PRINCIPLES OF RADIOGRAPHIC PROCESSING€¦ · Film fed on feed tray in darkroom Entrance rollers grab film and draw it into developer Entrance rollers separate slightly, film passes

HDR 104

CHAPTER 5

RADIOGRAPHIC EQUIPMENT AND IMAGE RECORDING 1

PRINCIPLES OF RADIOGRAPHIC

PROCESSING

PREPARED BY:MR KAMARUL AMIN BIN ABDULLAH

SCHOOL OF MEDICAL IMAGINGFACULTY OF HEALTH SCIENCE

Slide 2 of 52

TOPIC

CHAPTER 5: Principle of Radiographic Processing

LEARNING OUTCOMES

At the end of the lesson, student should able to:-

Briefly explain the chemicals used and roles in radiographic processing.

The agents and roles in the developer and fixer.

Describe the 4 steps of processing

Describe the path of the film traveling through the processor

Slide 3 of 52

TOPIC


Purpose of PROCESSING

Change silver halide crystals from film emulsion (after exposure to x-ray or

light photons) to black metallic silver.

Latent image (invisible until processed) is developed into a visible image.

Improper or careless processing can cause poor diagnostic quality.

Slide 4 of 52

TOPIC


FOUR (4) Steps of PROCESSING

Developing – formation of the image, converts latent image into visible image

Fixing – stopping of development, permanent fixing of image on film, clear

the film of unexposed, undeveloped silver bromide crystals, promotes archival

quality

Washing – removal of residual fixer.

Drying – warm air blowing over film.

Slide 5 of 52

TOPIC


Manual Feed Processing

Slide 6 of 52

TOPIC


Hand Processing in the Early years

• Strong smell of chemicals

• Messy

• Time consuming

Slide 7 of 52

TOPIC


Film Hanger for Drying

Slide 8 of 52

TOPIC


1956 – first roller transport6 minute processing time

Slide 9 of 52

TOPIC


Processing Time

3 MINUTES 90 SECONDS

Slide 10 of 52

TOPIC


Processing FilmTable top Processors

• Can process as fast as 60 seconds

TABLE TOP

PROCESSOR

http://dba.med.sc.edu/price/irf/images/Xomat.jpg

Slide 11 of 52

TOPIC


DAYLIGHT PROCESSOR

Slide 12 of 52

TOPIC


Daylight Processor

Enable film to be processed without need for darkroom

Special cassettes

Increase in department efficiency, no need for special darkroom staff

Disadvantages – cost, mechanical breakdowns

Slide 13 of 52

TOPIC


AUTOMATIC PROCESSING

1. TRANSPORTATION SYSTEM

2. DEVELOPER

3. FIXER

4. WASHER

5. DRYER

6. REPLENISHMENT SYSTEM

Slide 14 of 52

TOPIC


PROCESSING CHEMICALS

Solutions are PRE-MIXED

Outside Company usually provides service-

Weekly or monthly

Solutions should be replenished as necessary & changed regularly

Solutions must be monitored (Daily QC strip).

http://www.made-in-china.com/image/2f0j00wveTrlQhvtbEM/X-Ray-Film-Processing-Kit-GG-TY002-.jpg

Slide 15 of 52

TOPIC


AUTOMATIC PROCESSOR

Slide 16 of 52

TOPIC


DEVELOPER

Developing is actually the reduction of the exposed silver halides to

metallic or elemental silver (the converting of the latent image to a

visible image).

The developer causes a reaction of the silver halide crystals & thus

makes them visible.

This is done through a pair of redox reactions where an electron is

made available to unite with a silver ion that has a single (+) charge

(from light hitting the film), thus reducing the silver ion to

metallic/elemental silver.

Slide 17 of 52

TOPIC


Developer Solution (6 Ingredients)

1. Reducing Agent: reduce exposed silver halide to black metallic

silver.

-Hydroquinone (Blacks)

-Phenidone (Grays)

2. Activator: softens gelatin, maintains alkaline pH (increase pH).

-Sodium Carbonate

Slide 18 of 52

TOPIC


Developer Solution

3. Hardener: prevents damage to the film from over swelling of gelatin

in automatic processors.

-Gluteraldehyde

4. Preservative: Antioxidant that prevents oxidation of developer

-Sodium Sulfite

Slide 19 of 52

TOPIC


Developer Solution

5. Restrainer: prevents chemical fog protects crystals from chemicals

-Potassium Bromide

6. Solvent: dissolves & ionizes the developer chemicals

-Water

Slide 20 of 52

TOPIC


In Summary (Developer)

Slide 21 of 52

TOPIC


Fixing

Once development is complete, the film must be treated so

that the image will not fade but will remain permanently.

