Apex- Radiology Flashcards
Which unit of measurement quantifies occupational exposure to electromagnetic radation?
A. Curie
B. Rad
C. Rem
D. Roentgen
Rem
Roentgen (R) = unit of radiation exposure
Rad (Radation absorbed dose): quantity of radiation received by individual
Rem (Radiation equivalent man): unit of occupational radiation exposure
Curie (Ci): a quantity of radioactive material
Xrays are a form of (long/short) wavelength, (high/low) frequenciy ionizing radation that prenetrate matter at the molecular level
short wavelength
high frequency
T/F- xray exposure can damage ceullular compontents such as RNA and DNA
true + create reactive oxidative species and predispose a person to cancer
What is the unit of radiation exposure
vs. unit of OCCUPATIONAL radiation exposure
The Roentgen (R)
describes the output intensity of the xray machine
Rem - Raidation equivalent man
what describes the quantity of radiation received by an individual
Radiation absorbed dose (Rad)
What is the unit of OCCUPATIONAL radation exposure
Radiation equivalent man (Rem)
Roentgen is the unit of ration exposure - not occupational
Rem sleep - sleep while your work- work = occupation, occupational radiation expsoure
Rems account for the differences in types of radiation exposure based on a weighting factor
What is Curie (Ci)
a quantity of radioactive material
3 very highly sensitive body areas to radiation
3 highly sensitive
very highly sensitive = bone marrow, intestinal epitherlium, reproductive cells
highly senstive = optic lens, thyroid epithelium, mucous membranes
you should stand at least how many feet away from the xray source
3 feet
What is XRAY?
why is it called “ionizing radiation”
It’s high energy electromagnetic radiation
because they ionize atoms (remove electrons from the outer shell)
Match: radiology terms: Rem, Roentgen, Rad
“the total dose administered”
“total dose received at tissue level”
“effective dose”
“the total dose administered” = Roentgen
“total dose received at tissue level” = Rad
“effective dose” = Rem
Yearly maximum radiation exposure for adults
for fetus (per year and per month)
adults = 5rem per year
fetus = 0.5rem/year
0.05rem/month
What defines the amount of ardioactive substance that decays at the same rate with 1g radium?
what describes decay in one second?
Curie (Ci)
Becquerel (Bq)
What describes the number of electrons used to generate the X-ray beam?
What describes the quality of xrays produced?
Milliamperes
T/F: Radiation obeys the inverse square law
True
states the amount of exposure is inversely proportional to the square distance of the distance of the source
3 ways to limit radiation exposure
- distance
- duration
- shielding
minimum safe distance from the radiation source
this is how many inches of concrete
and how many mm of lead
6 feet of air
9 inches of concrete
2.5mm of lead (lead aprons usually contaon 0.25-0.5mm of lead - perfect)
Which features will be present in a normal chest X-ray? (select 2):
- domed hemidiaphragm
- heart borders > 60% chest width
- Blunted costophrenic angles
- Left hilum slightly larger than the right
Domed hemidiaphragm
Left hilum slighlty higher than the right
Order of increasing density (darkest to lightest):
Water (soft tisssue), bone (metal, fat, gas (air)
densest = lightest
- Gas/Air (xray passes most easily thru - darkest)
- Fat
- Water (soft tissue)
- bone (metal) ( denest - xray passes less easily thru - lightest)
label cxr
T/F: the best image quality is obtained when the film is taken with teh patient in the upright position
True
Three most common CXR views
*which one is most common
- Posterior Anterior* -xray passes from back to front (PA)
- Anterior Posterior (AP) - xray passes from front to back
- Lateral- xays pass from one side ot the other
Why should people hold their breath on inspiration with cxrs
bc inspiration seperates the soft tissues and vessels, making the structures easier to see
what happens if the cxr is taken on expiration?
lungs and heart
lungs will appear cloudy and heart will appear larger than it actually is
How is adequate inspiratory effort indicated?
by identifying the right hemidiaphragm at the 9th or 10th rib posteriorly
if the right hemidiaphrgam is elevated at which ribs, overinflation would be likely (either iatrogenic or pathologic)
11th or 12th
what 2 things could widened intercostal spaces indicate?
- overinflated lungs
- ipsilateral PTX
Which view provides the most accurate assessment of heart size: AP. PA, or lateral
PA
heart wideth < 50% of thorax wideth
PA vs AP view and cardiac assessment
PA = width of heart is < 50% of thorax width
AP = width of heart is < 60% of thorax width
How is cardiac assessment altered in the AP view?
heart is relatively further when AP view is used, creating a shadow that can cause a 20% false increase in size
T/F: the heart can appear englarged (regardless of which view) if the xray beam does not encounter the chest at a 90 degree angle
True
*pt position is important!
label structures cxr
Which side of the diaphragm sits higher left or right
why
right
bc of the liver
T/F- a domed diaphragm is normal
true
What would unilateral depressed or flattened hemidiaphragm indicate?
what about b/l flattening?
tension PTX
COPD or chornic asthma
label differences in COPD cxr
What is the most common cause of free air under the diaphrgam?
hollow viscus perforation
ie) loss of GI wall integrity
label cxr
what is the signficance of this?
pleural fluid tends to rise higher along the edges producing a meniscus or U shape - good indicator of pleural effusion (increased density at the costophrenic angle)
what are costophrenic angles?
arcs where the chest wall and diaphragm meet
normal - sharp and clearly defined
blunted may indicate pleural effusions
what might blunted costophrenic angles indicate
pleural effusions
costophrenic angles are arcs wehre the chest wall and diaphragm meet