What is a transducer, and what types are available for US?
A transducer is an electronic device that is used to produce ultrasound waves for transmission into the patient and to receive reflected ultrasound waves (echoes) to create digital images. Lower-frequency ultrasound transducers have a greater depth of tissue penetration, whereas higher-frequency ultrasound transducers have a higher spatial resolution. For general abdominal US, which requires sufficient depth of penetration to image the liver, spleen, and pancreas, a 3- to 5-MHz transducer may be utilized. For US of superficial structures such as the thyroid gland or scrotum, a 10-MHz transducer is often used. Endovaginal transducers are commonly used for gynecologic and early pregnancy examinations, whereas endorectal probes are available for prostate gland examinations.