A high-sensitivity and low dose energy-dispersive X-ray fluorescence system for identification of gadolium accumulations in planar X-ray fluorescence images

M. SANTIBANEZ; M. VÁSQUEZ; A. SILVA; F. MALANO; MAURO VALENTE; R. FIGUEROAS

APPLIED RADIATION AND ISOTOPES

PERGAMON-ELSEVIER SCIENCE LTD

Lugar: Amsterdam; Año: 2019 vol. 151 p. 46 - 51

0969-8043

A new technique, based on in-vivo energy dispersive X-rayfluorescence (EDXRF), has been developed to ga-dolinium (Gd) concentrations identification in planar X-rayfluorescence (XRF) images. Higher signal-to-noise(SNR) ratios while keeping a low radiation dose were achieved. Experimental validation was performed usingtissue equivalent phantoms under two different data acquisition criteria. Thefirst criteria consisted on acquiringthe energy spectra from different experimental narrow spectrum beam (FWHM = 2.5 keV) with peak centralenergy above the L edge energy and determining the spectrum which producing Lowest-Limit-of-Detection(Lowest-LoD) for a specific acquisition time. This also provided the minimum dose expected under the conditionof minimum irradiation time. The second criteria consisted on measuring the surface dose required to obtain aspecific LoD by different narrow spectrum beam, providing the Lowest-Dose setting. Surface (2D) Gd-dopedtissue-equivalent phantoms scanning were performed according to optimized scenarios: Lowest-LoD setting(obtaining to central energy of 10.9 keV) and Lowest-Dose setting (obtaining to central energy 12.9 keV). 625pixel images were acquired in two different conditions: a pre-defined time (5 s) per pixel was set in thefirstapproach, whereas a pre-defined total surface dose (4 mGy) was set to the second approach. According to theresults obtained for thefirst approach, a 58 times reduction was observed when comparing SNR between theLowest-LoD and Lowest-Dose settings. On the other hand, for the second approach pre-defining total dose duringthe whole examination, the best SNR was obtained for the Lowest-Dose configuration exhibiting a 42% of in-crement respecting to the Lowest-LoD configuration and 47 times higher when compared with the limit case ofno optimization