RAD03-2004 How much radiation do you use?

Question 1

Define radiation dose

Answer 1

Describes the amount of radiation that is received by patients from different x-ray examinations

Question 2

Define reference dose

Answer 2

A dose level which is set for every radiographic examination which should not be exceeded

Question 3

Define radiation dose limits

Answer 3

Describes maximum levels of radiation to individuals which should not be exceeded

Question 4

define natural background radiation

Answer 4

Dose which describes naturally occuring radiation levels

Question 5

What are the 3 main dose units?

Answer 5

Radiation absorbed dose (D)
Equivalent dose (H)
Effective Dose (E)

Question 6

What is the radiation absorbed dose a measure of?

Answer 6

The amount of energy absorbed from the radiation beam per unit mass of tissue

Question 7

What are the units for radiation absorbed dose?

Answer 7

Gray (Gy)

Question 8

What are milliGrays measured in?

Answer 8

joules per kilogram

Question 9

Is the radiation absorbed dose a comparable figure?

Answer 9

No

Question 10

Why is the radiation absorbed dose not a comparable figure?

Answer 10

It is only a measure o the amount of energy absorbed from the radiation beam and doesn’t account for how dangerous the radiation is or how sensitive the particular body part is to radiation

Question 11

What is the formula for equivalent dose?

Answer 11

Radiation absorbed dose x Wr

Question 12

What is Wr?

Answer 12

Radiation quality weighting factor which represent the biological effects of different radiations on different tissues

Question 13

What is the units of the equivalent dose?

Answer 13

Sieverts

Question 14

What is the Wr of X-rays?

Answer 14

1

Question 15

What is the formula for Effective dose?

Answer 15

Equivalent dose x Wt

Question 16

What is Wt?

Answer 16

Tissue weighting factor

Question 17

What does the effective dose consider?

Answer 17

Different parts of the body

Question 18

How do you calculate the weighting factor for the whole body?

Answer 18

Sum of the individual weighting factors

Question 19

What is the radiation dose for intra-oral periodical dental radiography?

Answer 19

0.0001-0.0008mSv

Question 20

What is the radiation dose for panoramic radiograph?

Answer 20

0.016-0.026mSv

Question 21

What factors can lower the effective dose?

Answer 21

E-speed film (faster film)
70kV + 200mm fsd
Rectangular collimation

Question 22

What is the reference dose?

Answer 22

Published maximum absorbed dose for every investigation

Question 23

What are the radiation dose limits for the 3 categories of people?

Answer 23

Classfied workers= 20mSv
Non-classified workers= 6mSv
General public= 1mSv

Question 24

What is the Natural background radiation dose?

Answer 24

2.6mSv

Question 25

Where does natural background radiation come from?

Answer 25

Rock, soil, outer space

Question 26

How long is the average periapical equivalent to of background radiation?

Answer 26

16 hours of background radiaiton

Question 27

How long is the average panoramic equivalent to of background radiation?

Answer 27

2 days

Question 28

How does the size of the exposure affect the severity of damage?

Answer 28

Size of exposure does not affect the severity only the probability of it occuring

Question 29

How does age affect risk from radiation?

Answer 29

The younger the patient, the greater the risk