Optimization of the sensitivity/doses relationship for a bench-top EDXRF system used for in vivo quantification of gold nanoparticles

SANTIBÁÑEZ, M.; SAAVEDRA, R.; VÁSQUEZ, M.; MALANO, F.; PÉREZ, P.; VALENTE, M.; FIGUEROA, R.G.

APPLIED RADIATION AND ISOTOPES

PERGAMON-ELSEVIER SCIENCE LTD

Año: 2017 vol. 129 p. 17 - 29

0969-8043

The present work is devoted to optimizing the sensitivity-doses relationship of a bench-top EDXRFsystem, with the aim of achieving a detection limit of 0.010 mg/ml of gold nanoparticles in tumor tissue(clinical values expected), for doses below 10 mGy (value fixed for in vivo application). Tumor phantomsof 0.3 cm3 made of a suspension of gold nanoparticles (15 nm AurovistTM, Nanoprobes Inc.) were studiedat depths of 0-4 mm in a tissue equivalent cylindrical phantom. The optimization process wasimplemented configuring several tube voltages and aluminum filters, to obtain non-symmetrical narrowspectra with fixed FWHM of 5 keV and centered among the 11.2-20.3 keV. The used statistical figure ofmerit was the obtained sensitivity (with each spectrum at each depth) weighted by the delivered surfacedoses. The detection limit of the system was determined measuring several gold nanoparticlesconcentrations ranging from 0.0010 to 5.0 mg/ml and a blank sample into tumor phantoms, considering astatistical fluctuation within 95% of confidence. The results show the possibility of obtaining a detectionlimit for gold nanoparticles concentrations around 0.010 mg/ml for surface tumor phantoms requiringdoses around 2 mGy.