Optimal theranostic SPECT imaging protocol for 223radium dichloride therapy.

223Radium dichloride image-based individual dosimetry requires an optimal acquisition and reconstruction protocol and proper image correction methods for theranostic applications. To assess this problem, radium-223 dichloride SPECT images were acquired from a Jaszczak simulator with a dual-headed gamma camera, LEHR collimator, 128 × 128 matrix, and total time of 32 minutes. A cylindrical PMMA phantom was used to calibrate the measurements performed with Jaszczak. The image quality parameters (noise coefficient, contrast, contrast-to-noise ratio and recovery coefficient) and septal penetration correction were calculated by MATLAB®. The best results for the investigated image quality parameters were obtained with an 89 keV energy window (24% wide) produced together with OSEM/MLEM reconstruction (8 subsets and 4 iterations) applying a Butterworth filter (order 10 and cutoff frequency of 0.48 cycles·cm-1). The successfully performed recovery coefficient parameter evaluation allows uptake correction for future patient dosimetry applications.

Seqüência dos estudos sobre a produção experimental de megassíndromes em camundongos

A capacidade de produção de megassíndrome de três cepas de Trypanosoma cruzi de diferentes origens foram examinadas usando-se técnicas previamente descritas. Uma correlação significante foi encontrada entre volume e peso do estômago através de autópsia e a área correspondente a silhueta de bário do órgão. Todas as três cepas causam dilatação significante da área do estômago, após prolongada infecção em camundongos quando comparados com o grupo controle não infectado. Todavia, o modelo de comportamento da cepa (MEGA), previamente estudada, pode ter sido alterada pela reciclagem em camundongos nos laboratórios.

The mega-producing capacity of three strains of Trypanosoma cruzi of widely different origins was examined using techniques previously described. A significant correlation was found for two of the strains between the volume and weight of the stomach at autopsy and measurement of the area of a barium silhouette of this organ. All three strains caused significant stomach dilatation after prolonged infection in the mice when compare with a control uninfected group. However the behavior of a strain (mega) previously studied in this model had altered, possibly as a result ofrepeated mice passage in the laboratory.