IPE.pptx RADIATION TECHNIQUE RADIATION TECHNIQUE

“RADIOGRAPHY BEGINS IN THE
DARKROOM AND ENDS IN THE
DARKROOM”

Importance of Processing Room
1. Location
2. Size (15ft X 9.5ft) = 200 radiographs
wet and dry section = 4ft
3. Protection against radiation
4. Ventilation
-humidity range = 40 to 60%
-temperature rate =67-83F/20C
- air movement =15 to 25 ft/min
5. Cleanliness

6. Light tight entrance
a. Single door dark room
b. Light lock door/ double door
c. Labyrinth/ maze
d. Revolving door

b. Light lock door/
Double door

8. Illumination
o White light illumination
o Safe light illumination
o 7 ½ - 15 watts tungsten bulb
o Filter
o Wratten 6B filter-monochromatic film or blue
o GBX2 filter - orthochromatic film or green
9. Color of walls
10. Electric wiring

Importance of the Processing Room
Location
Size
Protection
against
radiation
ventilation
Cleanliness
Light tight
entrance
illumination
Color of
walls
Electric
wiring

Quality Control For The Darkroom And
Automatic Processor

Quality Control Test Schedule Standard
Darkroom environment Daily Maintained clean, well ventilated,
organized and safe
Safelight test Semi-annually Less than = 0.05 optical density
added as fog
Automatic Processor
temperature
Weekly Should not vary more than +- 0.5ºF
(0.3ºC)
Replenishment Rates Weekly Should fall within +- 5% of
manufacturer’s specification for
replenishment type

Quality Control Test Schedule Standard
Developer Solution pH Quarterly Maintained between 10-11.5
Fixer solution pH Quarterly Maintained between 4-4.5
Developer Specific Gravity Quarterly Should not vary more than =-0.004
from the manufacturer’s
specifications
Processor Control Chart
Monitoring
Daily Speed and contrast indicators should not
vary more =- 0.15 optical density from
baseline measurements

¨ 1895 – photographic plates
¨ 1914 – single coated cellulose nitrate films
¨ 1918 – duplitized films
¨ 1924 – cellulose acetate film base
¨ 1933 – tinted film base
¨ 1936 – direct film exposure
¨ 1940 – film suitable for both direct and indirect
exposure
¨ 1958 – fast light-sensitive film
¨ 1960’s – polyester film base and film for rapid
processing

¨ 1. Monochromatic film – Blue-sensitive film;
with globular grains
Øsensitive to spectral wavelength of photons emitted
from CaWO4

¨ 2. Orthochromatic film – green- sensitive film;
with tabular grains
Øsensitive to the green light emitted by rare earth
screens, particular gadolinium oxysulfide and
lanthanum oxysulfide.

Types of Film
• There are two general types of film:
1. Direct Exposure film- is often called
nonscreen film.
- It is intended to be used in a cardboard holder
and without intensifying screens.
- it has a single emulsion that significantly is
thicker than screen film and requires more
development time.
- Compared with screen film, it requires
considerably more exposure and may necessitate
mannual processing.
- Commonly used for intra oral dental
radiography
- Considered out date technologies

Types of Film ( con’t)
2. Screen film – is the most widely used
radiographic film.
- it is intended to be used with one or two
intensifying screens.
- it is more sensitive to light and less
intensifying to x-rays
- the emulsion layer is thinner than those of the
direct exposure film and requires less
developing time.
- require less x-ray exposure, can be either
manually or automatically processed and can have
either a single or double emulsion coating (
sometimes referred to as Duplitized.

1. Mammographic film
– for radiography of the breast.
- Fine grain; single emulsion; greater detail

2. Therapy localization film
- given acceptable radiographic detail under a
wide range of exposures to x-rays and gamma
rays.
- Direct exposure; fine grain

3. Dental x-ray film
Ø Intraoral films :
a. periapical film
b. bitewing or inter proximal film
c. occlusal film
Ø Extraoral film – panoramic film

4.Video film – single emulsion film
Ø exposed in a device called multiformat
camera or a laser camera.

5. Photofluographic film – single coated film
Øfor photography of the image on the
fluorescent screen by a camera in area chest x-
ray examination.

6. Cine film – single emulsion film with sprocket
holes.

7. Copy or duplicating film – single – emulsion
film
Øexposed to ultraviolet light through existing
radiograph to produce a copy using a
ultraviolet lamp.

