Quality control - patient doses - guidance dose levels from diagnostic radiology in Tunisia

Radiation doses from diagnostic radiology are the most important exposure collective doses of the man. Entrance Surface Dose is one of the basic dosimetric quantities for measuring the patient dose and hence, an excellent tool for optimization purposes and for comparison with the international reference values. The aim of the study was to assess the delivred quantitis of rayon x to patients who undervent radiography; For the first time in Tunisia the doses delivered to the patient undergoing the most common type of X ray examinations [chest, abdomen, lumbar spin] were performed in two university hospitals of Tunis. Entrance Surface Dose measurements were conducted using thermoluminescent dosimeters calibrated at the National Centre of Radiation Protection. Before measurements, quality control tests were carried out on each radiological equipment used for examinations. From this study of 112 patients, it was deduced that the obtained values were comparable to the internationally recommended guidance levels. The diagnostic guidance dose levels established for Tunis area are preliminary results. The study should therefore be implemented on a national scale as an approach to establish the national guidance levels

[Air radon in Tunisia dwellings]

Radon is a natural radioactive gas produced by decay of uranium and radium present in soils. Diluted in air, in confined atmospheres, it may accumulate in high concentration. Inhalation of radio and its progeny is thought to increase lung cancer risk. For the first time, air radon concentrations were determined in 1151 dwellings situated in all the inhabited regions of Tunisia, using open alpha-track dosimeters exposed during two months. The median of 1864 measurements was 36 B[q] m[-3] [with a maximum of 512 B[q] M[-3] most of tem being less than 100 B[q] M[-3]. All results were under the International Instances recommended range

Contamination interne du personnel d'un service hospitalier de medecine nucleaire par l'iode 131

Therapeutic applications in nuclear medicine use high activities of 131 iodine in sodium iodide liquid form which is volatile at ambient temperature. Besides external exposure there is, for the nuclear medicine personnel, an internal exposure risk induced by 131 iodine inhalation. So we tried to assess this risk among the personnel in a nuclear medicine department. We used direct method for measuring 131 radioactivity in vivo by external counting. gamma ray detector with a Nal [TI] probe positioned near the thyroid gland allows investigation of 131 radioactivity. We realised 34 measurements among the personnel, two times at an interval of one month. The results indicate that an 131 iodine internal contamination is found. Estimated thyroid activities were ranging from 35 to 132 Bq. The highest activities has been found in the thyroid of the technicians involved in the administration of 131 iodine therapy. Therefore this values are lower than norms. This study must lead to the implementation control of the 131 iodine internal cantamination in order to optimise the personnel protection in nuclear medicine departments