3 planes and what they divide
coronal - A/P
sagittal - R/L
transverse - S/I
Common radiographic views
AP/PA
RAO/LAO/RPO/LPO
axial
lateral
Roentgen
unit of radiation intensity in air
coulomb/kg
Rad
radiation absorbed dose - quantity of radiation received by pt.
Rem
radiation equivalent man - quantity of radiation received by radiation worker
Gray =?
= 100 rad
Sv =?
= 100 rem
Which body substance has the least radiographic density? How would it appear?
Air. Dark.
Which body substance has the greatest radiographic density? How would it appear?
Metal/bone. Light/white.
What is attenuation?
Loss of energy of a beam of radiant energy because of absorption, scattering, and other causes as the beam propagates through a medium
How does pathology affect attenuation?
• Additive Condition
Increased Attenuation (blastic)
• Destructive Condition
Decreased Attenuation (lytic)How are attenuation and radiographic blackness related?
The more attenuation, the less blackness
Which body substance attenuates most? least?
air (least), fat, water/muscle, bone, metal (most)
What is radiographic density? What x-ray factor controls it?
amount of blackness on film.
mA controls.
(density = blackness)
When you double mA and leave everything else as is, what happens to your radiographic image?
What happens to your patient?
Image blackness increased
Patient exposure increased
When you double exposure time and leave everything else as is, what happens to your image?
What happens to your patient?
Image blackness increased
Patient exposure increased
Which will give greater radiographic density, 100 mA at 1 sec or 200 mA at 0.5 sec?
Which is more likely to have motion blur?
Same density
100 mA at 1 sec more likely to have motion blur
(Incr mA, incr speed of exposure both decr motion blur)
What Xray factor is primarily responsible for controlling contrast?
kVp
What is generally meant by improving contrast?
Increasing # of shades of gray
What is beam restriction?
reduces scatter, improves image quality and
greatly reduces patient exposure. Beam must always be restricted.
What is scatter? Good? Bad?
secondary radiation that occurs when the useful beam intercepts any object. patient is the most significant source of scatter. serves no good purpose.
How is scatter minimized?
beam restriction
What is the purpose of a radiographic grid?
Grids absorb scatter radiation as it
exits patient’s body. This reduces
radiation fog and improves contrast.
When should a radiographic grid be used?
Grids should be used with larger body
parts and higher kVp.
Where is a radiographic grid placed? What is the visible effect of using a grid? Does it require more or less radiation?
placed between film and pt
increases sharpness and improves contrast
more radiation
What is shape distortion? How can it be minimized?
elongation or foreshortening. Elongation occurs when tube or film are improperly
aligned. Foreshortening occurs when
body part is improperly aligned with film.
What is size distortion? How can it be minimized?
magnification. results from
increased OID. Increased SID may
compensate.
Are children more sensitive to radiation than adults?
yes
What are the most sensitive body cells to radiation? least?
MOST Bone Marrow Gonadal Eye Lenses GI
(young, simple, rapidly dividing cells that use energy rapidly)
LEAST Muscle Nerve Chondrocyte
How many REM = 1mSv?
1/10 REM
1 REM = 10 mSv
Which joint spaces are seen well on routine shoulder (int and ext rot) views? Which joint space is not seen well?
glenohumeral joint not seen well
Which views will demonstrate what is not seen well on routine shoulder views?
b
When to order a PA/lateral chest exam?
b
When to order a thoracic spine exam?
b
When to order a rib exam?
b
Why include an upright chest radiograph with a rib study?
b
What are the differences between chest, thoracic spine, and rib exams?
THORACIC Higher contrast than chest studies, 60-80 kVp/small focal spot
CHEST
RIB
What is a scaphoid view? Which side of the wrist is the scaphoid on?
Lateral side
How to image lumbar spine instability?
b
What is a pars interarticularis fracture? What condition might it result in?
b
In addition to the routine three-view which cervical spine views are indicated when radicular sx are noted?
b
Single best view for sacroiliac joints and lumbosacral area?
b
A common fracture site in cases of inversion ankle sprain is the base of the 5th MT. Which additional views demonstrate the area?
b
What study demonstrates the pneumoperitoneum and/or bowel obstruction?
AP abdomen view upright,
PA Chest X-ray , or
Left lateral decubitus if patient cannot stand
What plain radiographic study will be useful in determining whether a pt has a leg length inequality?
b
