What is the PDD at 10 cm depth for a 60Co beam in a 10x10 cm field?

The percent depth dose (PDD) at a specific depth is crucial for understanding the dose distribution of radiation therapy beams, such as those produced by a 60Co source. For a 60Co photon beam, which emits radiation at two principal energy levels (1.17 MeV and 1.33 MeV), the PDD at a depth of 10 cm is characterized by its interaction with tissue.

For a field size of 10x10 cm, the PDD is influenced by several factors, including beam energy, field size, and the depth at which the dose is measured. At a depth of 10 cm, the energy from the 60Co beam has sufficient penetration to deliver a significant dose, but the PDD will not be as high as those of higher energy beams like 6 MV or 10 MV due to the attenuation of radiation as it travels through tissue.

The reported PDD value for a 10x10 cm field at 10 cm depth for a 60Co beam is approximately 55.6%. This value reflects the fact that while the beam is capable of delivering a dose to the target tissue, it is also affected by scattering and absorption as the dose builds up to deeper tissues.

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