8. Dosimeter film ( personnel monitoring film)
Ømeasures radiation absorbed dose.

9. Automatic Serial Changer film
ØFor serial radiography such as angiography
ØHas special protective coating

10. Industrial film
ØFor high energy
radiography

11. Polaroid radiographic film – paper –based
12. Laser film
- Used in laser printing such as M.R.I and CT-Scan

A. Storing Unexposed Film
➢Unexposed film should be stored in its original
packaging so that important information about the
film can be maintained.
➢Film boxes should be stored vertically, not
horizontally, to prevent pressure artifacts on the film.
➢Film should be stored at temperatures ranging from
50º to 70ºF (10º to 21ºC) and a relative humidity of
40% to 60%.
•

Possible Consequences of Storing
Unexposed Film in Environments with
Improper Temperature and Relative
Humidity
Storage Environment
Problem
Possible Consequence
Temperature too high Increased fog level
Temperature too low Increased static discharge
Humidity too high Increased fog level
Humidity too low Increased static discharge

QUESTION:
In order to adequately protect the sensitive silver
emulsion film must be stored in a cool:
A. 50-70°F and 50% humidity area
B. 100-110°F and 80%
C. 80-100°F and 70%
D. 70-80°F and 60%

B. Packaging of film
Ø Films are packed in a photo-inert
polyethylene bag or in metal foil to protect
them from light and moisture. Film sheets
may or may not be separated by photo-inert
leaves of paper.

C. Storage precautions
Ø Films must be protected from:
ú Heat
ú Radiation
ú Chemical fumes
ú Pressure

D. Expiration date
Ø Adhere to “first in, first out (FIFO) system”
EXPIRED!!!

C. Handling of film
Ø Hand creams should be avoided.
Ø Rubber gloves should be avoided. Use cotton
glove when it necessary.

E. Kinds of fog that can affect the film:
1. Age fog
2. Chemical fog
3. Safelight fog
4. Heat fog
5. Secondary radiation fog

QUESTION
The artifacts that are caused by low humidity and
improper handling of film is called:
A. Static electricity
B. Fogging
C. Scratches
D. Sensitized marks

Image Receptors
• Double Emulsion Radiographic film, as used in a
cassette with intensifying screens, is the most
common film-screen receptor used in
radiography today.
• The intensifying screens absorb the transmitted
x-rays and produce light, which exposes the film.

Image Receptors (con’t)
• The film records the image based on the pattern
transmitted x-rays and light produced by the
intensifying screens.
• The cassette is the rigid, light – tight container
that holds the screens and film in close contact.

Radiographic film
• Several types of radiographic film are used in the
medical imaging departments depending on the
specific applications. Film manufacturers
produce a film in a variety of sizes, ranging from
20x25 cm (8x10 inches) to 35x43 cm (14x17
inches)

Film Construction
• The composition of film can be described in
layers:
1. Super coat/ top coat – is a durable
protective layer that is intended to prevent
damage to the sensitive emulsion layer
underneath it.

2. Emulsions - is the radiation sensitive and light
sensitive layer of the film.
It consists of:
a. Silver Halide crystals – is the material
sensitive to radiation light. It is made up of silver
bromide (AgBr) and silver iodide (AgI). It is believed
that silver bromide constitutes 90% to 99% of the silver
halide in film emulsions and that silver iodide makes up
remaining 1% to 10%
b. Gelatin – made up of the calf skin. It is an ideal
suspension medium for the silver halide crystals.

Film Construction (con’t)
3. Base – is polyester (plastic) that gives the film
physical stability. The emulsion layer is fairly
fragile and must have this plastic base so that
film can be handled and processed, let
physically strong after processing. Most film
used in radiographic procedures has a blue
dye or tint added to the base layer to decrease
eye strain while one views the finished
radiograph.

• 4. Adhesive layer – between the emulsion layer
and the base. It simply adheres one layer of the
film to another.

Film Characteristics
1. Film Speed
➢ Is the degree to which the emulsion is sensitive to x-
rays or to light. The greater the speed of a film the
more sensitive it is. This increase in sensitivity results
in less exposure necessary to produce a specific
density.
Two primary factors that affect the speed of
radiographic film:
1. The number of silver halide crystals present in the film
2. The size of silver halide crystals present in the film

Film Characteristics
2. Film Contrast
➢Refers to the ability of radiographic film to
provide a certain level of image contrast.
3. Exposure Latitude
➢Refers to the range of exposures that produce
optical densities with the straight line region of
the sensitometric curve.

Spectral sensitivity
➢Refers to the color of light to which particular
film is most sensitive. In radiography, there
are generally two categories of spectral
sensitivity films
▪ Blue sensitive (monochromatic)
▪ Green sensitive (orthochromatic)
➢When radiographic film is used with
intensifying screens, it is important to match
the spectral sensitivity of the film with
spectral emission of the screens.

Spectral emission
Refers to the color of light produced by a
particular intensifying screen.
Spectral matching
Refers to correctly matching the color sensitivity
of the film to the color emission of the
intensifying screen.

Crossover
➢Refers to the light that has been produced by an
intensifying screen that exposes one emulsion
and then crosses over the base layer of the film to
expose other emulsion. It is a radiographic
problem because it decreases recorded detail as
seen on the image.

