The determination of the absolute neutrino mass scale remains one of the pressing questions in modern physics, with implications for both particle physics and cosmology. In addition to $\beta^-$-decay studies, electron-capture (EC) decays with low $Q$ values offer a complementary approach.
In this work, we investigate the potential of $^{95}$Tc and $^{97}$Tc as candidate isotopes for neutrino-mass determination, comparing their decay characteristics with the benchmark case of $^{163}$Ho. Using the atomic self-consistent Dirac--Hartree--Fock--Slater (DHFS) method, we calculated the energy-release distributions for selected ground-state-to-excited-state EC transitions.
Our results indicate that the $^{95}$Tc transition with $Q^*_{\text{EC}}=20.52(61)$~keV most closely resembles the spectral behavior of $^{163}$Ho, while the $^{97}$Tc decay also exhibits promising features.
However, significant uncertainties remain in both $Q^*_{\text{EC}}$ values and transition assignments.
These findings underline the importance of precision mass measurements and transition-type determinations to fully assess the suitability of these isotopes for future neutrino-mass studies.