A cassette is alight-tight metal container which
is designed to hold the x-ray film and intensifying screens in close contact.
The front face which is of aluminum or plastic,
faces the tube while the other side have a sheet of lead to absorbed
back-scatter screens and cassettes are of course made in various sizes to
correspond with standard film sizes.
Mounting intensifying screens in the cassette
Intensifying screens should be never be loose but must be properly mounted into
Because certain adhesives interact with the screens it is advisable to use only
the double-sided tape provided by the manufacturers.
The care of cassettes
Do not drop them on a hard
Do not trap the edges of the
screens when the cassette is closed
Cassettes should be kept
clean and there is always the danger of blood or urine leaking to the inside of
the cassette. When a cassette must be placed in a dirty situation put it in a
Check for contrast
The dry bench is where the
cassette are unloaded and recharged with fresh film. It must be impossible for
splashes of developer to reach the dry bench surface.
The top of the dry bench must be large enough to
accommodate the largest cassette in use when opened out.
The top surface should be either of wood or
linoleum. Plastic laminates are not recommended because they hold static charges
of electricity which can cause marks on films.
It is usual to store film boxes, especially
those in current use , beneath the dry bench , either in a cupboard ( protected
if near an X-ray set ) or in a film hopper.
The processing frames should
hang above the bench , cash size on its appropriate. There are two designs of
processing frame– the channel type and the clip type.
The wet bench is where the processing of the
films is carried out . It is possible to process the individual films in flat
dishes but the method has a number of disadvantages and is not be recommended.
The usual method is to use a set of tanks
holding developer ,rinse water and fixer , and a larger tank for washing the
requires the developer to be at the optimum temperature of 20c (68 f).
The heater is put into the
developer and the current switched on. On an average, the temperature will be
raised by 1 degree per minute. In very cold weather it is also desirable to heat
The washing tank should be at
least four times larger than the developer tank, with a supply of cold water
constantly circulating through it, via a rubber hose, when films are being
X-ray film before processing is sensitive to
white light; it must only be handled under safe-lighting.
A safe-light is a box containing a low wattage
bulb behind a specified filter. This is a sheet of dyed gelatin between glass.
Two forms of safe light can be
used in the radiographic dark room:
Safe light efficiency
Top Processing room and equipment
A radiographic processing
room must capable of being made completely dark. The room must be kept clean and
it should not be used for other purposes. A red, orange or yellow safe light may
The arrangement of the dark room should provide
easy accessibility during processing a bench for loading and unloading cassettes
should be placed at one side of the room and the processing tanks at the
opposite side the bench should be some distance from the processing tanks.
Immediately above or below the bench there
should be space for storing film hangers. Unexposed x-ray film and cassettes
should be stored in a cool dry place such as the processing room.
The processing equipment
include a developing tank of sufficient size to contain a 14x17 inch x-ray film
an intermediate wash tank and a fixer tank.
Processing tanks should be
cleaned periodically, usually at every changes of solution. Sodium hypochlorite
(Clorox) diluted in 4 parts of water is recommended for stainless-steel and
hard-rubber tanks. These tanks should be scrubbed with a fiber brush.