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Flashcards in MIDTERM 1 Deck (53)
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1
Q

Mid-sagittal plane divides:

A

left & right.

2
Q

Mid-coronal plane divides:

A

anterior & posterior

3
Q

Horizontal (transverse) plane divides:

A

superior & inferior

4
Q

Define the term position;

A

Position = side of body nearest film;

should be marked as such (ie RAO)

5
Q

Define the term projection;

A

Projection = path of the x-ray beam

AP/PA/oblique

6
Q

Define the term view;

A

View = side of anatomy best visualized,

usually side nearest film.

7
Q

What is attenuation?

A

Attenuation = How easily a material or medium can be penetrated by a beam of light, sound, particles, or other energy or matter

8
Q

How does pathology affect attenuation?

A

Disease may affect the way tissue attenuates x-rays.

9
Q

How are attenuation and radiographic blackness related?

A

Less attenuation= greater radiographic blackness;
mAs controls it (milliamps X seconds = mAs)

  • Additive Condition - Increased Attenuation (blastic)
  • Destructive Condition- Decreased Attenuation (lytic)
10
Q

Which body substance attenuates most? Least?

A

Air – Least attenuation - radiolucent
Muscle/water – Moderate attenuation
Bone – Very attenuated
Metal – Most/Greatest attenuation - radiopaque

11
Q

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

A

Radiographic Density = Radiographic blackness
(amount of blackness on film)
mAs controls it (milliamps X seconds = mAs)

12
Q

When you double mA and leave everything else as is, what happens to your radiographic image?

What happens to your patient?

A

Increases in radiographic blackness
(double the Blackness)

The patient receives double the radiation.

13
Q

When you double exposure time and leave everything else as is, what happens to your image?

What happens to your patient?

A

The image may be blurred & darker.

Patient receives more radiation.

14
Q

Which will give greater radiographic density (blackness), 100 mA @ 1 second or 200 mA @ ½ second? Which is more likely to have motion blur?

A

They’ll have the same blackness, but the shorter exposure will be less blurred probably.

15
Q

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

A

It is controlled by kVp, kilovolt peak.

Improving contrast means lowering kVp so more shades show up.

(Contrast is how many different shade of gray will show up on an image.)

  • If you increase kVp–>contrast goes down and gray scale goes up
  • If you decrease kVp->contrast goes up and gray scale goes down
16
Q

What is beam restriction?

A

Beam restriction = Reduces scatter for a clearer image by blocking some of the rays.

17
Q

What is scatter? Good? Bad?

A

Scatter = result of some x-rays bouncing off tissue in oddball directions.

It is always bad.

18
Q

How is scatter minimized?

A

Minimized with appropriate:

kVp,
Grid,
Beam restriction

19
Q

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?

A

Grid = Aluminum casing with lead lines that are aligned to catch scatter, but straight beams go straight through.

This greatly improves image contrast and sharpness.

Using a grid increases the amount of radiation needed to get a good image.

20
Q

What is shape distortion? How can they be minimized?

A

When something is elongated or foreshortened from improper placement of film, tube, or body part.

21
Q

What is size distortion? How can they be minimized?

A

When the shadow of an object is magnified as the object moves further from the film.

It can be minimized by putting the object of interest as close to the film as possible.

22
Q

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

A

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.

23
Q

What is a ROENTGEN?

A

Ionization produced by a specific amount of radiation in the AIR.

(SI = C/kg.)

24
Q

What is a RAD?

A

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

25
Q

What is a REM?

A

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

26
Q

What is the SI equivalent to REM? To RAD? To ROENTGEN? How many rem = 1 mSv?

A

0.1 rem = 1 mSv,

1 rem =10mSv

27
Q

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?

A

The latter;

Eating Twinkies while driving a pinto is remarkably perilous.

28
Q

Which joint space(s) are seen well on routine shoulder (internal & external rotation) views?

A

Seen well? = Proximal humerus, scapula, clavicle; acromion clearance

29
Q

Which joint space is not seen well on those views?

A

The A/C joint;

It is often overexposed and may require a filter.

30
Q

Which view(s) will demonstrate what is not seen on routine views?

A

Glenohumeral joint=> Need Grashey view;

AC joint=> Axial projection,

Scapulo-thoracic=> Scapular “Y” view

31
Q

When to order PA/lateral chest exam?

A

PA to see;

  1. lung fields, heart, great vessles, ribs,
  2. soft tissues

Lateral to see (L);

  1. Reduce cardiac magnifcation,
  2. localize mediastinum and lesions,
  3. lung fields, heart, great vessels, ribs

(Exposed on 2nd full inspiration)

32
Q

When to order thoracic spine exam? Rib exam?

