Is there a benefit of using bladder sub-volume equivalent uniform dose constraints in prostate IMRT

• 作 者: JianZhu AntoineSimon PascalHaigron CarolineLafond OscarAcosta HuazhongShu JoelCastelli BaoshengLi RenaudDe Crevoisier
• 机 构: Laboratory of Image Science and Technology, Southeast University, Nanjing, PR China;Department of Ra
• 出 处: 中华放射学学术大会2016、中华医学会第23次全国放射学学术大会暨中华医学会第24次全国影像技术学术大会
• 发表日期: 2016年5期
• 关键词: prostate IMRT equivalent uniform dose

　　Background To assess the benefits of bladder wall sub-volume equivalent uniform dose (EUD) constraints in prostate cancer IMRT planning. Methods Two IMRT plans, with and without EUD constraints on the bladder wall, were generated and compared in 53 prostate cancer patients to deliver 80 Gy to the prostate and 46 Gy in the seminal vesicles.The bladder wall was defined as the volume between the external manually delineated wall and a contraction of 7 mm apart from it.The bladder wall was then separated into two parts: the internal-bladder wall (bla-in) represented by the portion of the bladder wall that intersected with the planning target volume (PTV) plus 5 mm extension; the external-bladder wall (bla-ex) represented by the remaining part of the bladder wall.In the plan with EUD constraints, the values of “a” parameter of the EUD models were: 10.0 for bla-in and 2.3 for bla-ex. The plans with and without EUD constraints were compared in terms of DVHs, 5 year bladder and rectum NTCP values, as well as TCP values.