RAD 202 Chapter 5 Test 4

When discussing the rotating anode's target area, the term _______ _______ is used to represent the circular path that is impacted by the electron beam.

focal track

The focusing cup's purpose is to narrow the _______________ as its driven toward the anode.

electrons

The filament is a small coil of thoriated _______________ wire.

tungsten

Radiation intensity is greater on the cathode side can be termed __________ _____ __________.

anode heel effect

Where the primary beam exits the glass/ metal envelope can be termed the _____________.

window

Electromagnets that turn the anode are called the __________.

stator

X-rays that are not produced at the focal spot are called _____-_________ ______________.

off-focus radiation

______-_________ _____________ is used to reduce the effective focal spot area.

Line-focus principle

The ________________ ______ focuses the electrons toward one another in a convergence pattern.

focusing cup

The length and width of the _____________ have a great effect on the x-ray tubes ability to image fine details.

filament

The precise point where x-rays are created is called the ______ _______.

focal spot

The rectification constant for a high-frequency generator is ________.

1.40

The rectification constant for a single-phase generator is _________.

1.00

Electrons run into the __________ and are converted into heat and radiant energy.

anode

Radiant energy is known as _________.

x-rays

The source of elections are where ________________ are produced. This can be found on the _____________ filament wires.

electrons; cathode

What are the 4 things needed to produce an x-ray?

1. Source of electrons

2. Target

3. High-voltage

4. Vacuum

Where is the target located?

located on the anode side

The anode is shaped ____________ and electrons _____ into it.

round; run

What does it mean when it says x-rays are air-evacuated vacuums?

It means that all the air has been taken out of the vacuum to make sure no electrons interact with air molecules.

The high-voltage ________________ the electrons from the cathode to the anode.

pushes

The rotors job is to _______ the anode during an ______________.

turn; exposure

The __________ is the only part of the x-ray tube that is not inside the glass envelope.

stator

There are __ filament wires in the tube. What sizes are they?

2; Big and small

The _________ is sent to the stator (electromagnets) which causes them to have lines of force and _________ inductions induces the _______ to turn the anode.

current; mutual; rotor

True or false: The vacuum is not air-evacuated.

False

True or false: The filament wires are different sizes and they have different diameters.

True

In order to get the best detail/spatial resolution you will want to have a _______ focal spot and a _______ filament wire.

small; small

Coiled tungsten wire helix is called a _____________.

filament

Tubes that have 2 filament wires located in them are called a _______ focused tube.

dual

The focusing _____ goes around 2 wires and focuses electrons to hit the anode.

cup

Why is the focusing cup important in herding all the electrons?

The electrons all have negative charges therefore they are going to repel each other and want to get as far away as possible

If the mA is 100 and below than the __________ wire and focal spot will be used.

small

200 mA and above the ___________ wire will be used and a focal spot.

large

Why is tungsten selected to be a filament material?

Tungsten has a high melting point and it is difficult to vaporize.

_____________ and ___________________ are also good choices to be filament material.

Rhenium and molybdenum

____________________ _____________ is the process of heating up electrons and causing them to be released from the filament.

Thermionic emission

Tube ____________ can be cause when vaporized tungsten is collected in the envelope.

arcing

Most modern x-ray tubes will last between _____________ - ____________ exposures

10,000 - 20,000

What is the focusing cup composed of?

Nickel

The focusing cup is located ___________ of the wires.

outside

___________________ current can be described as too many electrons going to the anode.

Saturation

Space charge effect __________ exposures to 1,000 - 1,200

limits

True or false: The Grid-Biased tubes permit very short, rapid sequencing of exposures

True

The anode assembly has ____ functions. What are they?

3; target surface; conducts high voltage; primary thermal conductor

How does the anode assembly serve as a primary thermal conductor?

The anode will turn/rotate and conducts heat while moving because the electrons are hitting the focal spot.

What are the 3 components in the anode assembly?

anode, stator, and rotor

What is the rotating anode made out of (front part of anode)?

Tungsten-rhenium alloy

What is the back part of the anode made out of?

molybdenum and/or graphite

The anode layering assists with ______ loading and the back part can act as a "heat-sink" this ___________ x-ray tube thermal capacity.

heat; increase

Why is the warm-up procedure important?

It gradually warms up the anode to prevent cracking. Helps maintain an air-evacuated vacuum

What exactly is a warm-up procedure?

There might be a certain set low mA and a low kVp and a long exposure time to gradually warm up the anode.

The low mA for the warm up procedure can range ___-______

The low kVp for the warm up procedure can range ___-____

The long exposure time for the warm up procedure is ____ seconds

50-100; 60-70; 2

True or false: The warm up procedure techniques can range from each manufacturer.

True

The target area can be referred to as a _________, _______, focal ________, focal ______, and focal ________

target; focus; point; spot; track

The rotating anode can range from _______ - ________ revolutions per minute (rpm) to _________ - _________ rpm.

3,200 - 3,600

10,000 - 12,000

The actual focal spot is found on the ________ and is the physical area of the focal track being hit by the _________.

anode; electrons

The effective focal spot is the ____________ area of the beam.

projected

The effective focal spot is controlled by the actual focal spot ________ and the target ________.

size; angle

The effective focal spot is found on the ____________ and can be seen by the tech.

patient

_______-_________ ____________ is the relationship of the actual and the effective focal spot.

line-focus principle

The effective focal spot is _______ than the actual focal spot.

smaller

Even though the actual focal spot is a rectangle due to the _________ on the anode the effective focal spot looks like a box.

angle

True or false: If there is a small angle the effective focal spot will be small, if there is a large angle the effective focal spot will be bigger.

True

Which of the following anode angles will produce the smallest effective focal spot?

-12 degrees

-7 degrees

-24 degrees

-60 degrees

7 degrees

Due to the anode heel effect the x-ray beam will be more intense under the _____________ side.

cathode

How much can the beam intensity vary from the cathode to the anode side based on the anode heel effect?

45 degrees

The stator is located on the _______________ of the envelope.

outside

The ________ induces the rotor to turn the anode through mutual induction

stator

The rotor is located _________ the glass envelope.

inside

True or false: Anode rotations can be standard speed or high speed.

True

What is the rpm for standard speed rotating anode?

3,200 - 3,600

What is the rpm for the high speed rotating anodes?

10,000- 12,000

True or false: you should handle the x-ray tube with rough, fast movement during a high speed rotation. Why?

False, you could cause breaking within the x-ray tube since it does have fragile parts

What are the 2 functions of the glass envelope?

1. support the anode/cathode assemblies

2. maintain a vacuum

True or false: The tube window is an area where the x-ray beam exits to the IR.

True

The protective ___________ controls leakage and scatter radiation

housing

True or false: the protective housing is lead line in order to absorb leakage and scatter radiation.

True

The protective housing has a cooling _____ around the tube and cooling _____.

oil; fans

The amount of leakage radiation limit is __ milliGray per hour at 1 meter or _____ milliroengtens

1; 100

True or false: Off focus radiation occurs when x-rays are produced in the tube, but not at the actual focal spot on the anode.

True

Can you get rid of off-focus radiation?

No you can only reduce it

How can you reduce off-focus radiation?

You can reduce by collimating down the upper shutters in the collimator box

Off-focus radiation has ____ energy and is of ___ diagnostic value

low; no

What is the formula or calculation of heat units?

kVp x mAs x time x recification constant

What is the calculation of heat units measured for?

Measures how much heat the tube can take during an exposure