<prompt> For the treatment of deep seated tumors, the following rays are used.X- rays and Gamma- raysAlpha rays and Beta -raysElectrons and positronsHigh power laser beams  <response>: Ans. is a i.e. X-rays and Gamma-rays X-rays and gamma rays are electromagnetic waves with highest penetrating power.For deep seated tumours rays with maximum penetrating power is required so x-rays and gamma rays are used.Harrison 141he states - Megavoltage X-rays are used to irradiate internal deep seated lesions since high energy penetrating beams deliver a less intense superficial dose and spares the skin. 