IGRT 2016 Madrid

Whole Pelvic nodal RT and prostate IGRT : unsolvable? Which target for repositioning? (independent motion) Ä TRADE-OFF If you want to spare more bowels from a large volume? A wider margin around the prostate and a smaller margin around the nodes are required If you want to spare more rectum from a high dose? A smaller margin around the prostate and a wider margin around the nodes are required If the target is : Prostate (Mobile) ? 0 cm prostate shift resulted in an underdosage of pelvic nodes by 14% ±6% If the target is : Pelvis (Less mobile) ? 1 cm prostate shift resulted in an average decrease of 14% in D95% ? Isoshift bone = 30% prostate missed! Hwang AB, Med Phys 2012 Ferjani S, IJROBP 2014