Establishing local diagnostic reference levels for adult computed tomography in Morocco

In Morocco, the radiation doses received by adult patients are increasing due to the number of CT examinations performed and the larger number of computed tomography (CT) scanners installed. The aim of this study was to evaluate the radiation doses received by patients for the most common adult CT examinations in order to establish local diagnostic reference levels (DRLs). Data from 1016 adult patients were collected during 3 months from four Moroccan hospitals. Dose length product (DLP) and volumetric computed tomography dose index (CTDIvol) were evaluated by determining the 75th percentile as diagnostic reference levels for the most common examinations including head, chest and abdomen. The DRL for each examination was compared with other studies. The established DRLs in Morocco in terms of CTDIvol were 57.4, 12.3 and 10.9 for CT examinations of the head, chest, abdomen, respectively. For DLP, they were 1020, 632 and 714, respectively. These established DRLs for CTDIvol were almost similar to the UK DRLs at all examinations, higher than the Egyptian DRLs and lower than the Japanese DRLs at the head CT examination, lower than the DRLs from Egypt and Japan at the CT abdomen examination. In terms of DLP, the DRLs were higher than those of the British studies, lower than those of the Egyptian and Japanese studies at the head CT examination were higher at chest CT and lower at abdominal CT than those of all selected studies. The higher level of established DRLs in our study demonstrates the requirement of an optimization process while keeping a good image quality for a reliable diagnosis.

Intraoral and dental panoramic imaging: A diagnostic reference level study comparing radiation dose using two dosimeters in Saudi Arabia

The purpose of this study was to determine local diagnostic reference levels (DRLs) for patients undergoing intraoral and panoramic dental examinations at the intraoral radiology units of the public hospitals in Najran, Saudi Arabia. DRLs were determined based on measurements of dose area product (DAP) at intraoral and dental panoramic radiology units. This study has covered over 47% of the public hospitals in Najran with the intention to establish the local DRLs for all the possible intraoral and panoramic X-ray examinations for children and adults. For intraoral, the values for the estimated DAP ranged from 6 to 70 mGy.cm2 (average: 27.6, 29.8, 39.9 and 39.6 mGy.cm2 for incisive, both premolar and canine, molar upper and lower jaw, respectively). For panoramic, the mean value of DAP is 61.5 and 89.8 mGy.cm2 for paediatric and adult patients, respectively. DRLs were established at the 3rd quartile for incisive, both premolar and canine, molar upper and lower jaw protocols are 29.2, 37.1, 50.2 and 50.1 mGy.cm2, respectively. Furthermore, DRLs for panoramic radiography for paediatric and adult patients are 72.7 and 92.3 mGy.cm2, respectively. The proposed DRLs were comparable to those previously reported in other countries, such as UK and India.

Evaluation of the radiological risk in cargo scanning by comparison with known biological consequences

This study proposes a quick, easy, and low-cost method that can be used to assess the radiological safety of an irradiation line used for cargo and container inspection facilities. The radiation-emitting equipment used was a Smiths Heimam particle accelerator model HCVP4029 operating at 4.5 MeV. The radiation dose measurements were performed using a personal radiation monitor Ultra Radac mod MRAD 111 (Geiger–Muller). The ambient equivalent dose H*(10) was estimated for two facilities: A (real) (1.12E-03 mSv per scan) and B (fictitious) (3.25E-03 mSv per scan). The dimensionless factor R, which represents a ratio between two specific scanning (Ss) quantities regarding the facilities A and B, is introduced as a reference for assessing the level of radiological safety. This study compares facilities A and B by using a simple alternative safety assessment based on the R factor. The dimensionless R-value appears to be able to facilitate both the personnel’s and the general public’s perception of risk levels, even with no fixed scale.

