CONCLUSION
prostate
PROSTATE
This is the first comparative retrospective study to assess the dosimetry effectiveness of balloon spacer and SpaceOAR during prostate VMAT and UH treatments. Noteworthy rectal dose reduction greater than 75% was achieved in the post‐balloon spacer when using VMAT and UH treatment techniques. The use of balloon spacer significantly reduced the rectal dose regardless of the retrospective nature of this study.Despite the expected superior advantages of the balloon spacer technique, a randomized prospective study is required to determine whether the balloon spacer will result also in a superior benefit for several clinical aspects of radiation including particle therapy, brachytherapy and post‐ prostatectomy setting for prostate radiotherapy patients.