An ultrasound scan builds up pictures of organs and areas inside the body using sound waves. These sound waves have a frequency beyond human hearing. An ultrasound scan is often used during pregnancy to obtain pictures of a baby in the womb.
An ultrasound scan does not use x-rays and is entirely safe. The ultrasound waves are delivered by a small handheld sensor, which is similar to a microphone. The sensor is moved over the surface of the skin and it picks up the sound waves as they bounce off various organs within the body. A computer, which is linked to the sensor, turns the sound waves into pictures that are viewed on a television screen. Photographs are taken of these pictures and then interpreted by trained specialists.
Ultrasound scans can be used to help doctors to make a diagnosis or assess the effects of treatment. Your doctor will recommend an ultrasound scan based on the type of cancer you have and the information needed. Ultrasound can also be used to detect blood flow and whether there is any narrowing or blockage of blood vessels.
There are no known risks with ultrasound and it is considered to be very safe. The scan does not hurt but you will feel a gentle pressure of the sensor over the skin. If you are to have an internal scan any sensations you may feel will be explained to you. Most scans take about half an hour, however it is not always possible to know how long a scan will take until scanning begins.
There are several types of ultrasound scans and the procedure for your scan will be explained to you before your appointment. Sometimes, doctors need to put a special ultrasound microphone inside the body to get a clearer picture. Special transducers have been developed to 'look inside' the body.
Guided biopsies/Fine Needle Aspirate (FNA)
Other procedures, for example, biopsies, may be performed at the same time as the ultrasound. If the doctor performing the scan notices an area which looks unusual, in the breast or liver for example, they may want to take a biopsy or fine needle aspirate (FNA) – a sample of cells or tissue – from that area. With some biopsies, for example a liver biopsy, you may need to stay in hospital overnight. If you have questions or there is anything you don’t understand, please ask.
What happens during the scan?
Your scan will be carried out by a sonographer, a specialist radiographer. You may also see a specialist doctor called a radiologist.
You will be told if you need any special preparation before your scan. All instructions will be on your appointment letter. Please read it carefully.
When you arrive in the department you may be asked to undress and change into a hospital gown. You will then be asked to lie on an examination couch. The lights in the room will be dimmed so that the pictures on the television screen can be seen more clearly. A gel will be applied to your skin in the area to be scanned, such as the abdomen. The gel allows the sound waves to pass into the body. The sensor can also move over the skin more easily. The gel will be wiped off at the end of the scan.
As soon as the scan is completed you may get ready to go home or back to your hospital ward if you are an inpatient. The gel will be removed before you get dressed. You may go to the toilet and eat and drink as usual. There are no side effects to the ultrasound scan and it is safe to drive or return to work after your scan.