X-rays/CT scan/Ultra Sound

Question 1

CT X

Answer 1

X-Ray: Series of x-ray images

Question 2

CT A

Answer 2

Angles: Different angles are used

Question 3

CT I

Answer 3

Image: To give the image of the slice

Question 4

CT S

Answer 4

Slice: Repeated for many different slices

Question 5

CT 3

Answer 5

3D: To build a 3D image

Question 6

Formula for half life

Answer 6

Half life = ln(2) / decay constant

Question 7

Formula for activity

Answer 7

A = Decay Constant * Number of undecided

Question 8

How are x-rays produced?

Answer 8

Metal target bombarded with electrons, when ever a particle is accelerated it emits electromagnetic radiation

Question 9

X-ray ratio between acceleration and wavelength

Answer 9

Inversely proportional

Question 10

X-rays are emitted from?

Answer 10

The heated cathode

Question 11

X-rays: How is intensity controlled?

Answer 11

Controlling rate of arrival of electrons at the anode by controlling the heat of the cathode

Question 12

X-rays: How is hardness controlled?

Answer 12

Potential Difference

Question 13

X-rays: How is sharpness controlled?

Answer 13

X-ray beam width, inversely proportional

Question 14

X-rays: What are soft x-rays?

Answer 14

Set of peaks at longer wavelengths that don’t add to the image but increase background radiation, absorbed by using a aluminium window

Question 15

X-rays: What absorbs more bone or muscle?

Answer 15

Bone

Question 16

Formula for attenuation of X-rays

Answer 16

I = I * e ^-yx where y is a constant

Question 17

What is HVT

Answer 17

Half value thickness, depth required to reduce intensity by one half

Question 18

Steps for working out CT scan

Answer 18

Remove background, divide by number of scans-1

Question 19

Formula for acoustic impedance

Answer 19

Z = pc where c is the speed of sound in a medium

Question 20

What is acoustic impedance

Answer 20

The resistance sound waves encounter in a medium

Question 21

Formula for intensity at a certain depth

Answer 21

I = I * e ^ -kx where k is the absorption constant

Question 22

What is ultrasound used for

Answer 22

To gather information about internal structures of the body

Question 23

How does ultrasound work

Answer 23

Monitoring pulses of ultrasound are sent into the body at regular intervals, the ultrasound is reflected on large changes in acoustic impedance, this reflected sound is mapped based on the time it took to return which produces an image

Question 24

Why is cellulose gel used

Answer 24

To limit the large change of acoustic impedance at the boundary

Question 25

What is an A-Scan

Answer 25

Distance, time and strength of reflected sound waves are used to map using a transducer and a C.R.O

Question 26

What is a B-Scan

Answer 26

Multiple A-Scans put together to build a 2-D image