RADR 1213 Exam 1: Chapters 2, 6, 7

The unit of mass is the

kg

An electron is ______________ charged and has a mass of _________ amu(s)

negatively; 0.000548

The orderly arrangement of electrons in the periodic table is based upon

Atomic number

Photon wavelength is

inversely proportional to photon frequency

What are true statements of EM energies?

-They are illustrated as sinusoidal waves

-They possess both wave and particle characteristics

-They are arranged in an orderly spectrum according to frequency and wavelength

The maximum number of electrons found in any energy level (shell) at any point in time is calculated by the formula?

2n^2

The sum of protons and neutrons in a nucleus is called?

mass number

Groups of the periodic table

represents elements with the same outer electron configuration

Carbon has an atomic number of 6. One of its isotopes has a mass number of 14. The number of neutrons in this isotope is?

8

A period in the periodic table is

principal quantum number

In the excitation process, electrons in an atom are moved to a/an ____ energy state.

Higher

The maximum number of electrons in a period with a principal quantum number of 4 is

32

Isotopes have ____ mass numbers and ____ atomic numbers.

different, same

In a vacuum, electromagnetic radiation

has a velocity equal to the speed of light

If the photon frequency of electromagnetic radiation is increased tenfold, then the

wavelength will decrease to 1/10

The atomic number is the number of ___________ contained in the nucleus.

Protons

An isotope of boron has 5 protons and 6 neutrons. The atomic number of boron is

5

An element with an atomic number of 22 has how many electrons in the second principal quantum number level (L shell)?

8

The nuclear components that distinguish one element from another are the

Protons

An atom has an atomic number of 18 and a mass number of 38. Letting P = the number of protons and N = the number of neutrons, what atoms is the isotope of this atom?

P = 18, N = 21

According to the "rule of octets,"

the valence shell is chemically inert

What are the basic characteristics of the wave equation?

Velocity, wavelength, and frequency

If an electron is gained or lost from an atom, that atom becomes

an ion

What are some forms of energy?

Thermal, electrical, and nuclear

Quarks may behave according to the _____________ theory

String

What is true about the substance glucose (C6H12O6)?

The smallest subdivision of the molecule is glucose, it is a compound, and it consists of 3 elements

When comparing iodine (Z=53) with barium (Z=56),

Iodine has five (5) orbitals with electrons

What is needed for X-Rays to exist

A source of electrons, a vacuum, and a large potential difference

The function of the cathode is to produce

a thermionic cloud

What does the cathode consist of?

Filament, focusing cup, and associated wiring

What are the preferred filament materials?

Tungsten, rhenium, and molybdenum

Filament materials are chosen primarily for their

High melting points

What can affect the production of a thermionic cloud?

Filament diameter, filament length, and filament temperature

A filament may break due to

vaporization

Driving the thermionic cloud from the cathode to the anode requires?

A small amperage

In order to time the x-ray exposure with rapid inspiration on an infant,

Three-phase, high-frequency generators are preferred

The cathode focusing cup has an ___________ charge

negative

As more and more electrons build up in the area of the filament, their negative charges oppose the emission of additional electrons. This phenomenon is known as

Space charge effect

X-ray photon production occurs at the

Anode

Tungsten is the material of choice for the source of x-ray photons primarily because of its

High atomic number

Pitting of the anode commonly occurs

with extended use

Melting of the anode commonly occurs

when the stator fails and the rotor ceases to turn

Cracking of the anode typically occurs

When a cold anode is hit with a high kVp exposure

The exact point on the anode where the x-ray beam emanates is the

Focal spot

The physical area of a rotating anode focal track, affected by the cathode electron beam, is the

Actual focal spot

The area of the focal spot that is projected out of the tube toward the object being radiographed is the

Effective focal spot

The actual focal spot is controlled by the

Length of the filament

The most common diagnostic radiography x-ray tube target angle is __________ degrees

12

As the actual focal spot size increase, the effective focal spot size

Increases

As the angle of the anode increases and the incident electron beam size remains the same, the effective focal spot size

Increases

The use of the line-focus principle causes a problem known as the _______ effect

Anode heel

The only portion of the anode assembly placed outside of the vacuum of the glass envelope is the

Stator

The function of the stator and rotor assembly is to

Rotate the anode

The protective housing controls leakage and scatter radiation through

Absorption

Insulation of the high-voltage components of the tube and absorption of the heat produced by x-ray production is achieved through the use of?

