DI 1 Midterm

Question 1

Name the body planes and what they divide

Answer 1

mid-sagittal: L from R
mid-coronal: anterior from posterior
horizontal/transerve: top from bottom

Question 2

differentiation b/w position, projection and view

Answer 2

position: side of body nearest to film (R, L or O)
projection: path of x-ray beam (AP or PA or O)
view: side of anatomy best visualized

Question 3

what areas are best taken with an AP projection? (2)

Answer 3

pelvis and femur

Question 4

what areas are best taken with AP and lateral projections? (4)

Answer 4

knee, humerus, scapula, elbow

Question 5

what areas are best taken with AP, MO and lateral projections? (2)

Answer 5

ankle, foot

Question 6

what areas are best taken with PA, O and L projections? (4)

Answer 6

wrist, hand, fingers, thumb

Question 7

what area requires AP and frog leg?

Answer 7

hip

Question 8

what area requires axial and lateral?

Answer 8

calcaneus

Question 9

what area requires AP, O and L?

Answer 9

toes

Question 10

special movements you must do with shoulder x-ray and projection? special movements you must do for AC joint x-ray and projection?

Answer 10

AP internal and AP external rotation for shoulder

BL weight bearing and non-weight bearing AP

Question 11

what 2 projections must you do for a good clavicle shot?

Answer 11

AP/PA and axial AP/PA

Question 12

what two projections must one do for a good chest x-ray?

Answer 12

PA and LL

Question 13

what special projections must you do for rib studies? 2

Answer 13

frontal (AP/PA) and AO/PO (appropriate to area of interest)

Question 14

what two projections must you do for a good sternum study?

Answer 14

RAO (on 2nd inspiration) and L

Question 15

what two projections produces a good abdominal study?

Answer 15

AP abdomen (KUB) and upright abdomen

Question 16

what body substance has the least subject density? The greatest? radiographically how do they look?

Answer 16

least subject density= air= radiolucent

most subject density= bone (metal if they have)= radiopaque

Question 17

what is attenuation? how does pathology affect it? how are attenuation and radiographic blackness related? which body substance attenuates most? least?

Answer 17

attenuation is how much a tissue absorbs of the radiation
attenuation and radiographic blackness are related by that they are inversely related, more attenuation= less radiographic blackness in that area
additive pathology (-blastic) will make it more radiopaque
destructive pathology (-lytic) will make it more radiolucent
bone (metal) attenuate the most
air and gas attenuate the least

Question 18

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

Answer 18

radiographic density: radiographic blackness, amount of black film (radiolucency)
mAs control radiographic blackness the best (kVp’s can also control but better to adjust mAs)
need at least 25% change in mAs to see visible change in radiographic density

Question 19

double mA only, what happens to image? to pt? double exposure time only what happens to image? to pt? will 100 mA @ 1 s or 200 mA @ 1/2 s give greater radiographic density? which is more likely to have motion blur?

Answer 19

double mA= greater radiographic density, blackness, radiolucency; also exposes pt to more radiation
double exposure time= greater radiographic density, blackness, radiolucency; also exposes pt to more radiation
100 mA @ 1 s= 200 mA @ 1/2 s
100 mA @ 1 s is more likely to have motion blur

Question 20

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

Answer 20

controlled by kVp
15% rule: 15% increase in mA causes 100% increase in blackness
kVp not affected by distance
changing kVp does allow for lower dosage to pt
improving contrast means making there be greater distinction b/w the shades of grey= clearer image

Question 21

what is beam restriction? what is scatter? scatter good or bad? how is scatter minimized?

Answer 21

beam restriction= making sure it is limited to the area you want an image of
scatter is a result of photons interacting w/loosely bound outer-shell electrons in the body, producing a less clear image so it is bad
scatter can be minimized using a collimator, aperature, diaphragm, cones and cylinders before the beam enters the pt whereas grids can reduce scatter as the photons exit the patient

Question 22

purpose of a radiographic grid? when should it be used? where is is placed? visible effect of using a grid? does it require more or less radiation?

