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IPE 200 LECTURE
Darkroom
| Term | Definition |
|---|---|
| It is a room devoid of all white light | DARKROOM |
| Starting and end point of radiography | DARKROOM |
| Where the latent image is processed | DARKROOM |
| Single most important room in the radiology department | DARKROOM |
| Unobservable image stored in the silver halide emulsion; it is made manifest by processing. It is the precursor of the visible image before chemical processing. | Latent image |
| The darkroom is near/adjacent to the ? | exposure rooms |
| The darkroom should be able to accommodate how many imaging rooms as possible? | as many but 4 at most |
| (TRUE/FALSE) The darkroom is at located at the sides of the imaging rooms. | FALSE. It is centrally located. |
| Passbox is also called the? | cassette hatch (bridgeway from procedure room to darkroom) |
| This region of the darkroom must be light and radiation proof. | PASSBOX/CASSETTE HATCH |
| The cassette hatch should be lined with how many millimeters of Pb/Lead? | 2 mm |
| This region of the darkroom transfers cassettes directly to and from the darkroom. Equipped with two windows; exposed and unexposed and an interlocking system. | PASSBOX/CASSETTE HATCH |
| The size of the darkroom is dependent on what criteria? | The number of patients the department caters to. |
| A darkroom which is to be in constant use and where one full-time technician is to be employed requires a minimum floor area of _______ and a ceiling height of around __________. | 10 m² : 2.5-3 m (atleast 1.3 m) |
| Measurement of SMALL DARKROOMS | 8 x 8 ft |
| Measurement of LARGE DARKROOMS | 9.5 x 15 ft |
| The walls of the darkroom should be protected against what? | x-ray radiation penetration |
| Materials for Walls of darkroom | concrete and hollow blocks (filled with cement) |
| The concrete walls should be how many inches thick? | greater than 6 inches |
| What device is used to measure radiation leaks inside the darkroom? | Dosimeter (TLD thermoluminescent dosimeter or OSL optically stimulated luminescence) |
| The lead-lining thickness of the walls should be how many millimeters thick? | Primary walls (1/16 in/ 1.6 mm) Secondary barrier (1/32 in) |
| It is the wall that is directly affected by the radiation. | Primary walls |
| It is the wall that receives scatter radiation. | Secondary walls |
| This the region of the darkroom that must be durable and easy to maintain; light-colored; processing areas should be non-slip, non-porous flooring material to avoid accidents; is resistant to chemical staining | Floors |
| Why do you think the floors should be light-colored? | Light-colored floors in a darkroom help REFLECT THE SAFE LIGHT, enhancing overall visibility without exposing the film to harmful light. This reduces the risk of accidental film fogging while allowing workers to see more clearly, ensuring safety and accur |
| The walls should be of what colors? And why? | Light/Ivory/Pastel colour - to increase reflectance of safe light |
| What does the matte finish of the walls help with? | To absorb white light - Matte surfaces scatter light in multiple directions when it hits the wall, absorbing more light and reducing the amount of reflected light in the room. - Glossy surfaces reflect light more directly, which could increase the risk |
| (TRUE/FALSE) The walls should be easy to wipe and kept clean. | TRUE |
| 2 areas in the darkroom | DRY AREA & WET AREA |
| The area in which loading and unloading of films, handling and processing of radiographic films and digital detectors, storing of film cassettes and imaging equipment, and preparation of film or detector materials for exposure. | DRY AREA |
| The area in which processing of traditional radiographic films, including developing, fixing, and washing, handling of chemicals used in film processing, & cleaning of processing equipment and film. | WET AREA |
| The floors of the dry area should be made of what? How about wet area? | dry = ceramic tiles wet = rubber tiles |
| Changes in ___________ and ______ can cause films to show increased density and fog, along with inadequate drying. | humidity : heat |
| To prevent problems caused by changes of humidity and heat, the relative humidity is maintained at around __________. | 40-60% |
| To prevent problems caused by changes of humidity and heat, a minimum of ____ air changes per hour. | 8-10 room air/hr |
| To prevent problems caused by changes of humidity and heat, air movement should be around at ____________. | 15-25 ft/hr |
| To prevent problems caused by changes of humidity and heat, room temperature maintained between ____________. | 18-20/24°C or 65-75 °F |
| Humidity is measured using what device? | Psychrometer |
| Types of entrance | 1. Single door system 2. Double door system 3. Revolving door 4. Maze/Labyrinth |
| • Has an electronically linked door-locking mechanism with the lighting circuit • Simplest and inexpensive • Requires a pass box / cassette transfer cabinet | SINGLE-DOOR SYSTEM |
