Radiography And Ultrasonography

Question 0

Describe the x-Ray tube. Why is each component important?

Answer 0

Anode and cathode (source of x-ray production) placed in Pyrex vacuum (air particles don’t interfere), surround by lead (to stop x-rays escaping), surrounded by black aluminium (aids in heat loss). Aluminium filter placed over pre-determined window to catch low energy beams that would be absorbed by patient

Question 1

What is thermionic emission?

Answer 1

When a cloud of electrons are generated from the heating of the tungsten cathode, during production of X-rays.

Question 2

In terms of ultrasonography, what is a speculate reflection?

Answer 2

A reflection created when the beam hits a large smooth surface eg bladder

Question 3

Give five advantages of ultrasound

Answer 3

1. safer than X-Ray, no ionisation
2. Widely available
3. Non-invasive
4. Rarely needs GA
5. see soft tissue better than on X-Ray

Question 4

Give 5 disadvantages to ultrasonography

Answer 4

Equipment is expenisive and easily damaged
Need to clip hair (not great for show animals)
Experience needed to interpret images
Gas and bone hinder image, less info than with X-Ray for these mediums
Often need post-scan biopsy, not definitive answer

Question 5

How many days into pregnancy can you diagnose puppies/kittens in dogs/cats?

Answer 5

25 days in a dog and 20 days in a cat

Question 6

Name the layers that make up single sided emulsion film

Answer 6

Super coat: hardened layer of gelatin
Emulsion: silver halides and gelatin
Subbing layer: gelatin and polyester blend, holds emulsion to base
Film base: polyester

Question 7

How is Computed Radiography different from Direct Digital Systems?

Answer 7

Computed is similar to cassette style, crystals store light energy, which is released by lasers in a scanner. Light released converted into a signal, which is converted into an image.
DR involves the detector directly capturing the image and relaying it immediately to a computer.

Question 8

What are the advantages of digital radiography?

Answer 8

Decreases running costs (no films), easily transferable between practices, space saving, reduced radiation doses, saves time, images are of better quality, manipulation of image.

Question 9

What are the hazards of the X-Ray beam?

Answer 9

1. Cannot be felt
2. Penetrating
3. Invisible
4. Effects living tissue

Question 10

What is the MPD for someone aged 18+ per year?

Answer 10

20mSv/Y

Question 11

What is the MPD for someone 16-18 years old per year?

Answer 11

6mSv/Y

Question 12

What is the MPD for a pregnant woman per year?

Answer 12

1mSv/Y

Question 13

What is the MPD for a member of the public per year?

Answer 13

1mSv/Y

Question 14

What is FFD?

Answer 14

Film focal distance, the distance from the X-ray tube to the cassette

Question 15

What is OFD?

Answer 15

Object film distance: distance between the object being radiographed and the X-Ray film.

Question 16

What is Penumbra?

Answer 16

The blurring around the X-Ray image

Question 17

Give 2 examples of developing agents

Answer 17

Hydroquinone and phenidone.

Question 18

What are the 5 steps of X-Ray film processing?

Answer 18

Development, rinsing, fixing, washing, drying

Question 19

Give 2 examples of radio opaque, positive contrast medias.

Answer 19

Iodine and barium, high atomic number so can absorb X-rays

Question 20

Give 2 examples of substances that can be used as negative contrast media.

Answer 20

Room air, oxygen, nitrous oxide, carbon dioxide

Question 21

How would you prepare a horse for an ultrasound?

Answer 21

Clip hair, scrub skin thoroughly with hibiscrub, add surgical spirit, add gel.