Answer 22

purpose is to reduce scatter photons as they exit the patient
should be used to reduce scatter and when body part is > 10 cm and/or >70 kVp is being used on the exam
it is placed b/w the patient and the film
can see the grid itself on film and can lead to improper cut-off or absorb the primary radiation
requires more radiation

Question 23

shape distortion? how can they be minimized? what is size distortion? how can they be minimized?

Answer 23

shape distortion is elongation or foreshortening
elongation can be minimized by making sure the beam is perpendicular to the plane of the film
foreshortening is a result of a body part not being parallel to the plane of the film
size distortion is where magnification is off, can be minimized by making sure OID and SID are appropriate

Question 24

children or adults more sensitive to radiation effects? what are the most sensitive cells? least sensitive?

Answer 24

children b/c they have more actively dividing cells, cells that use more E and simple cells
most sensitive cells: BM, gonads, eye lenses, GI
low sensitivity cells: muscle, nerves, chondrocytes

Question 25

what is a roentgen? a rad? a rem? SI equivalents for each? x rem= 1 mSv?

Answer 25

roentgen: unit of radiation intensity in air
rad: radiation absorbed dose, how much a pt absorbs
rem: radiation equivalent men, how much a worker in the field would absorb
1 R= 1 rad= 1 rem
rad–> Gray, 1 Gray= 100 rad
rem–> Sievert, 1 Sv= 100 rem
1 mSv= 100,000 rad

Question 26

what is more dangerous- being an unmarried male who eats Twinkies and drinks soda while driving a Ford Pinto or having a CXR?

Answer 26

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

Question 27

jt spaces seen well on routine shoulder views? which joint space is not seem well on int and ext rotation? which views will demonstrate what is not seen on routine views?

Answer 27

greater and lesser tubercles, bicipital groove, proximal humerus, scapula, clavicle, acromion clearance seen well
GH joint space along with AC jt are not seen well on routine shoulder views
need a Grashy view for GH jt and either axial projection, scapulothoracic or Y view for AC jt

Question 28

when to order PA/lateral chest film?

Answer 28

PA: to see lungs, heart, great vessels, ribs, soft tissue
L chest: reduce cardiac magnification (LA), localize mediastinum and lesions, lung fields, heart, great vessels and ribs (RA)
take these on the 2nd full inspiration

Question 29

when to order thoracic spine exam? rib exam? why upright chest radiograph with rib study? differences b/w chest, thoracic spine and rib exams?

Answer 29

AP thoracic spine: when suspect spine lesions (will overexpose lungs and ribs)
rib exam: when suspect fractures, O to see around angle of ribs and collimate down to rib in question
upright CXR: underlying lung/soft tissue damage/injury
differences: thoracic not useful for diagnosing respiratory complaints or visualizing rib fractures, PA chest for soft tissue dx, rib films for bony structures

Question 30

what is a scaphoid view? what side of the wrist if the scaphoid on?

Answer 30

scaphoid view: ulnar deviation so can see entirety of scaphoid
on the radial side of the wrist

Question 31

how to image lumbar spine instability? what is pars interarticularis fracture? what condition might it result in?

Answer 31

lateral flexion and extension imaging
pars is a fracture of bone b/w lamina and pedicle- will need LAO and RAO of lumbar spine
can indicate spondylolysis

Question 32

routine views for cervical spine? what additional views are indicated when radicular sxs are noted?

Answer 32

AP, AP open mouth, lateral

oblique is indicated when radicular sxs are noted so as to visualize intervertebral foramina and possible osteophytes

Question 33

single best view for SI jts and lumbosacral area?

Answer 33

AP spot view at 25-30 deg

Question 34

common fracture in ankle inversion is at the 5ht MT, routine view? what additional views demonstrate the area?

Answer 34

routine: AP dorsoplantar projection, MO, lateral
can do these of just the toes or of the entire foot and can do for the ankle too (AP ankle or lateral ankle)
can also consider doing weight bearing

Question 35

what study demonstrates pneumoperitoneum and/or bowel obstruction?

Answer 35

supine AP aka KUB
scout film to provide an overview of the entire abd
upright chest film for pneumoperitoneum as it will capture free air b/w liver and diaphragm along with any pathology at the base of the lung
can also do LL decubitus if pt can’t stand to observe for any bowel obstruction

Question 36

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

Answer 36

AP pelvis