RESUMO
In the event of a criticality accident, not only the maximal doses received by the victims must be determined but it is also crucial to evaluate the doses to the different organs. With a neutron component, morphology is a key parameter in the organ dose calculation. As the simulation tools can be time consuming to proceed, especially if morphology is taken into account, for all the victims, it may be very useful to have a database of conversion coefficients that allow to obtain the organ doses from the dose measured in the dosemeter for different kinds of morphology. In this paper, we present a study performed to evaluate such conversion coefficients using voxelized anthropomorphic phantoms. These coefficients take into account two crucial parameters having an impact on the dose at the organs: the orientation of the victim in the radiation field and the morphology, that is to say the body mass index of the different victims.
Assuntos
Nêutrons , Radiometria , Acidentes , Método de Monte Carlo , Imagens de Fantasmas , Doses de RadiaçãoRESUMO
OBJECTIVE: To study the prevalence of Cervical Intraepithelial Neoplasia (CIN) and its association with HIV-I infection, controlling for other risk factors of CIN. DESIGN: Cross-sectional survey. SUBJECTS AND METHODS: HIV-1 seropositive (HIV+) and seronegative (HIV-) women were enrolled at the Obstetrics-Gynecologic Departments of the Bordeaux University Hospital from April 1993 to June 1995. A gynecologic check-up was performed with a clinical examination, a colposcopy and a Papanicolaou smear. Sexually Transmitted Diseases (STDs) were screened. Colposcopy was interpreted as: normal, low-grade or high-grade lesions. Interpretation of Papanicolaou smears was based on the 1988 Bethesda system using three descriptive diagnoses: normal, low-grade and high-grade Squamous Intraepithelial lesions (SILs). If colposcopy showed a high grade lesion or Papanicolaou smear a high-grade SIL, a cervical biopsy was performed. Absence of CIN was defined by normal Papanicolaou smear and colposcopy. High grade CIN was defined by either identification of high grade SIL on Papanicolaou smear or high grade lesion on colposcopy confirmed by CIN2-3 lesion on biopsy. Other cases were classified as low-grade CIN. HPV infection was diagnosed on presence of koilocytosis on cytological or histological specimens. RESULTS: Prevalence of CIN was significantly higher in the 128 HIV+ women than in the 102 HIV- women: 34.4% vs. 13.7% (O.R.=3.30). Among HIV+ women, 25.8% had low-grade CIN and 8.6% high-grade CIN versus 10.8% and 2.9%, respectively among the HIV- women. Prevalence of HPV infection was 50.0% among women with CIN vs. 5.8% in women without CIN (P= 10(-6)). In the multivariate analysis of the determinants of CIN, smoking more than ten pack-years and HPV infection were the only two variables associated with CIN while association with HIV infection disappeared. Among HIV+ women, the variables associated with CIN were clinical AIDS and HPV infection.
