dark room construction Flashcards
- room from which the normal light is excluded.
- made completely dark to allow processing of light sensitive radiographic materials.
- laboratory where radiography starts and ends.
- has a controlled environment, designed to be functional and convenient. It is designed for film handling and storage.
dark room
DR Location
- Centrally located Serviced by hatches from the adjacent imaging room
- Placed in the department where the radtech is required to walk as few steps as possible
- Away from damp or hot areas
- Accessible in terms of power and water supply
- Adjoining viewing room
- designed to transfer film cassettes to and from the darkroom without radiation light entering.
- consists of metallic structures with a lead lining to provide x-ray shielding.
- typically wall-mounted and include automatic interlocks that close one door when the other is opened.
- also used for the temporary storage of loaded cassettes,
DR Hatches
Minimum floor area of
10 square meter
15 x 9.5 ft or greater for
200 radiographs per day
ceiling height
2.5 - 3 meters
wet and dry section must be __ away from each other
4ft
negatoscope can be located at the ___ section.
wet
- Component of wall:
concrete
hollow blocks
wood
concrete
greater than 6 inches
hollow block
filled with cement
wood
lined with 1.5 mm Pb
Floors
- Non-porous flooring
- Non-slip flooring
- Chemical resistant
- Stain proof
- Durable and easy to maintain
- Light colored (low-light working conditions)
Floor materials
asphalt tiles
porcelain tiles
clay tiles
plastic tiles may be used in the dry dark room
color of wall and ceilings
ivory or light gray
designed to eliminate heat and fumes.
ventilation and heating
acceptable relative humidity sa storage room and dark room
40 to 60% - storage room
30 to 60% - darkroom
Acceptable room temperature old
20 degree celsius
Acceptable room temperature new
18 to 24 degrees celsius
air changes per hour, exhaust fan
8 to 10 per hour
air movement, fan
15 to 25 ft/min
4 entrances
single door system
double door system
labyrinth or maze type entrance
rotating or revolving door system
simplest type
single
used only when there is darkroom personnel exclusive in the darkroom
double door system
easy access
labyrinth or maze type
most efficient but most expensive. Composed of two black cylinders. The outer is fixed and the inner is a revolving door with only one opening
rotating or revolving
- For inspection and maintenance of cassettes and screens
- Cleaning of work surfaces Servicing of equipment
- Sited close to the ceiling
white light
moderate in intensity of illumination
60W tungsten, 30W fluorescent
Types of Darkroom illumination
- Direct Safelight Fixture type
- Indirect Safelight Ceiling type
- Light from safe lamp directly falls onto the work surface (ex. Beehive safelamp). Most common in the hospital
- Best for loading and unloading areas
direct safelight fixture type
- Directs the light towards the ceiling which reflects light back into the room It uses sodium vapor bulb Distance from workbench must be 6 ft
indirect safelight ceiling type
- Sheet of gelatin dyed to the appropriate color and sandwiched between two sheets of glass for protection
safelight filters
- Used in conjunction with an appropriate wattage of tungsten bulb:
- 7.5W at 3 ft distance
- 15W at 4 ft distance
Monochromatic film
(Blue sensitive)
* Amber filter (400 to 450 nm)
* Kodak Wratten 6B filter
* Kodak Morlite
Orthochromatic film
(Blue and Green Sensitive)
* Red filter (500 to 550 nm)
* Kodak GBX2
Panchromatic film
(Sensitive to all light)
Total darkness (1200)
- Two principal features occur when film is exposed to safelights for too long:
Increase in gross fog and Overall loss of contrast
- It is composed of four tanks: Developer; Rinsing; Fixer; Washing
- Processing tanks are made up of stainless steel to avoid erosion. The width of the tank may vary according to its capacity
manual processing unit
- Chemical used to convert latent image to manifest image.
- To amplify the amount of metallic silver on the film by increasing the number of silver.
developer
- Chemical used to remove, dissolve, and clear away undeveloped silver halide crystals from the film, forming a silver complex of thiosulfate called monoargento-dithiosulfuric acid.
- To permanent the latent image.
fixer
silver complex of thiosulfate called
monoargento-dithiosulfuric acid
- It is an instrument or device for holding radiographic film during processing procedure. Available in various sizes.
- Made up of stainless steel.
film hangers
types of film hangers
clip type
channel type
spring type
- rectangular or square plastic or metallic container used to hold x ray film (exposed or unexposed) and intensifying screens in close uniform contact with one another.
- holds Intensifying screen and protects them from being damaged.
- exclude all light from entering the cassette and fogging the film.
- maintain a close and uniform contact between the screen and the film.
- exclude dust and dirt from the sensitive films.
- act as a medium from exposure up to processing of film.
cassettes
diff sizes of cassettes
14 x 17 inches
14 x 14 inches
11 x 14 inches
10 x 12 inches
8 x 10 inches
used to keep the film boxes
film racks
must be always kept vertically placed to avoid pressure on them that may result in artifacts.
film boxes
How often should a safelight filter be cleaned?
periodically
indirect safelight uses ___ bulb
sodium vapor
type of DR safelight best used for loading and unloading areas
direct
effects of excessive safelight exposure
fogging, loss of contrast
Storage of unexposed film?
film hopper
darkroom equipment are
- Automatic Processor
- Manual Processing Unit
- Processing Chemicals
- Film Hangers
- Cassette
- Film Storage Hopper
- Loading Bench
- Cupboards
3 health safety in processing area?
- Electrical safety
- General safety
- Chemical hazards
electrical equipment should be kept away from sinks and manual processing units. Adequate earthing of all electrical appliances No trailing cables from appliances Pull-cord switching for lights. What type of safety is this?
electrical safety
DR can have at least____(number) tanks
3
by-product of fixer solution during processing
SILVER complex of monoargento-dithiosulfuric acid
Type of switch used in DR?
pull-chord switch for lights
