This study is conducted by a working group of the French Society of Medical Physics (SFPM). Its main aim is to establish reference dose levels for the most common procedures performed in operating rooms using mobile X-ray systems, hence helping medical physicists and surgeons to evaluate their practice and optimize patient radiation protection.

This is a multi-centric prospective study involving 73 medical institutions of different categories (public university hospitals, clinics, centers dedicated to cancer treatment, etc.). It consists on progressively collecting anonymous data for 15 to 30 procedures from a list of 62 types of procedures, belonging to 7 surgery specialties (neurosurgery, orthopedic surgery, digestive surgery, urology, cardiology, vascular surgery and multi-specialty). Collected data include patient BMI and information about the X-ray equipment, the medical procedure and the dosimetric parameters. Data collection doesn't require the access to the patient medical record and doesn't impact his medical care.

Proposed dose reference levels will be expressed in terms of KAP (Kerma-Area-Product), fluoroscopy time and air Kerma. Moreover, multiple statistical analyses will be done to investigate the impact of different variables on the procedure X-ray doses.

Context:

Reference dose levels, introduced by the International Commission on Radiological Protection (ICRP) in 1996, are intended to help professionals using medical imaging to evaluate their practice and optimize patient's doses. European directive 2013/59/Euratom emphasizes the need to establish, use and regularly review reference levels for diagnostic and interventional procedures and to publish guidelines on this topic. Furthermore, national reference levels were established for conventional radiology and CT exams. They are used as a tool for the optimization of medical practices. Besides, a working group of the French Society of Medical Physics (SFPM) has published in 2017 reference levels for interventional radiology procedures performed in a dedicated room and using fixed angiographic equipment. Although radiation protection is a big challenge encountered in operating rooms using mobile X-ray equipment, few data are available in the literature regarding the use of this type of equipment.

In this context, the SFPM suggested the creation of a working group in 2017 to establish reference levels for the main procedures realized in the operating rooms using mobile X-ray systems. The aim of this working group is to help medical physicists and surgeons in evaluating their practice and optimizing patient radiation protection.

Scope of the study: The main purpose of the study is to establish dosimetric reference levels, in terms of KAP (Kerma-Area-Product). Additional objectives consist on proposing reference levels in terms of fluoroscopy time and air kerma and on studying the impact of different parameters (surgical specialty, body mass index, use of zoom, fluoroscopy pulse rate) on the delivered doses.

Study type and cohort: This is a multi-centric prospective study which consists on progressively collecting anonymous data for 15 to 30 procedures from a list of 62 surgical procedures (n=62) belonging to 7 different surgery specialties. Selected specialties are neurosurgery (n=12), orthopedic surgery (n=15), digestive surgery (n=6), urology (n=10), cardiology (n=6), vascular surgery (n=11), multi-specialty (n=2). 73 health institutions of different categories (University hospitals, clinics, centers dedicated to cancer treatment, etc..) confirmed their participations to the study.

Data collection: Data will be collected using a password-protected Excel spreadsheet. This excel file will be sent to all the participating institutions at the beginning of data collection. Every institution will send the excel file completed with anonymized data to the scientific responsible of the study through the secure email server of the APHP (Assistance Publique des Hopitaux de Paris)) institution.

Analysis: The main goal of this study is to publish descriptive statistics parameters (mean, standard deviation, median, 1st quartile, 3rd quartile) for each dosimetric data (KAP, fluoroscopy time, kerma, etc..) and for each category of surgical procedures. Results will be presented with a 95 percentage confidence interval.

Moreover, correlation analysis between several variables will be done. The differences between detector and equipment technologies will be also studied using appropriate statistical tests.

Inclusion Criteria:

• Fluoroscopy guided procedures performed on adult patients (≥16 years old)
• Fluoroscopy guided procedures performed with mobile X-ray systems. Procedures performed outside of the operating rooms but using mobile X-ray systems are included in this study.
• Fluoroscopy guided procedures performed using mini C-arms or O-arms

Exclusion Criteria:

• Fluoroscopy guided procedures performed on pediatric patients (<16 years old)
• Fluoroscopy guided procedures performed with a fixed interventional radiology imaging system even if it was located in the operating rooms .
• Medical procedures performed using both a mobile X-ray system and a fixed CT scanner.
• Medical procedures performed using a mobile intra-operative CT scanner

Study population consists on unhealthy patients undergoing surgical procedures with the use of X-ray mobile equipement. 62 types of procedures, belonging to 7 surgery specialties (neurosurgery, orthopedic, digestive, urology, cardiology, vascular and multi-specialty) are included in this study. For each procedure and each participating institution among the 73 centers that have sent their participation agreement, 15 to 30 procedures will be collected and analysed.

Only the final results of this study will be shared with the medical physicist members of the French Society of Medical Physicist. These results are statistical data analysis based on the collected patient data.

Moreover, the study main results would be probably shared with the scientific community through a published paper in a scientific peer-reviewed journal.