Bushong Chapter 5 & 6

The high-voltage generator contains three primary parts:

1. High-voltage transformer 2. Filament Transformer 3. Rectifiers

What are the 3 parts that the external x-ray tube consists of?

1. Support structure 2. Protective housing 3. Glass or metal enclosure

Manufactures must provide tubes that leak no more than _____ mR/hr at ____ meter

100; 1

Transformer only operates off what current?

AC (alternating current)

What measures the quantity of radiation that reaches the image receptor?

AEC

The area of the target exposed to the electrons from the cathode

Actual Focal Spot

What is mA measured in ?

Amperes

Carries a postive charge?

Anode

What voltage type is not allowed to swing negatively ?

Half-wave rectification

An electrical power transformer that converts 220 - 250 volts AC current to high voltage

High-Voltage generator

What steps up voltage supplied by power company?

High-voltage generators

What "fine tunes" the selected technique?

Minor kVp adjustment

How many percent of electrons kinetic energy, from the cathode, becomes heat when it interacts with the anode?

More than 99%

What serves as an insulator against shock and as a thermal cushion to dissipate heat?

Oil

Allows adjustments of tube current (mA) and voltage (kVp)

Operating console

The product of voltage and current is known as?

Power

What is the position of the x-ray tube in when it is centered above the examination table at the standard SID?

Preferred Detent

What conducts the input power to the autotransformer?

Primary Connections

Where is the location of the Line compensation?

Primary side of the x-ray circuit

What is the location of Line compensation?

Primary side of x-ray circuit

What guards against excessive radiation exposure and electric shock?

Protective housing

Transfer of heat by the emission of inferred energy

Radiation

What is most important because in conveys which radiographic techniques are safe and which techniques are unsafe for x-ray tube operation?

Radiographic rating chart

The process of changing alternating current and voltage into direct current and voltage is known as?

Rectification

What monitors the voltage before the exposure?

Rereading voltmeter

What type of anode is used when high-intensity x-ray beams with a short time are needed (general purposed x-ray tubes)?

Rotating

Filament current that has risen to its maximum value because all available electrons have been used.

Saturation Current

What is located closer to middle of winding allows for a decrease in voltage?

Secondary Connection E

What is located closed to the end of the winding which allows for increase in voltage?

Secondary connection C

Have holes where there are no electrons

p-type

What is the process of converting AC to DC?

rectification

Excessive heat for a long period of time?

tungsten evaporation

What is the number one reason the tube usually over heats?

tungsten evaportaion

An electrical device that contains 2 electrodes, which is known as a

Diode

Area projected onto the patient and image receptor

Effective Focal Spot

What is the Autotransformers principle of operation?

Electromagnetic Self Induction

What timer is the most accurate?

Electronic Timer

What is the most accurate timer?

Electronic timer

What is the main advantage of full-wave rectification?

Exposure time for any technique is cut in half

What tells the x-ray tube how long to emit x-rays?

Exposure timers

X-ray tube current is controlled through a separate circuit called the

Filament Circuit

What is a step-down transformer?

Filament Transformer

What is mA controlled by?

Filament temperature

Has a single column with rollers at each end, one attached to the a ceiling mounted rail and the other to a floor mounted rail

Floor-to-ceiling support

What is the actual x-ray source?

Focal Spot

What is the area of the target from which x-rays are emitted therefore this makes the _______ _______ the source of radiation in the x-ray tube

Focal Spot

Condense electron beam to a small area on the anode (focal spot)

Focusing Cup

What rectifies the entire AC wave into unstable output?

Full-Wave Rectification

Loosely bound electrons that are free to move

n-type

What are two types of semi-conductors?

n-type and p-type

What are most x-ray table tops made of?

Carbon Fiber

Carries a negative charge?

Cathode

What are the 2 electrodes that the glass envelope contains?

Cathode, Anode

Tube current goes to ______ to the ____

Cathode, anode

Most frequently used it consist of 2 perpendicular sets of ceiling-mounted rails; allows longitudinal and transverse travel of the x-ray tube.

Ceiling support

The transfer of energy from one area of an object to another

Conduction

The transfer of heat by the movement of a heated substance from one place to another

Convection

What is the importance of the 1.5 sec backup time in AEC?

Terminates the exposure in case the AEC fails

What x-ray imaging system is first to receive power?

The Autotransformer

What are fluoroscopic tables identified by?

Their degree of tilt

What is the release of electrons form a heated filament?

Thermionic emission

X-rays systems are usually operated at voltages of ____ and at tuber currents of _______

25-150 kVp; 100to 1200 mA

What is the range of filament current?

3 to 6 amps

What happens to the effective size as the target angle decrease?

As the target angle, decreases, so does the effective focal spot size

What measures the quantity of radiation that reaches the image receptor; x-ray exposure automatically terminates when optical density is reached; reduces the number of repeats- no guessing at tissue thickness or patient abnormalities

Automatic Exposure Control (AEC)

A type of transformer having a single winding is known as the

Autotransformer

What has a single winding and is designed to supply a precise voltage to the filament circuit and the high-voltage circuit of the x-ray imaging system

Autotransformer

When you set kVp what are you setting?

Autotransformer

Shaped like a "C", this is ceiling mounted with the image receptor attached to the other end of the C-arm from the x-ray tube.

C-Arm support

kVp is expressed in ?

Kilovolt peak or half-value layer

What are the type of rectifiers that are used in todays imaging equipment?

Solid-state rectifies

Electron cloud near the filament

Space charge

What type of anode is used when high tube current and power are not required (dental, portable)

Stationary

What are two types of anode?

Stationary and rotating

Filament transformer is a what transformer?

Step-down transformer

What is the area of the anode where electrons strike?

Target

What is the purpose of the x-ray imaging system?

To provide a control flow of electrons intense enough to produce an x-ray beam appropriate for imaging

A vacuum tube that produces x-rays?

X-ray Tube

Most table tops are ______ and are made of ______

floating ; carbon fiber

Quality is

kVp

What determines the quality of the x-ray beam?

kVp

What is penetrating power?

kVp

Quantity is

mA

What is called the tube current?

mA

What timer gives highest safe tube current for shortest period of time?

mAs

What does the x-ray come out of?

window