Activity 1.5 - Ultrasound imaging

• To identify advantages and disadvantages of ultrasound imaging for humans
• To explain how an ultrasound machine works
• To explain how an ultrasound examination is done
• To establish an informational folder for patients having an ultrasound examination

This activity is an excursion to a hospital department where ultrasounds are taken and an interview with a sonographer.

Students should prepare their visit by first exploring ultrasound safety and ultrasound advantages and disadvantages of ultrasound (activity 1) and by preparing interview questions (activity 2). During the visit they should understand what the sonographer profession is. If an excursion to a hospital is not possible then at least a sonographer should be invited for an interview at school.Based on information collected during the excursion students have to prepare a folder for patients who will have to undergo an ultrasound examination.

Advantages of ultrasound:

1. Ultrasound examinations are non-invasive i.e. they do not require the body to be opened up, or anything to be inserted into the body. This is a major advantage compared to fibre-optic endoscopy, for example, which may involve much more patient discomfort as the probe is inserted.
2. Ultrasound methods are relatively inexpensive, quick and convenient, compared to techniques such as X-rays or MRI scans. The equipment can be made portable, and the images can be stored electronically.
3. No harmful effects have been detected, at the intensity levels used for examinations and imaging. This contrasts with methods based on X-rays or on radioactive isotopes, which have known risks associated with them, and ultrasound methods are preferred whenever possible. This is particularly relevant to examination of expectant mothers.
4. Ultrasound is particularly suited to imaging soft tissues such as the eye, heart and other internal organs, and examining blood vessels.

Disadvantages of ultrasound:

1. The major disadvantage is that the resolution of the images is often limited. This is being overcome as time passes, but there are still many situations where X-rays produce a much higher resolution.
2. Ultrasound is reflected very strong on passing from tissue to gas, or vice versa. This means that ultrasound cannot be used for examinations of areas of the body containing gas, such as the lung and the digestive system.
3. Ultrasound also does not pass well through bone, so that the method is of limited use in diagnosing fractures.

• Is ultrasound safe?
• Does ultrasound hurt?
• How does an ultrasound machine work?
• What are the main parts of an ultrasound machine?
• How is an ultrasound examination performed?