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Susan

Chapter 38 Radiography

Question	Answer
ALARA concept	Concept of radiation protection that states that all exposures should be kept “as low as reasonably achievable.”
Anode	The positive electrode Consists of a wafer-thin tungsten plate embedded in a solid copper rod Converts electrons into x-ray photons The tungsten target is a focal spot and converts electrons into photons The copper stem dissipates heat away from the t
Atom	The basic unit of matter.
Bremsstrahlung radiation	“Braking radiation.” The sudden deceleration of electrons as they interact with highly positively charged nuclei.
Cathode	The negative electrode Consists of a tungsten wire filament in a cup-shaped holder made of molybdenum Supplies the electrons necessary to generate x-rays The tungsten filament produces electrons when heated The molybdenum cup focuses electrons into a
Central ray	X-rays at the center of the beam.
Contrast	Differences in degrees of blackness on an image.
Control panel	The portion of the x-ray unit that contains the master switch, the indicator light, the selector buttons, and the exposure button.
Density	The overall darkness or blackness of an image.
Dental radiography	The process of recording images of the teeth and adjacent structures by exposure to x-radiation.
Digital imaging	A filmless method of capturing an image and displaying it by using an image receptor, an electronic signal, and a computer to process and store the image.
Distortion	Change in the size of an image caused by incorrect vertical angulation.
Dose of radiation	The amount of energy absorbed by tissues.
Dosimeter	A device used to detect and measure an accumulated dosage of radiation.
Electron	A negatively charged particle in the atom.
Energy	The ability to do work.
Extension arm	Flexible arm that is attached to the x-ray tubehead.
Image	Film-based or digitally produced recordings of anatomic structures.
Image receptor	A recording medium for an image, normally film, phosphor storage plate (PSP), or a digital sensor.
Intensity	The total energy of the x-ray beam.
ion	An electrically charged particle.
ionization	Process by which electrons are removed from atoms, causing the harmful effects of radiation in humans.
ionizing	radiation Radiation that produces ionization, resulting in harmful effects.
Kilovoltage peak (kVp)	Highest voltage of x-ray tube used during an exposure and it is used to control the penetrating power of the x-ray beam It is used to control the penetrating power of the x-ray beam. Dental x-ray machines generally operate at 70 or 90 kVp
Latent period	Time between exposure to ionizing radiation and appearance of symptoms.
Lead apron	Device used to protect the reproductive and blood-forming tissues from scatter radiation.
Magnification	The proportional enlargement of an image.
Master switch, indicator light, selector buttons, exposure button	Components of control panel.
Matter	Anything that occupies space and has form or shape.
Milliampere (mA)	One one-thousandth (1/1000) of an ampere; a unit of measurement used to describe the intensity of an electrical current.
Penumbra	The blurred or indistinct area that surrounds an image.
Personal radiation monitoring badge	A device that measures exposure of personnel to ionizing radiation by measuring the intensity of visible light emitted from a crystal in the detector when heated. The intensity of light emitted is dependent upon the radiation exposure.
Photon	A minute (tiny) bundle of pure energy that has no weight or mass.
Primary beam	The most penetrating beam produced at the target of the anode.
Primary radiation	Same as primary beam.
Quality of x-ray beam	The mean energy or penetrating ability of the x-ray beam.
Quantity of x-ray beam	The number of x-rays produced in the dental unit; the quantity of x-rays produced is controlled by milliamperage.
Radiation	Forms of waves of energy emission through space or material.
Radiograph	Image produced on photosensitive film by exposing the film to radiation and then processing it.
Radiology	The science or study of radiation as used in medicine.
Scatter radiation	A form of secondary radiation that occurs when an x-ray beam has been deflected from its path by interaction with matter.
Secondary radiation	X-radiation that is created when the primary beam interacts with matter.
Sensor	A solid-state image receptor that contains a silicon chip with an electric circuit.
Sharpness	A measure of how well an image reproduces the fine details or outline of an object.
Somatic	effects Effects of radiation that cause illness and are responsible for poor health (such as cancer, leukemia, and cataracts) but are not passed on to offspring.
Thyroid collar	A flexible lead shield that is placed securely around the neck.
Tubehead	The part of the x-ray unit that contains the x-ray tube, the high-voltage and low-voltage transformers, and insulating oil.
Tungsten target	A focal spot in the anode.
X-radiation	High-energy ionizing electromagnetic radiation.
