Multicentre survey on patient dose in paediatric imaging and proposal for updated diagnostic reference levels for France. Part 1: computed tomography

International audienceOBJECTIVES: To report on a dose survey conducted by the French societies of radiology and paediatric imaging (SFR and SFIPP) and the French public service expert in nuclear and radiological risks (IRSN), and to suggest new diagnostic reference levels (DRLs) for paediatric CT.METHODS: Dose reports concerning children aged 0-15 years and five CT procedures (brain, petrous bone, mediastinum, lung and abdomen-pelvis) performed in 2015-2016 were collected from 15 imaging departments on a voluntary basis. Volume CT dose index (CTDIvol) and dose-length product (DLP) were recorded for at least 10 patients per procedure, per centre and per age group. New DRLs were calculated as the 3rd quartiles of the distributions of the median values.RESULTS: Results from 3253 CT examinations were obtained. The exposure levels observed were much lower than for the previous surveys (2007-2008 and 2010-2013) and among the lowest values currently published. A good homogeneity between facilities was also observed. New DRLs are proposed for each procedure and age group.CONCLUSIONS: This new survey contributes to the continuing optimisation process in French paediatric CT practice. Its results have been recently used to update the national paediatric CT DRLs.KEY POINTS: * New national diagnostic reference levels (DRLs) are proposed for several paediatric CT procedures. * The DRLs proposed for brain, chest and abdomen-pelvis procedures are among the lowest published worldwide

Long-term experience and analysis of data on diagnostic reference levels: the good, the bad, and the ugly

International audienceOBJECTIVES: To analyze 11-year data of France for temporal trends in dose indices and dose optimization and draw lessons for those who are willing to work on creation and update of diagnostic reference levels (DRLs).METHODS: The data from about 3000 radiology departments leading to about 750,000 imaging exams between 2004 and 2015 was analyzed, and patterns of reductions in dose for those below and above the DRLs were estimated and correlated with technology change.RESULTS: Dose optimization achieved was important and significant in departments which were above or just below the DRL (p = .006) but not in those which were around half of the DRL values. The decrease in 75th percentile value of Kerma air product (KAP) for chest radiography by 27.4% between 2004 and 2015 was observed with the number of flat panel detectors increase from 6 to 43%. A good correlation between the detector type distribution and the level of patient radiation exposure is observed. Otherwise, setting DRLs for standard-sized patient excludes patients lower and higher weighted than "standard."CONCLUSIONS: The concept of DRL may become obsolete unless lessons drawn from the experience of users are taken into account. While establishing DRLs should be part of the regulations, setting up and updating values should be governed by bodies whose decision-making cycle is short, at the most 1 year. A local rather than national approach, taking into account body habitus and image quality, needs to be organized.KEY POINTS: * The technology changes faster than regulations. Requirement of DRL establishment should be part of the regulations; however, setting and updating values should be the role of professional societies. * The concept of DRL, highlighting the 75th percentile values and dedicated to standard-sized adult, misses optimization opportunities in the majority of patients who are below the 75th percentile value and outside the range of standard-sized adult. * The ugly aspects of the DRL concept include its non-applicability to individuals, no customization to clinical indications, and lack of consideration of image quality

Multicentre survey on patient dose in paediatric imaging and proposal for updated diagnostic reference levels for France. Part 2: plain radiography and diagnostic fluoroscopy

International audienceOBJECTIVES: To report on a dose survey conducted by the French societies of radiology and paediatric imaging (SFR and SFIPP) and the French public service expert in nuclear and radiological risks (IRSN), and to suggest new diagnostic reference levels (DRLs) for paediatric plain radiography and diagnostic fluoroscopy.METHODS: Dose reports concerning four radiography procedures and three diagnostic fluoroscopy procedures performed in 2015-2016 on children aged 0-15 years were collected from 16 imaging departments on a voluntary basis. Air kerma-area product (PKA) was recorded for at least 10 patients per procedure, per centre and per age group. New DRLs were calculated as the 3rd quartiles of the distributions of the median values.RESULTS: Results from 2249 radiography examinations and 1235 diagnostic fluoroscopy procedures were obtained. A noticeable variability in patient exposure between facilities was observed in diagnostic fluoroscopy and to a lesser extent in plain radiography. DRLs are proposed for each procedure and each age group.CONCLUSIONS: This study showed that the applicable national DRLs in plain radiography were obsolete and its results have been recently used by the French authorities to update them. In diagnostic fluoroscopy, large differences of doses were observed, even among departments accustomed to paediatric procedures. The new national DRLs will be useful for optimising diagnostic practice.KEY POINTS: * New national diagnostic reference levels (DRLs) are proposed for several paediatric procedures in plain radiography and diagnostic fluoroscopy. * Even between departments accustomed to paediatric procedures, substantial differences of practice were observed, especially in diagnostic fluoroscopy