Image receptors 1

Question 1

what are the two ways to capture an x-ray image?

Answer 1

film and digital

Question 2

remember digital has no orientation dot so can get muddled up

Question 3

name 2 types of film

Answer 3

direct action film

indirect action film

Question 4

what do the x-rays act on in direct action film?

Answer 4

directly on silver halide crystals in film emulsion

Question 5

what do the x-rays act on in indirect action film?

Answer 5

on intensifying screens to produce light that acts on silver halide crystals in film emulsion

Question 6

what is indirect action film used for?

Answer 6

extra-oral radiographs

Question 7

what are the 2 types of digital x-ray imaging?

Answer 7

solid state sensors

photostimulable phosphor psp

Question 8

what are the 2 types of solid state sensor (digital imaging)?

Answer 8

CCD charged-coupled device

CMOS complementary metal-oxide semiconductor

Question 9

a CCD charged coupled device (solid state sensor - digital) has 4 layers.
front cover
scintillator layer
silicon wafer
back cover

what is the purpose of the scintillator layer?

Answer 9

converts x-rays to light

Question 10

a CCD charged coupled device (solid state sensor - digital) has 4 layers.
front cover
scintillator layer
silicon wafer
back cover

what is the purpose of the silicone wafer?

Answer 10

converts the light into an electrical signal

Question 11

a CCD charged coupled device (solid state sensor - digital) has 4 layers.
front cover
scintillator layer
silicon wafer
back cover with cable

what is the purpose of the back cover?

Answer 11

to carry signal to a PC can be wireless though

Question 12

digital - solid state sensor - CCD
how does it work

X-rays hit ??, reaction gives off ?

? hits photosensitive cells in ??

? in each cell are released forming a ? through neighbouring cells which is converted to an ?

Answer 12

scintillator layer
light

light
silicon wafer

electrons
charge
image

Question 13

digital - solid state sensor

Charged coupled device and complementary metal-oxide semiconductor work in a similar way.

what is the difference between CCD and CMOS?

Answer 13

Difference is each cell electrically isolated so signal is sent from individual cell not line of neighbouring cells

Question 14

advantage of digital solid state sensors (CCD & CMOS) compared to phosphor plates

Answer 14

Resolution (detail) better that phosphor plates

Question 15

what digital image system is used in DDH?

Answer 15

Photo-stimulable phosphor

Question 16

digital - photo-stimulable phosphor

x-rays react with ? which stores radiation in local ? energies called the ?? -> ?? state

Plate scanned by ?? in vista scan unit causing electrons to ? to ??? by emitting ?? -> ?? state

Blue light is converted into an image using an ???? ADC

Plate ? by exposing phosphor to ??

Answer 16

phosphor
electron
latent image
stable excited

red laser
drop
lower energy levels
blue light
unstable excited

analogue to digital converter

erased
bright light

Question 17

digital advantages over film 6

Answer 17

No chemicals
Faster processing times
Easy archiving - almost instant access to image
Easy image transfer - can send the image to anyone easily
Image manipulation - bigger, darker, lighter
Dose reduction

Question 18

digital disadvantages to film 6

Answer 18

Expensive
easily damaged
Reduction in resolution due to pixel size and dose reduction
Archiving - back up, software issues, power-cuts etc
Easy image transfer - security concern
Image manipulation - incorrect diagnosis

Question 19

what has caused the little variation in grey shades?

Answer 19

overexposure

Question 20

what has caused the white mottling on image?

Answer 20

underexposure
not enough radiation hit the receptor

Question 21

what is the archiving and communicating system used in DDH?

Answer 21

PACS