ESTRO meets Asia 2024 - Abstract Book

S389

RTT – Treatment planning, OAR and target definitions

ESTRO meets Asia 2024

In relation to OARs, when we compare both plans, it is observed that the maximum dose of the contralateral breast exceeds plan b) to plan a) by almost 12%. Similarly, the esophagus and left lung receive less dose in a); specific, the left lung is the one with the greatest dose difference (16,39%) when evaluating D4%<10Gy.

On the other hand, the monitor units obtained in plan a) are almost 100 times less than in plan b), which makes the plan even less modulated.

However, the coverage of the PTV of plan b) is better than in a), observed in the following figure:

Conclusion:

Although at first we may think that a greater number of arcs provide better dose coverage, contrary results are obtained.

However, although in the 2 arcs plan we obtain better PTV coverage, this difference is not significant since when we evaluate V>95%, the difference between plans is less than 2%. So, due to we obtain a lower number of MUs