Determination of X-ray shielding thickness in two tertiary hospitals in Kano metropolis, Nigeria

Background: Radiation dose depends on the total workload (Wtot) which is affected by the number of patients, tube potential, and tube current. Despite the increment in patients visiting the X-ray units under study and X-ray tube revolutions, changes have not been made in the shielding material to suit the current situation. Aims: This study aims to evaluate the thickness of X-ray shielding barriers in two tertiary hospitals in Kano Metropolis using XRAYBAR software. Materials and Methods: This was a prospective, cross-sectional study and was undertaken from March 2017 to October 2017. A purposive sampling technique was employed to select two hospitals out of five. The two were named A and B, respectively. The minimum required thickness in each barrier was determined by XRAYBAR software. Results: The Wtot (workload) for room I, II and III was found to be 199.9, 146, and 149.1 mA-min per week. The shielding barrier thickness required to reduce the unshielded radiation dose to the design dose limit for wall 1, 2, 3, 4, and operating console of the Room I was found to be 17.5, 5.5, 0.2, 0.00, 3.3 cm, that of wall 1, 2, 3, and 4 of room II was found to be 9.1, 3.4, 0.02, 2.3 cm, while for the wall 1, 2, 3, 4, and operating console of room III was found to be 12.3, 4.8, 3.8, 3.2, and 26.5 cm, respectively. Conclusion: The calculated shielding barrier thickness from XRAYBARR code when compared to the design barrier thickness was found to be adequate

Evaluation de la dose d'entrée des rayons X aux patients lors de la radiographie du thorax en pédiatrie

Objectif. Peu d'études ont été consacrées aux doses reçues par les enfants lors des examens de radiologie conventionnelle, alors même que leur plus grande radiosensibilité par rapport aux adultes est avérée. Nous rapportons dans ce travail, les doses d'entrée à la peau au cours de la radiographie du thorax de l'enfant au Cameroun et les comparons aux niveaux de références diagnostiques internationales.Méthodes. il s'agit d'une étude transversale descriptive, effectuée de mai à septembre 2015. 117 enfants ont été recrutés dans six centres d'imagerie médicale répartis dans cinq capitales régionales du Cameroun : Garoua, Ngaoundéré, Ebolowa et Bafoussam, Douala, et Yaoundé. Les données recueillies et analysées étaient l'âge, le sexe, le poids, la distance foyer film, les paramètres d'irradiation (kV, mAs, temps d'exposition), la position, l'utilisation ou non des moyens de contention, la reprise des examens ainsi que les raisons de cette reprise. Par la suite, nous avons déterminé la dose à l'entrée (De) des patients par utilisation du Module Internet de Calcul de Dose recommandée par l''Institut de Radioprotection et de Sûreté Nucléaire (IRSN) de France. Résultats. Les 75e percentiles de dose étaient de 0,125 ; 0,185 ; 0,25 et 0,27 mGy respectivement pour les tranches d'âges de 0 à 1 an, 2 à 5 ans, 6 à 10 ans et 11 à 15 ans. Bien que ces doses fussent inférieures à celles obtenues dans une étude similaire en Afrique de l'ouest, elles étaient cependant supérieures aux niveaux de références diagnostiques internationales. Les raisons de ces dépassements étaient liées à la vétusté des équipements, à l'absence des protocoles de travail et du contrôle qualité et à la compétence du technologue en radiologie et imagerie médicale. Conclusion. Les doses d'entrée à la peau lors de la radiographie du thorax de l'enfant sont encore élevées dans les hôpitaux du Cameroun. Les mesures correctives de cette situation incluent le renouvellement et la maintenance des équipements, l'instauration de protocoles d'examen et de mécanismes d'assurance qualité et la formation des personnels

Local Reference Dose Level Evaluation in Chest Radiography in Yaounde

Purpose: Patient radiation doses encountered during conventional X-ray examinations are not exactly known.This study aims to realize a radiation dose audit for chest posterior-anterior (PA) and chest lateral (LAT) examinations;analyze the procedures and establish local diagnostic reference level (LDRL).Method: A total number of 882 radiographs of 715 patients from seven selected hospitals in Yaounde were considered in this work.Entrance surface dose (ESD) ofadult patients undergoing chest PA and chest LAT examinations is estimated; using a mathematical algorithm and a standard backscatter factor.Results: Estimated mean ESDs in the hospitals range from 0.28 to 0.73mGy for chest PA and from 0.39 to 2.08 mGy for chest LAT. For each projection there is a wide variation in patientsESD within hospitals for individual patients and between hospitals.The third quartile ESD value 0.39 mGy for chest PA examinations was found to be above both the Diagnostic Reference Levels (DRLs)reported from similar studies in some African countries and the international established DRLs; while the value 1.33 mGy obtained for chest LAT was within the established international DRLs.Conclusion:The major contribution to the high dose has been identified in the use of shorter focus-film distance (FFD) and higher charge (mAs). Other factors are boththeabsence of quality control and the equipment performance.This study shows the need of the implementation of protocol and technics that can reduce patient dose and regular quality control and quality assurance

Radiation Dose in Paediatric Computed Tomography: Risks and Benefits

Computed tomography (CT) is a powerful tool for the accurate and effective diagnosis and treatment of a variety of conditions because it allows high-resolution three-dimensional images to be acquired very quickly. However as the number of CT procedures performed globally have continued to increase; with growing concerns about patient protection. Currently; no system is in place to track patient doses and the lifetime cumulative dose from medical sources. The widespread use of CT even in developing countries has raised questions regarding the possible threat to public health especially in children. The best available risk estimates suggest that paediatric CT will result in significantly increased lifetime radiation risk over adult CT. Studies have shown that lower milliampere-second (mAs) settings can be used for children without significant loss of information. Although the risk-benefit balance is still strongly tilted toward benefit; there is still need for caution. Furthermore since the frequency of paediatric CT examinations is rapidly increasing; and estimates suggest that quantitative lifetime radiation risks for children are not negligible; efforts should be made toward more active reduction of CT exposure settings in paediatric patients. This article hopes to address this concerns and draw attention to the fact that children are not 'small adults ' and should therefore be treated differently