THE FINAL STEP: IMAGE PROCESSING Lavin: Chapter 8 CTVT: 560-564

Learning Objectives Understand darkroom specifications Understand the purpose of the various chemicals used in x-ray processing Distinguish between manual and automated processing Know the purpose of the darkroom safelight Be able to list the steps of film processing

Film Processing Developing and fixing an exposed x-ray film Proper processing is vital to the production of a quality radiograph. Most mistakes made in veterinary radiography are related to processing Processing can be done either manually or automatically. Steps are basically the same..

The Darkroom Three qualities of a good darkroom: Clean Organized Lightproof

The Darkroom Should be separate from radiographic suite Should be used for only one purpose - processing exposed radiographs Most of work in darkrooms is with minimal light (hence the word “dark”). Layout should be organized to help reduce possibility of film damage.

Darkroom Cleanliness & Organization Should be clean – The only room where intensifying screens and x-ray film are exposed to the air Should have proper climate control Chemicals should be changed, replenished, maintained, and mixed carefully & safely.

Dry Side of Darkroom Where cassettes are unloaded and reloaded. Countertop should accommodate largest cassette in an open position Countertop should be easy to clean Nothing “wet” should be brought to the dry side. Customary to store film under the dry table in a bin or cupboard. How should film be stored? Film hangers for each size film should be hung above the table on the dry side. Film Storage

Wet Side of Darkroom Where actual chemical processing occurs Hand or manual processing in three tanks. Developer – Converts the sensitized silver halide crystals into black metallic silver Crystals were sensitized when exposed to x-rays Water – Used as a solvent to keep all the ingredients in solution & to wash films Fixer – Removes the unchanged crystals from the film emulsion, leaving the black metallic silver

Manual Processing Tanks

Lightproofing Light leaks: May be hard to perceive Common sources: Around entrance door Ceiling Phones/watches Entrance ideally has a double or revolving door Door should fit tightly in its frame. Use weather stripping to ensure light proofing. Door should lock

Darkroom Safelight Light will not affect the film. Human eye needs 5-8 minutes to adjust. Uses a small-wattage bulb and special filter to eliminate light from the blue and green spectrum. Bulb is 15 watts or less Never closer than 4 feet away from work area.

Safelights (cont.) Direct - Indirect - Positioned so darkroom work can be performed without fumbling Two types of safe-lighting Direct - Diffused light that shines directly over a work area such as the dry or wet side of the darkroom Indirect - A filtered light directed toward the ceiling and reflected over the entire room The two types of lighting may be combined.

Film-processing Techniques Two types of processing: Manual - May take up to an hour to develop Automatic - Can generally be processed in 90 seconds Both can produce a quality radiograph. Feed Tray Developer – Converts the sensitized silver halide crystals into black metallic silver Crystals were sensitized when exposed to x-rays Water – Used as a solvent to keep all the ingredients in solution & to wash films Fixer – Removes the unchanged crystals from the film emulsion, leaving the black metallic silver

Film-Processing Solutions Film processing consists of five basic steps. Developing Rinsing or stop bath Fixing Washing Drying Manual or automated Never backtrack or pull film back

Film Hangers Available in two designs: Channel Hangers Clip Hangers

The Developer Developer - Converts latent image to visible image Chemicals convert exposed grains of silver halide to black metallic silver. Amount of metallic silver on film is amplified Little to no effect on the unexposed silver halide crystals Developer temperature affects developing time Consists of developing agents, accelerators, preservatives, restrainers, hardeners, and a solvent

Exhausted Developer

Film-Processing Solutions Film processing consists of five basic steps. Developing Rinsing or stop bath Fixing Washing Drying

The Rinse Bath Rinse bath serves to: Stop the developing process Rinses the developer from the film Prevents carryover contamination to the fixer After film is in the developer, retains a substantial amount of developer in the gelatin. If film went straight from developer to fixer, then the alkaline developer would neutralize the acid of the fixer.

Over-rinsed film

Film-Processing Solutions Film processing consists of five basic steps. Developing Rinsing or stop bath Fixing Washing Drying

The Fixer Basic functions: Removes unexposed silver halide crystals from the film Unexposed emulsion is removed from film, leaving developed image intact & permanent. Hardens the image to the base

Improper Fixing

Film-Processing Solutions Film processing consists of five basic steps. Developing Rinsing or stop bath Fixing Washing Drying

The Wash bath Removes all waste chemicals from film If not washed properly, image will eventually discolor and fade. Wash in circulating water so both surfaces of film receive water continuously. Manual processing wash time is normally 20-30 mins. A wetting agent bath can hasten drying process

Under washed film Sulfiding

No Final Wash Applied

Film-Processing Solutions Film processing consists of five basic steps. Developing Rinsing or stop bath Fixing Washing Drying

Wet side/Drying area Drying completes the process Drying Cabinet Drying completes the process May use a film drying rack or a drying cabinet Drying rack should be dust free. Drying cabinet is a heated forced-air unit that hastens the drying process Illuminator is recommended on wet side of darkroom.

Chemicals Usually concentrated and need to be diluted Correct preparation matters, or resulting solution may adversely affect the image. Use caution: Developer is alkaline, fixer is acidic. A drop of fixer concentrate can melt the lens of the eye in seconds.

Solution Replacement Used/old chemicals are primary cause of poor-quality radiographs. Check chemicals every time PRIOR to development of film. Developer may turn from brown to green. In general, chemicals should be changed every 4-6 weeks.

Automatic Processing Advantages over manual method: Standardized & consistent Produces radiograph fast Reduces labor time Smaller darkroom space required. Film is transported through processor by rollers Rollers can cause damage Lots of artifacts Roughly the same procedure as manual

Automated Transport System

Automatic Processor (cont.) Chemicals need to be checked and processor warmed up. Feed films one at a time to prevent sticking together. Will be signaled by the processor to feed the next film Don’t forget to turn on vent fan

Biologic Growth May have bacterial growth in solutions. Needs to be controlled. When changing chemicals, clean tanks as well. Wash tank of automatic processor should be drained at the end of day to prevent growth.

Stuck in processor

Films stuck together

Folded Film

Film Identification Proper Labeling & ID is vital. All labeling systems should include. Name/address of hospital or veterinarian. Date radiograph was taken Patient identification including name of the owner and patient name, age, sex, and breed. Can be done via lead lettering, lead impregnated tape, or photo-imprinting labels.

Other markers Right (R) and Left (L) markers are essential to identify size and position of image on radiograph. May need to label both the front and rear in large animals If label not a part of film itself, can add later with marker, or scratching into film while still wet.

Film Filing Organized film filing system is needed in veterinary practice Must be placed in suitable holder and filed appropriately Should be labeled, numbered if necessary and filed correctly for easy future reference X-ray logs also help with film identification.