RESUMO
The quasi-elastic scattering of 1 GeV protons permits the three-dimensional reconstruction of the density distribution in extended bodies. Fast multiwire proportional chambers are used to localize the position of every incoming and outgoing charged particle and to determine the coordinates at the interaction vertex. This article describes tests on a human head fixed on formalin. The comparison with computed tomography scans and anatomical sections is encouraging. Slices with a volume element of 5.5 mm3 illustrate the sensitivity of the method. The results also demonstrate the ability of the method to select the density distribution of hydrogen by making use of the kinematic relations specific to elastic scattering. Trials of this method in living humans are being planned.
Assuntos
Tomografia Computadorizada por Raios X , Encéfalo/anatomia & histologia , Encéfalo/diagnóstico por imagem , Relação Dose-Resposta à Radiação , Humanos , Matemática , Fotografação , Prótons , Espalhamento de Radiação , Crânio/anatomia & histologia , Crânio/diagnóstico por imagem , Tecnologia Radiológica , Tomografia Computadorizada por Raios X/métodosRESUMO
Nuclear scattering radiographs of a portion of a spine and a sphenoid bone have been obtained using a 1 GeV proton beam. The ability of the method to yield three-dimensional representations is illustrated by three series of adjacent pictures corresponding to the three orthogonal planes (elementary volume: 5.2 mm3 and 0.9 mm3). The sensitivity of the method is discussed. Nuclear scattering radiographs are compared with ones obtained by conventional X-ray tomography and computed tomography. Nuclear scattering radiography also may be used to analyze the partition of hydrogen within the tissures. Hydrogen radiographs obtained in this way are shown.
Assuntos
Osso Esfenoide/diagnóstico por imagem , Coluna Vertebral/diagnóstico por imagem , Partículas Elementares , Hidrogênio , Métodos , Radiografia , Espalhamento de RadiaçãoRESUMO
A further investigation of the nuclear scattering of 500-1000 MeV protons is described. Three-demensional information on the desity distribution within carbon, CH and H2O phantoms is obtained with a volume resolution of 2 mm3. The separation of scattering on hydrogen from that on heavier nuclei, such as carbon and oxygen, is demonstrated, providing the statistics are sufficient. Some preliminary measurements on animals are reported, but with a volume resolution limited by statistics to 43 mm3.
Assuntos
Prótons , Radiografia/instrumentação , Espalhamento de Radiação , Animais , Carbono , Cabeça/diagnóstico por imagem , Neoplasias Intestinais/diagnóstico por imagem , Camundongos , Neoplasias Experimentais/diagnóstico por imagem , Coelhos , ÁguaRESUMO
The possibility of using the nuclear scattering of 500-1000 MeV protons was investigated, in order to obtain direct, three-dimensional reconstruction of an object with only one exposure. The resolution should be about 1 mm3. Preliminary measurements with an incomplete set-up give a resolution of 10 mm3. Additional independent information on the relative concentration of hydrogen compared to other elements should also be obtainable by nuclear scattering radiography. The radiation doses involved are comparable to those of other techniques. The first experimental results are given.