X-RAY SPECTRA BY MEANS OF EXPERIMENTAL DATA AND MONTE CARLO SIMULATIONS FOR IMAGING APPLICATIONS

G. TIRAO, C. QUINTANA, F. MALANO, M. VALENTE

Cabo Frio (Rio de Janeiro) Brasil

Congreso; XI Latin American Seminar of Analysis by X-ray techniques; 2008

Universidade Federalñ do Rio de Janeiro

X?ray tubes have worldwide a broad range of applications, including several techniques for atomic physics, like x?ray fluorescence as well as for medical imaging, like computed tomography. The performances of x?ray imaging detectors have shown to be significantly sensitive to the incident beam spectrum. Therefore, an accurate knowledge of the x?ray beam becomes necessary for the emission source characterization and the whole imaging process comprehension. Direct measurements and suitable Monte Carlo simulations may be used in order to establish the x?ray spectra. Dedicated Monte Carlo simulation routines, based on the PENELOPE code, have been developed in order to determine the Bremsstrahlung x?ray spectra generated by conventional x?ray tubes. The simulated spectra have been validated by comparison with the corresponding experimental data showing an overall good agreement. The incorporation of a suitably designed virtual grid allowed to assess the angular distribution of Bremsstrahlung yield, showing a remarkable anisotropy. In addition, dedicated program has been developed for virtual imaging, which enables to perform suitable x?ray absorption contrast images. Also, the developed program includes a user?friendly graphic interface in order to allow the upload of required input parameters, which include set up arrangement, beam characteristics, sample properties and image simulation parameters (spatial resolution, tracks per run, etc). The obtained results may constitute useful information for the comprehension and improvement of x?ray image quality, like absorption contrast optimization, detail visualization, definition and detectability.