Allows adjustment to the incoming line voltage to an appropriate operating level for the system.

Consists of a single winding which is common to both primary and secondary circuits.

This can be a step-up or step-down transformer

Adjustment requires making a physical electrical connection to an end terminal point based on an average level of incoming voltage.

Used to determine proper voltage levels to the system and monitor any compensation adjustments that need to be made by the operator prior to use

Adjustment provides minor changes of the incoming line voltage.

Done manually at the operator console OR automatically by the system circuit.

Once the auto-transformer is energized, it becomes the voltage source for ____ and ____

A step-up transformer which is used to create the kVoltage necessary for x-ray production.

Used to measure the primary voltage.

Is connected across the primary.

Located in the Oil filled tank

Not located in the Oil filled tank

voltage potential across the primary winding of the filament transformer will be around 100-220Vac, with a turn ratio of 20:1. Secondary voltage is reduced to ___ Vac and the appropriate Amperage

voltage potential across the primary winding of the filament transformer will be around 100-220Vac, with a turn ratio of 20:1. Secondary voltage is reduced to the appropriate voltage and ___ Ampere range

Filament current has to be high enough to ensure ____ occurs at the x-ray tube.

Located in the Oil filled tank

Located in the Oil filled tank

Full wave rectifiers operating with single phase power supply contain ____ rectifying diodes

Full wave rectifiers operating with three phase power supply contain ____ rectifying diodes

Principles of transformers: the voltage in 2 circuits is proportional to the numbers of turns in the two coils.

Principles of transformers: A transformer cannot create energy

Principles of transformers: The product of voltage and current is power

Three different input line phases that are applied to the primary are ___ out of phase with each other

If the input voltage is applied to a Delta-Wye (unmatched), the output voltage will have a ___ degree shift in the phase between the primary and secondary. This phase shift is critical in the twelve pulse transformer

Having 100% ripple means that the voltage in the tube drops to ___ at certain points. The X-Rays produced when the voltage is at [same] are of little value bc of their low penetrability.

Having 3 distinct sets of secondary wave-forms 120-deg apart from each other and then fully rectified will create a 6-pulse per cycle (360/sec) with ___ ripple

The secondary is set up with both types of windings. The Secondary-Unmatched Delta-Wye creates an additional phase shift of ___ between the two.

Due to the ___ shift, a total of 12 pulses/cycle (720 pulses/sec) of DC was produced from the rectifier.

A 12-pulse generator produces an output waveform with only ___ % ripple. This makes the 12-pulse system more desirable bc of the constant DC potential.

By altering the incoming 60HZ electrical circuit, the rest of the circuit will produce a nearly constant DC voltage wave form with extremely low ripple, ___

Energy that comes from a source and travels through space at the speed of light.

Can come from unstable atoms that undergo radioactive decay or it can be produced by machines.

Has enough energy to move atoms around or cause them to vibrate, but not enough to remove electrons from atoms.

ie: Radio waves, microwaves, infrared waves, and visible light

Any type of particulate radiation or electromagnetic radiation that carries so much energy it can remove electrons from atoms of materials that include air, water, and living tissue.

the spontaneous disintegration of the nucleus of an unstable atom resulting in the release of energy and matter in the form of ionizing radiation.

Involves fast moving particles of electrons, neutrons, and protons that have both high energy and mass.

Produced during the decay of an unstable atom including Alpha particles and Beta particles.

Consist of two protons and two neutrons tightly bound together.

Form of radiation with high-ionizing energy arising from the charge of the two protons.

Positive charge, slow speed, high mass = they interact more readily with matter

Slow speed: 9000-20000 miles per second

Can travel about 5cm in air

High energy, high speed electrons

Electrons are ejected from the nucleus during radioactive decay

High speed: 100,000 to 186,000 miles per second.

Travel 10-100 cm in air.

energy in the form of oscillating waves of electric and magnetic fields which travel at right angles to each other.

Travels at 186,000 miles per second (speed of light).

Most highly penetrating type of naturally occurring ionizing radiation.

Weightless packets of pure energy called photons are emitted by the nucleus of radio-nuclides as a result of radioactive decay.

Photon of pure energy.

Generally lower in energy and less penetrating.

Two categories: Soft and Hard

3 conditions to produce:

1. Source of free electrons
2. Means of accelerating those electrons to extreme speeds.
3. Means of quickly decelerating the electrons.

energies of 100eV-5keV

energies of 5keV-10keV

More useful for radiography because they pass through tissue

X-ray spectrum for diagnostic radiography purposes has an energy

Braking radiation or decelerating radiation accounting for the vast majority of the overall x-ray type produced.

Responsible for the diverse quality of the X-ray beam

a.k.a. collisional radiation.

Makes up a small portion of the overall x-ray beam.

