Controlling heterogeneity within the lymphatic target volume for dose painted treatment of prostate cancer

Introduction: For patients with high risk prostate cancer, conventionally fractionated treatment of the pelvic lymphatics and hypofractionated treatment to the prostate can be delivered simultaneously with dose painting. The purpose of this technical note is to highlight unexpected hot spots within the low dose lymphatic target volume as a clinical problem that we have observed with dose painting, and to describe a simple approach to account for this during treatment planning.