Dielectric oil

What type of radiation is composed of photons not produced at the actual focal spot?

Off-focus and extra-focal radiation

When radiographing a wedge-shaped anatomical structure such as the femur, the thicker portion of the anatomy should be positioned

Under the cathode end of the tube

Leakage radiation from the lead-lined housing must not exceed

100 mR/hr measured at 1 meter

What can lengthen the x-ray tube life?

Minimize anode rotation times and prepping, avoid sudden movements of the tube head assembly, and use low mA selection whenever clinically possible

To determine the allowable combination of exposure factors, thus preventing x-ray tube damage,

An x-ray tube rating chart is check prior to exposure

As the x-ray tube anode target angle increase from 10 degree to 15 degrees

The higher exposure values (mA, time, kVp) may be used, the size of the actual focal spot increases, and image resolution decreases

What is the function of the filament?

When the rotor is depressed, the filament is heated prior to exposure. During the exposure, the filament, located on the cathode side, is responsible for producing a thermionic source/cloud of electrons

What are the three parts of the anode assembly?

Anode, stator, and rotor

In which direction should the anode be placed for an AP projection of the abdomen? Why?

The anode should be placed over the superior portion of the abdomen for an AP projection. This is done because the Anode Heel Effect causes more x-ray intensity to be projected to the cathode side.

How many heat units are generated by an exposure of 70 kVp, 300 mA, and 0.1 second on a 1 rectified unit?

2100 Heat Units

How many heat units are generated by an exposure of 70 kVp, 400 mA, and 0.1 second on a high frequency unit?

3920 Heat Units

How many heat units are generated by an exposure of 100 kVp, 400 mA, and 0.01 second on a high frequency unit?

560 Heat Units

During x-ray production, almost all of the kinetic energy of the incident electron is converted to

Heat

What percentage of target interactions results in the production of x-ray photons?

1 percent

The transfer of the incident electrons' kinetic energy to the outer-shell electrons, causing vibration of the outer-shell electron, results in the emission of

Infrared radiation

The types of target interactions that occur in the production of x-ray photons in the diagnostic range are dependent upon the

Incident electron kinetic energy

The energy of a bremsstrahlung photon is

the difference between the entering and exiting kinetic energy of the incoming electron

Bremsstrahlung interactions may occur only when the incident electron interacts with

The force field around the nucleus

Characteristic interactions may occur only when the incident electron interacts with

An inner-shell electron

During a characteristic interaction, the kinetic energy of the incident electron must be ___________ of the electron it knocks from its orbit

Greater than that

During a characteristic interaction, the dropping of a higher-energy state electron into a lower-energy state "hole" results in the emission of

A photon of electromagnetic energy

The energy of a characteristic photon is

the difference between the binding energy of the outer and inner shells between which the electron dropped

At the end of the characteristic cascade, the _________ shell is missing an electron

Outermost

The K shell can hold a maximum of _______ electrons

2

If the peak kVp is 110, the average keV energy of the beam would be

33-44 keV

X-rays are characterized as

Electromagnetic waves of short wavelength and electromagnetic waves with high frequencies

The emission spectrum of an x-ray beam from a tungsten anode consists of

A characteristic spike at 69 keV, a significant portion due to bremsstrahlung interactions, and a mixture of brems and characteristic interactions

Electrons traveling from the cathode filament to the anode are called

Incident electrons

When comparing the x-ray emission spectrum between brems produced at 70 kVp and 110 kVp,

the 110 kVp beam would demonstrate more brems and a higher characteristic spike

When the x-ray emission spectra between single-and-three phase generators are compared,

Three-phase beams would have a higher average energy

Tungsten is the anode material of choice for x-ray production because of its

Excellent k-edge value for x-ray production

Molybdenum is an excellent target material for mammography studies due to its

K-edge production of characteristic radiation, to match soft tissues of the breast