Card Set Information
Radiology Midterm Review
The grid is generally used when the area being radiographed is _____________________.
You can take advantage of the heel effect by:
Positioning the head towards the anode.
The most common cause of tube failure is:
What is recommended to reduce unneccesary ratiation of the patient and to decrease scatter?
Adjustment of the collimator to the smallest field size possible.
What is an example of Somatic Damage caused by radiation?
What is the maximum radiation dose during your pregnancy?
0.5 REM/ pregnancy
You should radiograph your lead gloves every __________ and gowns every _______.
Six Months (gloves)
One year (gowns)
Name the landmarks for a thoracic radiograph.
Cranial= Manubrium sterni or thoracic inlet
Caudal= halfway between xiphoid process and last rib
Center= over the heart
Name the landmarks for an abdominal radiograph.
Cranial= 3 rib spaces cranial to the xiphoid process
Caudal= greater trochanter
Center= over last rib if possible
What is the purpose of the aluminum filter?
To absorb lazy or soft x-rays.
When is the most critical time for the fetus?
Most: Preimplantation (0-9 days)
Least: 6 weeks to term
What is the maximum permissible dose for an occupationally exposed person?
What is the recommended lead thickness for attire worn while in radiology?
What are 3 protective accessories one should wear when staying in the room radiographing a patient?
1. Lead Gown
2. Lead Gloves
3. Thyroid Shield
What does Sv stand for?
(1Sv = 100REM)
There is a direct relationship between mA and length of exposure (s).
There is a direct relationship between kVp and mAs.
(there is an inverse relationship)
Scatter radiation does not contribute any useful radiographic qualities.
A dosimetry badge is worn on the thyroid collar under the lead gown.
(worn over the lead gown)
Fluorocospy provides real time exposure.
mA has a direct relationship to the number of x-rays produced.
mAs determines the quality of the x-ray beam and its ability to penetrate.
(kVp does this)
Which of the following (abdomen, thorax or femur) should have the shortest scale of contrast?
aka more black and white
High subject contrast _________ radiographic contrast.
What do grids contain that controls scatter radiation?
Where is the grid located?
Between the patient and the cassette.
Which of the beam limiting devices is most effective in reducing scatter radiation?
Foreshortening is most often seen with _______ bones.
What happens when OFD is increased?
Increases pneumbra on radiograph.
To prevent magnification and distortion of an object being radiographed, the patient must_________.
-Be as parallell to the film as possible.
- Be as close to the film as possible.
When changing the kVp to halve the radiographic density, one would decrease the kvP by ____.
When changing the kVp to double the radiographic density, one would increase the kvP by ____.
What does SID stand for?
Source Image Distnance
(Normal range is 36-40 inches.)
Same as FFD (focal film distance)
List subject densities from least dense to most dense.
1. Air (black)
5. Metal (white)
A processed film that has not been exposed to ionizing radiation or visible light will appear ______.
Film speed rated as slow is also known as:
How far away should the safelight be away from the work area?
At least 4 feet (48 inches).
Unexposed silver halide crystals remaining on the film are removed at what stage?
If the cassette is not directly under the primary x-ray beam, how will the film look after processing?
The part of the film not directly under the beam is white or unexposed.
The greater the film sensitivity, the lower the required mAs and kVp.
The most commonly used type of film is blue sensitive film because it is multipurpose.
When going from a high to a par speed screen, the mAs must be increased by 4x.
should be increased by 2x
List the steps and time involved for manual film processing.
What is the optimum temp?
1. Developer (5 min)
2. Rinse (30 seconds)
3. Fixer (10 minutes)
4. Wash (30 minutes)
Optimal temp 68 degrees F.
When would you choose to use a non-screen film? Give an example.
When shooting thinner objects as it is used to increase detail.
Ex- Dental Rads, or radiographing the mandible or maxilla
What does the fixer contain?
-Solvents (dissolve unsesitized crystals)
- Fixing agens (maintain sensitized crystals)
- Acidifier (removed unsensitized crystals)
-Hardener (decreases scratches)
-Preservative (protects for storage)
Minimal info needed to label a film properly is:
What is the purpose of the developer?
Converts sensitized silver halide crystals to black metallic silver.
What is the purpose of the fixer?
How can you prevent Foreshortening?
Make sure imaged object is parallel to cassette.
How can you prevent Magnification?
Subject must be as close as possible to the recording surface.
How can you prevent False Narrowing?
Center primary beam over joint of interest.
If the FFD is increased by 2, what should be done to adjust the mA to maintain the same density?
mA should be increased by 4x.
(If the distance from the primary beam is doubled, the radiation exposure is decreased by 1/4.)
What is grid cutoff?
When the tube head is not lined up with the cassette.