[en] This paper presents a brief history of the development of cumulative effects, the current requirements in North America and elsewhere in the world, challenges at the project level, thoughts on how emerging concepts of strategic environmental assessment and regional assessment may offer means to improve the examination of cumulative effects and offers suggestions for current and future needs in cumulative effects assessment.

No abstract available

[en] The intravenous administration of any radioactive tracer results in an initial vascular component prior to organ extraction. Calculation of the absorbed values for short-lived radioisotopes (e.g., T 1/2 < 5 min) from biodistribution data obtained with long lived analogue radioisotopes (e.g. Ir-192 for Ir-191m) is particularly biased because vascular radioactivity during the initial vascular phase contributes the major radiation dose and occurs only in the early time period after injection. This initial phase is dominated in the experimental uptake curve measured with long or medium-lived radioisotopes by the late points characteristic of organ uptake. We have now developed a new method for estimating the organ cumulated activities for short-lived radioisotopes obtained from generators. This method is based on the measurement of the transit of the injected activity followed with a conventional gamma camera. Estimates of the absorbed dose values calculated for Ir-191m (T 1/2 4.96 s), Kr-81m (T 1/2 13 s), Rb-82 (T 1/2 1.25 min) and Au-195m (T 1/2 30.6 sec) will be discussed

[en] In a French large population-based case-control study we investigated the dose-response relationship between lung cancer and occupational exposure to diesel motor exhaust (DME), taking into account asbestos exposure. Methods. Exposure to DME was assessed by questionnaire. Asbestos was taken into account through a global indicator of exposure to occupational carcinogens or by a specific JEM. Results. We found a crude dose response relationship with most of the indicators of DME exposure, including with the cumulative exposure index. All results were affected by adjustment for asbestos exposure. The dose response relationships between DME and lung cancer were observed among subjects never exposed to asbestos. Conclusions. Exposure to DME and to asbestos is frequently found among the same subjects, which may explain why dose-response relationships in previous studies that adjusted for asbestos exposure were inconsistent.

[en] As per UNSCEAR 2000, CT contributes over 34% of collective dose from diagnostic X-Ray examinations in the world. The radiation dose in CT particular importance for children, it is very well known that children are more sensitive and likely to get radiation induced cancer than adults. This paper discusses the radiation dose of patients (adults and children) in Computed Tomography in syria ( 30 CT units form 6 different manufacturers). The radiation dose measurements has covered computed tomography dose index, dose length product and effective dose. The result of this study indicating, that most computed tomography dose index and dose length product values recorded were below dose reference levels, only for high resolution chest protocol, the dose length product results were higher than that of the International Commission on Radiological Protection (author)

[en] The distribution of individual lifetime exposures to radon was estimated using data from studies on radon concentrations, mobility, and time-activity patterns in the state of California. The distributions of radon concentrations in various geographic regions were obtained from the results of year-long radon measurements of 310 residences. The mobility patterns were acquired through a survey of the moving histories of the members of 507 households. The indoor and outdoor time-activity data were collected for 1,780 individuals in 1,596 households. Based on these data, a computer simulation technique was used to estimate the distribution of radon exposures with a parametric (lognormal model) and a nonparametric approach (bootstrap method). The estimated average lifetime exposure for radon was 2,448 Bq.m-3.yr for the lognormal model and 2,487 Bq.m-3.yr for the bootstrap method. The standard deviation was 1,130 and 1,145 Bq.m-3.yr respectively. Assuming no move over the lifetime, the estimated average lifetime exposure to radon was 2,052 Bq.m-3.yr for the lognormal model and 2,078 Bq.m-3.yr for the bootstrap method, while the standard deviation increased to 1,378 Bq.m-3.yr for the lognormal model and 1,514 Bq.m-3.yr for the bootstrap method

[en] The authors applied chromosomal aberration counting to determine possible changes in the cell genome of subjects occupationally exposed to x-radiation. Subjects were restricted to those exposed to annual radiation levels no higher than 25 mSv as determined by regular dosimetry monitoring in the previous two years. Results indicate the possibility of a cumulative effect of ionising radiation and point to the need for more frequent and controlled health surveillance of occupationally exposed subjects. (UK)

[en] The ²¹⁰Po activity in the surface layer of an object is determined by the total deposition flux of Rn progeny. The total deposition flux is mainly a function of deposition fraction and concentration of attached and unattached progeny. A linear relationship between the activity of ²¹⁰Po incorporated in the surface of a glass object and the average potential α-energy concentration (PAEC) in air is found by using the Jacobi-Porstendoerfer predictive model for short-lived Rn progeny. The cumulative exposure to Rn progeny over a certain time period is also found to be related to the surface activity of ²¹⁰Po. The surface of a glass object can be used as an effective dosimeter for retrospective dose estimation, but with inherent uncertainties involved

[en] Epidemiological studies support a link between cumulative sun exposure and cutaneous squamous cell carcinoma (SCC) development. However, the presumed effects of extended ultraviolet light B (UVB) exposure on tumorigenesis in the sexes have not been formally investigated. We examined differences in ultimate tumorigenesis at 25 weeks in mice exposed to UVB for either 10 or 25 weeks. Additionally, we investigated the effect of continued UVB exposure on the efficacy of topical treatment with anti-inflammatory (diclofenac) or antioxidant (C E Ferulic or vitamin E) compounds on modulating tumorigenesis. Vehicle-treated mice in the 25-week UVB exposure model exhibited an increased tumor burden and a higher percentage of malignant tumors compared to mice in the 10-week exposure model, which correlated with increases in total and mutant p53-positive epidermal cells. Only topical diclofenac decreased tumor number and burden in both sexes regardless of UVB exposure length. These data support the commonly assumed but not previously demonstrated fact that increased cumulative UVB exposure increases the risk of UVB-induced SCC development and can also affect therapeutic efficacies. Our study suggests that cessation of UVB exposure by at-risk patients may decrease tumor development and that topical NSAIDs such as diclofenac may be chemo preventive.

[en] Short communication