Technical Fators Flashcards
factors that influence and determine the quantity and quality of xradiation to which rhe patient is exposed
Exposure Factor
refers to the radiation intensity (measure in mGya or mGya/mAs)
Radiation Quantity
refers to the xray beam penetrability (best measured by the halve value layer or HVL
Radiation Quality
the combination of setting selected on the control panel of the xray imaging system to produce a high qaulity image
Radiographic Technique
What are the exposure factors that may influence xray quantity and quality
A. kilovolt peak
B. milliampere
C. exposure time
D. milliampere-second
E. distance
F. voltage ripple
G. filtration
A-E are the four primary exposure factors they are under the control of the ______
Radiologic Technologist
F-G Voltage ripple and Filtration are not or ___
have limited control
are the most important and principally responsible for xray quality and quantity
kilovolt peak and milliampere
primary control factor of xray beam qaulity, and therefore, of beam penetrability
Kilovolt Peak
incrased the kilivolt peak
increase tube voltage
increase kinetic energy of electron
increase xray energy (quality)
increase xray beam penetrability
has the most effect on image receptor exposure because it can affect both beam qaulity and qauntity
kVp
quantity increased because
increase kVp
increase tube voltage
increase number of electrons that can leave the cathode
increase number of xray produced (quantity)
side effect of high kVp
higher energy xray tend to interact more by compton effect, thus increasing scatter which reduces image contrast
it controls screen film readiographic contrast
kVp
determines the number of xray produced, and therefore, the radiation quantity
Milliampere
if increased mA?
increase mA
increased number of electrons
increased number of xray produced (quantity)
1A=1C/s = ??
6.3x10^18
mA and number of electron are ______
directly proportional
when xray quantity is doubled patient dose is ____
double
a change in ____ does not change the kinetic energy of projectile electron
milliampere
with a constant exposure time mA, controls the xray quantity (and the patient dose) but not xray _____
Quality
the duration of exposure
Exposure Time
kept as short as possible to minimize motion blur that can kccur because of patient motion
Exposure Time
they can also compensate each kther depending on the situation
combined with mA and used as mAs
mAs controls ____
OD optical density
the blackness or darkness of a film
Optical Density
the blackness or darkness of a film
Optical Density
mA, exposure time, and mAs are all ______ to rafition quantity, and all of them do not affect radiation quality
Directly Proportional
affects the exposure of the image receptor according to the inverse square law
source to inage receptor distance (SID)
largely determine the intensity of the xray beam at the image receptor
source to image receptor distance (SID)
it has no eefect on radiation quality
source to image receptor distance (SID)
can be used to calculate the required change in mAs after a change in SID to maintain constant OD
Direct square law
_____ results in better rafiograph, but needs to be compensated with a larger mAs
Longer SID
