Testimonials. Everyone plays a role in dose reduction: doctors, radiologists, technicians, patients, constructors and, in the backdrop, experts.
The professionals at the paediatric radiology department at Trousseau hospital (Paris) are convinced of this: dose reduction all started with one man, Prof. Hubert Ducou le Pointe, the clinical director. An evaluation system was therefore set up internally, in order to determine the dose dispensed in conventional radiology or computed tomography, for each of the 45,000 to 50,000 children consulting in the department each year.
This database originally resulted from collaboration between IRSN, looking for such information, and Prof. Ducou le Pointe's department, looking for someone to be able to process it. “I wanted to know what dose was dispensed according to which type of examination, and if the dose tended to be stable, to increase or to reduce”, he says, before admitting to be disappointed by the 2007 figures. We set up a protocol for each examination, according to the child's weight, and the study demonstrated that it was not followed through.”
Problem raised by the results of IRSN study: radiologists and technicians keep the same default settings, standard values determined by the constructor for a given patient type, instead of adjusting them to individual patients. It is sometimes difficult to change habits.
“When we began reducing the doses, we were confronted with dissatisfied radiologists”, says Laurence, CT-scan technician at Trousseau hospital since 1986; she nevertheless knows that she can count on the support of her department manager to convince certain radiologists still focussing too much on image quality. She also admits to her share of responsibility: "In stressful situations, when children are agitated or upset, we sometimes forget to adjust the settings."
However, radiation protection is not limited to settings alone. Significant research has also been conducted in relation with the justification for such examinations. “In CT-scanning, an appointment is not given without the prior agreement of the department radiologist”, explains Laurence. “In conventional radiology, images that are considered to be pointless are not taken.” Special attention is also paid to the use of gonad shields or to the position: for an x-ray of the hand, the child must turn their head and place their legs to the side. In other words, many new routines to put into practice on a daily basis and to pass on to young technicians, generally already made highly aware of radiation protection during their training.
The need for regular reminders
Dr Christelle NGuyen Bourgain, paediatrician in the emergency department at Trousseau hospital (Paris).
An initial evaluation of the number of chest x-rays prescribed in our emergency department in February 2007, showed that 25% of the examinations were not justified. Coughing and fever for 24 or 48 hours are enough for a chest x-ray to be wrongfully prescribed, for fear of neglecting pneumopathy.
We edited an information sheet recalling the rules for prescription, for both junior doctors and senior doctors supervising them. Two months later, the number of non-necessary imaging examinations had dropped to 10%. But the bad habits gradually came back: 13% in October 2007, and 24 % in June 2009. Regular reminders are as much necessary as effective: in September 2010, the measures once again lowered the number of unjustified chest x-rays to 16%.
Results of a joint effort
The disappointment of 2007 in the past, and the causes identified, corrective actions have been implemented. “Protocols have been revised with the manufacturer for each weight range”, continues Prof. Ducou le Pointe. “A CT-scanner has been modified so that the technician not only has to enter the anatomical area, but also the child's weight.”
Good news came one year later. The data show a clear drop in the doses received by young patients. Immediately afterwards, a “physicist” was recruited, who continues to run this study today: his name is Aurélien Bouëtté. Specialist in medical radiation physics, he divides his time between two hospitals in Paris (Trousseau and Saint-Antoine) and several departments (radiology, nuclear medicine). His mission: ensure patient radiation protection. “In the first three years, I focused on quality control of the devices, in keeping with recent regulations. Today, I focus more on optimisation”, he explains, with three years' experience behind him. “Processing of the 2010 data highlighted the absence of a decline, and even, in conventional radiology, a reduction in doses of up to 50%”, he says delightedly, with the plan to present such results every year from now on.
The department staff is keen to see tangible results. Significant work has been conducted in-house to implement automatic processing, to enable a whole year's data to be compiled rapidly. These figures will identify the most irradiating examinations and set priorities, and even modify constants, in partnership with radiologists, technicians and constructors.
A direction confirmed by Prof. Ducou le Pointe, convinced of the need for such data: “Beyond continuous monitoring of the results to prevent deviations in CT-scan doses, we must extend the research conducted in conventional radiology and also collect the examination data from the surgical unit.” In other words, ensure that the radiation protection tradition “radiates” throughout the department.
The survey by the French association for victims of medical accidents (Aviam) on patient information, and associations' concern faced with the increasing number of radiographic procedures, gave rise in 2010 to the pluralistic working group “Patient information and diagnostic radiology”.
“It brings together patient associations, hospital physicians, technicians, learned societies, the Institut Curie, the national medical council etc.”, specifies Audrey Lebeau, leading the survey at IRSN. After one year's work, an information document was tested on doctors and patients. “The feedback should enable us to draft recommendations to inform patients exposed.” It should be ready for the first quarter 2012.
Constructors train their staff
2011. IRSN dispensed training sessions on patient radiation protection and protection of exposed personnel, for more than 150 maintenance technicians, application engineers (equipment installation) and technical support engineers (repairs) at Siemens, manufacturer of medical imaging equipment.
“The dose also depends on the machine and its settings” recalls Patrice Fraboulet, trainer. “Engineers and technicians must understand that equipment maintenance and quality control have a significant effect on the dose dispensed to patients.”
Abroad : For a child-sized dose
In the United States, health organisations are running an information and awareness-raising campaign, Image Gently Campaign, for health professionals and patients. The message: to make doses dispensed to children suited to their size.
In France, the French Society for Paediatric and Prenatal Imaging (SFIPP) informs the public, patients and professionals, on their website.