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

Hospital or Clinic. A transrectal ultrasound (trus) can be done at a hospital or clinic with the appropriate equipment. They are often done to look at pelvic organs. For women, transvaginal ultrasound is more common because it can allow better visualization of female pelvic organs. For men, a trus is often performed to look at the prostate (to check for lesions, hypertrophy, etc.) or guide prostate biopsies.
Office typically. Transrectal ultrasound is typically performed in a urologist office. The procedure involves placing a ultrasound probe into the rectum usually to visual the prostate. Generally performed to assess the size of prostate and take biopsies of the prostate if indicated. This procedure may be performed under local anesthesia or occasionally under sedation.