Properties of X-rays/ X-ray Interaction with Tissue

Question 1

Who Discovered the Properties of X-rays?

Answer 1

Wilhelm Conrad Roentgen

Question 2

What are the different properties of X-rays?

Answer 2

1. Polyenergetic and Heterogeneous
2. Highly Penetrating
3. Invisible
4. Produce Chemical and Biological Changes
5. Capable of Ionizing Gas
6. Produce Secondary Radiation
7. X-rays Cannot be focused by a lens
8. Travel in straight line and diverge a source
9. Electrically and Magnetically Neutral
10. Affect Photographic Film

Question 3

Why are X-rays Polyenergetic and Heterogeneous?

Answer 3

Due to different interactions between the high speed electrons emitted from the cathode and the tungsten atoms of the anode

Question 4

If 90kv is selected what will the energy level range be?

Answer 4

• 90 kV/3= 30
• Range will be 30-90 kV

Question 5

Why are X-rays Highly Penetrating?

Answer 5

Due to the high atomic number of the Tungsten Target

Question 6

Why are X-rays Invisible?

Answer 6

X-rays cannot be smelled, touched, or tasted

• Result of early pioneers suffering from radiation as safety standards were not yet set

Question 7

Why do X-rays produce chemical and biological changes?

Answer 7

Certain chemical are known to fluoresce or glow when activated by x-rays

Question 8

What chemicals glow or fluoresce when activated by x-rays?

Answer 8

• Barium Platinocyanide
• Rare earths and calcium tungstate phosphors

Question 9

How did chemical and biological changes become apparent?

Answer 9

• Atomic bomb, Three-Mile Island, Chernobyl, Fukushima Daiichi
• Radiation Poisoning Erythema, alopecia, cataracts, leukemia

Question 10

Why are x-rays capable of ionizing gas?

Answer 10

By Interaction with the outer shell electrons

Question 11

What devices are used to detect the presence of radiation?

Answer 11

• Geiger Counters
• Ionization Chambers

Question 12

What are the two different types of secondary radiation?

Answer 12

1. Leakage Radiation
2. Scatter Radiation

Question 13

What is Leakage Radiation?

Answer 13

Radiation emitted from the x-ray tube housing in all directions other than that of the useful beam

Question 14

What is Scatter Radiation?

Answer 14

Radiation that has interacted with atom and has been redirected in a different direction from the original path

Question 15

Scatter radiation is of _________ than the ________ or __________ radiation energy

Answer 15

• less energy
• primary
• original

Question 16

Why is it that X-rays cannot be focused by a lens?

Answer 16

X-rays are highly penetrating and can pass through lens making it difficult to focus the x-rays

Question 17

The focusing cup in the x-ray tube only contains the _____________ to a narrower path which in turn produces __________ that are closer together as a beam

Answer 17

• electron stream
• x-ray photons

Question 18

Why do x-rays travel in a straight line and diverge from a source?

Question 19

X-ray travels at the _________.

Answer 19

Speed of light

Question 20

Why are x-rays electrically and magnetically neutral?

Answer 20

Not influenced by either an electric or magnetic field

Question 21

How do X-rays affect photographic film?

Answer 21

By ionizing silver halide crystals in the film emulsion and then processing to produce varying degrees of blackness on the film

Question 22

X-ray beam consists of many energies. Who sets the controlling factors?

Answer 22

Technologist

Question 23

In this energy level what does the 70 kV determine?
70 kV @ 5 mAs

Answer 23

The energy or penetrating ability of the x-ray beam

• some photons (or quanta) will have energies of 70kV or less

Question 24

In this energy level what does the 5 mAs determine?
70 kV @ 5 mAs

Answer 24

• The amount of electrons present to produce the x-rays
• The length of time such electrons are allowed to flow

Question 25

The weaker ______ will not have enough energy to pass through the body and will be _______ or _______ by tissue

Answer 25

• Quanta
• Absorbed
• Attenuated

Question 26

Higher _______ will penetrate the bones and muscle of the body to form an image on the radiograph

Answer 26

Quanta

Question 27

What are the two factors the influence the absorption or attenuation of x-rays?

Answer 27

1. Thickness of the Material
2. Density and atomic number of the material

Question 28

Why does the thickness of material influence attenuation of x-rays?

Answer 28

Thick piece of material will absorb more x-rays than a thin piece of same material

Question 29

Why does density and atomic number of material influence attenuation of x-rays?

Answer 29

Material with higher density or atomic number will attenuate more x-rays than a material with low density or atomic number

Question 30

_______ attenuates x-rays so there a less x-rays to interact with the image receptor (IR) underneath the patient. It appears as _______.

Answer 30

• Bone
• White

Question 31

______ is thin and has low atomic number so x-rays, strong, and weak, will pass through and interact with the IR to produce________ shades.

Answer 31

• Air
• Black

Question 32

______ and________ are less dense. Stronger x-rays will pass through the object and interact with the IR, while some will be attenuated. ______ shades will be produced.

Answer 32

• Muscle and Fat
• Gray