Fig 4.From: Hydrogel spacer shrinkage during external-beam radiation therapy following low-dose-rate brachytherapy for high-risk prostate cancer: a case series Hydrogel spacer volume changes during external-beam radiation therapy (EBRT). No significant change in volume was observed between baseline (the next day after brachytherapy) and at EBRT planning. The hydrogel spacer volume during EBRT was significantly decreased compared with at treatment planning.Back to article page