How much does electron beam energy reduce in unit density tissue per centimeter?

The loss of energy of electron beams as they travel through tissue is an important characteristic to understand, especially in the context of radiation therapy and dosimetry. For clinical electron beams, the energy reduction in tissue is typically around 2 MeV per centimeter of tissue at standard densities.

Electrons interact with matter predominantly through inelastic collisions with atomic electrons, leading to a decrease in their energy as they traverse through the material. The rate of energy loss is more pronounced in materials like soft tissue, which have similar properties to water—serving as a reference for many radiation therapy calculations.

The specified rate indicates a significant understanding of how electron beams behave and how this energy loss affects treatment planning and radiation dose distribution. Thus, the 2 MeV per centimeter figure is a standard value used in clinical practice, making it the correct choice among the options provided.