If there is a concern that prostate cancer may be present, for example, if there is an abnormal digital rectal exam or an elevated PSA, then further evaluation is carried out with transrectal ultrasound (TRUS) and prostate biopsy. For this procedure, an ultrasound probe is placed in the rectum to visualize the prostate. Needle (core) biopsy of the prostate is taken in a grid-like systematic fashion to obtain samples of the prostate. The ultrasound does not specifically show areas in the prostate that are suspicious for prostate cancer. Rather, it allows precise placement of the biopsy needle to obtain samples. Once the samples are removed, a pathologist can look at the prostate biopsies under a microscope to determine if cancer is present. Hazards of biopsy include blood in the urine, stool, or semen; infection, and inability to urinate.