Transrectal ultrasound (TRUS) uses sound waves to make an image of the prostate on a video screen. For this test, a small probe that gives off sound waves is placed in the rectum. The sound waves enter the prostate and create echoes that are picked up by the probe. A computer turns the pattern of echoes into a black and white image of the prostate.
The procedure often takes less than 10 minutes and is done in a doctor’s office or outpatient clinic. The ultrasound probe is about the width of a finger and is lubricated before it is placed in your rectum. You will feel some pressure when the TRUS probe is placed in your rectum, but it is usually not painful. The area may be numbed before the procedure.
TRUS is not used as a screening test for prostate cancer because it can’t always tell the difference between normal tissue and cancer. Instead, it is most often used during a prostate biopsy (described in the section €œWhat if the test results aren’t normal?€). TRUS is used to guide the biopsy needles into the right area of the prostate.
TRUS is useful in other situations as well. It can be used to measure the size of the prostate gland, which can help determine the PSA density and may also affect which treatment options a man has.