X-rays in Medicine

Question 1

Why can x-rays damage living cells?

Answer 1

Because they are ionising

Question 2

Describe the frequency of x-rays

Answer 2

High-frequency

Question 3

What kind of waves are x-rays?

Answer 3

SHORT wavelength ELECTROMAGNETIC waves

Question 4

What is the wavelength of x-rays roughly the same size as/ how short are they?

Answer 4

The diameter of an atom

Question 5

What material are x-rays transmitted from?

a) healthy tissue (i.e. flesh)
b) denser materials (i.e. bones or metal)

Answer 5

a) healthy tissue

Question 6

What material are x-rays absorbed by?

a) healthy tissue (i.e. flesh)
b) denser materials (i.e. bones or metal)

Answer 6

b) denser materials

Question 7

Name 2 ‘denser materials’

Answer 7

Bones

Metal

Question 8

What does ‘x-rays are transmitted by healthy tissue’ mean?

Answer 8

X-rays pass THROUGH healthy tissue

Question 9

Why can x-rays be used to take photographs?

Answer 9

Because they affect photographic film in the same way as visible (normal) light

Question 10

Name 2 medical conditions that x-ray photographs can be used to diagnose

Answer 10

1. Bone fractures

2. Dental problems

Question 11

On an x-ray, are the brighter bits where:

a) fewer
or
b) more

x-rays have passed through the material?

Answer 11

a) fewer

The plate that the x-rays hit starts off white, and the electrons react with it to turn it darker.

Question 12

Do x-rays produce

a) positive
or
b) negative

images?

Answer 12

b) negative

Question 13

How can x-rays be formed, and using what?

Answer 13

Electronically, using charge-coupled devices (CCDs)

Question 14

What are CCDs?

Answer 14

Silicon chips about the size of a postage stamp, divided into a grid of millions of identical pixels

Question 15

How do CCDs work?

Answer 15

They detect x-rays and produce electromagnetic signals which are used to form high resolution images.

Question 16

Where else are CCDs used?

Answer 16

In digital cameras

Question 17

What other initial-ism beginning with ‘C’ are x-rays used in?

Answer 17

CCT scans

Question 18

What does ‘CT’ stand for?

Answer 18

Computerised axial tomography

Question 19

What do CT scans do?

Answer 19

Take HIGH RESOLUTION IMAGES of soft and hard tissue

Question 20

What can be done with the images taken using a CT scan?

Answer 20

Multiple 2D CT scans can be put together to make a 3D image of the inside of the body

Question 21

Describe the step-by-step process of taking a CT scan

Answer 21

1. The patient is put inside the cylindrical scanner.
2. An X-ray beam is fired through the body from an X-ray tube and picked up by detectors on the opposite side.
3. The X-ray tube and detectors are rotated during the scan.
4. A computer interprets the signals from the detectors to form an image of a two-dimensional slice through the body.
5. Multiple two-dimensional CT scans can be put together to make a three-dimensional image of the inside of the body.