review of all tests Flashcards
the physical area of a rotating anode focal track, affected by the cathode electron beam is the
actual focal spot
the two types of anodes
rotating, stationary
what type of anode is typically used in dental radiography
stationary
what type of anode is best at dissipating heat
rotating
as the actual focal spot size increases, the effective focal spot size
increases
as the angle of the anode increases and the incident electron beam size remains the same, the effective focal spot size
increases
the area of the focal spot that is projected out of the tube toward the object being radiographed is the
effective focal spot
the exact point on the anode where the x ray beam is created is called the
focal spot
the actual focal spot is controlled by the
length of the filament
the most common range of diagnostic radiography target angle is between ___ degrees
12-17
in order to control motion when taking a radiograph, what focal spot size should be chosen so a lower time can be utilized
large
When radiographing a wedge - shaped anatomical structure such as a femur or foot the thicker portion of the anatomy should be positioned
under the cathode end of the tube
which theory states that when tube angles are less than 45 degrees , the effective focal spot is smaller than the actual focal spot
line focus principle
what is the percentage of heat produced in the production of x-rays
99%
the factors that directly affect x ray quality are
kVp & beam filtration
The factors that directly affect x-ray quantity are
mA, time, filtration
The product of the x-ray tube current and exposure time is equal to
x-ray beam quantity
as the mAs doubles, the number of electrons flowing from cathode to anode
increase times 2
mAs doesn’t directly affect
beam quality
3 prime factors that are under the direct control of the radiographer
kVp, mAs, distance
is how light or dark an image appears on the computer monitor
brightness
size bloom can be described as
an increase in the focal spot size
When a machine is described as “dual focus” this mean that
there are two filament lengths
when performing exams where a heavy heat load will be used what focal spot size should be chosen
large
which focal spot size should be used on an extremity exam, such as a hand
small
penumbra or “ghosting of an image is a result of
off focus radiation
The exposure of the beam should remain unchanged as long as the intensity and duration of the x-ray exposure remain unchanged
the reciprocity law
increasing the KVP for an exposure will
cause an increase in the speed at which the electrons travel from cathode to anode
if the mAs of a radiograph is increased from 10 to 20 the resulting radiograph will exhibit
increased film density
The relationship between mAs and exposure is
directly proportional
Kilovoltage is the primary controlling factor of
photon penetrability
the anode heel effect will be seen mostly with ____ films at ___ distances
large, short
the variation in beam intensity from anode to cathode is __%
45
x ray beam penetrability is primarily controlled by
kVp
after completing an upright abdomen radiograph using a manual technique, you notice some degree of motion artifact on the final image, to improve the repeat image results your best option would be to? 
Maintain the mAs but increase the mA and reduce the time
The reason for the anode heal effect is 
The anode absorbs a portion of the beam
An anode with a small effective and actual focal spot will improve
detail
what formula should be utilized to compensate for changes in intensity
inverse square law
the length of the exposure time for a radiograph is used primarily to control
motion
an increase in kVp by 15% will cause an approximate ___ in exposure
doubling
