Multi-slice computed tomography (MSCT) has proven in several studies to have a high diagnostic accuracy for the detection or exclusion of coronary artery disease. A major concern with coronary MSCT, however, is the associated radiation exposure of patients. Recent studies suggest that use of a 64-slice scanner is associated with a non-negligible lifetime attributable risk of cancer. Several strategies can be used to reduce patient exposure in coronary MSCT. The purpose of this multicenter study was to investigate the effects of the adjustment of tube voltage and current on radiation dose and image interpretability. MSCT with retrospective ECG gating was performed in 315 patients. The dose-length product (DLP) in the patients enrolled with the dose reduction protocol resulted in a 36% overall reduction in the mean radiation dose (911 ± 289 mGy.cm) compared with the standard protocol (1427 ± 226 mGy.cm, p < 0.001). Nevertheless, image interpretability was maintained. This study on coronary MSCT demonstrates that the radiation dose can be significantly reduced by parameter optimization, with maintained image interpretability.

Interventional cardiology procedures (ICPs), while providing important benefits to patients, also contribute to their radiation exposure, in particular for the organs surrounding the heart. This paper addresses the issue of radiation exposure to the lung and bone marrow related to coronary interventions in terms of organ doses for coronary angiography (CA) and percutaneous transluminal coronary angioplasty (PTCA), and risk assessment of potential radiation-induced cancer. Dosimetric information on 2095 ICPs from French patients was collected. The median lung dose for CA alone was 34 mGy for men and 22 mGy for women and the median bone marrow dose was 8 mGy and 4 mGy, respectively; doses were slightly higher for CA and ad hoc PTCA and nearly twice as high for CA and elective PTCA. Based on the French national mortality registry and Biological Effects of Ionising Radiation VII models, spontaneous and radiation-induced lung cancers and leukaemia were estimated. For men and women aged at least 60 years old at the first ICP, excess risk of potentially fatal cancers attributable to radiation ranged from 0.4% to 4%. This study provides evidence of the potential risk of radiation-induced cancer after an ICP. The limitations of such calculations are due to the difficulty of taking into account patients’ possibly shorter life expectancy than in the general population, linked to their comorbidities and coronary disease. Nevertheless, risk estimates can be used to illustrate the beneficial role of optimisation of doses delivered to the patient.

The concentrations of natural radionuclides in 6 different colors of volcanic tuff stones which are derived from the Cappadocia region in Turkey were determined using gamma-ray spectroscopy with a HPGe detector, and the mineralogical composition and formula of stones were determined by an X-ray powder diffractometer. The average activity concentrations of 238U, 232Th and 40K are 50.7, 58.6 and 717.6 Bq.kg–1, which are higher than the world averages of 35, 30 and 400 Bq.kg–1, respectively. The radium equivalent activities (Raeq), external hazard index (Hex), and internal hazard (Hin) associated with the natural radionuclides, alpha (Iα) and gamma indices (Iγ) were calculated to assess the radiation hazard of the natural radioactivity in the volcanic tuff stones. The average indoor annual effective dose equivalent is 0.1 mSv. All values of the indoor effective dose are lower than the exemption dose value of 0.3 mSv. The calculated radium equivalent activity values vary from 60.31 Bq.kg–1 to 281.32 Bq.kg–1 with a mean of 189.78 Bq.kg–1. All values of radium equivalent activity are lower than the world average. The average indoor absorbed dose rate (Din) for volcanic tuff stones, calculated to be 21.18 nGy.h–1, is lower than the world average of 84 nGy.h–1.

The uranium isotopes 238U, 235U and 234U are found naturally in the environment. 238U and 235U are parent nuclides of two independent decay series of isotopes, while 234U is a member of the 238U decay chain. When decay series occur in a closed system the series tends to reach, with time, the state of secular equilibrium in which the activities of all series members are equal to the activity of its first nuclide. The activity ratio 234U/238U in natural uranium may vary as a consequence of decay chain disequilibrium due to alpha recoil and biogeochemical processes. A study based on measurement of uranium concentration and 234U/238U activity ratios in soil samples collected from Nalgonda district, Andhra Pradesh, India, a proposed mining site, was carried out to find the spatial distribution of uranium and the state of secular equilibrium of 234U/238U to examine the possibility of applying uranium concentration and uranium isotopic activity ratios to detect any hydrogeochemical changes in the environment during/post-operation. Soil samples were collected and analyzed for uranium concentration using the conventional UV fluorimetric method, showing a uranium concentration in the range of 0.7 ± 0.2 ppm to 7.9 ± 0.4 ppm with an average of 3.4 ppm, and 234U/238U activity ratios were estimated using the alpha spectrometry technique, showing an activity ratio in the range of 0.92 ± 0.11 to 1.02 ± 0.11. The 234U/ 238U activity ratio obtained indicated that these two uranium isotopes are in the state of secular radioactive equilibrium. The percent activity ratio of 238U/total U and 234U /total U is observed to vary from 47.94 ± 4.83 to 50.76 ± 4.87 and 45.80 ± 3.83 to 49.14 ± 3.99, respectively.