Who discovered x-rays?	Wilhem Conrad Roentgen
Who was the first person to make practical use of x-rays in dentistry?	Edmund Kells
What is ionization?	The production of removing electrons from atoms, creating ions, and causing harmful effects of radiation in humans
What are the primary components of an x-ray machine?	1.Tubehead 2.Extension arm 3.Control panel
Name the negative electrode inside the x-ray tube	Cathode
Name the positive electrode inside the x-ray tube	Anode
What does the control panel contain?	1.Master switch 2.Indicator light 3.Selector buttons 4.Exposure button
abnormality	something abnormal, usually in the body
Cat NAP	Cathode N- Negative A-anode P-positive
Wave concept	Shorter wavelengths have greater energy Because of their energy, short wavelengths can penetrate matter more easily More useful, preferred
Metal housing	Metal body houses the x-ray tube Filled with insulating oil
Tubehead seal	Made of leaded glass or aluminum Keeps the oil in the tubehead, and acts as a filter for the x-ray beam
X-ray tube	Produces x-rays
Transformer	Alters the voltage of incoming electrical current
Aluminum filter/Aluminum disks	aluminum sheet 0.5 mm thick
Lead collimator	A metal disc with a small opening in the center, 2” control the size and shape of the x-ray beam as it leaves the tubehead
Position Indicating Device/PID	the open-ended, lead-lined cylinder extends from the opening of the metal housing used to aim the x-ray beam
A glass vacuum tube	Measures about 6 inches long by 1 inch in diameter Includes: Leaded-glass housing Cathode Anode
Leaded-glass vacuum tube	Prevents x-rays from escaping in all directions One area has a “window” that permits the x-ray beam to exit the tube and directs the beam toward the aluminum disks, lead collimator, and PID
Position indicator device	Lead-lined cylinder Used to aim the tubehead Placed as close as possible to the patient’s face Cylindrical or rectangular 8 inch or 16 inch in length
Exposure Buttons and Selector Buttons	Exposure button controls the flow of electricity to generate the x-rays Exposure time is measured in fractions of a second, called impulses 60 impulses = 1 second; 30 impulses = 0.5 second
Types of radiation	Primary radiation Secondary radiation Scatter radiation
what is Primary radiation ? Types of Radiation	is made up of the x-rays that come from the target of the x-ray tube. Primary radiation is often referred to as the useful beam
What is Secondary radiation? Types of Radiation	X-Radiation that is created when the primary beam interacts with matter it is less penetrating than primary radiation and also not useful radiation because it produces fog on the radiograph, damaging the diagnostic quality.
What is Scatter radiation? Types of Radiation	is a form of secondary radiation that occurs when an x-ray beam has been deflected from its path through interaction with matter. it is deflected in all directions by patient tissues and travels to all parts of the patient’s body and to all areas of the d
IMAGE CHARACTERISTICS	IS A TERM USED TO DESCRIBE WHAT OBJECTS LOOK LIKE IN A RADIOGRAPHIC IMAGE.
What is Radiolucent structures?	Body structures that radiation Can Easily pass through appear radiolucent (dark) on an image. For example, air spaces, soft tissues, abscesses, tooth decay, and dental pulp appear
What is Radiopaque structures ?	Body structures that radiation Does Not easily pass through appear radiopaque (white or light gray) on an image For example, tooth enamel, dense areas of bone, and metal restorations
RADIOLUCENT	OBJECT THAT ALLOW X-RAYS TO PASS THROUGH. IMAGE APPEARS DARK.
RADIOPAQUE	DOES NOT ALLOW X-RAYS TO PASS THROUGH. IMAGE APPEARS LIGHT.
Three characteristics of the x-ray beam.	1-quality, 2- quantity, 3- intensity this alow us to change the image of the radiopaque and the image detail as well
DIAGNOSTIC QUALITY IMAGES	DIAGNOSTIC QUALITY IMAGES ALLOW THE DENTIST TO LOOK AT A RADIOGRAPHIC IMAGE AND BE ABLE TO TELL WHAT EVERYTHING IS IN THE IMAGE AND BE ABLE TO MAKE AN ACCURATE DIAGNOSIS.
These characteristics determine the contrast, density, and image detail	the qualities necessary for a good image
Predetermined settings	Old machines adjusted manually
What is quality?	QUALITY IS PENETRATING ABILITY, OR STRENGTH, OR POWER. HOW STRONG IS YOUR BEAM IS DETERMINED BY KV.
