X-Ray Flashcards
used for large objects have a short exposure time increase penumbra (blurrred margins)
Large filaments
used for small objects
have a longer exposure time
produce a sharper image
decrease penumbra
Small filaments
is negatively charged and contains a focusing cup
cathode
is positively charged, made of tungsten, and is the target plate
anode
makes 85-90% of the x-ray beam and creates the image
Bremsstrahlung radiation (braking radiation or soft x-rays)
makes 10-15% of the x-ray beam and does not contribute to the formation of the image
Characteristic radiation (hard x-rays)
complete absorption of x-ray which does not affect the image
photoelectric effect
two types of radiographic noise
artifact and mottle
three types of mottle
quantum, structure, and film graininess
variation of density of a uniformly exposed film that results from random spatial distribution of x-ray quanta absorbed in the screen
quantum mottle
factors that affect scatter radiation
beam size, field size, and patient size
4 ways to reduce scatter radiation
reduce beam size
increase beam energy or increase Kvp
decrease field size w/ grid or collimator
air gap technique
purpose of the grid
to prevent scatter radiation and allow useful x-rays through
refers to the distance between the object and the film
air gap technique
what happens when you reduce the OFD
reduce scatter
image magnification
produces 99% heat and 1% x-rays
anode
reduces amount of radiation exposure to the patient
port filters and collimator
increasing the mAs incorporates the use of which filament
large filament
what is the best grid ratio that also has the greatest effect in reducing scatter radiation
16:1
what type of crystals does the film consist of
silver halide crystals
directly proportional to the Kvp and Ma and contributes to the overall darkness of the fil
density
refers to the differences in the shades of gray of an image and is indirectly related to the Kvp
contrast
contrast recommended for soft tissue
low contrast (high Kvp)
contrast recommended for bone
high contrast (low Kvp)
increasing the OFD results in
image magnification
exposes patient to less radiation, reduces penumbra, decreases magnification, and increases detail
FFD 72 inches (FFD of 40 inches does opposite)
blurred margins
penumbra
sharp margins
umbra
50% decrease in mAs is equivalent to a 15% increase in Kvp
50/15 rule
when decreasing the kvp by 16%, you have to double the mAs or it will halve the film distance
OR
when increasing the kvp by 20% you have to decrease the mAs by half or you will double the film density
16:20% rule
the anode heel effect is stronger on the cathode or anode
cathode
the cathode should be placed closer to the fatter part of the object in the anode heel effect
FAT CAT
increases film exposure, scatter radiation, and fog and decreases contrast
increasing the kvp
increases film exposure and darkens the film
increasing mAs
radio sensitivity of tissue is directly proportional to the rate at which the tissue multiplies (the more rapid a tissue grows, the more susceptible it is to damage)
bergonie-tribondeau law
radio resistant tissues
brain, spinal cord, thyroid, and muscle
radiosensitive tissues
gonads, bone marrow, lymphoid tissue, colon, and lungs
when taking x-rays in a female, within how many days should the procedure be performed
within 10 days of her LMP
in regards to density, which factors have a direct relationship
Kvp, mAs, collimator
in regard to density, which factors have an inverse relationship
FFD, OFD, grid
in regards to contrast, which factors have a direct relationship
OFD and grid
in regards to contrast, which factors have an inverse relationship
Kvp, mA, collimator
in regards to size distortion, which factor has a direct relationship
OFD
in regards to size distortion, which has an inverse relationship
FFD
in regards to detail, which has a direct relationship
FFD
in regards to detail, which has an inverse relationship
OFD
in regards to exposure time, which factors have a direct relationship
kvp, mAs, OFD
in regards to exposure time, which factors have a inverse relationship
FFD and collimator
all radiographic views have a FFD of 40 inches except the following which are at 72 inches
chest films
lateral sternum films
full spine films
Non-AP cervical films (lateral, oblique, flexion, extension)
all views are AP projections except the following which are PA projections
skull mandible chest wrist tunnel patella
all oblique films are midway between a PA and a lateral position (usually at 45 degrees) except
thoracic spine
SI joint
all views are taken on suspended on expiration except the following which are performed on full inspiration
PA and lateral chest
AP full spine
AP and lateral thoracic
gonadal shielding should be used on children and adults within what range
2 inches
grids should be used on
all body parts measuring >12cm to reduce scatter radiation and use 70kvp to penetrate the grid
all tube tilts are cephalic except the following which are caudal
cervical anterior oblique
lateral lumbar
AP coccyx
Y-scapula
CT is measured in what units
Hounsfield
Caldwell view shows what
Frontal sinus
Towne view shows
Foramen magnum
Water view shows
Maxillary sinus
Lateral skull shows
Sella turcica
APOM shows
C1 fractures
AP cervical shows
Luschka joints
Cervical oblique shows
Intervertebral foramina
Apical lordotic shows
Pancoast tumor
Swimmers shows what
C7 spinous process
Frog leg shows
Femoral head in abduction and external rotation
Tunnel shows
Intercondylar fossa in knee
Sunrise shows
Apical view of patella and the intercondylar groove
Lumbar oblique shows
Pars interarticularis
Lumbar lateral shows
IVF