How is an ultrasound test used to detect prostate cancer?

Ultrasound uses high frequency sound waves that bounce off organs and body structures to produce a computerized image. Ultrasound is usually used by passing a sensor over the surface of the body. The type of ultrasound that is used to examine the prostate is called transrectal ultrasonography. This exam is done by having a probe inserted into the rectum. This probe carries the sound waves to the nearby prostate, producing a better image. This imaging modality can be especially helpful when used as a guidance while performing a prostate biopsy.