High quality $^{\mathrm{99m}}$Tc obtained from $^{99}$Mo produced by $^{100}$Mo($n$,2$n)$ using accelerator neutrons

$^{\mathrm{99m}}$Tc, the daughter nuclide of $^{99}$Mo, is widely used for medical diagnosis. In Japan, about 0.9 million diagnostic procedures are carried out using $^{\mathrm{99m}}$Tc. $^{99}$Mo has been mostly produced using $^{235}$U in research reactors. Because of recent shortages of $^{99}$Mo, a variety of alternative production methods of $^{99}$Mo or $^{\mathrm{99m}}$Tc were proposed. We proposed to produce $^{99}$Mo by $^{100}$Mo($n$,2$n)$ using neutrons from an accelerator. The route is characterized to produce a large quantity of high-quality $^{99}$Mo with a minimum level of radioactive wastes, since the cross section of the $^{100}$Mo($n$,2$n)^{99}$Mo reaction at 11\textless $E_{\mathrm{n}}$\textless 18 MeV is large, and the cross sections of the ($n\alpha )$, (\textit{nn}$^{'}p)$, and (\textit{np}) reactions on $^{100}$Mo are quite small. Intense neutrons are available because of recent progresses of accelerator and target technologies. In the talk, we show our recent experimental results to obtain $^{\mathrm{99m}}$Tc with high-quality using $^{99}$Mo produced by $^{100}$Mo($n$,2$n)$