Chapter 2- The X-Ray Beam

The anode includes the:

-Stator -Rotor -Target

To produce x-rays, electrons must be A. suddenly decelerated and accelerated B. suddenly decelerated and liberated from the cathode filament C. accelerated and liberated from the cathode filament D. All of above

D. All of above

As kVp increases A. beam penetrability increases and beam wavelength decreases B. beam penetrability increases and beam frequency increases C. beam wavelength decreases and beam frequency increases D. All of these occur

D. All of these occur

What is founded in the Tube housing? A. Metal or glass envelope B. Negatively charged electrode C. Positively charged electrode D. All the parts that were mentioned where included

D. All the parts that were mentioned where included

Cathode

Drawing of the cathode

Anode Heel Effect

Due to the geometry of the angled anode target, the radiation intensity is greater on the cathode side.

The anode of an x-ray tube is a positively charged electrode composed of molybdenum, copper, tungsten, and graphite. A. Molybdenum B. Copper C. Tungsten D. Graphite E. All of the above

E. All of the above

The negative electrode 1.____ is heated, and electrons are emitted 2._____

1. Cathode 2. Thermionic emission

Extending X-ray Tube Life

1. if applicable, warm up tube 2. avoid excessive heat generation 3. do not hold down rotor button without making exposure 4. use lower mA and longer exposure time 5. don't move tube while energized 6. recognize unusual noises and report

Single phase

1.00 Factor

Three phase

1.35 Factor

High frequency

1.40 Factor

X-rays are more1._____on the cathode side of the tube; their intensity2. ______ toward the anode side.

1.Intense 2. decreases

What is added to the primary beam to alter its intensity

1.Wedge filter 2.Trough filter

The maximum speed the rotating anode will typically achieve is _____rpm

10,000

How many filaments are there?

2, a small and large

How many focusing cups

2, small focal spot and a large focal spot size.

Milliamperage × time = mAs

200 mA × 0.25 s = 50 mAs

Which of the following is classified as inherent filtration? 1. The collimator mirror 2. The tube envelope 3. The oil surrounding the tube

3. The oil surrounding the tube

Doubling mA results in 1. doubling the tube current. 2. doubling the quantity of x-ray photons. 3. doubling the thermionic emission. 4. All the above

4. All the above

The target angle of rotating targets typically ranges from

5° to 20

Because tungsten has a high atomic number (74) and a______ melting point, it efficiently produces x-rays. A. High B. Low C. Medium

A. High

_____envelopes are more commonly used in today's x-ray tubes. A. Metal B. Tungsten C. Iron D. Nickel

A. Metal

Inside the x-ray tube envelope you will find A. Vacuum B. Sweeper C. Idk dont care

A. Vacuum

The quantity of electrons in the tube current and quantity of x-rays produced are___to the mA A. directly proportional B. Inversely proportional C. Nothing

A. directly proportional

mA is______ to quantity of x-rays produced A. directly proportional B. Inversly proportional

A. directly proportional

Decreasing the exposure time results in___ A. fewer x-ray photons B. More x-ray photons

A. fewer x-ray photons

´Changing the mA or time will change the quantity of x-rays produced. A. quantity B. quality

A. quantity

The smaller the anode angle, the____ the effective focal spot size A. smaller B. larger

A. smaller vis versa

Exposure time determines the____ A. the length of time x-rays are produced. B. the length of time x-rays are NOT produced.

A. the length of time x-rays are produced.

Added Beam Filtration

Aluminum (Al)-added filtration is shown at the port, or window, of the x-ray tube and the collimator mirror.

Beam Filtration

Aluminum filtration added to x-ray beam to absorb low-energy photons

The electrons are attracted to the____, move rapidly toward the positive electrode, and are stopped or decelerated. Anode or Cathode?

Anode

Space charge effect

As more and more electrons build up in the area of the filament, their negative charges begin to oppose the emission of additional electrons.

