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More Resources are Needed for Developing and Using Diagnostic Reference Levels


46 participants, three ICTP affiliates and associates and 12 master students practiced how to establish diagnostic reference levels. (Photo: J. Vassileva/IAEA)

The IAEA and the International Centre for Theoretical Physics (ICTP) organized an international workshop on how to develop and use diagnostic reference levels (DRLs) in medical imaging.

Diagnostic reference levels, established in a country or in a region, serve as a practical tool for health professionals to compare diagnostic imaging procedures and to determine whether protection and safety for patients has been optimized. They apply for a specific patient group (e.g. adults or children of different age or weight) and relate to specific types of medical examinations such as X-rays, computed tomography, image guided interventional procedures, or nuclear medicine procedures. They can help medical professionals to detect if doses to patients in a department are unusually high or unusually low.

“DRLs can be extremely helpful as an optimization tool in diagnostic and interventional radiology or in nuclear medicine,” said Jenia Vassileva, IAEA Radiation Protection Specialist and one of the workshop’s organizers.

“If properly set and used, patient dose monitoring program can help hospitals to manage patient exposure to achieve the needed diagnostic image quality,” she added. “Establishing DRL values however requires knowledgeable staff, coordination and collaboration.”

With over 4 billion procedures performed around the world each year, there is an increasing trend of using high-dose procedures, which are often repeated, sometimes without medical justification. Many studies also show that imaging procedures are often performed with higher dose than needed for the clinical outcome. Children are particularly at risk when the imaging protocols are not optimized to their body size. Unfortunately, adult protocols are often used to imaging children.

Obstacles on the Way Towards DRLs

DRLs can help medical professionals to improve the situation but they are still not available in many countries. These values should be set from a representative survey in a country or a region to reflect the local practice of performing imaging procedures with the available equipment. According to the latest data, 94 % of low-income-countries and 75 % of middle-income countries lack sufficient patient dose data for setting up DRLs. As concluded at the workshop held from 18 to 22 November and at a 2016 IAEA technical meeting, this is related to a lack of qualified diagnostic medical physicists, lack of available tools, lack of appropriate methodology and lack of coordination at the national level.

Workshop participants, medical physicists from 50 countries, presented twenty-nine posters, which showcased national experience with setting and using DRLs. “We don’t have national DRLs for diagnostic imaging modalities. We are now collecting data to establish them for CT, at least for a small region in my country,” said Saravana Kumar Adhimoolam from India, one of the winners of the best poster awards.

To help bridge the knowledge gap, 11 experts showed participants how to decide on different aspects important for setting DRL programs such as which procedures to include, how to collect data, how to analyse results, and how to group patients. Participants had a chance to do practical exercises to help them with the future set-up at home. They also learned how to use dose monitoring software solutions to manage dose data.

“I have been postponing implementation of DRLs because I haven’t had the full understanding of the concept,” said Ana Buinac from Croatia. “The first thing what I will do when I get back home is to try to establish local values for our equipment.”

Experts also introduced a new IAEA e-learning course, which will be launched in the next months. It will help medical professionals from all over the world to understand the importance of DRLs and use of these levels in the optimization process.

Participants have also agreed to launch a data collection study from CT examinations from all medical centres represented at the workshop.

The workshop was organized jointly by the ICTP and IAEA and supported through Technical Cooperation Projects.

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