Rejets de tritium dans l’environnement et impact : évolutions récentes et perspectives

Plusieurs publications ont suscité des interrogations en France sur le comportement du tritium dans l’environnement et sur son impact sur la santé de l’homme. En 2008, l’ASN a demandé à deux groupes d’experts de faire le point de l’état de l’art sur le sujet. Un plan d’action découlant des recommandations exprimées a été présenté dans le Livre Blanc du Tritium publié en 2010. Depuis, le comité chargé de son suivi a abordé périodiquement les sujets identifiés. Les avancées métrologiques, les travaux de recherche concernant le transfert et le niveau d’activité du tritium dans l’environnement ont été étudiés. La compréhension de sa toxicité a progressé. Les exploitants des INB ont caractérisé les formes physico-chimiques des effluents tritiés existantes dans les rejets de leurs installations. Chaque année, l’ASN met à jour sur le site du Livre Blanc l’inventaire des rejets de tritium des INB et INBS et des impacts dosimétriques associés. Les actions du comité relatives aux sujets de recherche encore en cours étant maintenant limitées, l’ASN a proposé de clore les travaux du comité sous sa forme actuelle et de traiter les travaux de recherche non encore finalisés lors d’une journée dédiée qui sera organisée par l’IRSN.

Caractérisation des formes physico-chimiques des deux radionucléides principaux (18F et 11C) produits par irradiation de cible et du principal radionucléide parasite (13N) rejetés par les installations françaises de fabrication de radiopharmaceutiques au moyen d’un cyclotron

Cette étude, réalisée par l’IRSN (Institut de Radioprotection et de Sûreté Nucléaire) dans le cadre d’une demande de l’ASN (Autorité de Sûreté Nucléaire), concerne la caractérisation des formes physico-chimiques des composés radioactifs rejetés par les installations françaises de fabrication de radiopharmaceutiques au moyen d’un cyclotron. Elle vise à disposer d’une meilleure connaissance sur les effluents gazeux radioactifs rejetés par ces installations. Cette étude porte sur les deux principaux radionucléides produits par irradiation d’une cible à des fins de fabrication de radiopharmaceutiques : le fluor 18 (18F) et le carbone 11 (11C). L’azote 13 (13N), principal radionucléide parasite produit dans la cible et relâché essentiellement lors du transfert du contenu de cette dernière vers le laboratoire de radiochimie, a également été étudié.

The application of the optimization principle in the Italian and European context

The transposition of Directive 2013/59/Euratom has projected Italian radiation protection into the new safety culture, in which optimization is a multidisciplinary process pursuing a suitable balance among different risks. The fundamental tools in the application of the optimization principle are source-related dose constraints, introduced by the Directive to define the range of options to be considered. This article analyzes some critical issues in their use when managing radiation protection at work in any planned, existing or emergency exposure situation, which involves a risk from exposure to ionizing radiation. Simplified procedures and customized guidelines are outlined from international organizations, such as IAEA, OECD/NEA, and the European ALARA Network (EAN), paving the way to a correct implementation of the optimization principle.

How much is the effective dose from medical imaging in pediatric patients in the neurosurgery department?

Medical imaging with ionizing radiation in pediatric patients is rising, and their radiation sensitivity is 2–3 times more than adults. The objective of this study was to estimate the total effective dose (ED) of all medical imaging by CT scan and plain radiography in patients in pediatric neurosurgery department. Patients with at least one brain CT scan and recorded dose length product (DLP) were included. Patients’ imaging data were collected from the picture-archiving-and-communicating system (PACS) using their national code to find all their medical imaging. Total ED (mSv) from CT scans and plain radiographs were calculated. A total of 300 patients were included, of which 129 were females and 171 males with a mean age of 5.45 ± 4.34 years. Mean DLPs of brain, abdomen, and chest CT were 329.16, 393.06, 284.46 mGy.cm. The most frequent CT scans in these children were brain CT scans with ED range of 0.09 to 47.09 mSv. Total ED due to all CT scans and plain radiographs were in the range of 0.38 to 63.41 mSv. Although the mean DLP of each brain, chest, and abdomen CT of patients was in the range of DRLs reported by previous studies, the patients with numerous CT scans received more radiation doses than mean ED (6.21 mSv between all age groups). The most frequent CT scan was the brain, and the most frequent plain radiographs were chest and lower extremities. It can be concluded that reducing the number of CT scans or plain radiographs by appropriate physical exams or replacing them with modalities that do not use ionizing radiation can reduce ED.