X-ray Production and Emission

Created when an incoming electron is suddenly slowed down, changes direction, and leaves the tungsten atom

Bremsstrahlung radiation

This refers to the area on the target surface that is struck by the electron stream:

Actual focal spot

The negative, filament end of the x-ray tube is called the:

Cathode

What is the unit used to measure the voltage across the x-ray tube?

kVp (kilovolt peak)

Refers to the length of time that the x-rays are turned on:

Exposure time

What is the metal element used to make the filament and target in an x-ray tube?

Tungsten

What is the process of removing long wavelength photons from the x-ray beam?

Filtration

What is the tungsten focal area all around the beveled edge of the rotating anode called?

Focal track

The hollow area in the cathode where each filament is situated is the:

Focusing cup

What is the vertical projection of the actual focal spot onto the patient and image receptor?

Effective focal spot

The term used to describe the sharpness of the structures recorded in the image:

Spatial resolution

The source of electrons at one end of the x-ray tube that consists of a small coil of tungsten wire is the:

Filament

Created when an incoming electron interacts with the k-shell electron and knocks it out of orbit:

Characteristic radiation

Contains two filaments, one large and one small:

Dual-focus tube

The uneven distribution of radiation intensity in the x-ray beam resulting in a higher intensity on the cathode side is called the:

Anode heel effect

The positive, target end of the x-ray tube is the:

Anode

A small bundle of electromagnetic energy is called a(n):

Photon

The slant of the anode surface is the:

Target angle

What is the process in which heat speeds up the movement of the electrons in their orbit and increases their distance from the nucleus?

Thermionic emission

What is the measure of the rate of current flow across the x-ray tube?

Milliamperage (mA)

The precise area on the target where the electrons from the filament are repelled onto is the:

Focal spot

This means that the x-ray beam is made up of photons that have different wavelengths and energies:

Heterogeneous

What is used to indicate the quantity of exposure?

Milliampere-seconds (mAs).

Filtration that is built into the x-ray tube and includes the tube glass and its surrounding oil is called:

Inherent filtration

Equal to the inherent filtration plus the added filtration:

Total filtration

Also called space charge, is the source of free electrons for x-ray production:

Electron cloud

The x-ray tube inside the protective housing is made of:

Pyrex glass

The target of the x-ray tube is made of:

Tungsten

A device for removing long wavelength radiation from the primary x-ray beam is a:

Filter

Free electrons at the cathode that are used for x-ray production come from the:

Filament

When tungsten atoms are heated, their outermost electrons are moved out of the atom in space. This principle is called:

Thermionic emission

The anode, or target, of the x-ray tube is _____________ charged.

Positively

The cathode end of the x-ray tube is ____________ charged.

Negatively

Most x-ray tubes in use today have a standard rotation speed of ___________ rpm.

3,600

The greatest portion of the x-ray beam is made up of:

Bremsstrahlung-produced radiation

Below what kVp level is characteristic radiation no longer produced?

70 kVp

What is required to move the electron stream rapidly across the x-ray tube?

High potential difference

More than 99% of the energy applied to an x-ray tube is converted into:

Heat

What percentage of the total energy applied to an x-ray tube target is converted into x-rays?

Less than 1%

What type of radiation is produced in the anode by the sudden slowing and directional change of an incoming electron?

Bremsstrahlung radiation

What type of radiation is produced when an incoming electron interacts with the K-shell electron in the tungsten atom?

Characteristic radiation

The degree of angulation of the x-ray tube target will determine the:

effective focal spot

A smaller effective focal spot produces?

Greater image sharpness

Which of the following can be found on a dual-focus x-ray tube?

1. Two filaments

2. Two focal spot sizes

3. Two anodes

1 and 2 only

The penetrating power of the x-ray beam is controlled by varying the:

kilovoltage (kVp)

The current across the x-ray tube is measured in units of:

milliamperes (mA)

Which of the following occurs when the mA is doubled?

1. The number of x-ray photons decreases by 50%.

2. Radiographic density increases.

3. There are twice as many photons in the x-ray beam.

2 and 3 only

An x-ray exposure is made using the following factors: 400 mA, 0.02 seconds, 80 kVp, 40 inches SID, and the large focal spot. What is the mAs for this exposure technique?

8 mAs

When exposure time is very short, the time is usually measured in:

milliseconds

If an exposure time is measured as 35 milliseconds, what is the exposure time in seconds?

0.035 seconds

The x-ray beam is made up of many different energy x-rays. This beam is referred to as:

Heterogeneous

X-ray equipment capable of producing 70 kVp or more must have how much equivalent aluminum filtration?

2.5 mm Al equivalent

A steeper target angle provides:

smaller effective focal spot

Filtration _______________ the average wavelength of the x-ray beam.

Decreases

The precise area on the target where the x-rays strike is called the:

Focal spot

How is the electromagnetic induction motor used in the x-ray machine?

To rotate the anode

The difference in x-ray intensity (or volume of x-rays) between the anode and the cathode side of the x-ray beam is:

45%

The density in the radiographic image is primarily controlled by the:

mAs

The contrast in the radiographic image is controlled by the:

kVp

Which of the following would be considered inherent filtration?

1. Oil

2. Mirror

3. Pyrex glass

All 3

The “electron cloud” that surrounds the hot cathode is referred to as a:

Space charge

Projectile electrons travel from ______________.

cathode to anode

During an exposure, most of the ________ energy of the projectile electrons is converted to ________.

kinetic; heat

The production of heat at the anode is directly proportional to _________.

tube current

The efficiency of x-ray production increases as ______ increases.

kVp

Electron interactions at the inner shell of the target atoms produce _____ radiation.

characteristic

The useful characteristic x-rays from tungsten targets are ___-shell x-rays.

K

Characteristic K-shell x-rays have an effective energy of _____ keV.

69

Most of the x-rays produced at the target are _______________.

bremsstrahlung

At 55 kVp, _____ of the x-rays produced are bremsstrahlung.

100%

Bremsstrahlung x-rays are produced by ______________ at the target

slowing electrons

Characteristic x-rays are produced by __________________.

released binding energy

The quantity of bremsstrahlung radiation increases proportionately with increased _____.

mAs

The number of x-rays in the useful beam defines x-ray ________.

Intensity

X-ray intensity increases in direct proportion to increases in __________.

mAs

If a technologist changes the technique from 70 kVp @ 200 mAs to 70 kVp @ 400 mAs, the x-ray intensity will _________.

double

The penetrability of an x-ray beam is called x-ray ________.

quality

An x-ray beam that could pass through dense tissue would have high _____.

penetrability and quality

A low-quality beam would also have low _____.

penetrability

Beam energy is affected by ______________.

kVp and filtration