Either an ultrasound pubic arch study or a CT scan for pubic arch evaluation at the time of consultation is routinely performed. Why is this done?
One important determination in deciding whether seed implantation can be technically performed is to evaluate the position and shape of the pubic arch. The implant requires placing needles into the prostate. If the pubic bone, which is shaped like an upside down V or arch, is too narrow, it can be difficult or impossible to place the needles accurately. We have largely replaced the CT with an SPI developed ultrasound pubic arch study that evaluates the position of the pubic bone at the time of the volume study. Occasionally we will also order a CT, which can also do this evaluation. Determining whether the pubic arch will prevent a good implant is obviously valuable. For those patients who have large glands and arch interference, shrinking the gland with hormonal therapy can often make the patient an implant candidate.
