The primary objective of this prospective study was to describe the evolution of dose reference levels (DRLs) in a specialized French center during endoscopic procedures involving ionizing radiation and performed without a radiology technician. The secondary objective was to assess the influence of the operator on the recorded dose for each procedure.

This prospective study, approved by the Institutional Review Board (IRB) of the Groupement de Coopération Sanitaire Ramsay Santé (approval no. 2019-06-010), was conducted in the endoscopy unit of Jean Mermoz Hospital (Lyon, France).

To standardize practices, all operators underwent blended training (3 hours of e-learning and 3 hours of hands-on training on the Shine Enhancer system), which was completed and validated on June 25, 2018. As per guidelines, the graphic (cine) mode was never used. Only the latest fluoroscopic images were printed and archived.

The database includes all consecutive patients who underwent an endoscopic procedure between June 26, 2018, and December 31, 2021. Each report was retrospectively reviewed to confirm the therapeutic intention (intention-to-treat).

Initially, only the type of procedure and the dose-area product (DAP) were recorded. From October 7, 2019, fluoroscopy time (FT) was also systematically collected.

Six experienced endoscopists performed all procedures. The patient's position varied depending on the procedure, although most were performed in the supine position under general anesthesia. No radiologic technician was present during the procedures. The fluoroscopic system was entirely managed by the endoscopist, including all parameter adjustments (distance between patient and detector, use of pulsed vs continuous fluoroscopy, collimation, duration, etc.).

Two mobile C-arm X-ray systems were used throughout the study: Siemens Arcadis and GE OEC Fluorostar, both under-couch systems.

Inclusion Criteria:

• Patients aged 18 years or older, who have been informed of the research;
• Patients who have undergone an endoscopic procedure under radiological control
• Subjects for whom all data concerning the methods of exposure to ionizing radiation are available;

Exclusion Criteria:

• Patient under legal protection, guardianship, or curatorship;
• Patient who has indicated their opposition to the use of their medical data (by completing and returning the opposition form that will be sent to them).

Patients participating in the study underwent a digestive endoscopy under radiological control.