Ø The quantitative measurement of the
response of film to exposure and
development.

Ø A device that produces a constant simulated
x-ray exposure

Ø Made by exposing successive areas on a film
with a “one exposure area and progressively
making larger exposure until maximum
density of the film is reached.

¨ A device that measures the percentage of light
transmittance.
Light density units
100% 0
10% 1
1% 2
0.1% 3

¨ The product of sensitivity.
¡ Film characteristic curve
¡ H&D curve (Hurter and Driffield)

¨ Base density – the density resulting from the
manufacture of the film and is inherent in the
film base ( AVE: 0.14)
¨ Base plus fog – inherent fog cause by the
processing conditions.
- Acceptable B+F density
¨ D- min (minimum density) – the TOE of the
characteristic curve.
- Slightly higher than B+F density

¨ D-Max (maximum density) – the SHOULDER
of the characteristic curve.
¨ Average gradient – reflects the film contrast
which is measured at 0.25 density units above
B+F density and 2.0 density units above B+F.
The more the vertical this line, the greater is the
film contrast.

Intensifying Screen
• Is a device found in radiographic cassettes that contain
phosphor that convert x-ray energy to light, which then
exposes the radiographic film.
• Intensify or amplify the energy to which they where
exposed.
• With screens, the total amount of energy to which the
film was exposed is divided between x-rays and light.
Approximately 90% to 99% of the total energy to which
the film is exposed is light. X-rays account for the
remaining 1% to 10% of the energy.

Layers of Intensifying Screen
1. Protective Layer
2. Phosphor Layer
3. Reflective Layer
4. Base

¨ Helps prevent static
¨ Gives physical protection to the delicate
phosphor layer
¨ Provides a surface which can be cleaned
without damaging the phosphor.

¨ Active layer of I.S that emits light during
stimulation by x-ray.
A. Characteristic of a good phosphor:
1. quantum detection efficiency
2. conversion efficiency
3. spectral matching
4. minimum after glow

B. Phosphor materials
1. Calcium Tungstate (CaWO4) – introduced
by Thomas Edison. Scheelit-natural
tungstate.
2. Barium lead sulfate – used for high kVp
techniques
3. Zinc sulfide – for low kVp
4. Rare earth crystals

¨ Intercepts light photons headed in other
directions and redirects them to the film.
¨ Made of shiny substance such as magnesium
oxide and titanium dioxide.

¨ Made of high grade cardboard or
polyester which provides support to
the phosphor layer.
¡ Must be rugged and moisture
resistant
¡ Must not suffer radiation damage
nor discoloration
¡ Must be chemically inert and not
interact with the phosphor layer
¡ Must be flexible
¡ Must not contain impurities that
would be imaged by x-rays

Luminescence
• Is the emission of light from the screen when
stimulated by radiation. IS operates in this
process.

Fluorescence
➢Refers to the ability of phosphors to emit visible
light only while exposed to x-rays.
BEFORE AFTER

Phosphorescence
➢ Occurs when screen phosphors continue to
emit light after the x-ray exposure has
stopped. It is also called screen lag or
afterglow.

Intensifying Screens Phosphor Materials
and their Spectral Emissions
Phosphor Spectral Emissions
Calcium Tungstate( CaWO4) Blue
Rare earth elements
Lanthanum oxybromide ( LaOBr)
Yttrium tantalate
Gadolinium oxysulfide ( Gd2O2S)
Blue
Ultraviolet blue
Green
Others
Barium Lead Sulfate
Barium Strontium sulfate
Blue
Blue

Screen Speed
• The capability of the screen to produce visible
light.
Screen Speed and light Emission
• The faster an intensifying screen, the more
light emitted for the same intensity of x-ray
exposure.

Intensification Factor
• The intensifying action of the screen.
• The intensification factor (IF) can be stated
as follows:
Exposure required without screens
Exposure required with screens
IF

Screen Speed and Patient Doses
• As screen speed increases, less radiation is
necessary and radiation dose to the patient
decreases, as screen speed decreases, more
radiation dose to the patient increases.
• Relative speed – the ability of the screen to
produce light, and therefore density.

Screen Speed and Density
• For the same exposure, as screen speed
increases, density increases; as screen speed
decreases, density decreases.
• Screen Speed and density are directly
proportional.
• The mAs conversion formula for screens is a
formula for the radiographer to use in
determining how to compensate or adjust mAs
changing intensifying screen system speeds.

