[Approval Status and Suggestions on Supervision of Class II Innovative Medical Device].

Based on the current situation of approval and publicity of class II innovative medical devices in various provinces and cities, especially after analyzing the problems found in the review of class II innovative medical devices in Shanghai and the factors affecting the listing process of innovative medical devices, this study puts forward some thoughts on supervision for reference in establishing and perfecting systems and regulations, changing the review and approval thinking, extending services to the development of innovative medical devices and the formulation of clinical trial schemes.

[Discussion on Technical Evaluation of Tongue Diagnosis Equipment of Traditional Chinese Medicine].

This study briefly introduces the tongue diagnostic equipment of traditional Chinese medicine. It analyzes and discusses the key points of technical evaluation of tongue diagnostic equipment from the aspects of product name, performance parameters, image processing functions, product use methods, clinical evaluation, etc. It analyzes the safety risks and effectiveness indicators of tongue diagnostic equipment, hoping to bring some help to the gradual standardization of tongue diagnostic equipment and the registration of enterprises.

[Discussion on Technical Evaluation of Enzyme Electrode Biosensor Blood Glucose Meter].

Enzyme electrode biosensor blood glucose detector is a new rapid blood glucose measurement method. There is no corresponding product standard and industry standard reference at home and abroad, and there is a lack of corresponding reference experience in performance research and clinical evaluation. This study discusses the safety and effectiveness of enzyme electrode biosensor blood glucose detector from the perspective of technical evaluation of medical devices. It is expected to provide some reference for medical device registration technical reviewers and registration application enterprises.

A new radiation force balance method for measuring diverging piston source power in the frequency range 20-100 kHz: Theory and experimental verification.

The purpose of this work was to present the results of a theoretical and experimental study in which a new acoustic output power measurement method was developed for a strongly diverged ultrasonic beam (ka < 3, where k is the circular wave number and a is the radius of transducer) using acoustic radiation force. To the best of our knowledge, there is no acceptable and effective method to measure acoustic power P for diverging piston transducers from 20 kHz to 100 kHz in the range ka < 3, it is a unsolved problem acutely. In the study, we used radiation force balance (RFB) method with a novel concave semi-spherical absorbing target in far field to measure the acoustic power up to 54 W. Based on the phase inverse mirror-image model we developed and Bridge's product theorem, the axial radiation force F on the target was first calculated and measured. The maximum difference of the ratio rP/cF (=P/cF) between theoretic and experimental values was smaller than 5%, where c is speed of sound in water. The reproducibility test of acoustic power measurements using two independent methods showed that the measurement uncertainty evaluated less than 10% by the new RFB method was much smaller than that (30%) by the traditional acoustic pressure method in underwater acoustics. It is indicated that the new RFB method is a primary and effective method for acoustic power measurement at least up to 20 W for frequency range 20 kHz to 100 kHz. The similar method was extended to power measurement for the rectangular transducer. Based on this method a new primary method of hydrophone calibration was also developed.

[Discuss on risk management of medical device production and after-production].

By analysis on the risk management regulations and the situation of medical device after the product on the market, information list of problems and risk analysis process of the production and after-production were described, simultaneously, the suggestions were put forward to risk management after the product on the market, with the aim of providing reference for manufacturers and administrators.

[Analysis on the development strategy for hearing aid fitting].

Based on the investigation and analysis of the current situation for hearing aid fitting, some analysis results and suggestions for the development of the industry are presented, including manufacturer, association for medical devices industry and supervision division.

Acoustic power measurement of high intensity focused ultrasound in medicine based on radiation force.

How to measure the acoustic power of HIFU is one of the most important tasks in its medical application. In the paper a whole series of formula for calculating the radiation force related to the acoustic power radiated by a single element focusing transducer and by the focusing transducer array were given. Various system of radiation force balance (RFB) to measure the acoustic power of HIFU in medicine were designed and applied in China. In high power experiments, the dependence of radiation force acting the absorbing target on the target position at the beam axis of focusing transducer was fined. There is a peak value of "radiation force" acting the absorbing target in the focal region when the acoustic power through the focal plane exceeds some threshold. In order to avoid this big measurement error caused by the 'peak effect' in focal region, the distance between the absorbing target of RFB and the focusing transducer or transducer array was defined to be equal to or less than 0.7 times of the focal length in the National Standard of China for the measurements of acoustic power and field characteristics of HIFU. More than six different therapeutic equipments of HIFU have been examined by RFB for measuring the acoustic power since 1998. These results show that RFB with the absorbing target is valid in the acoustic power range up to 500W with good linearity for the drive voltage squared of focusing transducer or array. The uncertainty of measurement is within +/-15%.

Calibration of a focusing transducer and miniature hydrophone as well as acoustic power measurement based on free-field reciprocity in a spherically focused wave field.

The free-field transmitting voltage response at the pressure focus of a spherically focusing transducer was defined and calibrated based on the reciprocity theorem of a free-field spherically focused acoustic wave. The acoustic power, the radiation conductance, and the pressure at the pressure focus were derived and measured accordingly from the transmitting current response on the imaginary mirror symmetric spherical surface of the radiating surface. A miniature hydrophone was calibrated by the self-reciprocity of the spherically focusing source. Comparison results show that the measured acoustic power deviation between the reciprocity method and the radiation force balance method are within +/- 5% for two air-backed focusing transducers at 1.53 MHz and 5.27 MHz, respectively, and the maximum deviation of a hydrophone calibration between the new method and the free-field plane wave reciprocity method is within 1.4 dB in the frequency range from 1 MHz to 2 MHz in experiments.