Exam Review

Question 1

what setting is controlled by mA?

Answer 1

quantity of the beam

Question 2

what kind of crystal is in a dosimeter?

Answer 2

lithium crystal

Question 3

when a radiograph is developed for too long, what happens to the image?

Answer 3

it appears too dark

Question 4

what part of cells is most negatively affected by radiation?

Answer 4

DNA

Question 5

true or false; does changing the SID change the density of the radiograph?

Answer 5

true

Question 6

how thick is the layer of lead in our gloves, gowns, etc?

Answer 6

0.5mm

Question 7

as the energy of an x-ray photon increase, does the wavelength increase or decrease?

Answer 7

decrease

Question 8

true or false; when electrons collide with the target anode 1% is heat and 99% is photons

Answer 8

false; collisions result in only 1% photons (x-rays) and 99% result in only heat

Question 9

how long are clinics required to keep their log books on record?

Answer 9

5 years

Question 10

if you are preparing to take radiographs and the SID is set at 65 inches, is this a problem? why?

Answer 10

yes; SID should always be maintained at 40 inches otherwise the radiograph will be too intense

Question 11

what is the relationship between mA and electrons? kVp?

Answer 11

mA is directly related to the AMOUNT of electrons, kVp is directly related to the SPEED of electrons

Question 12

what is the purpose of the developer?

Answer 12

converts exposed silver halide crystals to black metallic silver; makes the latent image visible

Question 13

what is the purpose of the fixer?

Answer 13

clear the unexposed silver halide crystals; hardens the emulsion

Question 14

where would you measure for a lateral abdomen radiograph? peripheral borders?

Answer 14

measure: caudal of the thirteenth rib to T7 (thoracolumbar junction)
peripheral borders: caudal of 13th rib, femoral head

Question 15

what three things will increase scatter?

Answer 15

larger field of view, higher kVp, higher mAs

Question 16

how are x-rays produced? explain the process of excitation.

Answer 16

1. electrons released from negatively charged cathode
2. electrons accelerated via kVp toward positively charged metal anode
3. electrons collide with particles (electrons) from the anode
4. they react; process of excitation begins
5. as electron gains energy, it is able to move up in orbit
6. when it gains even more energy, it is able to “fall” back to original orbit
7. during “fall” an electromagnetic photon (x-ray) is released by loss of energy

Question 17

why would you not perform a VD abdominal radiograph? give at least 3 reasons

Answer 17

bloated patient, obese animal, pregnancy, trauma, spinal injury, etc

Question 18

how would you alter settings for a repeat radiograph if your bones appear too grey?

Answer 18

contrast was too low; lower kVp by 10-15% to achieve higher contrast

Question 19

what MUST be included on every label ? list at least 3

Answer 19

patient name, RAD log number, date, etc

Question 20

landmarks that indicate the left side of the animal on a VD abdomen radiograph?

Answer 20

left kidney appears LOWER than the right right kidney
majority of stomach rests on left side
spleen

Question 21

what views should be taken if the vet suspects elbow dysplasia?

Answer 21

lateral with extension, lateral with flexation 9of elbow), cranial caudal

Question 22

how do radiographs get black crescent shaped artifacts? what are those black crescents? when are they acquired ?

Answer 22

crescents are scratches from handler’s nails, occurs after exposure but before development (i.e. when removing film from cassette)

Question 23

define: penumbra; how does this occur?

Answer 23

penumbra: an unclear image caused by movement (of animal)

Question 24

should thoracic radiographs be taken on inspiration or expiration? 3 differences you can appreciate between inspiration and expiration?

Answer 24

should be taken on inspiration; no contact between heart and diaphragm, less sternal contact, heart looks smaller on inspiration

Question 25

what types of crystals are in intensifying screens?

Answer 25

fluroescent phosphor crystals
lanthanide crystals (rare earth)
calcium tungstate crystals

Question 26

what factors affect the speed of intensifying screens?

Answer 26

type of phosphor crystals
thickness of crystal layer
size of crystals
efficiency of the reflective layer

Question 27

you’ve taken an abdominal radiograph and can only kind of make out the organs/soft tissue but not perfectly; how would you alter the settings?

Answer 27

double mAs

Question 28

how often are dosimeters replaced?

Answer 28

every 3 months

Question 29

what factors determine whether or not an x-ray will be absorbed or will penetrate through materials?

Answer 29

density of material
strength of the beam
what material is made up of

Question 30

true or false; when radiographing a young, squirmy animal, you would choose 100mA and 60ms over 200mA and 30ms for better results

Answer 30

false; in patients that are young/prone to moving during the x-ray process, it is advisable to

Question 31

what happens in the tube head when you press and hold the “ready” button?

Answer 31

the cathode is heated

Question 32

true or false; for a thoracic radiograph you want high density and low contrast settings

Answer 32

true; high density will allow you to distinguish between soft tissues, low contrast allows you to see past the ribs

Question 33

what 4 views could you take of a paw?

Answer 33

metacarpal-phalanges lateral
m-p dorsoplantar
m-p obliques
m-p ventropalmar

Question 34

what is different about a metacarpal-phalanges lateral radiograph and a m-p obliques radiograph?

Answer 34

m-p lateral is like any other lateral radiograph where as m-p obliques separates each toe to be viewed

Question 35

what is the optimal/most correct view for a thoracic radiograph?

Answer 35

DV

Question 36

what causes foreshortening on a limb radiograph?

Answer 36

limbs not parallel, tilted beam