how to create an x ray image

Question 1

radiographic film types

Answer 1

direct action or wrapped - intra oral

indirect action film - extraoral

Question 2

intra oral film packaging

Answer 2

surface facing X-ray beam is white
reverse surface is white and another colour
different speeds
have different colours

only open in dark

Question 3

intra oral film packaging

Answer 3

surface facing X-ray beam is white
reverse surface is white and another colour
different speeds
have different colours

only open in dark

Question 4

intra oral lead foil

Answer 4

prevents some residual radiation

prevents scattered photons coming back and hitting film

Question 5

self developing film

Answer 5

no protective lead and no need for darkroom

poor quality

Question 6

indirect action film

Answer 6

used in between intensifying screens
silver halide emulsion reactive to colour not X-rays
screens have phosphors that emit the correct light colour

photoelectric effect

lower dose to patient

Question 7

effects of KV mA and Time

Answer 7

kv: determines penetrating power of photons - less kv is more contrast
more kv makes it grey shades

mA and time :

determines quantity of X-ray photons

affect degree of blackening

over exposed - too black
under exposed - too pale

Question 8

how processing converts green to black/white?

Answer 8

not sure

Question 9

development

Answer 9

developer - alkaline solution, reduces sensitised silver halide to black metallic silver

time and temp dependent.

over developed too dark
under developed too pale

Question 10

fixation

Answer 10

fixer - acid solution
removes silver halide emulsion to reveal clan white base

under fixed films become brown with time

Question 11

image receptors - types of digital

Answer 11

1. solid state receptors - real time image to computer but quite bulky
2. phosphor plate receptors - not directly connected to computer, plate is inserted into reader

Question 12

digital imaging pixels problem

Answer 12

not always accurate when not full squares are filled

so smaller pixels = more accurate

increasing pixel value makes image brighter

max value is 8 = white

image can be embossed to make pseudo 3d

image can be reversed

Question 13

advantages of digital

Answer 13

lower radiation dose
no processing time 
electrical storage 
automated analysis 
patient education

Question 14

digital disadvantages

Answer 14

expensive

bulky sensors

large storage required

poor quality hard copy