image receptors 1

Question 1

what are the two ways to capture x rays?

Answer 1

film and digital

Question 2

what are the two forms of film known as?

Answer 2

direct action
indirect action

Question 3

what are the two forms of digital known as?

Answer 3

solid state sensor
photostimuable phosphur

Question 4

what is the scanner called that is used for PSP?

Answer 4

vista scan tower

Question 5

what are the advantages of using PSP?

Answer 5

-tolerated by most patients
-can be used with holders

Question 6

what are the disadvantages of using PSP?

Answer 6

-can be easily damaged
-expensive
-sensitive to background radiation (daylight)- must be cleared every 24hrs if unused

Question 7

how does PSP work?

Answer 7

-psp placed in mouth
-phosphur coated side exposed to X-rays (stable excited state)
-plate dropped into vista scan tower and scanned by red laser (unstable excited state)
-blue light is emitted and converted into image

Question 8

when is the latent image produced?

Answer 8

when x ray energy is stored in electrons of phosphur crystals

this is later emitted as blue light

Question 9

what converts blue light to image?

Answer 9

ADC

Question 10

how does ADC convert blue light to digital signal?

Answer 10

each pixel is given numerical value depending on intensity of light detected
-each numerical value represents shade of grey
-this forms image

Question 11

how is residual energy in phosphor electrons erased?

Answer 11

by bright light

Question 12

what are the two forms of solid state sensors?

Answer 12

CCD and CMOS

Question 13

what are the four layers of sensors?

Answer 13

front layer
scintillator layer
silicone water layer
back layer

Question 14

what happens at the scintillator later?

Answer 14

x ray is converted to light

Question 15

what happens at the silicone water late?

Answer 15

light is converted to electrical signal after it hits photosensitive cells

Question 16

what happens at back cover layer?

Answer 16

it is connected to pc and carries signal to computer

Question 17

in CCD, how are pixels connected and how are the formed?

Answer 17

pixels are connected to neighbours and signals are formed in lines

Question 18

what is the difference between CCD and CMOS?

Answer 18

it is the same process but in CMOS photosensitive cells are isolated and each released a signal instead of in lines

Question 19

what are the advantages of Digital over film?

Answer 19

-no chemicals
-less storage
-no ventilation needed for hazardous chemicals
-image processed faster
-can edit image
-archive image
-easily transferable
-dose reduction as less repeats

Question 20

what are the disadvantages of using digital over film?

Answer 20

-easily damaged
-image not as detailed
-stored on software- power cut-cyber attack?
-security- may be transferred to wrong place
-hackers
-may over edit image- affects diagnosis

Question 21

how are images stored?

Answer 21

locally and backed up nationally

Question 22

what is the storage system called in DDH?

Answer 22

PACS

Question 23

where are images stored and backed up?

Answer 23

NHS tayside and national archive

Question 24

what size of film is always used for solid state sensor?

Answer 24

2