Must husband had the stranded seeding and not one "escaped"!
Stranded seeding is relatively new in Toronto but we signed on anyway. There is a chance that a seed can migrate but typically it does not produce any problems. The patient beside us opted for "free seeding" we opted for "stranded". I think the idea is that they can better cover the prostate with the stranded as they drop in a line and not "willy nilly" so to speak. My husband has 91 permanently placed seeds. Although their raditation is no longer active, they stay in place.
You should be advised by your physician to strain your urine the first few times (they'll provide the strainer) to see if you lose any seeds through urination - there is a specific procedure for disposing of same. You should also be advised that you should use a condom for the first few months as a precaution.
If you have any other questions, fire away, I'll give tell you all I know ...