Xray - Outcome 3

Question 1

3 primary components of the x-ray unit

Answer 1

1. Tube Head - from which the Xrays are generated
2. Extension Arm - allows positioning of the tube head
3. Control Panel - contains the regulating devices

Question 2

Tube Head

Answer 2

The tube head is the housing that contains the x-ray tube. This is where x-radiation is generated. It consists of various components

The tube head is made of metal and lined with lead to protect the actual X-ray tube and to prevent the escape of radiation in any direction except toward the position indicating device (P.I.D.)

Question 3

Extension Arm

Answer 3

The extension arm is wall-mounted. It is hollow to allow the passage of electrical wires from the control panel to the x-ray tube head. It folds up and can be swiveled from side to side, allowing positioning of the tube head

Question 4

Control Panel

Answer 4

The control panel is mounted on the wall where it is electrically connected. The control panel consists of the indicator lights and activation buttons such as the ready lamp, tooth selection, and exposure times

Question 5

Volt

Answer 5

The volt is the unit used to measure electrical potential or work capacity. Because dental x-ray equipment operates at very high voltages, it is customary to express voltage in terms of kilovolts

(1 kV = 1000 volts). The abbreviation is kV.

Question 6

What is Kilovolt Peak?

Answer 6

The highest voltage to which the current in the tube rises during exposure is called the kilovolt peak, abbreviated kVp. Thus, if the x-ray machine controls are set at 65,000 volts, the maximum x-ray energy that can be produced during exposure is 65 kVp

Question 7

basic principles of electricity specific to the production of x-radiation..

Answer 7

Electrical current is the flow of electricity through a conductor which is required for the production of x-rays. The electrical current (circuit) is controlled by a transformer. The x-ray tube and transformers are housed in the tube head and one in the control panel (Iannucci & Howerton, 2022). The three transformers are step-down, step-up, and auto transformer.

Question 8

Why are transformers necessary?

Answer 8

The transformers are necessary because the line voltage coming to most dental offices is 110 or 220 volts and the x-ray tube operates at varying voltages. The low-voltage transformer is used to reduce the current to 3-5 volts which is enough to heat the cathode filament and form the electron cloud

Question 9

The high voltage transformer

Answer 9

The high-voltage transformer produces a voltage of 65,000 – 100,000 volts which is necessary to propel the electrons across the tube. The high-voltage current begins to flow when the activator button is depressed. When the voltage is increased, the electrons travel faster and produce the strongest type of radiation

Question 10

What is the purpose of a transformer?

Answer 10

The transformer is used to increase or decrease the electrical current.

Question 11

Step-down transformer is for..

Answer 11

• is used to decrease the voltage to allow for heating of the filament.

Question 12

A step-up transformer is for..

Answer 12

• is used to increase the voltage upon activation accelerating the electrons.

Question 13

A autotransformer is for…

Answer 13

• is used to maintain consistency of the current, to correct fluctuations.

Question 14

What is Constant Potential? (kVcp)

Answer 14

Constant Potential (kVcp) is the maintaining of consistent energy (acceleration) of electrons

Question 15

What will a higher kilovolt peak setting do?

Answer 15

A higher kilovolt peak setting will produce x-rays with greater penetrating power (quality) and therefore, a greater capacity to pass through matter.

Question 16

What is the ampere?

Answer 16

The ampere is the unit of quantity of electric current, or, the number of electrons flowing in an electrical circuit. Only a small current is required to operate the X-ray machine, therefore, the term milliampere (1/1000 of an ampere) is used. The abbreviation is mA

Question 17

What milliampere (mA) do dental xray machines usually operate at?

Answer 17

The majority of dental x-ray machines operate at 10 or 15 mA

Question 18

The milliamperage regulare determines…

Answer 18

The milliamperage regulator determines the number of X-rays produced by controlling the temperature of the tungsten coil. The higher the mA, the hotter the tungsten coil will become, and the greater will be the number of electrons produced in the electron cloud

Question 19

What does the kilovoltage control?

Answer 19

The speed of each electronc

Question 20

What does the milliamperage control?

Answer 20

The number of electrons

Question 21

The timer regulates..

