What is the depth of Dmax for a kV beam in a 10x10 field?

The depth of Dmax, or the point of maximum dose, is the point at which the dose delivered by a radiation beam reaches its peak before it starts to fall off with increasing depth. For kilovolt (kV) x-ray beams, which are commonly used in superficial radiation therapy, the Dmax typically occurs very close to the surface of the skin due to their low energy.

In general, the Dmax for kV beams is found to be at or just beneath the surface, often at around 0.0 cm for a 10x10 field. This characteristic is essential for treatments targeting superficial tumors, as it allows for a maximum concentration of radiation at the tumor site while minimizing exposure to underlying healthy tissues.

In contrast, as the energy of the beam increases (such as with megavoltage beams), the Dmax moves deeper into the tissue. Therefore, the concept of Dmax at 0.0 cm for kV beams aligns with the physical principles of radiation therapy and its application in clinical settings for treating skin lesions or similar conditions.