Verifying the Reliability of a Hardware-Implemented TIS System in Phantom and Ex-vivo Experiments

Temporal Interference Stimulation (TIS) advancement is hindered by technical limitations. This study aims to overcome these by developing a precision system and experimentally validating its core principle, focal point steering via current ratio control, through cross-validation in phantom, ex vivo, and computational models. We performed invasive experiments applying 108 and 100 Hz for an 8 Hz difference at 1:1, 2:1, and 1:2 ratios, maintaining 2.1 mA total current, in phantoms, ex vivo mouse brain, and muscle. Results consistently matched TIS theory: the 8 Hz envelope peak was centered at 1:1 and predictably shifted toward the weaker current side at 2:1/1:2 ratios. High concordance between experiments and simulations confirmed steering was maintained despite different tissue impedances. This integrative validation confirms TIS steering feasibility and provides a validated platform for future personalized stimulation.