Formula for Screen Speed:
Relative screen speed 2
Relative Screen speed 1
mAs 1
mAs 2
=

Phosphor thickness, Crystal Size,
and Screen Speed
• As the thickness of the phosphor layer
increases, the speed of the intensifying screen
increases; as the size of the phosphor crystals
increases; the speed of the screen increases

Summary of Effect of Screen factors on Screen
Speed, Recorded Detail, and Patient dose
Screen factor Screen
speed
Recorded
detail
Patient Dose
Thicker phosphor layer increase decrease decrease
Larger phosphor
crystal size
increase decrease decrease
Reflective layer increase decrease decrease
Absorbing layer decrease increase increase
Dye in Phosphor layer decrease increase increase

Screen Speed and Recorded Detail
• With any given phosphor type, as screen
speed increases, record detail decreases,
and as screen speed decreases, recorded
detail increases.

Quantum mottle
• Commonly called image noise, can be defined
as the statistical fluctuation in the quantity of
x-ray photons that contribute to image
formation per square millimeter.
• When a very low number of photons are
needed by the intensifying screens to produce
appropriate image density, the image appears
mottled or splotchy. This appearance can be
described as “ salt and pepper look.”

Screen Maintenance
• The maintenance of intensifying screens is
significant because radiographic quality
depends on a large part on how well the screens
are continuously maintained. Two important
procedures should be performed on the
intensifying screens:
1. regular cleaning
2. check cassette for film screen contact

¨ Worn contact felt
¨ Loose, bent or broken latches
¨ Loose, bent or broken hinges
¨ Warped screens caused by excessive moisture
¨ Warped cassette front
¨ Sprung or cracked cassette frames
¨ Foreign matter under the screen

¨ Type of phosphor used
¨ Thickness of the active layer
¨ Size of the phosphor
¨ Reflectance of the screen bucking

¨ Cassette front – made up of radioluscent (low
Z) material as bakelite or carbon fiber materials.
¨ Contact Felt/ compression layer – maintains
proper film-screen contact.

¨ Lead foil – absorbs
secondary radiation
( backscatter)
¨ Cassette back – made up
of steal of lightweight
metal such as magnesium.
¨ Phototimer cassette –
have a radioluscent back
to permit the radiation
reaching the film to
continue on the automatic
exposure control ( AEC)

¨ The developer provides electrons for the
reduction of the silver halide crystals:
1. by giving up electrons, the developer is
oxidized.
2. by gaining electrons, the silver halide is
reduced.

EUROPE
E – LECTRONS are
U – USED in
R – EDUCTION,
O – XIDATION
P – RODUCES
E - LECTRONS

Latent Image Formation
• Latent Image – refers to the image that exists on
film after the film has been exposed but before it
has been processed.
• Manifest Image – Refers to the image that exists
on film after exposure and processing.

Gurney-Mott Theory of Latent
Image Formation
• Before exposure, Silver Halide (AgBr and AgI) is
suspended in gelatin in the emulsion layer. Sensitivity
specks exists as a physical imperfections in the film
lattice.
• Exposure to x-rays and light ionizes the silver halide.
• Negatively charged electrons and positively charged
silver ions float freely in the emulsion gelatin.
• Sensitivity Specks trap electrons
• Each trapped electrons attracts a silver ion
• Silver clumps around the sensitivity specks

Sensitivity Specks and Latent Image
Centers
• Sensitivity Specks serves as the focal point for
the development of latent image centers. After
the exposure, these specs trap the free electrons
and then attract and neutralize the positive silver
ions. After enough silver is neutralized, the
specks become a latent image center and are
converted to black metallic silver after chemical
exposure.

¨ The purpose of the development is to
convert chemically the invisible (latent)
image to the visible silver image by
means of a developer solution. In the
conversion of the exposed AgBr crystals
to metallic silver, the film is immersed
in an alkaline developer solution that
soften and swells the gelatin .
¨ The unexposed AgBr is unaffected by
this treatment during the development
process.

Automatic Processor
Is a device that comprises chemical tanks, a roller transport
system, and a dryer system for processing of radiographic
film.
Processing Cycle
Refers to the amount of time it takes to process a single piece
of film. This amount of time varies between 45 seconds and
3.5 minutes, depending on the processor that is used.
Processor Capacity
Refers to the number of films that can be processed per hour.

Processing of radiograph
1. Developing
➢Converts the latent image into a
manifest or visible image. There
are also two secondary purposes
of developing:
1. To amplify the amount of metallic
silver on the film by increasing the
number of silver atoms in each
latent image center.
2. To reduce the exposed silver halide
crystals into metallic silver.

A. Reducing agents ( elon/ metol/ phenidone and
hydroquinone)
- reduce exposed AgBr crystals to black metallic silver.
¨ Metol and phenidone – build up detail quickly in first
half of the development process.
¨ Hydroquinone – builds up contrast slowly during
development period.

