The accuracy of RDM's DACS-integrated skin dose mapping software was acceptable considering measurement uncertainties associated with Gafchromic films.

Purpose. A national survey was performed to assess patient dose indicators based on clinical indication and on patient morphology for most common adult computed tomography (CT) examinations in France. Methods. Seventeen groups of clinical indications (GCIs) for diagnostic CT in adult patients were considered based on their frequency and on image quality requirements. Data was collected for 15-30 consecutive examinations performed between 2015 and 2017, per CT scanner and GCI. Distributions of total examination Dose-Length Product (DLP) and Volume CT Dose Index (CTDIvol) were assessed for each GCI as a function of patient gender or patient Body Mass Index (BMI) for head/neck and trunk examinations, respectively. Results. 6610 examinations were analysed. Median total exam DLP values were higher for men compared to women patients for head and neck examinations: difference ranged from 6% for ear trauma indication (577 vs 543 mGy•cm, p=0.01) to 35% for brain tumour GCI (1472 vs 1093 mGy•cm, p<0.01). For trunk examinations, total exam DLP increased consistently with patient's BMI. For normal-BMI patients, median CTDIvol and DLP differed significantly between different GCIs for single-phase CT of the chest (3 mGy and 112 mGy•cm, respectively, for chronic obstructive pulmonary disease group vs 5.8 mGy and 207 mGy•cm for pulmonary embolism group, p<0.05) and of the abdomen-pelvis (5.6 mGy and 284 mGy•cm, respectively, in renal colic group vs 9.5 mGy and 463 mGy•cm in occlusive syndrome group, p<0.05). Conclusion. This study provides morphological-and clinical-based patient dose indicators in CT as a practical tool for clinical practices optimisation.

• We determined reference levels (RLs) for bAVM embolization, DSA and SVM sclerotherapy. • The proposed RLs will permit benchmarking practice with an external standard. • The proposed RLs by age may help to develop paediatric dose guidelines.

• CTDIvol varied little with age for routine head scans.  • CTDIvol was lowest in youngest children for chest or abdominal scans.  • Individual and inter-department variability warrant enhanced standardisation of practices.  • Recent surveys support the need for revised diagnostic reference levels.  • More attention should be given to specific protocols (sinuses, neck, spine, mediastinum).

• Using ASIR allows 25 % to 41 % reduction in the ED. • Prospective protocol is used up to 51 % of children after premedication. • Low dose is possible using ASIR and optimized prospective paediatric cCT.