Slide 22 of 52

TOPIC


Fixer Solution (5 Ingredients)

1. Clearing Agent: dissolves undeveloped silver halide

-Ammonium Thiosulfate

2. Tanning Agent: shrinks, hardens, preserves emulsion

-Aluminum Salt

Slide 23 of 52

TOPIC


Fixer Solution

3. Activator: neutralizes developer, maintains acidic pH (decrease pH)

-Acetic Acid

4. Preservative: prevents oxidation, prolongs solution life

-Sodium Sulfite

5. Solvent: dissolves other ingredients

-Water

Slide 24 of 52

TOPIC


In Summary (Fixer)

Slide 25 of 52

TOPIC


Wash

Rid the film of residual chemicals

Residual chemicals on the film will discolor radiograph over time.

Cold water processors are less efficient in removing chemicals – Warm

water processors much better.

Agitation during wash process is essential

Slide 26 of 52

TOPIC


Fixer or Hypo Retention (Not Washed Off)

Slide 27 of 52

TOPIC


Dryer Systems

Dryer: Removes water from film by blowing warm, dry air

-Between 120 degrees & 130 degrees F.

Dries the film before its removal for viewing

If not dry, difficult to hang on viewing box

Consists of blower, ventilation ducts, vented dryer tubes & exhaust

system

Blower draws in air from room and passes it over heating coils

Heated air enters ventilation ducts & dryer tubes & then blows over

film

Moist warm air vented

Slide 28 of 52

TOPIC


Transport System in Automatic Processors

Conveys the film through different solutions (sections) by a series of

rollers driven by gears, chains & sprockets.

Done at a prescribed speed – determines length of time the film is in

each solution

Slide 29 of 52

TOPIC


Transport System

Film fed on feed tray in darkroom

Entrance rollers grab film and draw it into developer

Entrance rollers separate slightly, film passes between rollers

activating microswitch controlling replenishment of chemicals

When film completely in developer tank bell ring or light flicks on –

safe to turn on light

Slide 30 of 52

TOPIC


Transport System Components

Feed Tray

Rollers (Different Assemblies):

1. Entrance

2. Deep Racks

3. Turnaround

4. Crossover

5. Squeegee

6. Dryer

Receiving Bin

Slide 31 of 52

TOPIC


Transport System (Rollers)

Crossover

Squeegee

Dryer

Turnaround

Deep

Racks

Entrance

Slide 32 of 52

TOPIC


Feed Tray

Engages a micro switch to start the replenishment system.

Always feed the film evenly, using the side rails of the feed tray.

Alternate sides from film to film.

Short side of film against the side rail for proper replenishment.

Orientation of film when

placed in processor

important- transversely

along side rails of feed

tray

Transport system carries

film through developer,

fixer, wash tank and dryer

Rollers

Transport rollers – front

and back positions in

racks, 1inch in diameter

Turnaround Assembly – 3

inch roller master roller

Planetary Rollers surround

master roller

Transport Racks

Support rollers and

turnaround

assemblies

Can be removed for

cleaning

Drive Motor

Electric motor & a

system of gears

chains, sprockets, bel

ts and pulleys provide

power & motion in

transport system

Slide 37 of 52

TOPIC


Slide 38 of 52

TOPIC


Recirculation System

Controlled by recirculation pumps that agitate solutions to

keep them mixed to maintain constant temperature

Circulation of water required to wash residual fixer (12

litres per minute)

Provides agitation necessary for uniform solution

concentration

Slide 39 of 52

TOPIC


Replenishment System

Main function: Keep solution tanks full and assure proper solution

concentration.

As film is introduced into processor, sensor initiates solution

replenishment

Right & wrong way to feed in film

-Feed in along short edge

Slide 40 of 52

TOPIC


Replenishment System

Fixer & developer levels drop as films processed

system replaces lost chemicals

Microswitch of entrance rollers starts replenishment pump – stops

when film exits entrance rollers

Placing films transversely stops excess waste of chemicals

Slide 41 of 52

TOPIC


Replenishment tanks

http://www.alibaba.com/catalog/10190086/Automatic_X_ray_Film_Processor/showimg.html

Slide 42 of 52

TOPIC


Slide 43 of 52

TOPIC


Temperature Regulation

Main function: To control the temperature of each section of the

processor.

Developer – most important solution to regulate

Usually between 92 degrees and 95 degrees

Thermostatically controlled

Slide 44 of 52

TOPIC


Processing Rates

Amount of time it takes a

film to go through

processor – ranges from

45-210 seconds

Film manufacturers

determine temperatures

and replenishment rates

Processing Times

Developer 20-25secs

Fixer 20

Wash 20

Dryer 25-30

Slide 45 of 52

TOPIC


Silver Recovery

About ½ of the film’s silver remains in the emulsion after exposure &

processing.

Other ½ (unexposed silver) is removed from the film during fixing

process.

Silver is toxic to public water supply – must have proper disposal.

Documents

PRINCIPLES OF RADIOGRAPHIC PROCESSING€¦ · Film fed on feed tray in darkroom Entrance rollers grab film and draw it into developer Entrance rollers separate slightly, film passes