Tissue Lateral Effect

Definition

Tissue lateral effect (TLE) describes the situation in which, for parallel opposed beams, the dose near the surface becomes large relative to the dose at mid-plane for larger patients and for treatments with lower energies.

Tissue lateral effect becomes unacceptable when the maximum dose approaches 120% of mid-line dose.

Methods to Reduce TLE

• Increase treatment energy
• Change treatment position to reduce patient thickness
• Increase the number of beam angles