wks 4-5 Flashcards
what type of animal do you choose to develop a technique chart?
average size
how many test x-rays do you take?
3
what is the area of the body x-rayed?
abdomen
where is the measurement of that body part taken?
12th rib/thickest part
what is the field of view for that body part (abdomen)?
xiphoid process to coxofemoral joint
if 12 cm were measured what would the KVp be for the test radiographs if the factor is 37?
12 x 2 = 24
24 + 37 = 61
answer: 61 KVp
after choosing an x-ray with good technique what are the rules for adjusting the KVp as the cm change?
0-80 KVp: +- 2
80-100 KVp: +- 3
>100 KVp: +- 4
if you have reached the KVp limit on your machine what rules of you use to adjust you technique?
decrease KVp by 16% and double the mAs
a radiograph of an abdomen should have what scale contrast?
long; more gray
a radiograph of a skull should have what scale contrast?
short; black and white
the base mAs setting is used for radiographs taken of a patient’s what?
abdomen
when taking a radiograph of the thorax, you should use an mAs setting that is ____ than one of an abdomen
lower (by 1/2)
when taking a radiograph of the pelvis, you should use an mAs setting that is _____ than one of an abdomen
higher (x2)
the mAs mainly controls the ____ on a film
density
the KVp mainly controls the ____ on a film
contrast
the lateral thorax radiograph should have ____ letters placed in the ____
left or right; collimation light (whatever side is down)
the VD thorax radiograph should have ____ letters placed in the _____
VD; left/right side of animals (directional terms for beam entering and exiting)
extremity views are often taken table top due to their
lower density (not going through grid or table)
thorax
1/2 base
skull
x2 base
spine
x2 base
extremity
base/5
cat/puppy
1/2 base
obese thorax
base
name of the pattern created by the sensitized silver halide crystals
latent image
lead gloves, aprons, etc. are designed to protect handlers from
scatter radiation
the thicker the tissue, the ____ the KVp setting will be
more
a radiograph which has been exposed to light and then developed and fixed will be?
black
in order to use a grid when making an exposure the cassette would have to be placed
in the buckey
the amount of KVp needed to make an exposure is determined by the
thickness of the part
pertinent info about the patient and the date of the x-rays should be imprinted on the film…
in the darkroom
a film taken directly out of the film bin in the dark room and then developed and fixed will be?
clear (hasn’t been exposed yet, no crystals sensitized)
difference in density of adjacent tissues is called
contrast
amount of blackness on a film is termed
density
a lateral view of the abdomen should have ___ markers places in the beam
left or right
an x-ray film is composed of 2 layers of ___ on both sides of a polyester sheet
silver halide emulsion
instrument used to measure the part being radiographed
calipers
the developer solution changes sensitized silver halide crystals to
black metallic silver
when taking radiographs of a particular area the technician should use anatomical landmarks to help determine the correct
positioning (field of view)
radiographic positions are described by the ____ the beam travels through the body
direction
radiographic positions are also described by the surface of the body that is ____ the film
closest to
list 6 indications for taking dental radiographs
periodontal disease
missing or broken teeth
resorptive lesions
oral tumors
gingival inflammation
malformed or discolored teeth
T/F dental x-ray units are exactly the same as all other units
F
T/F FFD is the same for dental rads as abdominal rads
F
purpose of a bisecting angle
to avoid elongation or foreshortening of the radiographic image (reduce distortion)
two pieces of information needed to get a bisecting angle
- the plane of the film
- the plane of the long axis of the tooth
T/F parallel angle and bisecting angle are basically the same thing
F
if the bisecting angle is not correct ___ or ___ can occur resulting in distortion of the tooth root
elongation; foreshortening
T/F it is most important to make sure that the crown of the tooth shows up on the x-ray
F
who is responsible for the safety of the employees
owner of the practice
the main goals of the practice
– Gather as much information as possible
– Use minimum number of exposures
– Limit the level of radiation to as low as reasonably attainable
rad
unit of absorbed dose for any ionizing radiation
REM
unit of dose equivalent which has been correlated to living tissue
Dosimetry (film) badges
read in mREM which is 1/1000 of a REM
Early / Acute Exposure Effects
When the entire body is exposed to large amounts of radiation, many organ changes take place
Late / Chronic Exposure Effects
- fetal abnormalities
- susceptibility to disease or infection
- risk on cancers
- risk of cataracts
- risk of aplastic anemia
pregnant women
should be excluded from radiographic procedures - if this is not feasible, two aprons and two film badges should be worn, one at the collar and one at belt level
risk of the fetus is greatest when
during the first trimester of pregnancy when the fetal cells are dividing rapidly
base mAs
can be multiplied by 2, divided by 2, and divided 5 - must equal number on mAs table
mAs rules chart again
skull, spine, pelvis: x2 base
normal thorax: 1/2 base
obese dog thorax or fluid: base
cats and puppies: 1/2 base
extremities: 1/5 base
if the beam is perpendicular to the film
the image is foreshortened
if the beam is perpendicular to the tooth
the image is elongated
