SU-F-T-390: Dosimetric Impact of Leaf Interdigitation in Prostate Cancer Dynamic IMRT Treatment Planning




The aim of this work is to study the dosimetric impact of leaf interdigitation in prostate cancer dynamic IMRT treatment planning.


Fifteen previously treated prostate cancer patients were replanned for dynamic IMRT (dMLC) with and without leaf interdigitation using Monaco 3.3 TPS on the Elekta Synergy linear accelerator. The prescription dose of PTV was 70Gy/35 fractions. Various dosimetric variables, such as PTV coverage, OAR sparing, delivery efficiency and optimization time, were evaluated for each plan.


Interdigitation did not improve the coverage, HI and CI for PTV. Regarding OARs, sparing was equivalent with and without interdigitation. Interdigitation shown an increase in MUs and segments. It was worth noting that leaf interdigitation saved the optimization time.


This study shows that leaf interdigitation does not improve plan quality when performing dMLC treatment plan for prostate cancer. However, it influences delivery efficiency and optimization time. Interdigitation may gain efficiency for dosimetrist when designing the prostate cancer dMLC plans.