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Flashcards in Imaging Tumours Deck (114)
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1

What umbrella does most hospital imaging come under

Structural

2

Name 6 imaging techniques

How can all these methods be used

Fluorescence
Ultrasound
X Ray (including CT)
PET
SPECT
MRI

By injecting an imaging agent into the blood stream and imaging that

3

Define molecular imaging

Imaging molecules that are undergoing biological processes at the cellular or subcellular level

4

What is functional imaging

Imaging properties of tissues beyond their anatomical structure such as the size of their cells or the leakiness of blood vessels

5

How is energy transferred through space

Electromagnetic radiation

6

What form is the energy in electromagnetic radiation

Photons

7

What is an electromagnetic wave

A stream of photons all with the same frequency

8

What is the most common C isotope

How many neutrons and protons

What is another C isotope

C-12

6 protons and 6 neutrons

C-13 and C-14

9

Is C-13 stable

Yes

10

What do unstable C isotopes emit

What are the associated molecules

Gamma rays (Tc-99m) or positrons (F-18)

11

Name 2 imaging techniques that use MRI machines

MRI
and Magnetic Resonance Spectroscopy

12

Give the 4 key features of an MRI machine

1. A super conducting magnet that provides a strong permanent magnetic field
2. Radio frequency antennae (coils)
3. Gradient coils to spatially vary the magnetic field
4. Console

13

What do coils do in an MRI machine

Send and receive radio waves of the MRI signal

14

What is a pulse sequence

The specific set of pulses and timings of radio waves sent from the coil of the MRI machine into the patient

15

Do all isotope nuclei have spin

No

16

Name a common isotope that has spin

Hydrogen - 1 which makes up 99.98% of the hydrogen in water

17

What is the most common isotope of P

Does it have spin

P-31

Yes

18

Which carbon molecule has spin

C-13

19

How common is C-13

1% of all C molecules in the universe

20

What is chemical shift

Different chemicals in the body have NMR signals at different frequencies

21

What is the unit of the frequency axis in an NMR graph

ppm (part per million) NOT Hz

22

Why do we use ppm not Hz in NMR

The actual frequency of peaks is proportional to the static magnetic field of the MRI/NMR instrument

23

What does part per million mean

How many millionths of the static magnetic field the peak is from 0

24

How might your use C-13 glucose to image muscles

How many peaks would you see when doing this imaging on a resting muscle

Tune the coils of the MRI machine to send and detect C-13 nuclei frequencies
Inject the patient with C-13 glucose and watch its peaks

3 peaks: α-glucose, β-glucose, and glycogen

25

How is MRS an insensitive technique (2)

A large amount of muscle is used for each spectrum

Results take hours to acquire

26

Other than water, what molecule is very commonly imaged with clinical scanners

Fat

27

Why do the 2 H atoms in water only give 1 peak

The water molecule is symmetrical so they have the same frequency

28

What does turning on a gradient do when imaging water

It changes the magnetic field so it is smaller on the left and larger on the right

1 gradient turning on allows a 1 dimension image to be formed

29

What are the 3 dimensions produced by using 3 gradient coils in the bore of the MRI

Up down

Left right

In out

30

What is the main cause of an MRI signal appearing brighter in some places on the scan

What is another cause

Relaxation

Also some tissues have more water than others