Absorbed dose evaluation at different organs after 131I oral contamination of two Wistar rat models

Iodine-131 (131I) is one of the most frequently used radionuclides for diagnosis and therapy of thyroid diseases. It is administered orally in the treatment of cancer to eliminate the residual postoperative microscopic tumor foci, and the residual normal thyroid tissue for early detection of recurrence [1]. The comparative behavior of 131I concentration into two animalmodels with total and partial thyroid has been investigated in our previous work [2]. The accumulated activities have been measured in fourteen organs. In this study, the mean absorbed doses resulting from 131I accumulated in all organs have been evaluated using RODES software [3, 4]. With this software, mean absorbed doses were calculatedfor selected organs (thyroid, lungs, heart, liver, kidneys, stomach, spleen, large and small intestine, testes, urinary bladder wall) by combining the specific absorbed fractions (SAF) of energy with radiation emission spectra and biokinetic data determined from our previous experimental study [2]. Calculations were based on the 131I photon and electron emissions reported by [5] and SAFs previously calculated by Monte Carlo simulation in the voxel phantom of an adult male rate [3, 4]. The obtained results show high absorbed dosesdeliveredto stomach and lungs for both models compared to other organs. The dose received by the testes and salivary glands is found to be higher in the case of the rat model without thyroid. Conversely, the spleen and bladder wall received lower doses in this latter model compared to those received by the rat model with thyroid. One can also note that the difference in mean absorbed dose received by liver, lungs, heart, and walls of the stomach is not significant between the two rat models

Internal exposure in post-accidental situations: a multi-pollution to take into account?

International audienceMajor nuclear accidents (Chernobyl, Fukushima) induced the contamination of large areas with a mix of radionuclides (RNs), inducing both external and internal exposure at low dose and low dose rate. Numerous studies were conducted on the health effects in post accidental situations. However, in most cases, the exposure is ill-defined. Thus the health effects on exposed populations living in a contaminated territory remain a matter of controversy.Experimental results in rodents are somewhat in contradiction with results from the study of human populations. This might be due in obvious differences between rodent models and human physiology, but also could be due to simplified schemes of exposure used in the experimental settings. A hypothesis to explain these discrepancies is the differences in exposure schemes. Moreover, the exposure in real life is more complex than the simple exposure to ionizing radiation. In fact, the chemical pollution should also be taken into account.The hypothesis of a generalized model of interactions between chemical pollutants and radiological pollutants is reinforced by the recent descriptions of non-additive (either supra- or infra-) biological effects of mixtures of chemical pollutants. Since there is no available study on the health effects of mixed radiological exposures, it is not possible to exclude the hypothesis that a mixture of RNs may induce non-linear effects as compared to the effect of individual RNs. Thus it appears that futures studies on the health effects of radionuclides at low concentrations or external exposure at low dose rate should be done taking into account more realistic schemes of exposure, including mixtures of RNs, external exposure and chemical pollutants

Caracterisation des precurseurs lymphocytaires T humains: role du CD23 dans leur differenciation

SIGLEAvailable from INIST (FR), Document Supply Service, under shelf-number : T 79006 / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc

Internal exposure in post-accidental situations: a multi-pollution to take into account?

International audienceMajor nuclear accidents (Chernobyl, Fukushima) induced the contamination of large areas with a mix of radionuclides (RNs), inducing both external and internal exposure at low dose and low dose rate. Numerous studies were conducted on the health effects in post accidental situations. However, in most cases, the exposure is ill-defined. Thus the health effects on exposed populations living in a contaminated territory remain a matter of controversy.Experimental results in rodents are somewhat in contradiction with results from the study of human populations. This might be due in obvious differences between rodent models and human physiology, but also could be due to simplified schemes of exposure used in the experimental settings. A hypothesis to explain these discrepancies is the differences in exposure schemes. Moreover, the exposure in real life is more complex than the simple exposure to ionizing radiation. In fact, the chemical pollution should also be taken into account.The hypothesis of a generalized model of interactions between chemical pollutants and radiological pollutants is reinforced by the recent descriptions of non-additive (either supra- or infra-) biological effects of mixtures of chemical pollutants. Since there is no available study on the health effects of mixed radiological exposures, it is not possible to exclude the hypothesis that a mixture of RNs may induce non-linear effects as compared to the effect of individual RNs. Thus it appears that futures studies on the health effects of radionuclides at low concentrations or external exposure at low dose rate should be done taking into account more realistic schemes of exposure, including mixtures of RNs, external exposure and chemical pollutants

Les nouveaux concepts de diagnostic et de thérapie de l'irradiation accidentelle

Les accidents d'irradiation, bien que rares, restent difficiles à traiter essentiellement du fait d'une physiopathologie complexe et mal connue. En conséquence, l'issue reste fatale pour la plupart des victimes d'irradiation accidentelle à forte dose, par manque d'une estimation fiable des dommages radioinduits mais également par manque d'une stratégie thérapeutique claire et adaptée à la situation accidentelle. Les accidents d'irradiation récents, et en particulier l'accident de Tokai Mura, ont clairement montré que le choix d'une stratégie thérapeutique ne doit pas être basé uniquement sur l'estimation de la dose reçue, mais principalement sur l'estimation de l'étendue des dommages aux systèmes physiologiques vitaux pour la survie de la victime, particulièrement lorsqu'une irradiation hétérogène est soupçonnée. L'importance prise par cette notion d'hétérogénéité a amené à des changements importants dans les concepts thérapeutiques applicables à la situation d'irradiation accidentelle, avec en particulier la remise en cause de la greffe de moelle osseuse dans tous les cas d'irradiation hétérogène. Ceci a conduit au développement de nouvelles approches de thérapie cellulaire, qui semblent mieux adaptées à une situation d'irradiation accidentelle hétérogène en champ large et à forte dose

Protéger, réparer : la doctrine française après un accident nucléaire

Au-delà du renforcement des installations nucléaires, l’accident de Fukushima a rappelé la nécessité de rehausser le niveau de préparation à la gestion d’une crise nucléaire. Les principales dispositions de gestion accidentelles et post-accidentelles retenues en France sont pensées pour protéger la population et permettre le redémarrage de la vie économique et sociale