Week 2.1 Imaging Fundamentals

Question 1

what is the most common modality for bone and joint

Answer 1

conventional radiography

Question 2

what are the benefits of conventional radiography

Answer 2

first order diagnostic study
little risk
time effective
cost effective

Question 3

how are images produced in standard radiographs

Answer 3

on a sensitive plate or film,

• x-rays
• gamma rays
• similar radiation

Question 4

radiation passes through a patient where it is ____, and then what

Answer 4

attenuated (blocked by bones depending on the density)

then the remnant radiation is incepted by the receptor and creates a visual image

Question 5

what are the 4 key points when talking about ionizing radiation

Answer 5

• neural atoms gain or lose an electron
• disrupts composition of matter
• disrupts life processes
• protection against excessive exposure

Question 6

expand on the phrase “protection against excessive exposure”

Answer 6

do no harm, and is the information gained from this study more important then the risk you are putting the patient in, and the harm it does to them

Question 7

Air Kerma

Answer 7

absorbed in the absence of scatter, the radiant radiation absorbed by the air

Question 8

Dose area product

Answer 8

integral of air Kerma, for an entire x-ray beam

Question 9

Absorbed dose/CT dose

Answer 9

dose from the primary beam plus scatter from surrounding slices.

Question 10

Equivalent dose

Answer 10

absorbed dose adjusted by weighting factor of type of radiation (CT and X-ray weighting factor of 1)

Question 11

effective dose

Answer 11

adjustment to of equivalent dose based on the tissue susceptibility to ionizing radiation (type of tissue, abdomen vs ankle… very different)

Question 12

absorbed dose is the dose

Answer 12

of energy that is deposited in the patient

Question 13

equivalent dose is the

Answer 13

absorbed dose that is adjusted for harmful effects

Question 14

effective dose is

Answer 14

equivalent dose that is adjusted for harm that it causes to different tissues

Question 15

what is the cut off for tolerable levels of exposure

Answer 15

20mSv

Question 16

how many mSv do you get from the sun every year

Answer 16

2mSv

Question 17

what does tolerable levels of radiation mean

Answer 17

no symptoms, and no detectable increased risk for cancer.

Question 18

what is the cut off for moderate risk, and what does it mean

Answer 18

no immediate symptoms, and an increased risk of serious illness later in life. Cut off is 1000 mSv

Question 19

what are the components of a typical conventional radiograph

Answer 19

you have an emitting device that has a plate of some kind to absorb the remaining radiation

Question 20

what is radio density

Answer 20

the physical qualities of an object that determine how much radiation is absorbed

Question 21

what affects radio density

Answer 21

the composition of the tissue (anatomic number and the volume density)
thickness

Question 22

the greater the atomic number, volume density and or thickness, the ___ the radio density

Answer 22

greater

Question 23

what is the difference between radiolucent and radiopaque

Answer 23

radiolucent is black, and radiopaque is going to be white

Question 24

a single radiograph provides __ dimensions

Answer 24

2, length and width

Question 25

what adds a third dimension to a conventional radiographs

Answer 25

90 degree angle, another radiograph

Question 26

always need ___ images

Answer 26

2, if you have 1 you have none

Question 27

in conventional radiographs, the projection describes…

Answer 27

the path of the beam

• anterior to posterior (above to below)
• posterior to anterior (prone)

Question 28

what are the 4 image quality factors for a conventional radiograph

Answer 28

• density (blackening of image)
• contrast (difference between adjacent densities)
• detail (geometric sharpens or accuracy)
• distortion (difference between actual object and its recorded image- size and shape)