B. Activator/ Alkalinizer ( sodium hydroxide /
sodium bicarbonate)
- provides necessary alkaline medium and
swells gelatin emulsion so that reducing agents can
attack AgBr crystals. (pH 9.6 – 10.6)

C. Restrainer ( Sodium
Bromide / Potassium
Bromide)
- controls activity of
reducing agents and
tends to prevent fog.
(anti-foggant)

D. Preservative / antioxidant ( sodium sulfite /
potassium sulfite)
- prevents rapid oxidation of the reducing
agents.
- reacts with quinone ( a by product of
hydroquinone which is dye), capable of staining
the film and form a colorless compound called
hydroquinone monosulfate.
e. Solvent

1. Benzothiasole – an organic restrainer which is
added to PQ developer to prevent the action of
the phenidone on the unexposed AgBr crystals,
since phenidone is not restrained by bromide.
2. Hardening agents ( dialdehyde/
gluteraldehyde) – added to the developer for
automatic processing to prevent swelling of the
emulsion, thereby reducing film transportation
problems and preventing damage to the
emulsion film transport rollers.

3. Sequestering agent – prevents precipitation of a
calcium sludge which would show up as chalky
deposits on the film or cause scaling of the tank.
a. sodium salt of ethylene diamine tetra-acetic
acid (EDTA)
b. Sodium hexametaphosphate (CALGON)

4. Wetting agents – stimulate uniform
development by reducing surface tension.
5. Anti- frothant / anti- foaming – prevents bubble
formation on the solution.
6. Fungicides
7. Buffer – maintains the pH value of the solution. (
boric acid, sodium hydroxide)

Aerial Oxidation
Refers to a reduction in chemical strength as a result
of exposure to air.
Use oxidation
Refers to a reduction in chemical strength as a result
of exposure to increased temperature over an
extended period.

¨ An old or exhausted developer whose reducing
property has been reduced brought about by
aerial or chemical oxidation.
¨ What makes a developer?
1. Conc. of the reducing agent goes down.
2. Conc. Of the preservative goes down.
3. Conc. Of the alkalinizer goes down
4. Conc. Of the buffer solution goes down
5. Conc. Of the restrainer goes up
6. Conc. Of the by product of the developer as
monosulfates goes up

¨ The physical and chemical means of
maintaining the level of the processing solution.
¨ Replenisher – a solution containing more
reducing agents, activator, and preservative but
without restrainer to maintain the chemical
activity of the processing solution to the
original, and in proper dilution with water
maintain the physical level of the processing
solution.
1. MQ replenisher – without restrainer
2. PQ replensiher – with restrainer ( since
benzothiasole will be exhausted)

Microswitch – a device located at the entrance of
the automatic processor which controls the
replenishment rate of the processing chemicals.
Replenishing rates are normally established on
the basis of how much chemistry is required per
14 inches of film travel:
– 60 to 70 cc of developer
– 100 to 110 cc of fixer

Developer Solution Agents, Chemicals, and Their Functions
Agent Chemical(s) Function
Developing or
Reducing agents
Phenidone
Hydroquinone
Fast-reducing, produces gray
densities
Slow Reducing Produces
black densities
Accelerator or
activator
Sodium
Carbonate
Elevates and Maintains
Solution pH
Restrainer Potassium
Bromide
Decreases reduction of
unexposed silver halide
Preservative Sodium Sulfite Decrease oxidation of
solution
Hardener Glutaraldehyde Hardens the emulsion
Solvent Water Dilutes the chemical

Developer Solution
Reducing
Agent:
•Elon
•Metol
•Phenidone
•hydroquinone
Activator/
alkalinizer:
•Sodium
hydroxide
•Sodium
carbonate
Restrainer:
•Sodium
bromide
•Potassium
bromide
Preservative/
antioxidant:
•Sodium sulfite
•Potassium
sulfite
Solvent:
•water
Other
components:
•Benzothiasole
•Hardening agents
•Sequestering
agent
•Wetting agent
•Anti-frothant/
anti-foaming
•Fungicides
•Buffer

¨ Means that the activity of each individual
component of reducing agent in solution is
less then the activity when both are
combined in solution.
¨ Classification of a developer as to addivity:
1. MQ Developer ( elon/ metol-
hydroquinone developer)
2. PQ developer ( phenidone –
hydroquinone developer)
- has 15 times more super-addivity then MQ
developer combination.
SUPER ADDIVITY (Synergist)

1. Temperature of the solution
2. Size of the film
3. Size of the grains of the film
4. Agitation of film
5. Exhaustion of the developer

2. Fixing
➢ To remove unexposed silver halide from the film
and to make the remaining image permanent.
There are also two secondary functions of fixing:
➢ 1. To stop the development process.
➢ 2. To further harden the emulsion.
➢ It serves to clear the film of the undeveloped
crystals, forming a silver complex of thiosulfate,
technically called Monoargento-di-thiosulfuric
acid.

A. Fixing Agent (sodium thiosulfate/
ammonium thiosulfate)
= Dissolves unexposed AgBr crystals, thereby
producing a permanent visible image.