| DISADVANTAGE: May pose as safety hazard | SINGLE-DOOR SYSTEM (The locked single door also poses a safety hazard should an accident incapacitate the occupant. ) |
| How should we prevent a personnel getting trapped inside during fires or earthquakes in a single-door system? | Therefore, a means of overriding any safety interlock must be provided. A type of INTERNAL SLIDING BOLT, which is accessible from the outside, could be fitted. |
| A door system in which it has a two door access and dimensions can be made economical. | DOUBLE-DOOR SYSTEM |
| What does a double-door system has that prevents both doors from being opened at once? | Inter-locking light proof doors |
| • AKA: Maze / Zigzag Consist of two parallel passages and a facing wall | LABYRINTH SYSTEM |
| ADVANTAGES: • Provides easy and instant access • Great ventilation (continuous) | LABYRINTH SYSTEM |
| DISADVANTAGE: Requires a large amount of space | LABYRINTH SYSTEM |
| (Requirements for a labyrinth entrance system) Walls of the interior passages are painted ________ ________ eliminates internal light reflection | matte black |
| (Requirements for a labyrinth entrance system) Vertical height | 2 meters |
| (Requirements for a labyrinth entrance system) Length of passage | Length of passage - at least 3 meters |
| (Requirements for a labyrinth entrance system) Width of passage | 700 mm |
| (Requirements for a labyrinth entrance system) Safelight/white line at _____ level - to help with access for personnel | eye |
| (TRUE/FALSE) The labyrinth door system has no doors. | TRUE. However, it is for routine processing but in an event of a fire. a door is used for easy exit. |
| AKA: Revolving door • Employs a metal cylinder with an opening in its side for entry/exit • Does not require large floor area • Provides fast access, most efficient and great air circulation • Can be expensive | ROTATING DOOR SYSTEM |
| Two levels of lighting | 1. Ordinary white lighting 2. Safelight / red lighting |
| PURPOSE: 1. Inspection and maintenance of cassettes and screens 2. Cleaning of work surfaces and floors 3. Servicing of equipment | WHITE LIGHTING |
| Why is it ideal to have two light switches in a darkroom with a remote work surface? | To ensure proper lighting control both near the door and at the work area |
| Where should the white light switch be positioned in relation to the safelight in a darkroom? | Higher than the safelight (The white light switch should be higher than the safelight switch to ensure that the white light is not accidentally turned on while handling light-sensitive materials, reducing the risk of exposure and damage.) |
| Why should white lighting in the darkroom be sited close to the ceiling? | To avoid casting strong shadows |
| What is the recommended intensity for white lighting in the darkroom? | 60 W tungsten or 30 W fluorescent |
| Where should the white lighting ideally be placed in the darkroom? | Over the main working areas or centrally placed |
| What is the recommended distance for white lighting from the floor in the darkroom? | 5-6 ft (1.5 - 1.75 m) |
| What is the primary function of incandescent lamps with a color filter in the darkroom? | To provide light that illuminates the darkroom without exposing the film |
| These are incandescent lamps with a color filter. | SAFELIGHT |
| What is the main characteristic of safelights regarding brief exposures? | They minimize but do not eliminate fogging with brief exposures |
| Which type of safelight is directly aimed at the work area? | Direct safelight |
| What is a key limitation of using safelights in the darkroom? | There is no totally safe safelight; some risk of fogging always exists |
| Which type of safelight involves light that is reflected off surfaces to illuminate the darkroom? | Indirect safelight |
| How do safelights prevent film exposure in the darkroom? | By passing white light through colored filters that absorb certain wavelengths |
| What happens to the wavelengths of light that do not correspond to the color of the safelight filters? | They are absorbed by the filters |
| Usually consist of a sheet of gelatin dyed to the appropriate colour and sandwiched between two sheets of glass for protection | SAFELIGHT FILTERS |
| Indicates the part of the visible spectrum which will be transmitted by the filter, and so aids in matching the appropriate filter to the type of film in use. | SPECTRAL TRANSMISSION |
| It refers to the alignment of the wavelengths of light emitted by the safelight with the sensitivity of the photographic film or paper. | Spectral matching (The light emitted must be of proper wavelength (color) to match the sensitivity of the x-ray film. For example, if a film is sensitive to blue light, a safelight with a red filter would be used because red light is not sensitive to blu |
| It refers to the filter's ability to block certain wavelengths and allow only safe wavelengths to reach the film. | SPECTRAL TRANSMISSION |
| • Light from the safelight falls directly onto the work surface • Wall mounted / fixture type lighting •Most commonly used | DIRECT SAFELIGHT |
| What color range does the WRATTEN 6B filter cover? | Green - Violet |
