RESUMO
Skeletal growth and mineralization in 54 adolescent and adult patients with inflammatory bowel disease have been analyzed comprehensively. Quantitative and qualitative radiologic techniques consisted of conventional roentgenography, photon absorptiometry, and radiographic morphometry. The data are correlated with the type, duration, and severity of disease, and with several modes of therapy. The results indicate the osteopenia and retardation of growth are common in patients with inflammatory bowel disease, particularly in adolescents, in whom the effects of corticosteroids on the skeleton are most deleterious.
Assuntos
Distúrbios do Metabolismo do Cálcio/etiologia , Colite Ulcerativa/complicações , Doença de Crohn/complicações , Descalcificação Patológica/etiologia , Transtornos do Crescimento/etiologia , Adolescente , Corticosteroides/efeitos adversos , Corticosteroides/uso terapêutico , Adulto , Idoso , Criança , Colite Ulcerativa/tratamento farmacológico , Doença de Crohn/tratamento farmacológico , Descalcificação Patológica/induzido quimicamente , Feminino , Transtornos do Crescimento/induzido quimicamente , Humanos , Masculino , Pessoa de Meia-IdadeRESUMO
Our investigations of an iso-octane-filled liquid-dielectric ionization chamber indicate that this dosimeter is well suited for the measurement of dose distributions at distances close to 252Cf interstitial implant sources. Initial research has shown that such an instrument provides good discrimination between the radiation components of a mixed field and possesses excellent sensitivity. Calculations indicate that iso-octane will yield a neutron and gamma-ray dose response independent of energy over a major part of the 252Cf spectral range, while transmission measurements have demonstrated that the liquid causes little perturbation of the radiation field.
Assuntos
Califórnio/uso terapêutico , Radiometria/instrumentação , Dosagem Radioterapêutica , Tecnologia RadiológicaRESUMO
By using a tissue-equivalent (TE) ionization chamber filled with TE gas and a magnesium ionization chamber filled with argon gas as the dosimeter pair for the twin-chamber method, the authors obtained the neutron and gamma-ray components of the radiation dose from californium 252 (252Cf). The distribution of dose components as a function of different phantom dimensions was determined. The effect of neutron absorption and scattering was evaluated, as well as the absorption and production of gamma rays in the phantom. The results can be used for improvement of 252 Cf dosimetry when using a body of finite dimensions.
Assuntos
Califórnio , Raios gama , Modelos Estruturais , Nêutrons , Doses de Radiação , Radiometria/instrumentaçãoRESUMO
Afterloading techniques were developed for the in vivo assessment of the RBE of californium-252 with respect of radium-226 using a fibrosarcoma in mice. The afterloading holder positions sources so that the tumor is uniformly irradiated. Using the end points of tumor volumetric studies up to 150 days after irradiation, it was found that the RBE ranged from 5-8 at clinically relevant dose rates and total doses.