YY/T 1767-2021Ultrasonics—Power measurement—High intensity therapeutic ultrasound (HITU) transducers and systems (English PDF)

Foreword

This standard was drafted in accordance with the rules given in GB/T 1.1-2009.

This standard uses the translation method equivalent to IEC 62555:2013 "Ultrasonic Power Measurement High Intensity Therapeutic Ultrasound (HITU) Transducer" And System.

Introduction

For an ultrasonic sound field with a frequency in the order of megahertz, the radiation force balance method is generally used to measure the radiation force acting on the target to determine the ultrasonic sound field.

Acoustic output power [1-3]. However, the relationship between the radiation force and the ultrasonic output power is affected by factors such as sound field focusing or other geometric factors, and targets.

The type and shape, the distance between the target and the transducer, the absorption of sound energy in the water section (including "impact loss"), and the sound impulse flow, etc. influences. Although many of the above factors have little effect on the general diagnostic and physical therapy ultrasound sound field, for high-intensity therapeutic ultrasound (HITU), Especially for the high-intensity focused ultrasound (HIFU) [4] sound field that people often say, these effects are usually not negligible. In addition, for HI- TU, the physical quantity that people pay attention to is the power entering the patient's body, not the output power of the transducer surface. Because of the difference between the transducer and the patient Water is often used for coupling, so the impact of sound energy absorption and impact loss in the water section may be very large, and it will vary with distance. Variety.

The purpose of this standard is to establish a standard method for measuring the ultrasonic power of HITU equipment in the low MHz frequency range in liquid.

The gravitational balance method measures the radiation force, and the other is the use of calorimetry to measure thermal expansion. This standard identifies the source of error and how to evaluate The total uncertainty of measurement is systematically described. At the same time, the precautions and uncertain factors that should be considered in the process of power measurement are given.

The standard also provides practical guidance on how to determine the sound power of HITU transducers of various geometric shapes. With IEC 61161 The method of measuring "time average power" with radiation force is different. This standard gives another power measurement method.

Part of the structure and content of this standard is based on IEC 61161:2013.The power concerned by IEC 61161 is the output power, which specifies the measurement The position of the time target is close to the transducer, so it is not very suitable for a strong focus transducer. In some cases, it is more necessary to be at a certain distance from the transducer.

The incident power is measured on a specific surface (such as the surface of the patient's skin).

Will cause significant non-linear losses. Therefore, the main consideration in this standard is measured as the incident power, not the output power. Of course, using With an appropriate model combined with its own uncertainty, the incident power can be used as the basis for determining the output power. Ultrasonic power measurement High Intensity Therapeutic Ultrasound (HITU) Transducer and system

1 Scope

This standard.

Established a radiation force balance method for measuring the HITU sound field with an acoustic target;

Standardizes the calorimetry method of measuring the thermal expansion of the fluid to determine the total emitted sound power of the ultrasonic transducer;

Standardize the requirements for describing the electrical power characteristics of ultrasonic transducers;

Provides guidance and suggestions to prevent acoustic cavitation during the measurement process;

Provides HITU transducers for measuring different structures and geometries (including collimated, divergent and convergent transducers, as well as multivariate Transducer) guidance and suggestions; Provides guidance on choosing the most appropriate measurement method; Provides information for evaluating the total uncertainty of the measurement.

This standard is applicable to the measurement of ultrasonic power with an upper limit of 500W generated by HITU equipment in the frequency range of 0.5MHz to 5MHz. The sound field can be convergent, collimated or divergent.

This standard does not verify that the frequency is lower than 500kHz, and the user should be uncertain about the power measurement and measurement system at this frequency. Degree to be evaluated.

This standard does not apply to ultrasound equipment used in physical therapy, lithotripsy, and routine pain relief.

2 Normative references

The following documents are indispensable for the application of this document. For dated reference documents, only the dated version applies to this document. For undated reference documents, the latest version (including all amendments) is applicable to this document.

IEC 61161:2013 Ultra-acoustic power measurement radiation force balance and performance requirements (Ultrasonics-Powermeasure- ment-Radiationforcebalancesandperformancerequirements)

IEC /T R62781 Ultrasonic ultrasonic measurement water treatment (Ultrasonics-Conditioning of waterforultrasonic measurements)

3 Terms and definitions