DI 1- Midterm Flashcards

1
Q

Name the body planes and what they divide.

A

sagittal: left & right.
coronal: anterior & posterior
Horizontal (transverse): superior & inferior

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2
Q

Define the terms position, projection and view.

A
  • Position = side of body nearest film; should be marked as such (ie RAO)
  • Projection = path of the x-ray beam AP/PA/oblique
  • View = side of anatomy best visualized, usually side nearest film.
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3
Q

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

A

Denser tissues show up more opaque on radiographs. In increasing density: air, fat, water and muscle, bone, metal

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4
Q

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

A

Attenuation is the rate of absorption of x-rays as they go through tissue. The more a tissue attenuates, the more radiopaque it is. Radiographic blackness is how much blackness is on a film. The less attenuation, the more radiographic blackness on a film. In order of increasing attenuation: air, fat, water and muscle, bone, metal. Pathologies can affect the way a tissue attenuates, ex Breast CA decreases, an prostate CA increases attenuation.

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5
Q

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

A

• Radiographic Density = radiographic blackness = amount of blackness on film. mAs controls it (milliamps X seconds = mAs)
- Increasing either current or exposure time will increase the x-ray dosage, thus increasing radiographic blackness

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6
Q

When you double or halve mA and leave everything else as is, what happens to your film? What happens to your patient?

A

The image increases in radiographic blackness

The patient receives double the radiation.

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7
Q

What x-ray factor is primarily responsible for controlling contrast?

A

Contrast is how many different shade of gray will show up on an image. It is controlled by kVp, kilovolt peak. Improving contrast means lowering kVp so more shades show up

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8
Q

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

A

Beam restriction reduces scatter for a clearer image by blocking some of the rays. Scatter is the result of some x-rays bouncing off tissue in oddball directions and it is bad always. Minimize with appropriate kVp, grid, and beam restriction.

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9
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

aluminum casing with lead lines that are aligned to catch scatter, but straight beams go straight through. Placed between pt and film (remove scatter once it exits body). This greatly improves image contrast and sharpness. Using a grid increases the amount of radiation needed to get a good image.

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10
Q

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

A

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

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11
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.

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12
Q

What is a ROENTGEN?

A

Ionization produced by a specific amount of radiation in the AIR. SI = C/kg

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13
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 later. Alcohol use, being unmarried, smoking, MVA, pedestrian accident all greater risk than x-ray. Owning small car, long drive, consuming desert/sod, not fastening seatbelt all less than risk of x-ray

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14
Q

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?

A

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

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15
Q

When to order PA/lateral chest exam?

A

Order a PA chest exam when you want to see what’s going on in the chest, duh. Soft tissue dx and respiratory complaints NOT thoracic spine stuff.

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16
Q

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

A

Get a thoracic spine exam when you want to see the thoracic spine. The ribs and lungs will be overexposed in a thoracic spine study. Rib studies have higher contrast than chest studies and are often UL.

17
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. A scaphoid view is PA with ulnar deviation

18
Q

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

A

Need to do lateral flexion and extension to look for instability. Pars interarticularis fracture is when you crack the neck of the Scottie dog. If both sides fracture, then spondylolisthesis may result.

19
Q

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

A

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

20
Q

The best view for sacroiliac joints and lumbosacral area?

A

o AP spot view 25-30 degrees

21
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

A 5th metatarsal fracture will show up on an 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.

22
Q

What study demonstrates pneumoperitoneum and/or bowel obstruction?

A

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

23
Q

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

A

o AP pelvis=scanogram??

24
Q

what is a good view for the scaphoid?

A

Ulnar flexion minimizes overlap of carpals on the lateral side of the proximal row of carpal bones.

25
Q

what is the appropriate exam for a pt with a respiratory complaint?

A

Rib exams don’t show lung conditions, but if your patient has rib trauma, you should request or perform a chest film in addition to the rib study. Thoracic spine films are for thoracic spine only and don’t have good diagnostic information for either of the above.

26
Q

What is a good view for inversion of the ankle?

A
  1. Inversion of the ankle is a common injury. It often involves a fracture (Jones) of the base of the 5th metatarsal. An AP and/or medial oblique foot view demonstrates the area well.
27
Q

What view is good for hypermobility?

A
  1. Flexion and Extension studies of the lumbar spine in the lateral position are useful for evaluation of hyper mobility. A Neutral lateral lumbar film should be obtained prior to this study. CT would be the best advanced imaging.
28
Q

How is pneumoperitoneum imaged?

A

with the patient in the upright position. Free air is not seen in supine or prone films. 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.

29
Q

What is a useful view for pt with radicular symptoms?

A

cervical oblique views are useful in demonstrating intervertebral foramina.

30
Q

How is the glenohumeral joint best viewed?

A

The glenohumeral joint isn’t seen well in routine AP projections of the shoulder. The Grashey view and axial projection demonstrate it well.

31
Q

How is best to view the axillary portion of the ribs?

A

The axillary portion of the ribs is not seen well in frontal projections. Oblique views are required. The oblique position that puts the axillary portion parallel to the plane of the film without superimposition of the vertebral column is the correct position.

32
Q

What is good view for L5/S1 joint?

A

The AP axial lumbosacral joint spot film 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.

33
Q

How many projections should you always have 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.

34
Q

what is the best view for the SI jts?

A

AP or PA axial projection.

35
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 is much more likely to be blurred, and it will be darker
He receives more radiation

36
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.

37
Q

What is a RAD?

A

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

38
Q

What is a REM?

A

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