Answer 21

The timer regulates the length of time the current will pass through the X-ray tube, enabling the operator to predetermine the length of the exposure. The amount of time needed to adequately expose the film varies greatly depending on the anatomical feature (density, film speed, and distance to object and source to object distance)

Question 22

The exposure switch

Answer 22

All dental X-ray machines are required to be equipped with an exposure switch of the “deadman” type, which automatically terminates the exposure when the finger ceases to press the timer button. This makes it necessary to maintain firm pressure on the button during the entire exposure

Question 23

Mechanical Reduction of X-radiation - Aluminum Filter

Answer 23

an aluminum filter placed in the path of the primary beam before it leaves the unit. The filter is added in 0.5 mm increments usually to a required thickness of 1.5 – 2.5 mm. Only those x-rays with the shorter wavelengths pass through the filter; through the tissues to expose the film. The filter absorbs most of the longer wavelength rays so that the patient receives only those rays capable of exposing the film

Question 24

Mechanical Reduction of X-radiations - Lead Collimator

Answer 24

The lead collimator collimates or restricts the size of the beam. The collimator is used to restrict the size/shape of the x-ray beam. Collimation of the primary beam reduces patient exposure and increases film quality by reducing the amount of scattered radiation formed. The collimator is a lead disc that threads onto a fitting over the Porte of the tube head housing and shapes the x-ray beam. In the center of the disc is a circular opening through which the X-rays pass. These X-rays comprise the useful beam or the central ray. The size of the useful beam is 2.75 inches in diameter

Question 25

Three Types of Digital Imaging

Answer 25

1. Direct Digital Imaging
2. Indirect Digital Imaging
3. Storage Phosphor Imaging (commonly referred to as indirect digital imaging)

Question 26

Direct Digital Imaging

Answer 26

When using direct digital imaging, a sensor is used in place of a film. This sensor works like an exposed film. Once it is radiated, it must be processed. When the sensor has been struck, the source of radiation is activated producing an electronic charge on the sensor. The electronic charge is digitized and in turn, transmitted to the computer. This image is displayed within seconds. Once the image is captured and transmitted to the computer monitor, the software then enhances and stores the image.

Question 27

Indirect Digital Imaging

Answer 27

A film-based radiograph is required. The radiographs are then scanned or photographed. The recreated image is compromised in quality as it is a copy

Question 28

Storage Phosphor Imaging

Answer 28

Storage phosphor imaging uses a reusable imaging plate instead of a sensor. The phosphor-coated plate is similar to an intensifying screen. After exposure, the plate is electronically processed (scanned with a laser). This system is not as efficient

Question 29

Dental Management Software

Answer 29

Computer software allows the dental radiographer to digitally enhance images. An image may have any of the following features enhanced:

Contrast
Brightness
Image size (zoom)
Sharpness
Inversion (white to black and black to white)
Pseudocolor alteration

Question 31

automatic processor

Answer 31

machine that automates all film processing steps

Question 32

beam alignment device

Answer 32

XPC kit - assists in the positioning of the position indicated device

Question 33

emulsion

Answer 33

coating on the xray film that contains energy sensitive crystals

Question 34

intensifying screen

Answer 34

part inside an extra oral cassette that converts xray energy into visible light, which in turn exposes screen film

Question 35

cassette

Answer 35

contains extraoral films during exposure

Question 36

latent image

Answer 36

invisible image on the xray film after exposure but before processing

Question 37

anode

Answer 37

positive electrode in the xray tube

Question 38

cathode

Answer 38

negative electrode in the xray tube

Question 39

central ray

Answer 39

xrays at the center of the beam

Question 40

contrast

Answer 40

differences in degrees of blackness on an image

Question 41

density

Answer 41

overall darkness or blackness of an image

Question 42

electron

Answer 42

negatively charged particle in the atom

Question 43

image receptor

Answer 43

recording medium for an image, normally film, psp, or digital sensor

Question 44

penumbra

Answer 44

burred or indistinct area that surrounds an image

Question 45

photon

Answer 45

minute (tiny) bundle of pure energy that has no weight or mass

Question 46

quality of xray beam

Answer 46

mean energy or penetrating ability of the xray beam

Question 47

quantity of xray beam

Answer 47

number of xrays produced in the dental unit; the quantity of xrays produced is controlled by the milliamperage

Question 48

secondary radiation

Answer 48

xradiation that is created when the primary beam interacts with matter

Question 49

tungsten target

Answer 49

focal spot in the anode