Xrays Interaction With Matter

Question 1

5 basic ways X-rays interact with matter:

Answer 1

Coherent scattering, Compton effect, Photoelectric effect, Pair Production, Photodisintegration

Question 2

What are the three ways that X-rays interact with matter in diagnostic radiography?

Answer 2

Coherent scattering, Compton effect, photoelectric effect

Question 3

What three interactions occur once the primary beam interacts with the patient?

Answer 3

Remnant radiation, absorbed photon, and scattered photon (FOG)

Question 4

Coherent scattering

Answer 4

Excites the electron but doesn’t change its energy, low energy photons interact with bound inner electron and becomes excited, the atom then releases this access energy as scattered ray, the wavelength of this is the same, no ionization takes place

Question 5

________% of X-rays undergo classical scattering

Answer 5

3

Question 6

These are generally low energy X-rays and cause the general graying or film fog.

Answer 6

Coherent scattering

Question 7

Compton scattering

Answer 7

Travels on with less energy, can occur with all X-rays, an incoming photon interacts with a loosely bound outer shell electron, the photon surrenders some energy to dislodge the electron this freed electron is Compton scattering, posses energy capable of ionizing

Question 8

As kVp increases Compton scatter _________ and shades seen ________.

Answer 8

Increases; increases

Question 9

In Compton scattering, once the electron is ejected the atom becomes __________.

Answer 9

Ionized (charged) (+)

Question 10

In Compton scattering the ejected electron is equal to _______ energy plus ________ energy when it leaves the atom.

Answer 10

Binding ; kinetic

Question 11

Both the ________ electron and the ________ X-ray are capable of ionizing other atoms

Answer 11

Ejected ; scattered

Question 12

In Compton scattering, the X-ray is eventually…

Answer 12

Absorbed

Question 13

The Compton electron loses all its ________ energy when it combines with another atom

Answer 13

Kinetic

Question 14

Which effect cause the X-ray to lose ALL of its energy?

Answer 14

Photoelectric effect

Question 15

In the photoelectric effect, an incoming electron surrenders all energy to the ___________ electron.

Answer 15

K shell

Question 16

In the photoelectric effect, the ejected electron is a __________.

Answer 16

Photoelectron

Question 17

The photoelectric effect causes the atom to become __________.

Answer 17

Ionized (charged, +)

Question 18

The photoelectric effect results in what kind of damage to the human body?

Answer 18

Biological damage to the tissues

Question 19

The photoelectric effect is a form of ____________ radiation.

Answer 19

Characteristic

Question 20

The photoelectric effect is a major factor in radiographic ________.

Answer 20

Contrast between 30-140 kVp.

Question 21

______ undergoes more photoelectric.

Answer 21

Bone

Question 22

In the photoelectric effect the higher the atomic number the _______ the absorption value.

Answer 22

Greater

Question 23

In the photoelectric effect the lower the atomic number the ________ the absorption value but _______ contrast.

Answer 23

Lesser, greater

Question 24

The probability of interaction is both the energy of ________ and the _______ number of atom.

Answer 24

X-ray ; atomic

Question 25

The incident X-ray must have equal or greater energy than the _________ electron.

Answer 25

Binding

Question 26

Pair production

Answer 26

Annihilation reaction, incoming X-ray is attracted by a nuclear force to the atom that causes the X-ray to disappear, in its place a positron and an electron, only occurs in energy levels greater than 1.02 meV

Question 27

Photo disintegration

Answer 27

High energy photons that escape interaction and are absorbed by the nucleus, the nucleus then excites to where it emits a nucleon, rarely occurs in diagnostic radiography

Question 28

Differential absorption

Answer 28

Results in the bright area of the X-ray / the bone, the X-ray transmitted through the body

Question 29

Most X-ray that interact with matter do so by….

Answer 29

Compton

Question 30

Less than _____ % of Compton reach the film and only _______ interacts with the film

Answer 30

5 ; half

Question 31

What percentage of X-rays are actually the radiographic image emitted by the machine?

Answer 31

1%

Question 32

Differential absorption ________ as the kVp is lowered, making the bone more __________.

Answer 32

Increases ; photoelectric

Question 33

At ________ kVp Compton predominates.

Answer 33

High

Question 34

Why are barium and contrast used during examinations?

Answer 34

They both have high atomic number and high densities

Question 35

_______ kVp can be used to outline organs and also to penetrate the contrast media.

Answer 35

Higher

Question 36

In contrast examinations, During absorption the photon….

Answer 36

Disappears

Question 37

In contrast examinations, during attenuation the number of X-rays….

Answer 37

Reduces