How soon after SpaceOAR placement can radiation planning CT be performed?

At Univ of Utah, we serve a geographic footprint equivalent to 20% of the United States. As such, many patients travel from 100s of miles away from therapy at our center. We put in spacers, and perform CT simulation on the same day (usually 2 hours apart). Never noticed any significant issues with d...

We put in 4 fiducial markers in the prostate and a SpaceOAR as a single procedure with a sim/CT and MRI of the prostate for planning purposes on the same day one week later.

My rationale for the one week is to give any edema/trauma from the procedure a chance to resolve, and the placement of 4 seeds...

Practicing in rural Eastern Oregon, our patients also come from a wide geographic area. We routinely will perform a CT simulation on the same day as SpaceOAR hydrogel placement. One advantage to this timing is that we actually see a small amount of air mixed in with the SpaceOAR hydrogel on the CT s...

We always have given a 1-week interval between SpaceOAR placement and CT-MRI sim. It is good to know about the Univ of Utah experience.

Fariba Asrari, M.D.
Medical Director, Johns Hopkins at Green Spring Station
Department of Radiation Oncology & Molecular Sciences
Johns Hopkins University
Baltimore, MD

For a reference that it can be performed same day safely: Brenneman et al., PMID 34695615.

I have had a preference for waiting a week. They do look different when performed 1-2 days later than at 7 days. I have seen air when performed earlier. However, I cannot say it has had an impact on target defi...

Next day

Same day. Sometimes next day if the patient has had a long day. Literature supports. Never had any problems. Used hundreds of both spacers and have found no need to wait.