What are the controlled of The quality or wavelength and energy of the x-ray beam?	They are controlled by kilovoltage. HIGH KILOVOLTAGE = HIGH POWER, STRENGTH, POWER, MORE ENEGRY 85-100 kV produces more penetrating x-rays, more energy, shorter wavelengths 65-75 kV produces less penetrating x-rays, less energy, longer wavelengths
when do you need to use A higher kilovoltage?	It should be used when the area to be examined is dense or thick
WHAT IS IMGE DENSITY ?	IT IS HOW DARK IS YOUR IMAGE. A DENSE IMAGE IS VERY DARK. AN IMAGE THAT LACKS DENSITY IS TOO LIGHT. The image Too Dark because the quality of the beam too high The image Too Light because the quality of the beam too low
What is the number of mA use In dental radiography?	the use of 7 to 15 mA is required; a setting above 15 mA is not recommended because it would cause excessive heat production in the x-ray tube.
what is the different between quality and quanlity?	Kv = quaLity mA=Quanlity
What is Intensity?	It is Combination of quantity of photons and quality of photon energy
What is thh intensity of the x-ray beam is affected ?	Affected by number of factors: Kilovoltage peak Milliamperage Exposure time Distance
What is contrast?	The image on a radiograph appears in a range of shades from black to white with multiple shades of grayg. This range is referred to as the gray scale Referred to as grey scale
what is HIGH CONTRAST?	HIGH CONTRAST... DARKER BLACK AND LIGHTER WHITE, FEWER SHADES INBETWEEN. HIGH CONTRAST, SHORT SCALE CONTRAST.HIGHER KVP
what is LOWER CONTRAST?	LOWER CONTRAST.. BLACK ISN'T AS DARK, WHITE ISN'T AS LIGHT, MORE SHADES OF GREY BETWEEN. LOW CONTRAST, LONG GREY SCALE. LOWER KVP
what is the good CONTRAST for image ?	medium of high and lower contrast
what is a high number of HIGH CONTRAST?	90 kVp setting Requires less exposure time Image low contrast More shades of gray
what is a lower number LOWER CONTRAST?	70 kVp Requires more exposure time Image high contrast Fewer shades of gray
What is the density image?	is the overall blackness or darkness of a film. An image with the correct density enables the dentist to view black areas (air spaces), white areas (enamel, dentin, and bone), and gray areas (soft tissues).
What is controlled the degree of density?	The degree of density is controlled by the milliampere seconds (mAs).
what is Correct density enables the dentist to view?	Black areas (air spaces, pulp chamber, abscesses) White areas (enamel, dentin, bone) Grey areas (soft tissues)
what are Three geometric characteristics affect image quality?	Sharpness Distortion: Magnification
what is Sharpness?	-How well an image reproduces fine detail -Detail, sharpness, or definition -Penumbra
what is Penumbra?(important)	Fuzzy or blurred area surrounding an image
The sharpness of an image is influenced by the following factors.what is Influencing factors?	Focal spot size Smaller focal spot results in a sharper image Film composition Fast film speed results in less sharp detail Movement Slightest movement of patient, receptor, or PID
What the fuzzy or blurred area that surrounds an image is called?	is called penumbra
what is Distortion?	refers to the disproportionate change in the size of images that is caused by excessive or insufficient vertical angulation
WHat is Magnification?	refers to the proportionate enlargement of a dental image.
Name the types of Radiation.	Primary Radiation Secondary Radiation Scatter Radiation
Describe the difference between radiopaque and radiolucent.	Radiopaque does not allow passage of x-rays, images appear white/light Radiolucent does allow passage of x-rays, images appear black/dark
Give examples of structures that appear radiolucent on a radiograph.	Air space, soft tissues, cavities, abscesses, dental pulp
Give examples of structures that appear radiopaque on a radiograph.	Restorations, enamel, dense bone
What are the three characteristics of the x-ray beam?	Quality Quantity Intensity
Which exposure factor controls contrast?	Kilovoltage
What is meant by density on a dental radiograph?	The overall darkness or blackness of a film
Radiation effects	All ionizing radiation is harmful and produces biologic changes in living tissue Dental imaging is a low amount, however still harmful Entire x-ray area is a radiation hazard area Proper signage is required
ionizing radiation	All ionizing radiation is harmful and produces biologic changes in living tissue Dental imaging is a low amount, however still harmful Entire x-ray area is a radiation hazard area Proper signage is required
Tissue damage	Not all x-rays pass through the patient and reach the receptor Patient tissues absorb some x-rays When photon energy is absorbed, chemical changes result in biologic damage
ionization	Results in the harmful effects of x-rays in humans Can cause disruption of cellular metabolism and permanent damage to living cells and tissues Atoms that lose electrons become positive ions Unstable structures capable of interacting with and damaging
Biologic effects	Exposure can bring changes in body chemicals, cells, tissues, and organs Effects of radiation may not become evident for many years after absorption This is the latent period
Cumulative effects	Exposure to radiation has cumulative effect over a lifetime When tissues are exposed, some damage occurs Tissues can repair some damage, tissues do not return to their original state Cumulative effects of radiation can be compared with the cumulative e

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