What are the principles for choosing between quantitative and qualitative evaluation in cytotoxicity assessment?
Quantitative evaluation of cytotoxicity can objectively measure cell numbers, total protein content, enzyme release, release of vital dyes, reduction of vital dyes, or other measurable parameters. It is less susceptible to the subjective bias of the tester, offers relatively high sensitivity, and provides clear determination limits. Currently, the MTT assay is a widely used quantitative method in China. In contrast, qualitative evaluation of cytotoxicity involves more subjectivity on the part of the evaluator and is more suitable for screening purposes.
When adding a model to an active product, is testing mandatory?
When a registrant applies to amend a registration to add a product model, it is first necessary to confirm whether the new model can be considered part of the same registration unit as the existing models. If they are part of the same unit, an amendment to add the model can be applied for. If there are no new mandatory standards involved, the decision should be made based on the principles of typical model determination. If the existing models can represent the new model, then there is no need to test the new model again; if the test report of the existing model can represent some aspects of the new model, then those aspects do not need to be retested, but a test report for the new model is required for any aspects not covered. If new mandatory standards are involved, a test report must be provided showing that the new model complies with these standards, or a report proving that the existing models meet the new standards can also be submitted.
How to choose typical models for the inspection of medical endoscopes
Generally, when selecting typical models for testing within the same registration unit of medical endoscopes, the following factors should be considered: If there is a difference in the direction of view, the model with the largest viewing angle should be selected; if there is a difference in the field of view, the models with the largest and smallest field of view should be chosen; for variations in inner diameter, outer diameter, and working length, the model with the smallest diameter and the highest slenderness ratio (i.e., the ratio of length to diameter) should be selected. For products with a working channel, the diameter considered here should be the outer diameter of the insertion part minus the inner diameter of the working channel; if there are differences in optical performance indicators like angular resolution, the model with the highest requirements should be selected.
Can the structure and composition of a product reflect non-medical device components?
For product components that are not managed as medical devices, they cannot be registered separately but can be included as part of a medical device. If an applicant declares these components as part of a medical device, they should be evaluated as part of the whole. Therefore, these components should undergo the necessary validation and verification (including testing) along with the entire device. If they meet the requirements, they can be included in the structure and composition section of the product registration certificate. If the applicant does not declare these components as part of the product, or does not validate and verify them along with the entire device, they cannot be reflected as part of the product composition.
Can active medical device combination products be exempt from clinical evaluation?
If each individual module within the combination product is listed in the "Catalogue of Medical Devices Exempt from Clinical Evaluation," and the applicant can prove that there is no interaction between the modules, and that the clinical use does not exceed the scope of the catalogue, then the product can be considered a simple combination of multiple functional modules. Each module can then be evaluated separately according to the requirements of the catalogue. Additionally, the applicant should also assess any other risks that may arise from the combination of the modules.
Can an ultrasonic soft tissue cutting and hemostatic knife head be used with main units and transducers from other manufacturers?
The compatibility of the main unit, transducer, and cutting head in ultrasonic soft tissue cutting and hemostatic devices significantly affects the product's safety and efficacy. These components need to be designed and developed as a whole. Even if the use with products from other manufacturers that have already been approved for the market has been thoroughly verified and confirmed during the design and development phase, if changes in the design of the other party's products are not promptly understood, it is impossible to conduct a systematic analysis of these changes. This may lead to compatibility issues, introducing risks to safety and effectiveness. Therefore, unless there is a clear collaborative relationship between the registrants of the cutting head, main unit, and transducer, ensuring a systematic analysis of each other's product design changes, the use of the cutting head with main units and transducers from other manufacturers is not permitted.
Implantable Cardioverter Defibrillators and Similar Products on the Reference Issue of GB 16174.2-2015
For implantable cardioverter defibrillators and similar products that have already referenced the GB 16174.1 and YY 0989.6 standards in their product technical requirements, although implantable cardioverter defibrillators possess pacing functions, the YY 0989.6 standard has already adequately considered the pacing capabilities of these devices and made corresponding provisions. Therefore, there is no need to reference the GB 16174.2 standard.
When using multiple receiving coils together in a magnetic resonance imaging system, what issues should be considered in the registration documents?
When multiple receiving coils are used together in an MRI system, the registration documents should pay attention to the following issues: The overview should explain how the coils are combined during joint use, how the patient is positioned, and the corresponding areas scanned on the patient. The research documents should provide performance study data on signal-to-noise ratio, uniformity, 2D scan slice thickness, spatial resolution, ghosting, etc. In addition to the performance requirements for individual coils, the product technical requirements should also include the performance requirements when multiple coils are used together. The clinical evaluation data should assess the combined coils based on the applicable scanning areas.
What issues should be considered in the registration documents for large imaging equipment that provides a third-party physiological gating signal interface?
For large imaging equipment (such as CT, MR, PET/CT, etc.), if a third-party physiological gating interface is provided (but not including the gating device), such as respiratory gating interface, ECG gating interface, etc., the overview materials should clearly specify the relevant requirements for compatible third-party gating devices, such as connection methods, interface/data types, etc. If it is a dedicated interface, the manufacturer and product model of the compatible devices should also be specified. The research materials should provide verification and validation documents for testing with third-party devices. The technical requirements should clearly specify the connection methods, interface/data types, and the technical indicators related to gating should be tested.
How can frequent licensing changes due to computer configuration upgrades be avoided for active medical devices used with computers?
When describing computer configurations in the product technical requirements, such as CPU frequency, storage space, memory space, and monitor resolution, it is advisable to specify the minimum requirements. When upgrading computer configurations, verification of related design changes can be managed through the quality management system. If the upgrades do not involve changes to the product technical requirements, there is no need to register for a change in licensing matters.