A-level Applied Science/Energy Transfer Systems/Imaging Methods

You need to know the advantages and disadvantages of using each method and suggest, with reason, which methods could be used in particular situations.

X-rays

X-rays are powerful, short wavelength electrochromatic waves. They can be used for:

Bone fractures and dental decay- clear images can be produced quickly.

Lung examination- damaged tissue and fluid build up visible.

Narrowing of coronary arteries, using X-ray opque dye- obstruction can be detected in the coeonary arteries of the beating heart.

Disease of digestion tract, using X-ray opque dye- obstruction can be seen.

Advantages

Widely available

Quick and straightforward to use

Disadvantages

Harmful, particularly to gonads and unborn children.

Can cause localised tissue damage, cancers or damage that is passed on to the next generation

Soft tissues cannot be easily distinguished

2D images only.

CAT scans

Radioactive tracers

Ultrasound

Magnetic resonance imaging (MRI) Advantages The main advantages of magnetic resonance imaging (MRI) scans are that: •they do not involve exposure to radiation, so they can be safely used in people who might be particularly vulnerable to the effects of radiation, such as pregnant women and babies, •they are particularly useful for showing soft tissue structures, such as ligaments and cartilage, and organs such as the brain, heart, and eyes, and •they can provide information about how the blood moves through certain organs and blood vessels, allowing problems with blood circulation, such as blockages, to be identified.

Disadvantages The main disadvantages of magnetic resonance imaging (MRI) scans are listed below. •MRI scanners are very expensive; a single scanner can cost over a million pounds. This means that the number of scanners that a Primary Care Trust (PCT) can afford to fund is limited. Therefore, if your condition is non-urgent, you may have to wait several months to have a MRI scan. •The combination of being put in an enclosed space and the loud noises that are made by the magnets can make some people feel claustrophobic while they are having a MRI scan. •MRI scanners can be affected by movement, making them unsuitable for investigating problems such as mouth tumours because coughing, or swallowing, can make the images that are produced less clear.

http://www.nhs.uk/Conditions/MRI-scan/Pages/Advantages.aspx

Last modified on 20 June 2012, at 21:18