Cedo - (Section 3) Radiation Quantities And Units

Question 0

How many disintegrations (nuclear transformations) does 1 gram of radium undergo in 1 second?

Answer 0

3.7 x 10*10 or 37 Billion (37 000 000 000)

Question 1

Who is the organization that is selects and defines units and quantities of radiation?

Answer 1

The International Commission on Radiological Units and Measurements, in conjunction with the International Commission on Radiological Protection (ICRP)

Question 2

What is the activity of 1 gram of radium called?

Answer 2

1 Curie (Ci)

Question 3

1 curie is?

Answer 3

The amount of substance in which 37 billion atoms per second undergo radioactive disintegration.

Question 4

How is the activity of a radioactive isotope determined?

Answer 4

By the number of atoms of the material that will decay (disintegrate or stabilize) in a given period of time.

Question 5

1 curie (Ci) equals?

Answer 5

37 Billion disintegrations/second.

Question 6

The radioactivity in a material is determined by?

Answer 6

How Curies of the material are present.

Question 7

What does SI stand for?

Answer 7

The International System of Units.

Question 8

What does dps stand for?

Answer 8

Disintegrations per second.

Question 9

A Becquerel (Bq) is a measure of what?

Answer 9

A measure of disintegrations per second (dps).

Question 10

How many dps is a Becquerel?

Answer 10

1 dps.

Question 11

How many Becquerels is equal to 1 Curie?

Answer 11

37 Billion.

Question 12

What are some the prefixes, symbols and multiples used in conjunction with the SI system?

Answer 12

tera    (T)  - 10*(12)
giga   (G)  - 10*(9)
mega (M) - 10*(6)
kilo     (k)  - 10*(3)
centi   (c)  - 10*(-2)
milli     (m) - 10*(-3)
micro  (u)  - 10*(-6)
nano   (n)  - 10*(-9)

Question 13

The degree of concentration of radioactive material within a radioactive source is referred to as what?

Answer 13

Specific activity.

Question 14

How is specific activity measured?

Answer 14

In Curies (Ci) per gram or Becquerels (Bq) per gram of source material.

Question 15

What is the advantage to having a physically smaller source?

Answer 15

It will produce sharper radiograph images.

Question 16

1 Ci equals how many GBq and how many TBq?

Answer 16

37 GBq, 0.037 TBq

Question 17

50 Ci equals how many GBq and how many TBq?

Answer 17

740 GBq, 0.740 TBq

Question 18

How many disintegrations per second (dps) does 1 Bq equal?

Answer 18

1 dps.

Question 19

Even if the specific activity of two isotopes are the same what could differ between the two?

Answer 19

The number of Gamma rays resulting form the decay.

Question 20

How is intensity measured?

Answer 20

Roentgens per hour @ 1 metre.

Question 21

What is the characteristic intensity of Iridium, Cobalt and Selenium at 1 metre? Give answers in Ci and GBq.

Answer 21

Iridium - 550 mR/hr, 0.15 mSv/hr
Cobalt - 1350 mR/hr, 0.36 mSv/hr
Selenium - 200 mR/hr, 0.05 mSv/hr

Question 22

What does “exposure” refer to in Industrial Radiography?

Answer 22

The Quantity of radiation incident upon an object.

Question 23

What is the unit of radioactivity in the International System of units (SI)?

Answer 23

The Becquerel (Bq)

Question 24

Exposure is expressed in units referred to as?

Answer 24

Roentgens (R).

- there is no SI unit for exposure but the metric system expresses exposure in Coulomb/Kilogram(c/kg)

Question 25

Radiation intensity is also known as?

Answer 25

Dose Rate.

Question 26

Define Radiation intensity?

Answer 26

Energy absorbed by any matter placed in a radiation beam.

Question 27

Radiation effect can be in what forms?

Answer 27

Blackening of radio graphic film, biological killing of living cells, induction of cancer, etc

Question 28

Radiation effect is proportional to?

Answer 28

Radiation intensity.

Question 29

Radiation intensity is measured in what?

Answer 29

Roentgens/hour (R/hr) or the SI unit of Sieverts/hour (Sv/hr)

Question 30

Absorbed radiation dose is measured in what?

Answer 30

The SI unit Gray (Gy) or energy absorbed in joules/kg. Old unit of measurement is the RAD.

Question 31

What is the Quality Factor (Q) or Relative Biological Effectiveness (rbe) the four main types of radiation?

Answer 31

y-rays - 1Q (rbe)
x-rays - 1Q (rbe)
β particles - 1Q (rbe)
Α particles - 20Q (rbe)

Question 32

How much more harmful are Alpha particles (a) then Beta particles (β), Gamma rays (y) and X-rays (x)?

Answer 32

20 times.

Question 33

1 RAD (R) equals?
1 Gray (Gy) equals?

Answer 33

10 mGy.

100 RADs.

Question 34

What does rem stand for?

Answer 34

Roentgen Equivalent in Man

Question 35

If you multiply the absorbed dose rate (in R or Gy) by the Q factor, what is the resultant?

Answer 35

Dose Equivalent.

rem = RAD x Q or RBE

Question 36

Dose equivalent is measured in?

Answer 36

The SI unit Sievert (Sv) or the CGS unit Roentgen Equivalent in Man (rem).

Question 37

What’s is the relationship between Sieverts (Sv) and Roentgen Equivalent in Man (rem)?

Answer 37

1 Sievert (Sv) = 100 Roentgen Equivalent in Man (rem).
1 Roentgen Equivalent in Man (rem) = 10 millisieverts ( mSv) or 0.01 Sv

Question 38

The (rem) is the dose from any radiation that?

Answer 38

Produces biological effects in man equivalent to 1 RAD of X-Ray, Gamma-Ray or Beta Rays.

Question 39

What is Half Life?

Answer 39

The length of time required for the activity to decay to one-half it’s initial activity.

Question 40

What are the Half Life’s of Iridium 192 (IR 192), Cobalt 60 (Co 60) and Selenium 75 (Se 75)?

Answer 40

IR 192 - 74 days
Se 75 - 120 days
Co 60 - 5.3 years

Question 41

What are the formulas to calculate half-life?

Answer 41

See Pg 23-24