Optimizing Radiographic Processing: Techniques & Maintenance

Posted on Dec 15, 2024 in Chemistry

Extended Processing in Mammography

  1. Extended Processing – Particularly useful in mammography
  • 3 minutes (standard time is 90 seconds)
  • Developer immersion time – doubled, but it is not necessary to alter developer temperature
  • Significant disadvantage: longer dry-to-drop time.
  • 2 principal advantages of EXTENDED PROCESSING: Greater image contrast & low patient dose
  • Contrast increased by approximately 15%
  • Image receptor sensitivity increased by at least 30%
  • Thus, patient dose is reduced by at least 30%
  • Improvements in extended processing in terms of contrast and patient dose occur only with single-emulsion film.
  • Extended processing is not recommended for double emulsion films because improvements in contrast or dose are not significant with such films.

Daylight Automatic Processors

  • Enable film to be processed without the need for a darkroom
  • Uses special cassettes
  • Increase in department efficiency, no need for special darkroom staff
  • Disadvantages: cost, mechanical breakdowns
  • The radiologist needs only to position a cassette with an exposed film into the appropriate slot of the system.
  • The film is automatically extracted from the cassette and sent to the processor
  • Speed is an advantage
  • Only 15 seconds for the radiologic technologists to insert the exposed cassette into the daylight loader and retrieve a fresh cassette. Total load, unload, and processing time is approximately 2 minutes.
  • Microprocessors automatically monitor and control the unloading and reloading of the cassette by sensing the cassette size and the film consumption rate.


Thermography (TG)

  • Modulated heat source (print head)

  • No latent image (directly manifest image) formation because organic silver salts are directly developed by the application of localized heat

  • May result in a pixelated image

  • Uses a modulated thermal print head that converts electrical energy into heat using resistive elements.

  • More pixelated

Differences Between Manual and Automatic Processing

Automatic Processing

No stop bath between developer and fixer rollers to remove the chemicals.

Higher temperatures for automatic processors. Therefore, different chemicals are required.

Hardener placed in developer in automatic processors.

Additional hardeners are added to the fixer solution.

Because of the daylight-loader, a darkroom is not required.

Because of the heater in the automatic processor, the process is a dry-to-dry process.

Maintenance

To maintain quality, attention is needed in 3 areas:

  1. Quality control

  2. Processor cleanliness

  3. Basic operation


Need to regularly monitor:

  • Temperature of developer

  • Replenishment of film area

  • Speed of development cycle (dwell time)

  • Film drying temperature

Areas of concern:

  • Oxidation build-up on gears, rollers, tanks

  • Crossover guides – wash daily

  • Algae build-up in wash tank – wash weekly

  • Dirt and dust build-up in the dryer

  • Structural frame, panels, & lid

  • Entry & feed tray area – clean feed tray

  • Oxidation build-up in replenisher tanks

Daily check-up

Before starting:

  • Remove lid, check chemistry levels (room should be well ventilated before opening)

  • Shut wash tank water valve, standpipe in

  • Turn on water to desired flow rate

  • Check for seized rollers (water to free)

  • Power on

  • Observe agitation and replenisher pumps operating

  • Wait for developer temperature to reach set point

End of the day: make sure that the darkroom is clean and the lid partially open


Tools to Improve Radiographic Quality

  1. Patient Position

  • Good knowledge of human anatomy

  • Central axis – for chest – T7 level lower angle of scapula

  • Proper instruction

  • Distance from tube to patient

Image Receptors

  • Intensifying screens (RE or CTS)

  • Radiographic film

  • Speed of film and I.S.

  • Rare earth – green – ortho – red – GBX filter

  • CTS – blue – mono – amber – Wratten GB

  • The most common speed of film and IS – medium or par 100RS

  1. Selection of Technique Factors

  • kVp primarily controls beam quality, penetrability, contrast.

    • Increase kVp & less contrast = inversely

    • Increase kVp & energy = directly related

    • Increase kVp & OD = directly related

    • kVp & Scattered rad. = directly related


  • mAs = primarily controls radiation quantity, density, amount of x-ray produced

    • Quantity = number of x-rays/exposure/intensity

    • mAs & quantity = directly related

    • mAs & OD = Directly related

    • mAs & contrast – not related

    • mAs & energy = not related

    • mAs & scattered energy = not related

Cleaning of Processing Equipment

Tray and Tanks

– Stains from oxidized developers are visually brown or yellow-brown in color.

Fresh Stains

– Can be removed by washing it with water and soap.

Severe Stains

– Can be removed by using a strong oxidizing solution such as “Tray Cleaner Formula”

Wash Tank

  • After coated with a slimy growth of algae which tend to break loose and deposit to the film.

Remedy

  • The growth of the algae, especially in the inlet and outlet pipe, can be controlled by weekly treatment of diluted sodium hypochlorite in the solution tank.

  • A commercial solution can be used at a rate of:

  • 8 ounces for every 48-gallon tank.


Tray Cleaner Formula

  • Water – 32 ounces

  • Potassium – 3 ounces

  • Sulfuric Acid Treatment – 3 ounces

Caution:

  • Always add Sulfuric Acid to the solution slowly with constant stirring.

  • Never add the solution to the acid because the solution may boil and spatter the acids on the hands or body, which can cause serious burns.

Stop Bath Strong Formula

  • Water – 1 gallon

  • Acetic Acid (28%) – 16 ounces

Stop Bath Mild Formula

  • Water – 1 gallon

  • Acetic Acid (28%) – 8 ounces

Note:

  • To make approximately 28% acetic acid from glacial acetic acid, dilute 3 parts of glacial acetic acid with 8 parts of water.


Methods of Removing Stubborn Deposits from Film Hangers and Clips

  1. Acetic Acid Treatment

    1. Soak hangers and clips for an hour in a tray filled with 10% acetic acid solution (1 part of glacial acetic acid to 9 parts water or 1 part 28% acetic acid to 2 parts of water), then the acid loosens the deposits.

  2. Trisodium Phosphate Treatment

    1. Boil the equipment for several minutes in a 10% solution of trisodium phosphate, then wash it with water and scrub thoroughly with a stiff brush.

  3. Acid Bichromate Treatment

    1. If the silver deposits cling tenaciously to the metal hanger, dissolve it with tray cleaner formula. Immersion of 10 minutes is usually sufficient.

  4. Sand Blasting

    1. Heavy deposits are removed by the use of this treatment.