The Portascan bladder volume instrument is a battery operated, portable B-mode ultrasonic scanner, intended for the non-invasive measurement of urinary bladder volume. The scanner includes a 6.5”colour LCD screen to display cross sectional images of the bladder. A mechanical sector scanning transducer (with a round crystal) provides a symmetrical ultrasound beam giving high lateral and transverse resolution with high sensitivity and low signal to noise ratio. The estimated bladder volume is automatically calculated in millilitres and displayed on the screen.