RESUMO
PURPOSE: Our aim was to allocate a digital mammography unit to the screening programme on the basis of the ALARA (as low as reasonably achievable) radiation protection principle. MATERIALS AND METHODS: Two Hologic Selenia mammography units were studied: one with a molybdenum anode and the other with a tungsten anode. After optimisation of the image production chain, we evaluated doses in a phantom under standard conditions. In this phase, we exposed a polymethyl-methacrylate (PMMA) phantom to the two mammography units and recorded the exposure parameters used by them. The phantom was subsequently replaced by a dedicated Radcal ionisation chamber on which preliminary dose assessments were conducted. Image quality of the two systems was compared by exposing a phantom containing geometrical inserts and setting the exposure parameters used for the dose assessments on each mammography unit. Dosimetric assessments of exposure data were recorded from the mammographic examinations of approximately 400 women (1,600 exposures). RESULTS AND CONCLUSIONS: The unit with the tungsten anode achieved a lower patient dose. As a result, the Selenia-W device was allocated to the breast screening programme.
Assuntos
Neoplasias da Mama/diagnóstico por imagem , Mamografia/instrumentação , Intensificação de Imagem Radiográfica/instrumentação , Radiometria/instrumentação , Feminino , Humanos , Molibdênio , Imagens de Fantasmas , Doses de Radiação , TungstênioRESUMO
Life-table analysis of survival data of implants placed in subantral grafts reveals a high rate of survival, particularly in comparison with implants placed in non-grafted subantral sites. However, sample size (158 grafted, 140 non-grafted, in a total of 120 patients) and follow-up time remain insufficient to reach a definite conclusion. Results also appear improved over other reports in which the sinus was penetrated by the implants, possibly because the procedure has become more standard over the years.
Assuntos
Transplante Ósseo , Implantes Dentários/estatística & dados numéricos , Seio Maxilar/cirurgia , Procedimentos Cirúrgicos Pré-Protéticos Bucais/estatística & dados numéricos , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Tábuas de Vida , Masculino , Maxila , Pessoa de Meia-Idade , Análise de Sobrevida , Resultado do TratamentoRESUMO
The Authors present a clinical case of vertical bone loss in the peri-implant tissue, surgically treated. The adopted protocol led to the complete clinical and radiological recovery six months after surgery.
