Micro-CT evaluation of the radioprotective effect of resveratrol on the mandibular incisors of irradiated rats

Abstract The purpose of this study was to perform a microcomputed tomographic evaluation of the radioprotective effect of resveratrol on the volume of mandibular incisors of irradiated rats. A second aim was to make a quantitative assessment of the effect of x-ray exposure on these dental tissues. Twenty adult male rats were divided into four groups: control, irradiated control, resveratrol, and irradiated resveratrol. The resveratrol groups received 100 mg/kg of resveratrol, whereas the irradiated groups were exposed to 15 Gy of irradiation. The animals were sacrificed 30 days after the irradiation procedure, and their mandibles were removed and scanned in a microcomputed tomography unit. The images were loaded into Mimics software to allow segmentation of the mandibular incisor and assessment of its volume. The results were compared by One-way ANOVA and Tukey's post hoc test, considering a 5% significance level. The irradiated groups showed significantly diminished volumes of the evaluated teeth, as compared with the control group (p < 0.05). The resveratrol group presented higher values than those of the irradiated groups, and volumes similar to those of the control group. High radiation doses significantly affected tooth formation, resulting in alterations in the dental structure, and thus lower volumes. Moreover, resveratrol showed no effective radioprotective impact on dental tissues. Future studies are needed to evaluate different concentrations of this substance, in an endeavor to verify its potential as a radioprotector for these dental tissues.

Tomografia por emissão de pósitrons em tumores malignos de cabeça e pescoço / Positron-emission tomography in head and neck cancer

Head and neck cancer is considered a public health problem worldwide, given its high morbidity and mortality. The more advanced is the histopathologic grade, the more aggressive may be the therapies. The development of health policies, diagnosis and treatments lead to better prognostic perspectives. This paper aimed to review the literature regarding the application of positron emission tomography in headand neck cancer, including its impact in the diagnosis, image principles, radiotracers, positron emission tomography / computed tomographyimage fusion and other advantages. The review was performed following systematized search strategies reported in the literature. It could be observed that the use of positron emission tomography improves the diagnostic approach of the patients, especially when positron emission tomography is allied to computed tomography. As it provides physiological information, positron emission tomography also benefits the prognostic and reduces the morbidity related to the treatment of head and neck cancer.

Apresentando-se como um problema de saúde pública em todo o mundo, o câncer de cabeça e pescoço caracteriza-se por sua alta morbidadee mortalidade. Quanto mais avançado o grau de diferenciação tumoral, mais mutiladoras tendem a ser as terapias empregadas. Desta forma,os avanços nos âmbitos da promoção de saúde, diagnóstico e tratamento são extremamente benéficos ao prognóstico. Esta revista daliteratura tem por objetivo discorrer sobre a aplicação da tomografia por emissão de pósitrons no diagnóstico e planejamento terapêuticode pacientes portadores de tumores malignos de cabeça e pescoço, princípios de formação da imagem, radiofármacos utilizados, fusãode imagens tomografia por emissão de pósitrons e tomografia computadorizada e suas contribuições. O levantamento bibliográfico foiefetuado segundo estratégias sistematizadas relatadas em literatura. Fornecendo informações relativas à fisiologia das lesões através daadministração de radiofármacos, pode ser observado que a tomografia por emissão de pósitrons, especialmente quando aliada à tomografiacomputadorizada, maximiza as possibilidades diagnósticas em determinadas indicações, favorecendo ao prognóstico e sugerindo redução na morbidade decorrente do tratamento no câncer de cabeça e pescoço.