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Flashcards in DI 1 Midterm Deck (29)
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1

Name the body planes and what they divide.

Mid-sagittal: divides left and right
Mid-coronal: divides anterior, posterior
Horizontal/Transverse: divides superior, inferior

2

Understand the common radiographic views for various body regions.

View: term for radiographic exam
Described by position and projection (axial, tangential, oblique, lateral)

AP: back against film
PA: chest against film
Lateral: named for the side closest to the film
LAO/RAO: left/right anterior oblique
LPO/RPO: left/right posterior oblique

3

Which body substance has the least subject density? The greatest? How would they appear radiographically?

Least: air, looks dark/black
Greatest: metal, looks white

4

What is attenuation? How does pathology affect it? How are attenuation and radiographic blackness related? Which body substance attenuates most? Least?

Attenuation is the reduction in the number of photons as they pass through the body due to absorption.

An additive condition increases attenuation (blastic): more white ex. prostate CA
A destructive condition decreases attenuation (lytic): more black ex. breast CA

Radiographic blackness is inversely related to degree of attenuation

Bone attenuates the most
Fat attenuates the least

5

What is radiographic density? What x-ray factor controls it?

Radiographic density = Radiographic Blackness = The amount of blackening on an xray film
controlled by mAs

Increasing either current or exposure time will increase the x-ray dosage, thus increasing radiographic blackness

6

When you double mA and leave everything else as is, what happens to your radiographic image? What happens to your patient? When you double exposure time and leave everything else as is, what happens to your image? What happens to your patient? Which will give greater radiographic density (blackness), 100 mA @ 1 second or 200 mA @ ½ second? Which is more likely to have motion blur?

double mAs = double blackness, double pt exposure
double exposure time = doubles blackness, double pt exposure

100mA @ 1 sec = 200mA @ 1/2 sec

Motion blur is more likely with longer exposure at 1 sec

7

What x-ray factor is primarily responsible for controlling contrast? What is generally meant by improving contrast?

kVp
Higher contrast = fewer shades of gray
Lower contrast = more shades of gray

Lowering kVp increases contrast
Increasing kVp increases shades of gray

8

What is beam restriction? What is scatter? Good? Bad? How is scatter minimized?

Beam restriction is done by affecting the shape and diameter of the radiation beam. Improves image quality and reduces pt exposure.
Scatter is less focused radiation
It is always bad
Minimized by appropriate kVp, grid, and beam restriction.

9

What is the purpose of a radiographic grid? When should it be used? Where is the grid placed? What is the visible effect of using a grid? Does its use require more or less radiation?

Radiographic grids absorb scatter radiation as it exits pt body. They are aluminum casing with lead lines that are aligned to catch scatter, but straight beams go straight through
Reduces radiation fog and improves contrast.
Placed btw patient and film
Requires more radiation

10

What is shape distortion? How can they be minimized? What is size distortion? How can they be minimized?

Shape distortion is when something is elongated or foreshortened from improper placement of film, tube, or body part.

Size distortion is when the shadow of an object is magnified as the object moves further from the film.

Minimized by putting the object of interest as close to the film as possible.

11

Are children more sensitive to radiation than adults? What are the most sensitive body cells to radiation? The least sensitive?

Children are more sensitive to radiation because they have more mitotic cells and metabolically active cells.

The most sensitive cells are: bone marrow, gonadal, eye lens, GI tract.

Least sensitive are muscle, nerve, chondrocyte.

12

What is a ROENTGEN? SI equivalent?

Ionization produced by a specific amount of radiation in the AIR. SI = ROENTGEN (C/k)

13

What is a RAD? SI equivalent?

Radiation Absorbed Dose, how much energy is absorbed by any material. SI =Gray
1 Gray = 100 RAD

14

What is a REM? SI equivalent?

Radiation equivalent in man, Measurement of biological change.
SI = Sievert , 1 Sv = 100 rem

15

How many rem = 1 mSv?

1 rem = 10 mSv or 1 Sv = 100 rem

16

Which is more dangerous, having a chest x-ray or being an unmarried male who eats Twinkies and drinks soda pop while driving his Ford Pinto?

being an unmarried male who eats Twinkies and drinks soda pop while driving his Ford Pinto

17

Which joint space(s) are seen well on routine shoulder (internal & external rotation) views? Which joint space is not seen well on those views? Which view(s) will demonstrate what is not seen on routine views?

Glenohumeral joint is not seen well on routine should rotation views, and requires a special study, Grashey method to visualize it. The A/C joint is often overexposed and may require a filter

18

When to order PA/lateral chest exam?

Soft tissue dx and respiratory complaints NOT thoracic spine stuff.

19

When to order thoracic spine exam? Rib exam? Why include an upright chest radiograph with a rib study? What are the differences between chest, thoracic spine and rib exams?

Thoracic spine exam to see the thoracic spine. The ribs and lungs will be overexposed.

Rib films are for bony structures. They will overexposed and usually unilateral

20

What is a scaphoid view? Which side of the wrist is the scaphoid on?

PA with ulnar deviation
radial/lateral side of the wrist.

21

How to image lumbar spine instability? What is a pars interarticularis fracture? What condition might it result in?

Need to do lateral flexion and extension to look for instability.
Pars interarticularis fracture is when you crack the neck of the Scottie dog (part of vertebra located between the inferior and superior articular processes of the facet joint).
Bilateral fracture may result in spondylolisthesis.

22

In addition to the routine three-view which cervical spine views are indicated when radicular symptoms are noted?

Normal views are AP, AP open mouth, and Lateral. Do oblique views if patient is complaining of radicular symptoms.

23

The single best view for sacroiliac joints and lumbosacral area?

Axial AP spot view!

24

A common fracture site in cases of inversion ankle sprain is the base of the 5th metatarsal. Which additional views demonstrate the area?

AP foot study, medial oblique foot study, and if you ask your lateral ankle study to include the 5th metatarsal, it will show up there, too.

25

What study demonstrates pneumoperitoneum and/or bowel obstruction?

Get a AP abdomen view upright, PA crx, or a Left lateral decubitus if patient cannot stand. Contrast can be helpful for viewing the bowels

26

What plain radiograph study will be useful in determining whether a patient has a leg-length inequality?

Scanogram!

27

What are the standard views for the lower extremity?

AP and lateral
for the toes, you also want obliques
for the ankle, you also want medial oblique

28

What are the standard views for finger, hand and wrist?

PA, lateral, oblique

29

What are the standard views for the arm? Shoulder? clavicle?

arm: AP, lateral
shoulder: AP with internal and ext. rotation
clavical: AP, axial