Intro to CR/DR and PACS

Question 1

CR

Answer 1

computed radiography system

Question 2

DR

Answer 2

digital radiography

Question 3

DF

Answer 3

digital fluoroscopy

Question 4

NM

Answer 4

nuclear medicine

Question 5

MRI

Answer 5

magnetic resonance imaging

Question 6

CT

Answer 6

computed tomography

Question 7

DSA

Answer 7

digital subtraction angiography

Question 8

how do computers process numbers

Answer 8

on a binary base 0/1

Question 9

what do modern computers correspond to

Answer 9

off/ on of trillions electronic switches : transistors

Question 10

what is a bit

Answer 10

a binary digit ( base 2)

Question 11

what is an analogue image

Answer 11

an image viewed on film/tv as an image composed of CONTINUOUS variations of optical density (not separate clumps)

Question 12

what is a digital image

Answer 12

• analogue image converted to digital image via ADC
• matrix of binary numbers held in computer
• these numbers distinct from one another to determine shade of grey

Question 13

ADC

Answer 13

analogue to digital conversion

Question 14

what is sampling in ADC

Answer 14

conversion of analogue signal into digital signal via process of regular periodic measurement

Question 15

what do more pixels mean

Answer 15

smaller - pixel size determines smallest structure that can be demonstrated in an image
- the more pixels the better the resolution

Question 16

what does ADC determine

Answer 16

the digital values allocated to each pixel

Question 17

what is a photo diode

Answer 17

very fast switch activated by light

Question 18

what are flat panel detectors

Answer 18

they are an absorbing layer that converts x-rays into light

Question 19

what converts light into electrical signals

Answer 19

amorphous selenium

Question 20

difference between analog and digital image

Answer 20

• analog is various levels of brightness and colours and not broken down into individual pieces
• digital images are recorded as many binary numbers and divided into matrix of small pixels

Question 21

what is teleradiology

Answer 21

• images transferred via telephone line
• digital images transmitted to different location
• images received with image manipulation

Question 22

advantages of teleradiology

Answer 22

• hospital to home emergency reporting - efficient
• remote locations linked to larger hospital

Question 23

disadvantages of teleradiology

Answer 23

• doctors not discussing ur medical findings with you face to face leads to miscommunication

Question 24

what does matrix size determine (number of pixels)

Answer 24

determines spatial resolution

Question 25

what does matrix depth (number of bits) determine

Answer 25

contrast resolution

Question 26

pre-processing

Answer 26

automatically manipulates data to optimise display of image and reduces need for post processing

Question 27

post-processing

Answer 27

pre-processed image is displayed for review
- area under investigation
-patient positioning and collimation are checked

Question 28

examples of post processing

Answer 28

• addition of anatomical markers
• image annotation
• window and level adjustment
• electronic collimation
• magnification

Question 29

advantages of digital imaging

Answer 29

• wide latitude
• improved image contrast
• adjusts for over and under exposure
• eliminates repeats
• digital archiving
• radiographs comparable