RAD03-2001 What is an X-Ray?

Question 1

What is an X-ray?

Answer 1

A wave-packet of energy called a photon that can penetrate human tissues

Question 2

What occurs to x ray beams that have high energy?

Answer 2

They pass through patients

Question 3

What occurs to x ray beams that have low energy?

Answer 3

Stop inside the patient

Question 4

Where do x-rays originate from inside an x-ray machine?

Answer 4

From a tungsten target

Question 5

What type of wave from the EM spectrum have has the lowest photon energy?

Answer 5

Radio waves

Question 6

What type of wave from the EM spectrum has the highest photon energy

Answer 6

X-rays and gamma rays

Question 7

What forms of radiation are ionising?

Answer 7

X-rays and gamma rays

Question 8

What are gamma rays?

Answer 8

Gamma rays are one of the radioactive emissions, these include: alpha particles, beta (+ve) and beta (-ve) particles and gamma rays

Question 9

What is the difference between X-rays and gamma rays?

Answer 9

There is no difference
X-rays used in clinical practice are man-made and are produced and emitted by X-ray machines, however gamma rays are naturally occuring and emitted by radioisotopes that come from rocks and soils

Question 10

What occurs when the X-ray photons hit the patient?

Answer 10

Transmitted unchanged: Highest energy photons will pass straight through the patient unchanged
Absorbed: Lowest energy photons will be absorbed by the patient and disappear
Deflected: some photons lose some energy
Scattered: Some photons are just scattered with no loss of energy

Question 11

What are the 3 categories of damaging effects of X-rays on human tissue?

Answer 11

Somatic Deterministic/ Certainty effects
Somatic stochastic effects
Genetic stochastic effects

Question 12

What does somatic refer to?

Answer 12

The body of a person being irradiated and hence effects therefore develop in patients who have been x-rayed

Question 13

What does deterministic mean?

Answer 13

They will definitely happen (certainty)

Question 14

What is included in acute somatic deterministic effects?

Answer 14

Short-term including radiation sickness, coma and death

Question 15

What is included in chronic long-term somatic deterministic effects?

Answer 15

Hair loss, damage to blood vessels and cataract formation in the eye

Question 16

Can dentistry cause somatic deterministic effects?

Answer 16

No, large enough doses are not used

Question 17

What does stochastic mean?

Answer 17

By chance

Question 18

What is an example of a stochastic effect?

Answer 18

Cancer induction, as there is no known threshold dose for these effects

Question 19

How does the size of the exposure affect the somatic stochastic effects?

Answer 19

It does not effect the severity of the damage, only the probability of it happening

Question 20

Can dentistry cause somatic stochastic effects?

Answer 20

Yes, just because little films and small amounts of radiation are used, it may cause little cancers

Question 21

What do genetic effects involve?

Answer 21

The future offspring of the person being irradiated

The genetic material of the patient being irradiated, but the resultant damage only becomes apparent in their children

Question 22

Are genetic effects due to chance?

Answer 22

yes

Question 23

How can genetic stochastic effects occur?

Answer 23

reproductive organs need to be irradiated for genetic material to be damaged

Question 24

Can dentistry cause genetic stochastic effects?

Answer 24

Highly unlikely as, X-ray bean is aimed at the patient’s teeth and jaw

Question 25

What are the two main aims for patient and radiation protection?

Answer 25

Prevent detrimental deterministic or certainty effects

Limit probability of stochastic effects