Which waves are used in the treatment of cancer?

At a specific instant,the emission of a radioactive compound is deflected in a magnetic field. The compound can emit:
$(i)$ Electrons
$(ii)$ Protons
$(iii)$ $He^{2+}$
$(iv)$ Neutrons
The emission at that instant can be:

When an element ${}_{90}^{232}Th$ decays into ${}_{82}^{208}Pb$, the number of $\alpha$ and $\beta^{-}$ particles emitted respectively are

${ }_{82}^{290} X \xrightarrow{\alpha} Y \xrightarrow{e^{+}} Z \xrightarrow{\beta^{-}} P \xrightarrow{e^{-}} Q$
In the nuclear emission stated above, the mass number and atomic number of the product $Q$ respectively, are

Which one of the following is a possible nuclear reaction?

$A$ free neutron decays spontaneously into :