In the present paper, we estimated backscattering factors for the TLD and active personal dosimeters using 662 keV gamma-ray photons on a PMMA surface, which are, for the TLD, 1.12; Dosicard, 1.116; DRD, 0.99; and Saphydose, 1.073, and on a water slab phantom surface; for the TLD, 1.115; Dosicard, 1.112; DRD, 1; and Saphydose, 1.059. The backscattering factor contribution for the Saphydose is nearly half that of the TLD and Dosicard, whereas it is zero for the DRD. The DRD underestimates Hp(10) by 10.3–11.6%, whereas for the Saphydose it is 3.4–5% compared with the TLD or Dosicard. The response of the DRD to Hp(10) is nearly independent of the phantom, whereas the TLD, Dosicard and Saphydose require phantoms for calibration for personal monitoring. It is observed that the PMMA phantom contributes slightly higher backscattering compared with the water slab phantom. The backscattering factor of the selected dosimeters is comparable with ICRU tissue already reported.

Nous avons évalué l’intérêt des gants de radioprotection de radiologie interventionnelle pour de la manipulation de radionucléides dans un service de médecine nucléaire. Des mesures d’atténuation faites par des dosimètres thermo-luminescents placés à l’intérieur de gants au contact des flacons ont montré une augmentation significative de la dose aux extrémités dans le cas d’un émetteur γ, et une réduction de dose pour un émetteur β. Des mesures complémentaires faites au moyen d’un irradiateur X (150 kV) ont montré qu’il existe une production d’électrons secondaires dans le gant, dont le parcours dans l’air est estimé à 6 cm. Étant donné que l’utilisation d’un gant radio-atténuateur dans une boîte à gants de médecine nucléaire doit être compatible avec l’ensemble des radionucléides utilisés, notre équipe n’utilisera pas de tels gants dans la pratique quotidienne.

During an accidental release of tritium, mechanisms of hydrogen transfer from air to man are very numerous, dependent on multiple climate, physiological and biological parameters, and the kinetic is highly variable from one environmental compartment to another. To evaluate the impact of an acute tritium release requires either an overall assessment of the state of the environment during the release and the following hours from a number of restricted data, or the establishment of a significant data bank, a complex model and a system of data acquisition in real time whose potential for daily purposes is very hypothetical. To facilitate the first approach, this paper discusses the key elements of the mechanisms to guide the choice of parameters for a rapid assessment of the situation, and to clarify the types of measurements to carry out and their interpretation.

We used CR-39 detectors to evaluate radon activity concentrations in several habitations of Bamako. The calibration factor of the dosimeters was determined experimentally with known radon activity concentrations inside a radon chamber, and was also simulated with MCNPX. The experimental and simulated calibration factors are, respectively, kexp = 0.119 ± 0.017 and ksim = 0.126 ± 0.007 tr.cm-2.d-1.Bq-1.m3. Indoor radon activity concentrations in Bamako were found to vary from 70 ± 18 to 154 ± 35 Bq.m-3. No significant differences were observed in the mean radon activity concentrations compared with five other African countries. Taking into account an occupancy factor of 0.8 and an equilibrium factor of 0.4 for radon indoors, the effective dose rate ranges from 1.77 to 2.35 mSv.y-1. In all cases the radon activity concentrations measured were below the action limits recommended by the International Commission on Radiological Protection (ICRP) Statement on Radon.

The mass concentration of uranium in water samples collected from the Bathinda district of Punjab state, India, was estimated using the laser fluorimetric technique. The study region has shown a pronounced number of cancer cases in the recent period. The study aims to calculate the human radiological risk and chemical toxicity associated with uranium consumption through drinking water. The mass concentration of uranium was found to vary from 0.48 to 571.7 μg/l with a mean value of 84.70 μg/l. The radiological risk due to consumption of uranium through contaminated drinking water was observed to be in the range of 1.34 × 10-6 to 1.60 × 10-3 with a mean value of 2.37 × 10-4. The chemical toxicity was found to vary from 0.04–43.11 µg.kg-1.day-1 with a mean value of 6.38 µg.kg-1.day-1.