Title : Precise deep detection of tumoral biomarkers using large-scale confocal x-ray fluorescence

Precise detection of tumor targets located at clinically relevant depths remains a major challenge in oncologic imaging. In this work, a large-scale confocal X-ray fluorescence (XRF) system was evaluated for deep detection of high-Z biomarkers embedded in tissue-equivalent media. The proposed architecture is part of the COXIRIS (*) project, a theranostic platform designed for simultaneous cancer detection and imageguided therapeutic applications, and as a basis for the development of a new molecular imaging technique.

Experimental measurements were performed using a collimated orthovoltage X-ray source operating between 60 and 120 kV and a large-scale confocal detection geometry optimized for deep fluorescence acquisition. A water-equivalent phantom containing simulated tumoral points filled with a gadolinium-based biomarker solution (CLARISCAN, 0.5 mmol/ml) was evaluated at depths ranging from 5 to 15 cm.

Results demonstrated successful detection of characteristic gadolinium fluorescence peaks at all evaluated depths. At the maximum depth of 15 cm, clear EDXRF spectra were obtained with acquisition times close to 1 s under low-dose conditions. The confocal geometry improved spatial selectivity and signal-tobackground ratio, enabling stable localization of the biomarked tumoral points even at large depths.

These findings demonstrate the feasibility of large-scale confocal XRF systems for deep tumor biomarker detection and support their potential application in future real-time theranostic and molecular imaging technologies.

Patented and patent-pending technologies.

Dr. Rodolfo Gabriel Figueroa Saavedra is a Chilean Radiation Physicist and Full Professor at Universidad de La Frontera. He is Director of the Centro de Excelencia de Física e Ingeniería en Salud and founder of Chile’s first Master’s Program in Medical Physics (2008). His research focuses on X-ray fluorescence imaging (XRF), theranostics, radiotherapy, and advanced radiation devices for cancer detection and treatment. He is the inventor of the CONVERAY and COXIRIS technologies. Dr. Figueroa has approximately 24 patent records, around 100 scientific publications, numerous international conference invitations, and several recognitions for his contributions to medical physics, radiation sciences, and biomedical engineering.