The X-ray machine

Question 1

What is the effect of radiation on cells?

Answer 1

• Ionisation of atoms may cause disruption of molecules and breakage of molecular bonds
• Especially affects DNA by dividing cells

Question 2

What is the effect of radiation on the body?

Answer 2

• Somatic: changes in tissues (gastrointestinal effects, hair loss and cataracts)
• Carcinogenic: damage to DNA causes cancer
• Genetic effects: mutations in chromosome DNA of ova or spermatozoa, which can cause abnormalities in offspring

Question 3

What are the four main dangers of X-rays?

Answer 3

• Invisible
• Painless
• Latent
• Cumulative

Question 4

What are the sources of exposure to radiation?

Answer 4

• Primary beam
• Secondary: scatter

Question 5

What are the 4 basic principles of safety?

Answer 5

• No dose limit exceeded; should be an maximum permitted dose
• Exposure of personnel kept to a minimum
• No unnecessary procedures
• No physical restraint during X-rays

Question 6

What are the 8 safety considerations when using the X-ray?

Answer 6

• Local rules/personnel enforcing rules
• Premises/controlled area
• X-ray machine and table
• PPE
• Positioning Aids
• Monitoring exposure (dosimetry)
• Personnel taking X-rays
• Procedures

Question 7

How are X-rays produced?

Answer 7

• Fast moving electrons collide with an atom, which slows it down and loses it’s energy as an X-ray
• If slowed = low energy X-ray
• If stopped = high energy X-ray
• The greater the number of electrons, the greater number of X-rays produced
• The greater the speed of the electrons, the more energy they have to lose and the greater the energy of the X-rays

Question 8

What does the X tube head contain?

Answer 8

• Cathode
• Anode
• Vacuum

Question 9

What does the cathode do in the X-ray tube head?

Answer 9

• Negatively charged
• Releases electrons by thermionic emission

Question 10

What does the anode do in the X-ray tube head?

Answer 10

• Positively charged
• Slows the electrons, allowing the generation of X-rays

Question 11

What does the vacuum do in the X-ray tube head?

Answer 11

• Allows the passage of the electron beam

Question 12

How do electrons move in the X-ray tube head?

Answer 12

• Move from the cathode to the anode at a high speed and focussed into a beam

Question 13

What are the 3 different types of X-ray machines?

Answer 13

• Portable: Not very powerful, used for equine
• Mobile: More powerful, used in human hospitals
• Fixed: Most powerful, built into room and may be linked to the X-ray table