DI I Midterm

Question 1

Mid-sagittal plane

Answer 1

divides left and right

Question 2

Mid-coronal plane

Answer 2

divides anterior and posterior

Question 3

Horizontal (transverse) plane

Answer 3

divides superior and inferior

Question 4

Axial view angles along which body axis?

Answer 4

Tube is angled along longitudinal axis

Question 5

What is a tangential view?

Answer 5

beam passes through joint space

Question 6

What is an oblique view?

Answer 6

body rotated - named for body plane that is closest to film (eg Right anterior oblique)

Question 7

What is a lateral view?

Answer 7

beams enter side of patient (mediolateral or lateromedial)

Question 8

List densities of body substances from least to greatest.

Answer 8

Air
Fat
Water/muscle
Bone
(Metal)

Question 9

What is attenuation?

Which body substance is attenuated most? Least?

Answer 9

Attenuation is scatter of light (lightness in a film)
Air is attenuated least
Bone (or metal) is attenuated most

Question 10

How does pathology affect attenuation in the bone?

Answer 10

Additive conditions (blastic) increase attenuation
Destructive conditions (lytic) decrease attenuation

Question 11

How are attenuation and radiographic blackness related?

Answer 11

Radiographic blackness is the amount of blackness on the film - Attenuation is the amount of whiteness on the film.

Question 12

What variable controls the amount of radiographic density (blackness)?

Answer 12

mAs (milliamps X seconds)

Question 13

What is filtration of xrays?

Answer 13

Elimination of low energy, harmful, ‘soft’ photons - hardening the beam to improve quality

Question 14

What happens to the image when mAs is doubled? And the patient?

Answer 14

Increasing mA or seconds (exposure time) will double blackness, as well as dosage of radiation to patient.

Question 15

What is the benefit of increasing mA

Answer 15

Increased mA allows for faster exposure - less chance of motion blur

Question 16

What is contrast?

Answer 16

Contrast is quality of image

High contrast is fewer shades of gray - low contrast is more shades of gray - LOW contrast = BETTER quality image

Question 17

How is image contrast controlled?

Answer 17

kVp (kilovolt peak)

directly related to frequency and inversely related to wavelength

Question 18

Does increased kVp yield higher or lower contrast?

Answer 18

Increased kVp yields higher contrast (less shades of gray)

Question 19

Does increased kVp yield higher or lower patient exposure?

Answer 19

Increased kVp yields lower patient exposure

Question 20

How is distance related to radiation dosage?

Answer 20

As distance is doubled, energy is spread over an area 4 times as great, so intensity (dosage) becomes 1/4 of original

Question 21

What is scatter?

Answer 21

Increased grayness on the film (bad) caused by soft tissue (fat)

Question 22

What is beam restriction?

Answer 22

Beam restriction reduces scatter and improves image quality while reducing patient exposure

Question 23

What devices help restrict beam?

Answer 23

Aperture diaphragm, cones, cylinders, collimators

Question 24

What is a radiographic grid?

Answer 24

Grids absorb scatter radiation as it exits patient’s body - reduces radiation fog and improves contrast

Question 25

When should grids be used? Where are they placed?

Answer 25

Grids should be used with larger body parts and higher kVp | They are placed between patient and film

Question 26

Does using a grid require more or less radiation?

Answer 26

More

Question 27

What is shape distortion?

Answer 27

Elongation - when tube or film are improperly aligned | Foreshortening - when body part is improperly aligned with film

Question 28

How is shape distortion minimized?

Answer 28

By taking 2 images 90 degrees from one another

Question 29

What is size distortion?

Answer 29

Magnification - from increased object image-receptor distance (patient distant from film)

Question 30

How is size distortion minimized?

Answer 30

Increasing source image-receptor distance (moving patient closure to film)

Question 31

Are children more sensitive to radiation than adults?

Answer 31

YES - more rapidly dividing cells

Question 32

What are the most sensitive body cells to radiation?

Answer 32

Cells most rapidly divinding (bone marrow, gonadal, eye lense, GI tract)

Question 33

What cells are the least sensitive to radiation?

Answer 33

Muscle, nerves, chondrocytes

Question 34

What is a ROENTEGEN?

Answer 34

1 unit of radiation intensity in air (R)

Question 35

What is a RAD?

Answer 35

"radiation absorbed dose" | unit describing quantity of radiation received by patient

Question 36

What is a REM?

Answer 36

"radiation equivalent man" | unit describing quantity of radiation received by radiation worker

Question 37

What is the relationship of R to RAD to REM?

Answer 37

1 R = 1 RAD = 1 REM

Question 38

How many RAD make up 1 gray?

Answer 38

100 RAD = 1 gray

Question 39

How many REM (RAD) equal 1 mSv?

Answer 39

1 REM = 10 mSv or 1 Sv = 100 REM

Question 40

Which joint spaces are seen well on routine shoulder (internal/external rotation) views?

Answer 40

``` proximal humerus scapula clavicle AC joint CC joint ```

Question 41

Which joint space is NOT seen well on a routine shoulder? What view is needed to visualize this joint?

Answer 41

Glenohumeral | Grashey view is needed (30* AP)

Question 42

When should a PA/lateral chest exam be ordered?

Answer 42

To visualize lung fields, heart, great vessels, ribs, and soft tissues

Question 43

What is the distance of a chest study?

Answer 43

72 inches away - decreases heart shadow magnification

Question 44

How many posterior ribs should be seen in chest exam?

Answer 44

10 (with inspiration)

Question 45

When should a thoracic spine exam be ordered?

Answer 45

Spine exam ordered when spine lesions are suspected (lung/ribs will be overexposed)

Question 46

When should rib exam be ordered?

Answer 46

To study ribs (fractures, etc) - oblique needed to see around rib angle and collimated to focus on ribs of concern

Question 47

Why include an upright chest study with a rib study?

Answer 47

To fully visualize ribs to find any underlying lung/soft tissue injury

Question 48

What are the differences between chest, thoracic spine, and rib exams?

Answer 48

They are all very different studies focusing on different anatomy and should be ordered separately according to need

Question 49

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

Answer 49

PA ulnar flexion | Thumb side

Question 50

What views should be ordered to image lumbar spine instability?

Answer 50

Flexion/extension - AP/PA and lateral

Question 51

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

Answer 51

fracture of the scotty dog collar (between pedicle and lamina seen in oblique view) may indicate spondylosis

Question 52

In addition to the routine 3-view which cervical spine views are indicated when radicular symptoms are noted?

Answer 52

In addition to AP, AP open mouth, and lateral views oblique view may be needed to visualize intervertebral foramina and osteophytes

Question 53

What is the best for for SI joint and lumbosacral area?

Answer 53

AP spot view (25-30 degrees)

Question 54

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

Answer 54

Minimum ankle series is AP dorsoplantar, med oblique, and lateral fracture of 5th MT (danceres/Jones fracture) could require AP ankle or lateral ankle

Question 55

What study demonstrates pneumoperitoneum and/or bowel ubstruction?

Answer 55

acute abdomen - upright AP or PA chest looking for free air between right hemidiaphragm and liver (if pt is unable to stand then semi upright or left lateral decubitus)

Question 56

What study will be useful in determining whether a pt has a leg length inequality?

Answer 56

AP pelvis