Ammonium thiosulfate vs.
Sodium thiosulfate
1. Ammonium thiosulfate fixes the film more
rapidly than sodium thiosulfate when present in
equivalent concentration.
2. The ammonium complex is less stable than the
sodium complex, therefore staining and
deterioration will occur faster than the sodium
complex.
3. Ammonium thiosulfate is used mainly in liquid
concentration.

B. Neutralizer (acetic acid)
• Provides an acid medium and neutralizes the
developer carried over in the film. ( 4.2 - 4.9)

C. Preservative/ stabilizer (sodium
sulfite)
• Maintains equilibrium of chemicals in the
solution.
• Prevents aerial oxidation of the fixing agent.
• Prevents decomposition and precipitation of
sulfur from the thiosulfate fixing agent.

D. Hardener ( potassium
aluminum, chrome aluminum,
or aluminum chloride)
• Raises temperature at which gelatin softens
• Prevents too much absorption of water by
gelatin
• Makes the film less susceptible to physical
change.

E. Solvent (water)
❖ Boric acid = an anti-sludging agent which delays
precipitation of aluminum hydroxide. A buffer
agent.
❖ Hyponeutralizer = a solution used between the
fixing stage and the final washing cycle to reduce
the washing time of the films.
❖ Clearing = the process by which the fixing agent acts
on the unexposed crystals to form soluble complexes
which eventually diffuses out of the film into the
fixer solution. ( fixing time = 2 x clearing time

Fixer Solution Agents, Chemicals, and Their Functions
Agent Chemical Function
A. Fixing Agent Ammonium
Thiosulfate
Clears away unexposed
silver halide
B. Acidifier Acetic acid Stops development
C. Preservative Sodium Sulfite Prevents reaction
between fixing agent and
acidifier
D. Hardener Chrome Alum
Potassium Aluminum
Aluminum Chloride
Hardens the emulsion
E. Solvent Water Dilutes the chemicals

Processing of Radiograph
3. Washing
• The washing process removes the
residual processing and silver salts
from the radiograph.
• Water is used as the wash agent.
• In automatic processing the
temperature of the wash should be
maintained approximately 5 degrees
(2.8 degrees Celsius) below the
developer temperature to stabilize
the developer temperature.

Processing of Radiograph
4. Drying
➢The final process in film processing. It removes
85% to 90% of the moisture from the film so that
it can be handled easily and stored while
maintaining the quality of the diagnostic image.

Eagles don’t flock – you have to
find them one at a time.
From ordinary to Extraordinary...

Processing System Tanks
An automatic processor has three tanks:
❖ A. Developer tank
❖ B. Fixer tank
❖ C. Water tank

Transport System
• transports the film and controls processing by
controlling the time the film is immersed in each
of the wet chemistries.

Vertical Transport System
❖ Automatic processors use a vertical transport system of
rollers that advance the film through the various stages of
film processing. All rollers in a processor move at the
same speed.
❖ A film is introduced into the processor on the feed tray.
Feed tray is a flat metal surface with an edge on either
side that permits the film to enter the processor easily and
correctly aligned.
❖ The entrance roller assembly consist of rollers that are
covered with corrugated rubber, that straightens the path
of the film so that it moves through the processor
efficiently.

Vehicle Transport
❖ The next type of roller that the film encounters is a
transport rollers that moves the film through the chemical
tanks and dryer assembly.
❖ A turnaround roller at the bottom of the roller assembly
turns the film from moving down the transport assembly to
moving up the assembly.
❖ The final type of roller used in the vertical transport system
is the crossover roller that moves the film from one tank to
another and into dryer assembly.
❖ Guide plates are slightly curved metal plates that properly
guide the leading edge of the moving film through the
roller assembly.

Motor Drive
➢ An electric motor provides power for the roller assemblies to
transport the film through the processor.
➢ The on/off switch provides electrical power to the processor
activates this motor.
➢ The standby control is an electric circuit that shuts off power
to the roller assemblies when the processor is not being used.
➢ It consists of:
A. Belt and pulley
B. Chain and sprocket
C. Gears

Indicators of Inadequate Processing
Radiographic Appearance Processing Problem
Decrease in Density
Developer Exhausted
Developer Underreplenishment
Processor Running Too Fast
Low Developer Temperature
Developer Improperly Mixed
Increase in Density
Developer Overreplenishment
High Developer Temperature
Light Leak in Processor
Pinkish Stain (Dichronic Stain)
Contamination of developer by fixer
Developer or fixer undereplenishment
Brown Stain (Thiosulfate Stain) Inadequate washing
Emulsion Removed by Developer Insufficient hardener in developer
Milky Appearance Fixer Exhausted
Inadequate washing
Streaks Dirty processor rollers
Inadequate washing
Inadequate drying
Water Spots Inadequate drying
Minus-Density Scratches

Alternative Processing Methods
1. Rapid Processing – Processes film as rapidly as 30 seconds.
- Useful in angiography, special procedures, surgery, and
emergency rooms
- Used with more concentrated chemicals at higher
temperature
2. Extended Processing – Processing may be as long as 3 minutes
- Advantages:
– Greater image contrast
– Lower patient dose
– Applicable with single-emulsion film (mammography)

Alternative Processing Methods
3. Daylight Processing – It takes only about 15
seconds for the technologist to insert the exposed
cassette into the daylight loader and retrieve a
fresh cassette. Total load, unload, and process
time is about 2 minutes. Multiple film sizes are
automatically accommodated.

