Local Diagnostic Reference Levels in Interventional Radiology.

PURPOSE: Interventional cardiology procedures, during which live images are acquired, involve exposure to x-rays. The use of fluoroscopy can cause high radiation doses to patients and operators because of the prolonged duration of x-ray emission. For this reason, special attention and constant vigilance represent challenges for commissions and groups of experts in the field. The purpose of this study is to establish local diagnostic reference levels (DRLs) for these procedures, to improve radiological practice, and to optimize radiation doses. METHODS: This work was carried out in two university hospitals and two private medical facilities in Rabat, the capital of Morocco, during the period 2017-2018. The study concerns 657 interventional cardiology procedures (457 coronary angiography [CA] and 200 percutaneous transluminal coronary angioplasty [PTCA]), performed by 11 cardiologists on different installations in 5 catheterization rooms. The data collected for each procedure were patient age, height and weight, dosimeter indicators in terms of dose area product (PKA), total air kerma at the reference point (Kar), fluoroscopy time (FT), and the number of frames, together with the primary beam parameters as kV and total mAs. The proposed DRLs were set from the 75th percentile of the PKA and FT. RESULTS: The mean of PKA for CA and PTCA procedures were 29.2 Gy∗cm2 and 70.4 Gy∗cm2, respectively, the mean of fluoroscopy time were 4.0 min and 12.17 min for 334 and 685 frames, respectively. Results for the local DRLs were 37.3 and 87.1 Gy cm2 for PKA and 4.48 and 16.15 min for FT, corresponding to CA and PTCA procedures. CONCLUSION: This work focuses on proposing local DRLs in Morocco for CA and PTCA procedures. The results show that the values found conform with those of international studies.

Mammography Dose Survey Using International Quality Standards.

Digital mammography is the current standard for breast cancer screening. The absence of any dosimetric data, the quality standards, and the fear of radiation detriment, sometimes, hampers the smooth introduction of this technology and the launch of breast cancer screening programmes. As the breast cancer screening programmes are in development in Morocco, quality standards have been set in this study, so that any new breast cancer screening service could get started with their first analysis. The purpose of this study was to report the first Moroccan breast dose and to test quality standards compared with European guidelines. A dosimetric study is conducted by calculating mean glandular dose (MGD) for patients' breasts and polymethyl methacrylate (PMMA) for each thickness from recorded radiographic factors and X-ray tube (output and half-value layer) measurements using Dance's model for a digital mammography system. This is carried out to determine the correlation between phantom and patient measurements. The mean MGD for patient data was 1.02 ± 0.5 mGy and the compressed breast thickness was 55 ± 14 mm. For compressed breast thickness range of 50-60 mm, the MGD was 0.94 ± 0.3 mGy and the dose calculated with PMMA phantom for the same range thickness was 1.33 mGy. The results of MGD as a function of PMMA thickness is lower than the achievable limit curve proposed in the European guidelines. The average doses, which depend on the technical parameters of the mammography equipment, are in line with values obtained in European guidelines. In addition, an investigation is needed throughout the Moroccan territory, in the sense of optimization of radiological practices and techniques in mammographic centres aligning with the international recommendations.