Radiology M4 - R5 : Image receptors 2 Flashcards
what are the three types of intra-oral radiographs
peri-apical
bitewing
occlusal
what is the purpose of the outer plastic wrapping - in a film packet
keeps film dry - saliva free
protects film fromlight damge - fogging
indicates the correct orientation of the film in the mouth - white side towards x-ray tube
what is the purpose of the black paper - film packing
protect film from light leakage
stiffens and supports film, this is to prevent crimp/pressure marks on the film
what is the purpose of the lead foil - in a film packing
composed of a mixture of lead and aluminium
readily absorbs x-rays
prevents back scatter
what is the emulsion consist of
silver halide crystals suspended in gelatin
how is a latent image produced
it is the pattern produced within the emulsion by the sensitizing of silver bromide/iodide crystals, either by light or X-rays
film speed is dependant on the sensitivity of film to x-rays, what would determine the faster the film speed
the larger the crystals the faster the film speed
which radiographs use indirect films
DPT and Lateral Ceph
intensifying screens, allow a reduction in exposure and therefore a reduced dose to pateint - what other reduction does this lead to
reduction in detail in image
how does pressure affect film
pressure sensitieses the silver halide crystals
how would you hold film packets
hold by corners and side
how would you store film
cool - not too cool
dry - not too dry
away from radiation - x-rays, heat
stock rotation to prevent using old film
what are the three methods of film processing
automatic
manual
instant
what are the stages of processing
develop - make latent image visible
wash - stop development and remove dev from film (only in manual)
fix - make image permanent
wash - stop fix and remove residual fixer
dry - easier handled, prevent damage