High energy => X-rays are important

x-rays are absorbed (attenuated) in the body and exit at some lower energy. The exiting beam is what forms the latent x-ray

to additional forms of radiation are produced: scatter and secondary radiation.

The interactions that of the greatest importance in diagnostic radiology are:

X-ray photon is completely absorbed by an orbital electron in the innermost shell. Atom ejects the inner shell. Electrons shift to fill vacancy by emitting radiation.

Secondary radiation

Contributes to image contrast and the final X-ray image formation.

X-ray photon collides with a loosely bound outer-shell electron, ejecting it from its orbit. The X-ray photon then proceeds in a different direction or angle at a lower energy state as a scattered photon.

Compton effect becomes a main source of

Does not contribute to image contrast but instead reduces image quality

X-rays are:

Effects of ionization:

Effects of ionization: Photographic film

Effects of ionization: Phosphor screens

Effects of ionization: gas filled radiation detectors

Effects of ionization: solid state radiation detectors

Amount of radiation traveling though the air

No direct equivalent or Standard International Unit

Measurement of the radiation absorbed by material or tissue

Measurement of the biological effect of the absorbed radiation

Absorbed Dose = Gray (Gy)

Dose Equivalent = Sievert (Sv)

1 Gy =

Occupational exposure (whole body)

Embryo - Fetus Exposure (Monthly)

As low as reasonably possible

Overall responsibility for handling the program falls on ___

Doubling the distance reduces intensity of the x-ray beam by a factor of four

Film badges

Thermo-luminescent

Electronic

If a woman in the exposure area becomes pregnant they must notify their supervisor ___

Residual effects of exposure

(Repaired damage : Permanent damage)

Regulations require that leakage from tube housing not exceed 1 mGy/h as measured at ____ from the x-ray tube with an ion chamber

C-arm flouroscopy requires x-ray tube to be positioned below PT to reduce exposure to ___

Eyes and tyhroid greatly reduced. No effect on gonads

Walls must be designed to provide adequate protection to at least ___ feet high

outside walls with an unoccupied area of at least ___ does not require any lead

Solid mechanical support

Lead-lined metal

High voltage receptacles

Dielectric oil filled for isolation

Expandable gasket

Cooling fans

Made of pyrex.

Window/port is a slightly thinned area.

Vacuum condition inside of insert

Provides a focused free electron cloud.

Conducts the high voltage to the gap between C+A.

Coiled tungsten wire

Two filaments embedded in pits

Thermionic emission

Focusing cup

occurs when current flows through a filament which heats it up to a minimum of 2000degC

Electrical conductor

Thermal conductor - 99.8% of kinetic E of electron beam is converted to heat

Source of x-ray photons

EM is formed by the parts of the rotating anode assembly and a stator.

Major adjustment accomplished by the BMET which is typically done during initial installation of the system

Minor adjustment accomplished by the operator or automatically by the system.

Set for proper operating voltage prior to initiating an exposure.

indicates the voltage to be applied across the x-ray tube

Means of physically starting and stopping the exposure

Controls power to the x-ray

develops kV potential necessary for the s-ray tube to accelerate the electrons to the speed required to produce x-ray

Measures the current which actually flows across the s-ray tube.

Set up in series

Anode and Cathode cable lengths should not differ by more than ___ feet

electron stream's kinetic energy is converted to bremsstrahlung and characteristic radiation: x-ray

converted to another form of radiation: heat

Factors that directly affect x-ray quantity

Factors that directly affect x-ray quantity

Factors that directly affect x-ray quality

Keep mA constant throughout varying kVp during exposures

Device added to the filament circuit that automatically lowers the filament current as the kV is increased => keeps the mA constant

Keep KVP constant throughout the varying mA during exposures

Overheating of the dielectric oil filled tube housing may cause the expansion bellows to rupture allowing the oil to leak out.

Most common type of failure

Overtime, could cause arching

Caused by no warm up, or maintaining an elevated temperature for a long period of time

Modern x-ray systems automatically lock-out and prevent any ___

Calculation of "x-ray heat units" depends on

Heat production: 6-pulse formula

Heat production: 12-pulse formula

Factors that control the density of the dental x-ray image

Image to show the entire length of each tooth.

Used to detect any unusual changes in the root and surrounding bone structure.

Images the crowns of the posterior teeth

Used to reveal cavities, restorations, calculus

Images entire arch of teeth in either the upper or lower jaw.

Used to reveal impacted teeth, foreign bodies in the jaws, stones, fractures

Shows entire mouth area.

Does not show level of detail as with intra-oral image

Used primarily for orthodontic treatment planning.

x-ray tube

collimator

tube stand

hand-switch

flat panel detector

viewing monitor

motor driven base unit

Imaging system

Generator

Workstation

Devastating internal

Most penetrating

Angulation scale of the dental x-ray system