P3 - X Rays In Medicine Flashcards
What is the wavelength of an x Ray?
The same as the diameter of an atom.
What do x rays do?
They are transmitted by healthy tissue but are absorbed by denser materials like bones and metal.
Describe an x ray image.
It’s a negative image. It starts off all white. The brighter bits are where few x rays get through.
What can x ray photographs be used to diagnose?
Medical conditions such as bone fractures or dental problems.
How can x rays images be formed electronically?
Using charge-coupled devices (CCDs).
What are CCDs?
Silicon chips divided into a grid of pixels.
How do CCDs work?
They detect x rays and produce electronic signals to form high resolution images.
What does CT scan stand for?
Computerised axial tomography scan.
How do CT scans work?
An x ray is fired through the body from a tube and picked up by detectors on the other side.
It forms a 2D CT scan.
How do you form a 3D image using a CT scan?
Put multiple 2D CT scan images together.
What is the difference between x ray images and CT scans?
CT scans use more x rays to find small variations in tissue density.
Why can x rays be used to treat cancers?
They can cause ionisation.
What are the steps of using an x ray to treat cancers? [2].
1) x rays are focused on the tumour using a wide beam.
2) the beam is rotated to minimise the expose of normal cells.
What are x rays?
High frequency, short wavelength electromagnetic waves.
