Rad Biology and Safety

Question 1

What is thermionic emission?

Answer 1

The boiling off, or liberation of electrons

Question 2

Where does the current come from to produce thermionic emission?

Answer 2

Step-down transformer

Question 3

What is the unit of electric potential?

Answer 3

Volt/Voltage

Question 4

What charge is the anode?

Answer 4

positive

Question 5

What material makes up the target surface?

Answer 5

tungsten with rhenium

Question 6

What two components make up the cathode?

Answer 6

filament wires and focusing cup

Question 7

What charge does the cathode carry?

Answer 7

negative

Question 8

What material is the focusing cup?

Answer 8

molybdenum or nickel

Question 9

What material makes up filament wires?

Answer 9

thoriated tungsten

Question 10

Where do electrons turn into X-rays?

Answer 10

the tungsten target

Question 11

What is the Z-value of tungsten?

Answer 11

74

Question 12

First shell of electrons?

Answer 12

K-Shell

Question 13

Electrons have what charge?

Answer 13

Negative

Question 14

What is the maximum number of electrons in any shell?

Answer 14

Orbital shell # used in 2(n)^2

Question 15

What is the maximum number of electrons in the valence shell?

Answer 15

8 electrons

Question 16

What is the blinding energy of the K-shell of tungsten?

Answer 16

69.53 keV (other shells L=12, M=3, N=1)

Question 17

What does “A” stand for?

Answer 17

atomic mass

Question 18

What does ionization mean?

Answer 18

removal of an orbit shell electron

Question 19

After ionization takes place, what is the charge of the atom?

Answer 19

positive

Question 20

What interactions are formed in the tube? (production)

Answer 20

Brems and Characteristic

Question 21

In X-Ray production, what is the interaction with the electrostatic field of the nucleus?

Answer 21

Brems

Question 22

In X-Ray production, describe the interaction where a high speed electron interacts with a tungsten target atom by ejecting an INNER shell electron, causing a cascade effect and ionizing the atom?

Answer 22

Characteristic

Question 23

Which is more common, Brems or Characteristic?

Answer 23

Brems

Question 24

Which is more common, Brems or Characteristic?

Answer 24

Brems

Question 25

How do you calculate the energy of the new electron in characteristic radiation?

Answer 25

Take the energy of the K-Shell and subtract whichever shell replaces it. Ex. K=70 L=12 M=3 N=1 70-12= 58 keV is the new energy. Difference in the binding energies of each shell.

Question 26

What are types of particulate radiation?

Answer 26

Alpha and Beta

Question 27

What is frequency?

Answer 27

rate of rise and fall of electromagnetic photon and is measured in unit Hertz (hz)

Question 28

Every X-Ray, regardless of kV, travels at what speed?

Answer 28

3 x 10^8 meters/second (186,000 miles per second)

Question 29

Difference between X-rays and Gamma Rays?

Answer 29

Source of origin - X-ray from ionization - Gamma from nucleus decay

Question 30

Wavelength, Frequency, Energy relationships Direct or Inversely proprotional

Answer 30

Wavelength and Frequency- Inversely proportional ^*(most important and likely to show up)* Wavelength and Energy- Inversely proportional Frequency and Energy- Directly proportional

Question 31

mAs

Answer 31

- Controls patient dose | - Quantity

Question 32

kVp

Answer 32

- Controls quality | - Energy of X-Ray

Question 33

The intensity shows up only under inverse square law questions, not direct

Answer 33

The intensity shows up only under inverse square law questions, not direct

Question 34

What is the formula for inverse square law?

Answer 34

``` Intensity 1 (SID 2)^2 -------------- = ---------- Intensity 2 (SID 1)^2 ```

Question 35

What is the formula for direct square law?

Answer 35

``` Intensity 1 (SID 1)^2 -------------- = ---------- Intensity 2 (SID 2)^2 ```

Question 36

What effects the half-value-layer (HVL)?

Answer 36

kVp and filtration

Question 37

What is the half-value-layer (HVL)?

Answer 37

amount of material necessary to reduce the intensity to 1/2 of its original value

Question 38

What are the photon interactions with matter?

Answer 38

``` Compton Effect Photoelectric Absorption Coherent (Unmodified scatter, Classical, Thompson) Pair Production Photodisintegration ```

Question 39

What is another name of remnant radiation?

Answer 39

Exit Radiation

Question 40

What interaction with matter is called, partial absorption, contains an incident X-ray photon that interacts with an outer shell, resulting in image contrast and occupational exposure? One incoming electron and two leaving?

Answer 40

Compton Scatter (OUTER SHELL)

Question 41

What interaction with matter involves an incident X-ray photon that interacts with a K-Shell electron, involves absorption of energy, and is the primary source of patient radiation exposure?

Answer 41

Photoelectric Absorption

Question 42

What interaction with matter causes no ionization?

Answer 42

Classical/Unmodified scatter

Question 43

What energy level needs to be known for Pair Production?

Answer 43

1.022 MeV

Question 44

What energy level needs to be known for Photodisintegration?

Answer 44

>10 MeV

Question 45

What is the technologist largest source of occupational exposure?

Answer 45

Compton Scatter

Question 46

At what angle from the patient will the technologist receive the least exposure? (during fluoro)

Answer 46

At a 90 degree angle, or as close to it as possible

Question 47

What is better for the patient, fractionation or protraction?

Answer 47

Fractionation

Question 48

What is linear energy transfer? (LET)

Answer 48

Defines the rate of energy deposited per unit track length through an absorber

Question 49

What is relative biologic effectiveness? (RBE)

Answer 49

Defines the ability of aerobic conditions to enhance the effectiveness of radiation.

Question 50

All of the following are diagnostic imaging exposure energies, except?

Answer 50

Pair Production and Photodisintegration