Human-organ-scale x-ray fluorescence ghost imaging for radioisotope-free diagnostics

A wide range of diagnostic information in medicine is currently obtained using radioactive tracers. While central to nuclear medicine, these methods are inherently constrained: radiation dose limits repeat examinations, short tracer half-lives and complex logistics restrict access and raise costs, and their relatively poor spatial resolution often necessitates complementary CT or MRI. Here we present a first proof-of-concept demonstration of a non-radioactive alternative based on x-ray fluorescence (XRF) computational ghost imaging (CGI) at the human-organ scale. Using a thyroid phantom filled with iodine solution as a model system, we show that structured illuminations combined with fluorescence detection reconstruct the iodine distribution with high fidelity. This approach eliminates the need for radioactive tracers while preserving image quality, and in principle can reach spatial resolution comparable to CT. Beyond this demonstration, XRF-CGI establishes a generalizable framework for non-radioactive tracer imaging, opening a route toward safer, repeatable, and more accessible diagnostics.