Test 3 Ch 7,8,9 Flashcards
3 types of IR systems
Film
CR
DR
4 requirements to produce an X-ray:
Vacuum (tube housing)
Source of electrons (filament)
Accelerate electrons (voltage)
Stop electrons (target)
The beam of photons before it interacts with the patients body is called
Primary radiation
Invisible image created after exposure before processing
Latent image
Relationship of radiation intensity and distance from source of radiation
Inverse square law
The resulting beam that is able to exit from the patient is called
Remnant Radiation
The difference in ____________ allows for the formation of radiographs. As radiation is absorbed differently in different tissues of the body
Attenuation
Which bone structure would be radiopaque ?
Radiolucent?
Bones
Air, superficial tissues
Exposure factors that determine the quality of the image
mAs
KVP
SID
OID
DR has a scintillator typically made of what …. that will convert electrons one n stored in the TFT
Amorphous selenium (a-Se)
The ________ determines the individual size of each pixel.
Resolution
Indirect capture consists of a two step process:
X-ray photons converted to light using the scintillator and then -converted to electric signal
4 factors affecting image quality
Contrast
Density
Resolution
Distortion
The X-ray beam is described as
Polyenergetic or heterogeneous
The anode and cathode are what charges?
Cathode = negative Anode= positive
Form of X-ray beam collocation of field size that ensures the X-ray exposure field is no larger than receptor size
PBL
Positive beam limitation
The process of “coning down” indicates what?
Increased collimation
In the cathode, As temperature increases and electrons start “boiling off” through a process called???
Thermionic emission
The X-ray tube is made of
Pyrex glass
To withstand extreme amount of heat
X-ray tabletops are:
Radiolucent
The power of the X-ray system(the generator) is expressed in
Kilowatts
Although it is recommended to prep the X-ray tube, repeated prepping of the tube can..
Damage the tube and shorten its lifespan!
The most sophisticated and desired tube system?
OTC systems
What does it mean when the imaging plate needs conditioning ?
Needs an intense white light source to clear the image
Multiple views; 60 images sweep the patient in one breath hold
Tomosynthesis
Two basic sources of ionizing radiation:
Natural and man made
Natural ionizing radiation are
Man made radiation consists of
Uranium sun, and radium, (radon)
Stemming from sewers
Smoke detectors
Radionuclides
X-rays interact with matter in 5 ways!
Classic coherent Photoelectric Compton scattering Pair production Photodisintegration
The two interactions of X-rays with matter that directly influence patients and workers
Compton scattering -effecting workers
Photoelectric -effecting patients
coherent scattering is also known as
Thompson, classical
X-rays that change direction are known as:
Scattering
In Pair production, a minimum of _______ of energy must occur. Important in radiation therapy
1.02 MeV
Phitodisintegration occurs in the nuclear field but not in diagnostic radiography. X-ray photon energy must at least be —
10 MeV
1Sv=
1 Gy=
100 rem
100 Rad
Annual occupational exposure dose
Cumulative occupational exposure dose
50mSv
10mSv x age
The reproductive cells of an organism
Reproduce through meiosis
Germ cells
All types of cells and carry all 46 chromosomes n perform all body’s functions
Somatic cells
Early effects of radiation exposure include 3 effects; the first effect is:
Prodromal stage
NVD-nausea committing diarrhea
The second stage includes
The latent period;
Feel fine, body is biologically changing
The last stage is the manifest stage which is:
Where the patient feels full effects of exposure
Leading to recovery or death
The late effects occur after a long period of time and include 2 groups which are:
Somatic effects -results in patient who was exposed
Genetic effects -generations later are effected by the exposure
3 protective principles in protecting the patient from overexposure
Time
Distance
Shielding
It is recommended that during flouro procedures, lead aprons should have how much lead equivalency
0.5 at least
The most common dosimeter is the
OSL
