Test 1

Question 1

What is ionizing radiation?

Answer 1

Radiation that has enough energy to remove electrons from atoms (creates ions)

Question 2

Why is ionizing radiation dangerous?

Answer 2

When the electrons are stripped from atoms, they can then interact with other biological molecules (e.g. strands of DNA which then causes mutations/cell destruction) in the body. The radiation intensity depends on exposure time and strength of the radiation.

Question 3

True or false- Radiation damage in an individual can be passed onto their offspring.

Answer 3

True. Damage to the genetic code in reproductive cells can show up in future generations.

Question 4

What is the name of the device that monitors your personal radiation intake? How does it work?

Answer 4

Dosimeter. Contains a lithium or calcium fluoride crystal that absorbs radiation. When the crystal is heated, it releases the stored energy which can then be measured in the form of visible light.

Question 5

What is secondary radiation? What can lead to this?

Answer 5

Most often “scatter radiation” which is radiation that has deflected off of an object and onto yourself. Increased kVp and/or increased field size.

Question 6

Why are persons under the age of 19 more likely to develop cancer from exposure to radiation?

Answer 6

Tissues are still growing, meaning that cell divisions are more frequent. Cells are more susceptible to radiation damage during division.

Question 7

When manually restraining, what equipment should be worn?

Answer 7

Lead aprons, gloves, glasses, and thyroid protectors

Question 8

Why is the wall colour in a developing room important?

Answer 8

Lighter colour wall reflects less light.

Question 9

Why is the colour of the safelight light important?

Answer 9

Red light does not affect film due to its wave length.

Question 10

How do you test a safelight?

Answer 10

Expose film in 1/4 increments for 1min each. If safelight is not safe, exposure will darken the film.

Question 11

5 basic steps of manual processing?

Answer 11

Developer for 5mins @20C (if hotter; less time), rinse 30secs, fixer 2x developer time, rinse 2x fixer time, dry 5-10min

Question 12

What does developer do?

Answer 12

Converts silver halide crystals that got exposed to radiation, to black metallic silver

Question 13

What 2 purposes does the fixer provide?

Answer 13

Clears away unexposed silver halide crystals and hardens the emulsion

Question 14

What is reticulation? What causes this?

Answer 14

“wrinkles” or “cracks” in the film caused from temperature difference between the developer and the fixer.

Question 15

What will happen if you do not rinse/wash your radiograph?

Answer 15

The image will darken over time.

Question 16

How do you start up the automatic processor? 7 steps.

Answer 16

Make sure wash drain, developer, and fixer valves are closed; open water tap; closer processor and feed tray covers; turn on power breaker; press run, wait for ready lamp to light up (~20min); open feed tray cover and insert 1-2 cleaning sheets (1 at a time)

Question 17

2 differences between manual and automatic processors?

Answer 17

Automatic uses a higher temperature and does not rinse between developer and fixer.

Question 18

What information must be included on a label?

Answer 18

Name, address of hospital, practice, or veterinarian, date, and patient identification.

Question 19

Legally, how long must radiographs be kept for?

Answer 19

5 years

Question 20

What are x-rays and how do they compare to visible light?

Answer 20

Electromagnetic radiation. Greater energy and a short wavelength.

Question 21

What is excitation? How does it work?

Answer 21

A method of transporting energy through space. A collision with a moving particle excites an atom which causes an electron to “jump” to a higher energy level. When the electron “falls” to its original energy level, it releases the extra energy via a electromagnetic photon

Question 22

The shorter the wavelength, the _______ the energy

Answer 22

Greater.

Question 23

How are x-rays formed?

Answer 23

Negatively charged electrons are emitted from a cathode (via heating process) and accelerated (via kVp) towards a positively charged anode (metal). The electrons react with the metal anode, and when they collide with a nucleus, they knock an electron out of an inner ring of the target metal atom. This starts the process of excitation which releases an electromagnetic photon (x-ray). This only happens to ~1% of the electrons. The other 99% will “miss” and generate heat instead.

Question 24

What is brehmsstrahlung or “braking radiation?”

Answer 24

The process of the electrons decelerating and releasing electromagnetic radiation when hitting the metal anode.

Question 25

What affects exposure? How?

Answer 25

higher kVp = faster beam = more penetrating power; time (mAs) longer duration = more electrons converted to x-rays; shorter distance = more penetrating power

Question 26

What does milliamperage (mA in mAs) do?

Answer 26

Heats the cathode- more heat = more electrons

Question 27

What is thermionic emission?

Answer 27

The process of heating the cathode to release electrons.

Question 28

How can you differentiate if a too light or a too dark film was caused by the kVp setting or the mAs setting? How do you correct this?

Answer 28

First, determine if the problem was kVp by looking at the penetration of the image(no details on the image means a low kVp). If penetration was not a problem, then mAs was. If film does not have a high enough density, but penetration is okay, double the mAs (half mAs if too dense). If the film is over penetrated (grey bones), lower kVp by 10-15%.

Question 29

What is contrast? How does it apply to radiographs of soft tissue vs. bone?

Answer 29

The difference between the adjacent densities of the film. You want high contrast for bones (low kVp) and low (high kVp) for soft tissue.

Question 30

What object can be used to limit scatter radiation? When would you typically use it?

Answer 30

A grid. Body parts >10cm.

Question 31

4 basic criteria for patient positioning?

Answer 31

Patient welfare, restraint/immobilization that will be needed, potential trauma to area of interest, exposure to restrainers

Question 32

What views are required when taking a radiograph?

Answer 32

2 views at right angles to each other with the area of interest closest to the film.

Question 33

Where do you measure for thoracic positioning? Where do you include from? Max. inspiration or expiration? Why?

Answer 33

Caudal border of scapula. Scapulohumeral articulation to L1 (in large animals it is more important to get shoulder joint rather than whole rib cage). Inspiration. Gap between heart and diaphragm.

Question 34

Where do you measure for abdominal positioning? Where do you include from? Expiration or inspiration? Why?

Answer 34

Thoracic-lumbar junction (2-3 finger widths caudal in cats). T9 to femoral head (may need to take 2 views if patient is large). Expiration so that diaphragm is cranial.