A
Thoracic spine (AP): Suspect spine lesions; 
(FYI- lung and ribs will be over-exposed.)

Rib: 1. body structures, 2. rib fractures,

33
Q

Why include an upright chest film with a rib study? What are the differences between chest, thoracic spine and rib exams?

A

Upright chest film = lung/soft tissue injury

“Oblique” to see around angle of ribs
“Collimated” down to rib in question

34
Q

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

A

The scaphoid is on the radial or lateral side of the wrist (Thumb side)

A scaphoid view is PA with ulnar deviation
(Hand prone & deviated towards pinky)

35
Q

How to image lumbar spine instability?

A

Need to do lateral flexion and extension to look for instability.

36
Q

What is a pars interarticularis fracture? What condition might it result in?

A

Pars interarticularis fracture is when you crack the neck of the Scottie dog.

If both sides fracture, then spondylolisthesis may result.

The scotty dog sign refers to the normal appearance of the lumbar spine when seen on oblique radiographic projection. On oblique views, the posterior elements of vertebra form the figure of a Scotty dog with:

  • the transverse process being the nose
  • the pedicle forming the eye
  • the inferior articular facet being the front leg
  • the superior articular facet representing the ear
  • the pars interarticularis (the portion of the lamina that lies between the facets) equivalent to the neck of the dog.

If spondylolysis is present, the pars interarticularis, or the neck of the dog, will have a defect or break. It often looks as if the dog has a collar around the neck (or decapitation for those with a bloodier imagination).

Here is an example:
http://radiopaedia.org/images/136443

37
Q

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

A

Do ‘oblique’ views if patient is complaining of radicular symptoms.

Normal views are AP, AP open mouth, and Lateral.

38
Q

The single best view for sacroiliac joints and lumbosacral area?

A

Axial AP spot view!

25-30 degrees

39
Q

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

A

AP foot study,
Medial oblique foot study,
Lateral ankle study

40
Q

What study demonstrates pneumoperitoneum and/or bowel obstruction?

A

Get an AP abdomen view upright,
PA Chest X-ray , or
Left lateral decubitus if patient cannot stand.

(Contrast can be helpful for viewing the bowels)

41
Q

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

A

Scanogram or AP pelvis

42
Q

Ulnar flexion minimizes what?

A

Overlap of carpals on the lateral side of the proximal row of carpal bones.

*Good view for the scaphoid.

43
Q

If your patient has a respiratory complaint or fever, do what?

A

A chest study is the appropriate exam.

Rib exams don’t show lung conditions, but if your patient has rib trauma, you should request or perform a chest radiograph in addition to the rib study.

Thoracic spine radiographs are for thoracic spine only and don’t have good diagnostic information for either of the above.

44
Q

Inversion of the ankle is a common injury. It often involves what fracture?

A

(Jones/dancers fx) of the base of the 5th metatarsal.

An AP and/or medial oblique foot view demonstrates the area well.

45
Q

Flexion and extension studies of the lumbar spine in the lateral position are useful for evaluation of what?

A

Hypermobility.

Neutral upright lateral and AP lumbar radiographs should be obtained prior to this study.

46
Q

Pneumoperitoneum is imaged with the patient in the upright position such as upright AP abdomen or PA chest looking for what?

A

Free air between the right hemidiaphram and liver.

Free air is not seen in supine or prone radiographs. Any free air that is present will be layered along the diaphragm.

*If a patient is unable to stand, a viable alternative is the left lateral Decubitus abdomen.
(In this position free air is seen as it rises to the border of the liver.)

47
Q

When a patient exhibits radicular symptoms cervical oblique views are useful in demonstrating what?

A

Intervertebral foramina

48
Q

The glenohumeral joint isn’t seen well in routine AP projections of the shoulder. Which views demonstrate it well.

A

The Grashey view and axial projection.

49
Q

The axillary portion of the ribs is not seen well in frontal projections. What views are required.

A

Oblique views are required.

The oblique position that puts the axillary portion parallel to the plane of the radiograph without superimposition of the vertebral column is the correct position.

50
Q

Which views show L5/S1 joint space without overlap of L5 body.

A

“AP axial”

The AP axial lumbosacral joint spot radiograph demonstrates L5/S1 joint space without overlap of L5 body.

This joint is not seen well on AP lumbar projections. It also shows SI joints well.

51
Q

Always have at least two projections of an area.

A

Always have at least two projections of an area. Optimally they are 90° from one another.

(Two obliques suffice in some cases.)

52
Q

Which view(s) will demonstrate AC joint?

A

AC joint=> Axial projection,

53
Q

Which view(s) will demonstrate Scapulo-thoracic?

A

Scapulo-thoracic=> Scapular “Y” view