| What color does the KODAK GBX filter appear as? | (Dark) Red |
| Which filter transmits light in the wavelength range longer than 550 nm? | WRATTEN 6B Filter (Red-yellow) |
| Which type of film is best matched with the WRATTEN 6B filter? | Monochromatic Film (blue) |
| Which filter transmits red light above 600 nm? | KODAK GBX Filter |
| What is the appearance of the WRATTEN 6B filter? | Light brown / brown-orange |
| Which film should be used with the KODAK GBX filter? | Orthochromatic Film (green) |
| What is the wavelength range of light emitted by the LED? | 660 nm |
| LED ( light-emitting diode) | |
| What is the recommended distance from a 7.5 W safelight to the working bench? | 3 FT (90 cm) |
| What is the recommended distance from a 15 W safelight to the working bench? | 4 FT (120 cm) |
| What is the recommended distance from a 7.5 W safelight to the floor? | 5 FT (150 cm) |
| What is the recommended distance from a 15 W safelight to the floor? | 6 FT (180 cm) |
| Which direct safelight wattage is recommended to be placed 4 FT (120 cm) away from the working bench? | 15 W |
| For a 7.5 W safelight, what is the recommended distance between the safelight and the floor? | 5 FT (150 cm) |
| For a 15 W safelight, what is the recommended distance between the safelight and the floor? | 6 FT (180 cm) |
| This safelight is; • Ceiling mounted • Light is directed towards the ceiling, which is then reflect back into the room | INDIRECT SAFELIGHT |
| The bulb of the indirect safelight uses what kind? | Sodium vapor |
| The distance of the indirect safelight from the work bench is? | 2 m (6 ft) |
| Appearance/color of the indirect safelight | orange-yellow |
| The maximum time for which a film can be exposed to the safelights without causing any appreciable degree of fogging; between ____________. | 20-45 seconds |
| Excessive exposure to safelight results to: | Increased gross fog & Loss of contrast! |
| Which of the following is NOT a cause of safelight fog? a) White light leakage due to a faulty safelight housing b) A properly maintained safelight filter c) A faded, cracked, or incorrectly positioned safelight filter d) Too high a wattage bulb | B |
| The illumination intensity is too great for the particular speed of film material in use. This may be due to: (3) | • Too high a wattage bulb; • Too many safelights; • Distance between safelights and film being too small. |
| There is a safelight fog because the safelight filter is not compatible with the__________ _________________ of the film being used. | spectral sensitivity |
| When to conduct safelight testing (5) | • Semi-annually/annually • New darkroom commission • Safelights have been changed or additional safelights added • Faster film material is introduced • Suspected safelight fog is occuring |
| To do safelight testing, the film is divided into cube sections, what letter corresponds to which has been pre-exposed to X- radiation but received no safelight exposure during the test | A (x-ray only) |
| To do safelight testing, the film is divided into cube sections, what letter corresponds to which has been pre-exposed to X- radiation and received safelight exposure | B (x-ray + safelight) |
| To do safelight testing, the film is divided into cube sections, what letter corresponds to exposed to safelight exposure only | C (safelight only) |
| To do safelight testing, the film is divided into cube sections, what letter corresponds to a proportion of the film which has neither been pre-exposed nor received safelight exposure. | D (gross fog) |
| DRY WORK AREA LAYOUT (5/CFWWD) | 1. Cassette hatch 2. Film hanger brackets 3. Wall mounted lamp with safety filter 4. Work bench cabinet with storage drawers, and hinged film cabinet 5. Dark room light |
| WET WORK AREA LAYOUT (6/FWTFDD) | 1. Film viewing box" 2. Wall lamp with safety filter 3. Timer for processing times 4. Four-section processing unit 5. Draining rack 6. Drying cabinet |
| A darkroom dry bench system consists of; | 1. cassette storage rack 2. film hopper 3. cupboard and waste bin |
| • Storage of unexposed films • Intended for immediate use • Equipped with different film sizes • Must be light and radiation proof | FILM HOPPER |
| This storage is electronically linked with a microswitch - white light immediately switched off when hopper is opened. | FILM HOPPER |
| • Provides a means for securely holding the film during processing | FILM HANGERS |
| • Made of stainless steel • Equipped with clips to hold films in place | FILM HANGERS |
| • Room contiguous with the processing area • Area where the viewing, checking and sorting of films takes place | VIEWING AREA |
| • Needs to be as large as possible in order to accommodate both the high occupancy and the level of staff movement involved. | VIEWING AREA |
| Furnishings of a viewing area; (4) | • Work surfaces • Filing or shelving compartments for films / patient categories • Cassette storage racks • View boxes and spotlights |
| Needs to be capable for one to enter and leave the darkroom without admitting white light | ENTRANCE |
Created by:
yulyae