Temperature Control
An increase or decrease in developer temperature can
adversely affect the quality of the radiographic image.
In most 90-second automatic processors, developer
temperature must be maintained at 93º to 95ºF (33.8º to
35ºC).
1. Gross control of temperature – affected by a water-mixing
valve, a device that interconnects the incoming hot and cold
water.
2. Fine control of temperature – occurs within the developer
tank itself through a thermostatically controlled heating
element or by means of a heat exchanger.

Fixer Solution:
Fixing
Agent:
•Sodium
thiosulfate
•Ammonium
thiosulfate
Neutralizer/
acidifier:
•Acetic acid
Preservative/
stabilizer
•Sodium sulfite
Hardener:
•Potassium
aluminum
•Chrome
aluminum
•Aluminum
chloride
Solvent :
•water
Other
components:
•Boric acid
•Hyponeutralizer

Radiographic Artifacts
Is any unwanted image on the radiograph.
Are detrimental to radiographs because they can make
visibility of anatomy, a pathologic condition, or patient
identification information difficult or impossible.
They decrease the overall radiographic quality of the
image.
Can be classified as:
a. plus density artifacts– are greater in density than the
area of the radiograph immediately surrounding them.
b. minus density artifacts – are of less density than the
area of the radiograph immediately surrounding them.

Plus-Density Artifacts
Artifact Cause
vHalf-moon marks
vBending or kinking of
film
vScratches, abrasions vFingernail or other
scratches
vStatic discharges vSliding films over flat surface
vFogging
vExposure to white light,
ionizing radiation, heat,
safelight fogging; expired film
vDensity outside
collimated area
vOff-focus or “off-stem”
radiation

Minus-Density Artifacts
Artifact Cause
Fingerprints
Scratches, abrasions
Foreign object
Non specific decrease
Moisture on finger transferred to
the film before exposure
Scraping or removing emulsion
Some unintended object in the
imaging chain
Dirty screens or cassette

Silver Recovery
A. Chemical Recovery Units
1. Precipitation of the silver
- The silver in the fixer solution is precipitated as silver
sulfide by adding sodium sulfide to the solution.
2. Replacement of the silver by another metal (steel
wool)
- Electrolytic Recovery Units – An electrical current is
passed through an ionized solution. Two electrodes
are used: anode (carbon) and cathode (stain-steel)

1. Ag + e  Ag
2. 2AgBr + H2Q + Na2SO3 --develop 2Ag + HBr + HQSO3 +
NaBr
3. H2Q + Na2SO3 + O2 –oxidation HQSO3Na + NaOH + Na
SO4
Oxidation raises the pH of the solution by
forming NaOH. It doesn’t produce bromide.
Notes: Each time a film is processed, bromide and acid
are formed and some developer is consumed. It lowers the pH
of the solution.

Developer Solution Agents, Chemicals, and Their Functions
Agent Chemical(s) Function
Developing or
Reducing agents
Phenidone
Hyrdoquinone
Fast-reducing, produces gray
densities
Slow Reducing Produces
black densities
Accelerator or
activator
Sodium
Carbonate
Elevates and Maintains
Solution pH
Restrainer Potassium
Bromide
Decreases reduction of
unexposed silver halide
Preservative Sodium Sulfite Decrease oxidation of
solution
Hardener Glutaraldehyde Hardens the emulsion
Solvent Water Dilutes the chemical

2. Fixing
➢ To remove unexposed silver halide from the film
and to make the remaining image permanent.
There are also two secondary functions of fixing:
➢ 1. To stop the development process.
➢ 2. To further harden the emulsion.
➢ It serves to clear the film of the undeveloped
crystals, forming a silver complex of thiosulfate,
technically called Monoargento-di-thiosulfuric
acid. It also hardens the gelatin emulsion.

Classification of hardeners in fixing
solution:
1. Potassium aluminum = most widely used and keeps
its hardening property almost indefinitely. However,
beyond a pH of 5.5, a white bloom forms on the
surface of the film brought about by the
precipitation of aluminum hydroxide.
2. Chrome aluminum = does not keep its hardening
property for more than a few days.
3. Aluminum chloride = can be used in a concentrated
hardener solution. It has a rapid hardening action
and is associatied with ammonium thiosulfate fixers.