A dual-focus tube has two A. Anode Filaments B. Cathode Filaments C. No clue

B. Cathode Filaments

As compared to glass, which of the following is an advantage to having a metal envelope x-ray tube? A. Increase in off- focus radiation B. Decrease in off focus radiation C. Who cares

B. Decrease in off focus radiation

There is a direct relationship between the tungsten metal's atomic number and melting point. A. Inverse relationship B. direct relationship C. No relationship

B. direct relationship

The larger the anode angle, the___ the effective focal spot. A. Smaller B. Larger

B. larger

Changing the mA results in a____in the quantity (amplitude) of x-rays produced. A. Direct Change B. Proportional change C. Inverse Change

B.Proportional change

Filament current is approximately A. 5-9 A B. 7-8 A C. 3-5 A

C. 3-5 A

´The intensity of the x-rays____ toward the anode. A. Increase B. Stays the same C. Decreases

C. decreases

Exposure time and x-ray quantity are___proportional. A. Inversely B. Nothing C. directly

C. directly

(HU) = mA × time × kVp × generator factor.

Formula for Heat Units

_____mA or lower tube currents with longer exp. Times help to minimize wear on the filament. Lower or Higher?

Lower

´The production of x-rays requires a_____ moving stream of electrons that are suddenly decelerated or stopped. Slow or rapidly

Rapidly

The part of the x-ray tube that is connected to the target and causes it to turn is the___

Rotor

What is the name of the device in a rotating anode x-ray tube that turns the rotor?

Stator

Image of x-ray tube housing

Structure of a typical x-ray tube, including the major operational parts.

X-rays are more intense on the cathode side of the x-ray tube True or False

True

The cathode filament is made of

Tungsten

anode heel effect

Uneven distribution of radiation intensity in the x-ray beam.

Milliamperage

Unit to measure tube current or number of electrons flowing per unit time

The amount the voltage varies during an x-ray exposure is known as

Voltage Ripple

What does the filament look like?

a coil of wire

The positive side of the x-ray tube is the

anode

Actual focal spot

area on anode target exposed to tube current electrons

Why is the most important part of the x-ray machine?

because the tube is where the x-rays are produced.

The __ is the portion of the x-ray tube that contains the filament

cathode

The ____ is the portion of the x-ray tube that contains the filament

cathode

Characteristic interaction

could be defined as the production of an x-ray photon by a collision between the incident electron and a K-shell electron of the tungsten atom.

Bremsstrahlung interaction

could be defined as the production of an x-ray photon by the electrostatic attraction between the incident electron and the nucleus of the tungsten atom.

The_____ is the source of electrons during x-ray production

filament

Compensating Filtration

filters that are used to compensate for differences in subject radiopacity or to even out widely differing tissue densities

compensating filtration Wedge

filters that are used to compensate for differences in subject radiopacity or to even out widely differing tissue densities

Effective focal spot

focal spot size as measured directly under anode target

The device that nearly surrounds the filament is the

focusing cup

The device that nearly surrounds the filament is the___

focusing cup

total filtration

inherent filtration + added filtration

The focusing cup has a(n) _____ charge.

negative

The target is the part of the anode that is struck by_____ the opportunity for the production of x-rays.

the focused stream of electrons coming from the cathode. The target stops the electrons and creates

Thicker part of filter lined up with___ part allowing more even exposure to the image receptor.

thinner

Line Focus Principle

used to reduce the effective area of the focal spot

´Double the mA will double the number of____ produced.

x-ray photons

Objectives (1 of 2)

´Describe construction of an x-ray tube. ´State the function of each component of an x-ray tube. ´Describe how x-rays are produced. ´Explain the role of the primary exposure factors in determining the quality and quantity of x-rays. Explain the line focus principle.

Objectives (2 of 2)

´State how the anode heel effect can be used in radiography. ´Differentiate among the types of filtrations and explain their purpose. ´Calculate heat units. ´Recognize how changing generator output, kVp, mA, and filtration affect the x-ray emission spectrum. ´List the guidelines followed to extend the life of an x-ray tube.