Case Report: Role of an Iodinated Rectal Hydrogel Spacer, SpaceOAR Vue™, in the Context of Low-Dose-Rate Prostate Brachytherapy, for Enhanced Post-Operative Contouring to Aid in Accurate Implant Evaluation and Dosimetry

Abstract

We present a case series of 13 consecutive patients with prostate cancer treated with low-dose-rate (LDR) brachytherapy, utilizing SpaceOAR Vue™, the recent iodinated iteration of the SpaceOAR™ hydrogel rectal spacer. Low- and favorable intermediate-risk patients receiving monotherapy and unfavorable intermediate- and high-risk patients undergoing a brachytherapy boost were included. Permanent brachytherapy can result in subacute and late rectal toxicity, and precise contouring of the anterior rectal wall and posterior aspect of the prostate is essential for accurate dosimetry to confirm a safe implant. Clearly visible on non-contrast CT imaging, SpaceOAR Vue™ can substantially aid in post-implant contouring and analysis. Not previously described in the literature in the context of LDR brachytherapy, we demonstrate the added clinical benefit of placing a well-visualized rectal spacer.

Application of Hydrogel Spacer SpaceOAR Vue for Prostate Radiotherapy

“…For preparation, patients are instructed to do a Fleet enema the night before for accurate visualization when using the endorectal ultrasound probe and remain NPO (nothing by mouth) for 8 h prior to the procedure for moderate sedation. The risk of infection is much lower than transrectal procedures, and hence, prophylactic antibiotics are not typically used [ 40 ]. Patients are preferably given moderate sedation in the preprocedural holding to alleviate anxiety.…”

The role of a radiopaque peri-rectal hydrogel spacer in aiding accurate daily image-guidance for prostate stereotactic radiotherapy

“…Hydrogel placement prior to prostate radiotherapy has been demonstrated to be an effective method of decreasing the risk of high-grade rectal toxicity ( 5 – 9 ) with very low rates of reported complications ( 10 ). A newer iteration of one form of hydrogel spacer, contains a component of bound iodine making it easily visible on CT clearly demarcating the posterior prostate and anterior rectal wall ( 11 ).…”