Where is a scrotal ultrasound usually done? At a hospital?

Yes. Or Imaging ctr. Imaging procedures are done in hospitals or outpatient imaging centers.
Hospital or office. Scrotal ultrasound is a common test and easily done by a trained ultrasound technologist and interpreted by a radiologist. It is painless and uses sound waves to exam the structures. Hospital or outpatient office is equally as good.

Related Questions

Had a scrotal ultrasound done on left side. Found a couple of stones. Could this be testicular cancer?

Scrotal Stone. This is very question to answer as there is no consensus among experts, usually your history defines the recommendation, if u r a healthy person with no risk factor for testicular cancer then no further work up is needed, but if you have risk for cancer like undescended Testis then close follow up with Ultrasound is recommended.