China's NMPA Issues Regulatory Guidance on Reliability Evaluation for CT X-Ray Tube Assemblies
Beijing, February 28, 2026 — China's National Medical Products Administration (NMPA) Center for Medical Device Evaluation (CMDE) has issued new regulatory guidance governing the reliability evaluation of X-ray tube assemblies used in computed tomography (CT) equipment. Published as Announcement No. 8 of 2026, the Registration Review Guidance Principles for Reliability Evaluation of Tube Assemblies Used in X-Ray CT Equipment takes effect immediately and marks a significant step in China's effort to strengthen oversight of a component widely regarded as one of the most performance-critical and failure-prone parts of a CT system.
The guidance was prompted by the inherently non-repairable nature of CT tube assemblies. Unlike many medical device components, a failed tube assembly cannot be serviced on-site, meaning any malfunction directly disrupts clinical operations and patient care. To address this risk, the CMDE has established a standardized framework requiring manufacturers to formally define and validate a reliability index — expressed in terms of service life in years, total scan seconds, scan counts, or kilowatt-seconds — at a specified statistical confidence level before a product can be registered for the Chinese market.
Under the guidance, applicants may choose between two evaluation approaches. The first is a verification-based method, in which manufacturers pre-define a target reliability index and then conduct testing to confirm it is met. The second is a determination-based method, in which life distribution models — most commonly the Weibull distribution — are constructed from test data to derive the reliability index. Both normal-condition testing under rated operating parameters and accelerated life testing using frequency-acceleration models are accepted, provided they comply with GB/T 34986-2017 or IEC 62506:2023. Sample sizes must be statistically justified; for instance, verifying a reliability of 0.9 at a 90% confidence level over 100,000 scans requires a minimum of 22 test samples under a zero-failure binomial distribution model.
The guidance also requires applicants to conduct a comprehensive Failure Mode, Effects, and Criticality Analysis (FMECA), addressing six identified failure modes: filament short or open circuit, target disc cracking or melting, rotating anode seizure, vacuum envelope internal arcing, tube housing arcing, and overheating of the heat dissipation system. Failure criteria must be clearly defined, covering both gradual performance degradation and catastrophic events such as vacuum loss or physical tube rupture. Throughout and following reliability testing, manufacturers must evaluate key performance indicators including focal spot size and position, radiation dose output, high-voltage dielectric strength, leakage radiation, noise and vibration levels, and overall image quality.
On the regulatory submission side, all reliability study data must be filed under Section CH3.7 of the registration dossier, and product labeling and instructions must explicitly state the declared service life. For variation registrations, applicants are required to assess and justify whether any product changes affect the previously established reliability evaluation. The guidance applies to both standalone tube assembly registrations and those submitted as part of a complete CT system, and may serve as a reference for tube assemblies used in other X-ray modalities, including vascular angiography and dental imaging systems.
Industry observers note that this guidance reflects China's broader regulatory trajectory toward alignment with international standards, drawing on frameworks including IEC 62506:2023, GB/T 34986-2017, YY/T 1837-2022, and GB 9706.228-2020. For domestic and foreign manufacturers alike, early integration of these requirements into product development, testing protocols, and submission planning will be essential to navigating the increasingly rigorous Chinese medical device registration landscape.
Source: NMPA Center for Medical Device Evaluation (CMDE), Announcement No. 8, February 28, 2026.