On December 18, 2025, the French National Agency for the Safety of Medicines and Health Products (ANSM) published a new detailed protocol defining the quality control requirements for CT scanners in France. This decision represents a major update to the regulatory framework governing CT imaging, with clearly defined technical requirements for internal and external quality control procedures.
The protocol will become mandatory after an 18-month transition period, with an effective date set for June 18, 2027. This transition period allows healthcare institutions, medical physicists and accredited inspection bodies to adapt their quality control procedures accordingly.
Technical requirements for CT quality control phantoms
The decision explicitly defines the characteristics of phantoms required for CT scanner quality control. These phantoms must be specifically designed for CT imaging and must present dimensions representative of clinical examination conditions.
The required phantoms are cylindrical and must allow both head and body evaluations. Reference dimensions typically include:
- a nominal diameter of 160 mm for head-type evaluations,
- a nominal diameter of 320 mm for body-type evaluations.
These dimensions are intended to ensure measurement representativeness, inter-site comparability and long-term reproducibility.
Inserts and evaluated parameters
The phantoms must include a set of inserts enabling simultaneous assessment of multiple image quality and system performance parameters.
According to the protocol, these include:
- homogeneous regions for noise, uniformity and CT number stability analysis,
- inserts with different material densities for CT number accuracy evaluation,
- dedicated structures for spatial resolution and low-contrast resolution assessment,
- specific inserts for the evaluation of contrast-enhanced imaging performance.
In this context, the decision requires the use of inserts containing three distinct iodine concentrations, enabling evaluation of CT system response over a range representative of clinical contrast-enhanced imaging. These iodine concentrations are defined to cover low, intermediate and high attenuation levels, as specified in the ANSM application guide.
Acquisition conditions and result analysis
The decision also defines the acquisition conditions associated with quality control measurements, including reference scan parameters, reconstruction settings, phantom positioning and measurement repeatability conditions.
Particular emphasis is placed on result traceability, documentation, archiving and deviation analysis, allowing early detection of performance drift and reliable longitudinal monitoring of CT scanner performance.
Reference tools and harmonization of practices
In line with the December 18, 2025 decision, ANSM provides a reference image bank intended for the selection of software used to calculate the Noise Power Spectrum. This approach aims to harmonize image quality assessment methods and improve comparability of results across CT installations.
Overall, these requirements highlight the importance of selecting CT quality control phantoms that comply with the dimensional, insert-related and performance specifications defined by French regulations, in anticipation of the June 2027 regulatory deadline.
