Feasibility of Monitoring Tumor Response by Tracking Nanoparticle-Labelled T Cells Using X-ray Fluorescence Imaging-A Numerical Study

TY - JOUR

T1 - Feasibility of Monitoring Tumor Response by Tracking Nanoparticle-Labelled T Cells Using X-ray Fluorescence Imaging-A Numerical Study

AU - Kahl, Henrik

AU - Staufer, Theresa

AU - Körnig, Christian

AU - Schmutzler, Oliver

AU - Rothkamm, Kai

AU - Grüner, Florian

N1 - Bitte den Erstautor Henrik Kahl der Klinik für Strahlentherapie zuordnen.

PY - 2021/8/14

Y1 - 2021/8/14

N2 - 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.

AB - 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.

KW - Animals

KW - Computer Simulation

KW - Feasibility Studies

KW - Fluorescence

KW - Gold

KW - Immunotherapy

KW - Male

KW - Metal Nanoparticles

KW - Mice

KW - Mice, Nude

KW - Monte Carlo Method

KW - Neoplasms/diagnostic imaging

KW - Optical Imaging/methods

KW - Palladium

KW - Tomography, X-Ray Computed/methods

U2 - 10.3390/ijms22168736

DO - 10.3390/ijms22168736

M3 - SCORING: Journal article

C2 - 34445443

VL - 22

JO - INT J MOL SCI

JF - INT J MOL SCI

SN - 1661-6596

IS - 16

M1 - 8736

ER -