Medical Imaging Techniques

• Uses thousands of narrow beam X-rays rotated around the patient to pass through the tissue from different angles.
• Each anrrow beam is reduced in strength according to the density of the tissue in its path.
• The X rays are detected and used to produce an image of the brain in which different soft tissues can be distinguished.

Advantages

- This method is often cheaper than other scans such as MRI and fMRI.

- Individuals can feel less claustrophobic.

- Can identify brain structure.

Disadvantages

- It uses radiation and is not suitable for pregnant women or children.

- Still quite expensive.

• Uses a magnetic field and radio waves to detect soft tissues.
• Different tissues respond differently to the magnetic field so produce contrasting signals and distinct regions.
• It can be used in diagnosis of tumours, strokes, brain injuries and infection.

Advantages

- Does not use radiation so is suitable for pregnant women and children.

- Can identify brain structure.

Disadvantages

- Patients may feel claustrophobic in the scanner.

- Expensive.

- Cannot identify function.

• Looks at the function of the different areas of the brain by following the uptake of oxygen in active brain areas.
• Deoxyhaemoglobin absorbs the radio wave signal where as oxyhaemoglobin does not.
• Increased neural activity in the brain results in an increased demand for oxygen and hense increased blood flow.
• Less radio signals are absorbed so it will be highlighted according to when they are active.

Advantages

- Can identify the funciton of the brain as well as the structure.

- Does not use radiation and has virtually no risks.

Disadvantages

- Very expensive.

- Patients may feel extremely claustrophobic.