Radiology 1

Question 1

Properties of x-rays and how it can be used to create a radiograph

Answer 1

• high energy (to penetrate matter)
• can ionize atoms
• varies in wavelength and energy
• Creates a series of Silhouettes

Question 2

How can x-rays cause biological damage?

Answer 2

• They can ionize atoms (mutation and death)
• cancer
• effect on growth and development
• reduced lifespan
• premature aging
• Cataract

Question 3

Whole body limit of occupational radiation exposure? (mrem/yr)

Answer 3

5,000

Question 4

3 main principles of radiation protection

Answer 4

distance, time, and shielding

Question 5

What is the mA selector?

Answer 5

Controls current to the anode (x-ray quantity)

• more current= more x-rays produced
• toast analogy

Question 6

What is the mAs selector?

Answer 6

mA x Time (msec) = mAs

- x-ray quantity

Question 7

What is the kVp selector?

Answer 7

Energy of the beam and number of x-rays
(quantity AND quality)
- determines CONTRAST

energy of beam (quality) = penetrating power

Question 8

What is the focal spot selector?

Answer 8

2 filaments in the cathode (small and large)

small image= high detail
large image = low detail

Question 9

What is the timer?

Answer 9

number of x-rays in beam , (quantity) - (msec)

Question 10

How to control scatter radiation?

Answer 10

Collimated beams and grids

Question 11

What is scatter radiation?

Answer 11

Only a small % of radiation goes all the way through the object and onto the film

it decreases the contrast of image

Question 12

What is a collimated beam?

Answer 12

• limits the beam to an area of interest
• collimator knobs on machine (=, ||)
• decreases scatter
• improve image quality

Question 13

What is a grid?

Answer 13

Alternating strips of lead

• prevents scatter from reaching film
• improves contrast

Question 14

2 steps to forming a radiograph (think cathode/anode?

Answer 14

1. prep
   
   • electrons are made by an electrical current through a filament (cathode)
   • high voltage- so hot it glows
2. expose
   
   • x-rays are produced when the electrons interact with the metal in the anode, and shoots out an x-ray beam

Question 15

What are the 5 basic radiographic opacities ? (from highest attenuation to lowest)

Answer 15

Metal
Bone
Soft tissue
Fat
Air

Question 16

What is summation effect?

Answer 16

overlapping of 2 objects adds to the opacity

2 dimes or 2 kidneys overlapping

Question 17

What is the silhouetting effect?

Answer 17

2 objects of the same density will blend together
-causes border effacement
(almonds/diamonds in water or fluid in abdomen)

Question 18

What is magnification distortion?

Answer 18

image is larger when it is further away

right kidney looks bigger on film

Question 19

What is image distortion?

Answer 19

When the image is not in the center, it will look distorted

paper clip looks smaller at an angle or bones looking different sizes

Question 20

How does motion impact a radiograph?

Answer 20

it will blur the image

Question 21

Proper orientation of radiographs

Answer 21

cranial to caudal (left to right, or top to bottom)
dorsal to ventral (top to bottom)
Right to left 
use markers
mark film for each patient/hospital/date