Lecture 2.2 Flashcards Preview

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Flashcards in Lecture 2.2 Deck (17):
1

Energy sources for imaging can be putin two categories;

Ionising - detach electrons from atoms

e.g.....

Non-ionising

e.g.....

Ionising

x-rays

gamma rays (NM)

positrons (PET) decay - gamma rays

Nonionising

Sound

FM radio/magnetism (MRI)

2

  Radiography:

Pros and cons?

Pros:

Cheap

avaialble

excellenet spatial resolution

Cons:

ionising radiation

poor contrast resolution

planar technique

3

True or False

 

X-rays are used for detection of breast cancer

True

4

True or False:

 

CT scans use x rays

True

5

CT

 

pros and cons?

Pros:

Cross-sectional

better contrast resolution than radiography

good spatial resolution

Cons:

more ionising radiaiton

expensive

6

Ultrasound

uses piezoelectric crystal to produce ____waves

sound is ______back to the probe

 

Ultrasound

uses piezoelectric crystal to produce sound waves

sound is reflected back to the probe

 

(same idea as sonar

7

pros/cons on Ultrasound?

Pros:

no-ionising radiation

cheaper than CT

freely avaialbe

Cons:

oprator dependent (hands on)

sound penetration: (can't go well through fat/bone/gas)

8

Uses of Ultrasound:

children

pregnancy

screening for abdominal symptoms

pelviuc pathology

small parts (thyroid, testis, breast)

musculo-skeletal (esp. muscles, tendons, ligaments)

blood vessels (Doppler)

9

MRI

very powerful magnet and radio generator

looking at _____ denisty (most in water)

 

MRI

very powerful magnet and radio generator

looking at proton denisty (most in water)

 

10

MRI pros and cons:

 

Pros:

non-ionising radiation

excellent contrast resolution

reasonalble spatial resolution

Cons:

expensive

strong magnet (issues with metal inside people)

long scan times

claustrophobia

11

Uses of MRI:

brain (except acute trauma)

spine for pain or neurological deficit

joints for pain, bones where X-rays not helpful

liver and biliary tree where Ultrasound not helpful

breast in young female for CA

pelvic malignancy

non-invasive angiography

12

Nuclear medicine:

_____ emitting radioisotopes that are injected

targets specific organs - by attaching to a ___

 

 

Nuclear medicine:

gamma emitting radioisotopes that are injected

targets specific organs - by attaching to a drug

 

13

NM:

 

you want high signal coming from the ____ and low emmission from the ________  _____

you want high signal coming from the organ and low emmission from the surrounding tissues

14

NM pros and cons:

 

Pros:

excellent signal to noise

extremely senesitive

Cons:

ionising radiation

very poor spatial resolution

poor specificity ofor apthology

expensive

15

ALARA;

a principle of ionising radiaton

dose shoud be "just" enough to be clinically useful

ALARA;

a principle of ionising radiaton

dose shoud be "just" enough to be _______ useful

16

How do you reduce the harmful effects of ionising radiation?

Fewer procedures

prolonged interval between expsure (allow DNA to repair)

not children/pregnant (rapidly dividing cells)

17