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