Question

Why are the alpha particles not used in radiotherapy?
A. Alpha particles can penetrate the human skin.
B. Alpha particles are not radio waves.
C. Alpha particles cannot penetrate the bones.
D. Alpha particles cannot penetrate the human skin.

Answer 1

Hint: Among all the radioactive particles, alpha particles are a highly ionizing form of particle radiation, and short range and they cannot penetrate the human skin. They can be easily stopped by a few centimeters of air or by skin, hence they cannot penetrate skin, so they cannot be used in radiotherapy.

Complete step by step answer:
Alpha particles are charged particles, which are emitted from naturally occurring materials and man- made elements.
In general, alpha particles are short range and have a very limited ability to penetrate other materials. They cannot be used to irradiate a tumor from outside of one’s body.
Therefore, alpha particles cannot be used for radiotherapy due to low penetration property.

Hence, The correct option is D.

Additional information:
Radiation is a form of energy, it can be produced from unstable atoms that undergo radioactive decay or it can be obtained by machines. Three major radioactive particles are alpha, beta and gamma. Gamma rays are long range and high penetrating properties and they are majorly used in radiotherapy. Though they are useful in curing tumors, they are harmful to the human body.

Note:
Alpha particles would be useful under some circumstances because alpha particles do far more damage to cells than beta or gamma, so if we could just put some alpha emitters into a tumor it should be possible to wipe it out.