the above method can also be actively used for calibration after the device has been used for a long time.

[0058] The present invention realizes the consistency of the output energy of the transducer handle through a transducer handle calibration method. In the actual calibration process, software calculation is used to improve efficiency and avoid the complexity of manual calculation.

[0059] For example: amplitude tolerance Adet = 1 micron, target amplitude Ast = 85 microns, default output current I0 = 255mA, calibration constants C1 = 0.1, C2 = 0.2. After calculation, the calibrated current value IS is written into the chip in the transducer handle, usually in hexadecimal format, such as 255mA is written as "FF".

[0060] In the above embodiments, it can be implemented in whole or in part by software, hardware, firmware or any combination thereof. When implemented using software, it can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, the process or function described in the embodiment of the present application is generated in whole or in part. The computer may be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions may be stored in a computer-readable storage medium or transmitted through the computer-readable storage medium. The computer-readable storage medium may be any available medium that a computer can access or a data storage device such as a server or a data center that includes one or more available media integrated. The available medium may be a magnetic medium, (e.g., a floppy disk, a hard disk, a tape), an optical medium (e.g., a DVD), or a semiconductor medium (e.g., a solid state disk (SSD)), etc.

[0061] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of various equivalent modifications or replacements within the technical scope disclosed in the present application, and these modifications or replacements should be included in the protection scope of the present application. Therefore, the protection scope of the present application shall be based on the protection scope of the claims.

Claims

1. A calibration method for a transducer device of an ultrasonic surgical cutting instrument, characterized in that: include: Step 1, measure the current amplitude A0 of the transducer handle before leaving the factory; Step 2, calculating the amplitude difference T, where the amplitude difference T is equal to the absolute value of the difference between the target amplitude Ast and the current amplitude A0; Step 3, compare the amplitude difference T with the amplitude tolerance Adet; if the amplitude difference T is less than the amplitude tolerance Adet, the current value I0 initially set for the transducer handle is the final current value IS after the transducer handle is calibrated; if the amplitude difference T is greater than the amplitude tolerance Adet, proceed to step 4; Step 4, adjust the default output current and calculate the calibrated current value; Determine the magnitude relationship between the current amplitude A0 and the target amplitude Ast. If the current amplitude A0 is greater than the target amplitude Ast, reduce the default output current I0 and calculate the calibration current value IS. If the current amplitude A0 is less than the target amplitude Ast, increase the default output current I0 and calculate the calibration current value IS. If the current amplitude A0 is greater than the target amplitude Ast, the default output current I0 is reduced, and the formula for calculating the calibrated current value IS is: IS = I0 - (A0 - Ast) / C1; If the current amplitude A0 is less than the target amplitude Ast, the default output current I0 is increased, and the formula for calculating the calibrated current value IS is: IS=I0+(Ast-A0) / C2; Among them, C1 and C2 are calibration constants; Step 5, re-measure the current amplitude A0 of the output of the current transducer handle according to the calculated calibration current value IS, and return to step 2 to calculate the amplitude difference T until the amplitude difference T is less than the amplitude tolerance Adet. When the amplitude difference T is less than the amplitude tolerance Adet, the current value at this time is the calibrated current value; Step 6, writing the calibrated current value into the chip in the transducer handle.

2. The calibration method according to claim 1, characterized in that: The amplitude tolerance Aset is a constant, and its value range is 0 to 10 micrometers.

3. The calibration method according to claim 1, characterized in that: The target amplitude Ast is a constant, represents the performance benchmark of the transducer handle, and is obtained through experimental measurement and market data collection.

4. The calibration method according to claim 1, characterized in that: In step 6, the calibrated current value is written into the chip in the transducer handle. The calibrated current value is read by the power supply host and energy is output according to the current value, thereby ensuring that the energy output by each transducer handle is consistent.

5. The calibration method according to claim 1, characterized in that: In the step 1, a hydrophone method or a calorimeter method is used to measure the current amplitude A0 of the transducer handle.

6. The calibration method according to claim 4, characterized in that: In step 1, the amplitude of the energy output by the transducer handle is controlled by changing the magnitude of the output current of the power supply host.

7. The calibration method according to claim 1, characterized in that: Calibration constants C1=0.1, C2=0.2.

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