What is the PDD for a 4 MV beam at 10 cm depth in a 10x10 cm field?

The Percent Depth Dose (PDD) is an important parameter in radiation therapy that indicates the dose of radiation delivered at a specific depth within a medium, compared to the dose delivered at the surface. It varies based on factors like the energy of the radiation beam and the size of the field.

For a 4 MV photon beam, at a depth of 10 cm in a 10x10 cm field, the PDD typically reflects the radiation's penetration capability. Lower energy beams, such as 4 MV, generally have a PDD that is lower compared to higher energy beams due to their reduced penetrating power.

In this case, the PDD for a 4 MV beam at 10 cm depth in a 10x10 cm field has been established through empirical measurements and published data, indicating it to be approximately 64.8%. This value accurately represents the percentage of the dose delivered at that depth relative to the dose at a reference point, usually at the surface.

Understanding the significance of PDD is crucial for dosimetrists in planning radiation treatments, as it helps ensure that the prescribed dose reaches the targeted tissues effectively while minimizing exposure to surrounding healthy tissues.