RESUMEN
A small-animal multimodality tomography system dedicated to the coregistration of fluorescence optical signal and x-ray measurements has been developed in our laboratory. The purpose of such a system is to offer the possibility of getting in vivo anatomical and functional information simultaneously. Moreover, anatomical measurements can be used as a regularization factor to achieve more accurate reconstructions of the biodistribution of fluorochromes and to speed up treatment. A dedicated acquisition protocol has been established, and the methodology of the reconstruction of the three-dimensional distribution of the biomarkers under cylindrical geometry consistent with classic computed tomography has been implemented. A phantom study was conducted to evaluate and to fix the parameters for the coregistration. These test experiments were reproduced by considering anesthetized mice that had thin glass tubes containing fluorochromes inserted into their esophagus. The instrument is also used for an in vivo biological study conducted on mice with lung tumors, tagged with near-infrared optical probes (targeting probes such as Transferin-AlexaFluor750).
Asunto(s)
Dispositivos Ópticos , Tomografía Óptica , Tomografía Computarizada por Rayos X , Animales , Calibración , Femenino , Colorantes Fluorescentes , Procesamiento de Imagen Asistido por Computador , Neoplasias Pulmonares/diagnóstico , Neoplasias Pulmonares/secundario , Neoplasias Mamarias Experimentales/patología , Neoplasias Mamarias Experimentales/secundario , Ratones , Ratones Desnudos , Fantasmas de ImagenRESUMEN
A new concept of gamma emission imaging based on the use of scattered radiation with a non collimated gamma camera is put forward. A few years ago, scattered radiation by Compton effect is shown to be capable to reconstruct a three dimensional object using a standard collimated gamma camera. To increase drastically in sensitivity, we propose now that data acquisition should be performed without collimation. We present this new image formation by scattered radiation via the properties of its Point Spread Functions (PSF). Comparison with the PSF in the presence of a collimator exhibits a striking image enhancement. We also present numerical simulations on image formation and reconstruction to support the attractiveness of this modality.