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Purpose: To assess the benefit of using bladder wall sub-volume equivalent uniform dose (EUD)constraints in prostate cancer IMRT planning.Methods and Materials: Two IMRT plans, with and without EUD constraints on the bladder wall,were generated and compared for 53 prostate cancer patients, to deliver 80Gy to the prostate PTV.The bladder wall was defined by the volume between the external manually delineated wall and a contraction of 7 mm from this external wall.This 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 the "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, 3rd year and 5th year bladder NTCP values and TCP values.