Feasibility of Monitoring Tumor Response by Tracking Nanoparticle-Labelled T Cells Using X-ray Fluorescence Imaging-A Numerical Study.
Immunotherapy has been a breakthrough in cancer treatment, yet only a subgroup of patients responds to these novel drugs. Parameters such as cytotoxic T-cell infiltration into the tumor have been proposed for the early evaluation and prediction of therapeutic response, demanded for non-invasive, sensitive and longitudinal imaging. We have evaluated the feasibility of X-ray fluorescence imaging (XFI) to track immune cells and thus monitor the immune response. For that, we have performed Monte Carlo simulations using a mouse voxel model. Spherical targets, enriched with gold or palladium fluorescence agents, were positioned within the model and imaged using a monochromatic photon beam of 53 or 85 keV. Based on our simulation results, XFI may detect as few as 730 to 2400 T cells labelled with 195 pg gold each when imaging subcutaneous tumors in mice, with a spatial resolution of 1 mm. However, the detection threshold is influenced by the depth of the tumor as surrounding tissue increases scattering and absorption, especially when utilizing palladium imaging agents with low-energy characteristic fluorescence photons. Further evaluation and conduction of in vivo animal experiments will be required to validate and advance these promising results.
['Kahl|Henrik|H|', 'Staufer|Theresa|T|', 'Körnig|Christian|C|', 'Schmutzler|Oliver|O|', 'Rothkamm|Kai|K|0000-0001-7414-5729', 'Grüner|Florian|F|']
D000818:Animals D003198:Computer Simulation D005240:Feasibility Studies D005453:Fluorescence D006046:Gold D007167:Immunotherapy D008297:Male D053768:Metal Nanoparticles D051379:Mice D008819:Mice, Nude D009010:Monte Carlo Method D009369:Neoplasms D061848:Optical Imaging D010165:Palladium D014057:Tomography, X-Ray Computed
T cell immunotherapy X-ray fluorescence imaging XFI simulation gold palladium nanoparticles