Fixer Solution Agents, Chemicals, and Their Functions
Agent Chemical Function
A. Fixing Agent Ammonium
Thiosulfate
Clears away unexposed
silver halide
B. Acidifier Acetic acid Stops development
C. Preservative Sodium Sulfite Prevents reaction
between fixing agent and
acidifier
D. Hardener Chrome Alum
Potassium
Aluminum Sulfate
Aluminum Chloride
Hardens the emulsion
E. Solvent Water Dilutes the chemicals

Factors that affect the use of
the fixer
1. fixing agent used
2. concentration of the fixing agent
3. temperature of the solution
4. presence of hardener
5. film material used
6. agitation of the film
7. exhaustion of the fixing bath

Cause of exhaustion of fixers
1. dilution of water being carried into the tank
from the second stage
2. increasing alkalinity brought by the carry over
the alkaline developed
3. accumulation of the silver complexes which
retard the clearing action of the thiosulfates
4. decreasing acidity
5. loss of hardening power
6. oxidation of the sodium sulfite

Factors affecting the wash rate:
• Temperature of the wash bath
• Concentration of fixer in the emulsion and wash
bath
• agitation

Purposes of Washing:
• To remove the silver complexes from the film
• To remove the other salts from the film
• To remove the thiosulfate fixing agent from the
film

Factors affecting the Washing Rate:
• Temperature of the wash bath
• Agitation
• Concentration of fixer in the emulsion and wash
bath

A. Water rinse bath
B. Acid rinse bath ( stop-bath or short-stop)

Drying Process
• Factors affecting the drying process:
1. temperature
2. humidity
3. flow of the air into the emulsion

Replenishing pumps:
Diaphragm-type pump
Bellows-type pump
Magnetic-drive centrifugal pump
Percentage time pump
Piston-type pump

Recirculation System
➢ Acts to circulate the solutions in each of these tanks by
pumping solution out of one portion of the tank and
returning it to a different location with the same tank from
which it was removed.
➢ It keeps the chemicals mixed, which helps maintain solution
activity and provides agitation of the chemicals about the
film to facilitate fast processing.
➢ Helps maintain the proper temperature of the developer
solution. The developer recirculation system includes an in-
line filter that removes impurities as the developer solution
is being recirculated.

Temperature Control
Temperature control of the developer solution is important
because the activity of this solution depends directly on its
temperature. An increase or decrease in developer temperature
can adversely affect the quality of the radiographic image.
In most 90-second automatic processors, developer
temperature must be maintained at 93º to 95ºF (33.8º to 35ºC).
1. Gross control of temperature – affected by a water-mixing
valve, a device that interconnects the incoming hot and cold
water.
2. Fine control of temperature – occurs within the developer tank
itself through a thermostatically controlled heating element or
by means of a heat exchanger.

Drying System
The dryer assembly controls the amount of moisture to be
removed in order to maintain the archival quality of
radiographic film
Consist of a blower, ventilation ducts, drying tubes, and an
exhaust system. It completely extracts all residual moisture from
the processed radiograph so that it drops into the receiving bin
dry.
– The dryer blows hot air across the surface of the film
– Temperature of air = 110 to 120oF to remove surface moisture.
– The air is continually dried by a humidifier.
– The dryer must be vented to release built-up air as new air is
pulled into the system.

Indicators of Inadequate Processing
Radiographic Appearance Processing Problem
Decrease in Density
Developer Exhausted
Developer Underreplenishment
Processor Running Too Fast
Low Developer Temperature
Increase in Density
Developer Overreplenishment
High Developer Temperature
Light Leak in Processor
Pinkish Stain (Dichronic Stain)
Contamination of developer by fixer
Developer of fixer undereplenishment
Brown Stain (Thiosulfate Stain) Inadequate washing
Emulsion Removed by Developer Insufficient hardener in developer
Milky Appearance Fixer Exhausted
Inadequate washing
Streaks Dirty processor rollers
Inadequate washing
Inadequate drying
Water Spots Inadequate drying
Minus-Density Scratches

Pathology
• Pathologic condition that can alter the absorption characteristics of
the anatomic part being examined are divided into two categories:
1. Additive diseases – are diseases or conditions that increase the
absorption characteristics of the part, making the part more
difficult to penetrate.
2. Destructive diseases – are those diseases or conditions that
decrease the absorption characteristics of the part, making the part
less difficult to penetrate.
It is necessary to increase kVp when radiographing parts that have
been affected by additive disease and to decrease kVp when
radiographing parts that are affected by destructive diseases.

Restricting the Primary Beam
Increase Factor Result
Collimation Patient dose decreases
Scatter radiation decreases
Radiographic contrast increases
Radiographic density decreases
Field size Patient dose increases
Scatter radiation increases
Radiographic contrast decreases
Radiographic density increases

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