X-RAY PRODUCTION

L F A D A B C
ANODE HEAT BREMSSTRAHLUNG CHARACTERISTIC
LIBERATION FOCUSING ACCELERATION DECELARATION
U – UNEVEN ENERGIES I – INNER SHELL ELECTRON
O – OUTER SHELL ELECTRON N – NUCLEAR FIELD I - IONIZATION

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ROTOR SWITCH (mA) E - EXCITATION

- Supplies mA to the XRT. Electric current is supplied to the BOTH sides of the ANODE HEAT INTERACTION (99%)
- Projectile electrons interact with the outer shell electron. It will transfer small

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x-ray tube (filament and stator.
amount of energy and excitation (vibration of electrons) occurs. The outer
LIBERATION shell electrons will emit its energy through a HEAT PRODUCTION.
- ejection of electrons from the filament through heating (thermionic emission) - A single projectile electron may cause multiple excitation (heat production).
- electrons in the stator moves and starts the rotation of the rotor and target
CHARACTERISTIC INTERACTION

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(Electromagnetic Induction)
FLUORESCENT X-RAY
FOCUSING - Projectile electron interacts with inner shell electron and will transfer all its
- Electrons tends to accumulate at the center of the focusing cup (electron energy. Projectile electron disappears (law of conversation of energy). The
cloud) and electrons repels the negative focusing cup. inner shell electron will be ejected from the atom (ionization) leaving a
void/vacancy inside the atom.
EXPOSURE SWITCH (kV and exposure time) - Electron cascade/Electrons transition occurs.
- Characteristic x-ray will be emitted as the electron moves from outer shell to
ACCELERATION inner shell
-

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(positive).

DECELERATION
U-
Kilovoltage provides energy to each of the electrons (all electrons have the
same energy) and electrons moves from cathode (negative) to anode

The kinetic energy of the electrons will be converted into electromagnetic

- Dependent on the TARGET ATOM (Tungsten)

BREMSSTRAHLUNG INTERACTION
WHITE RADIATION
- Came from a German word means “braking-down” or “slow-down”
- Projectile electron loses its kinetic energy as it slows down to the NUCLEAR
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energy (x-rays) FIELD because of attraction force between the positive nucleus and negative
electron

LLL – Large distance/Little loss of energy/ Low energy x-rays

- CONTINUOUS EMISSION – provides the many energies of x-rays
ELECTRON INTERACTION WITH MATTER
 Interaction Atomic part By Product X-ray X-RAY QUALITY
Interaction Emission PARAMETERS:
Spectrum 1. WAVELENGTH
Anode Heat 2. FREQUENCY
3. VELOCITY

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HIGH KVP LOW KVP
Bremsstrahlung
HIGH ENERGY (HARD X-RAYS) LOW ENERGY (SOFT X-RAYS)
HIGH FREQUENCY LOW FREQUENCY

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SHORT WAVELENGTH LONG WAVELENGTH
Characteristic

RADIATION INTENSITY / X-RAY INTENSITY

RADIATION EXPOSURE / X-RAY EXPOSURE

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- Is the number of ionizations produced in air
- Is the number of ion pairs produced in air
- Measures the X-ray Quantity
EXPOSURE/ TECHNICAL FACTORS - Units: C/kg
Roentgen
Air KERMA
kVp mA sec SID Gray air
KVP AND RADIATION INTENSITY

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X-RAY QUALITY – refers to the energy/penetrability of x-rays
X-RAY QUANTITY – refers to the number of x-rays

1 Kilovoltage Peak
(direct but not proportion)
 As kVp increases, radiation intensity also increases
 As kVp decrease, radiation intensity also decrease
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- provides the energy of each electron during x-ray production
- energy produce is polyenergetic (many energies).
- controls: E - ENERGY
X - X-RAY QUALITY
Co - CONTRAST

FACTORS AFFECTED BY KVP:

X-RAY INTERACTION WITH MATTER 15% KVP RULE

TRANSMISSION +15% kVp = 100 % Density (x2)

ATTENUATION/ABSORPTION -15% kVp = 50%
Types: Density (÷2)
1. Total Absorption
2. Partial Absorption Increasing kVp by 15%, doubles the density

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Decreasing kVp by 15%, decreases the density
by half.

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PHOTOELECTRIC EFFECT COMPTON SCATTERING DENSITY MAINTENANCE FORMULA

AKA +15% kVp = ÷2 mAs

low patient dose, high scatter radiation, low contrast
-15% kVp = x2 mAs

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Proponent high patient dose, low scatter radiation, high contrast

Treshold
Energy KVP AND CONTRAST
(Inversely Proportional)

RADIOGRAPHIC CONTRAST
Condition - the variations/differences of densities

Interaction

Result
U- - Degree of differences of the light and dark areas in the radiograph

SCALE OF CONTRAST – scaling/scoring of contrast

- Refers to the number of gray tones

HIGH CONTRAST LOW CONTRAST

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KVP AND DENSITY
(Direct but not proportion)

RADIOGRAPHIC DENSITY
- overall blackness of the radiograph
1. Must be EXPOSED
2. Must be PROCESSED/DEVELOPED
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INVERSE SQUARE LAW

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Milliampere
Refers to the number of electrons produced in the filament during x-ray
- States that the intensity of x-ray reaching the image receptor is inverse to the
square of distance between tube and image receptor
production (thermionic emission)
- Happens when the distance is 7x the size of the focal spot
- Rotates the rotor and target during x-ray production (EMI)

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Exposure time (sec)
3

As SID increases, intensity decreases.

- Refers to the duration of x-ray production As SID decreases, intensity increases.

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- The length or period of time that there is x-ray production
DENSITY MAINTENNCE FORMULA
mAs=mA x sec DIRECT SQUARE LAW

RECIPROCITY LAW

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- Describe the relationship of Ma and sec in maintaining the density of
radiograph (inversely proportional). EXPOSURE TECHNIQUE CHART
- Any combination of Ma and exposure time that results to same mAs, the - It is a group of exposure factors and technique to ensure the consistency of
resultant density is also the same. radiograph produced.
- Happens when same patient is radiograph at a different day and time with
As mA increases, exposure time decreases different radiologic technologist
As mA decreases, exposure time increases TYPES:
1. VARIABLE KVP
MAS AND RADIATION INTENSITY
(directly proportional) U-
As mAs increases, radiation intensity also increases
As mAs decreases, radiation intensity also decreases
2. VARIABLE MAS
3. HIGH KVP TECHNIQUE
4. AUTOMATIC EXPOSURE CONTROL
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SID(source to image receptor distance) PATIENT AS BEAM ATTENUATOR
4
Distance FFD(focal to film distance)
AFD(anode to film distance) 1. TRANSMISSION
TFD(target to film distance)
- SID has no effect to quality nor to quantity of x-ray emitted from the x-ray tube 2. ATTENUATION
but to the x-ray intensity reaching the image receptor.
- The effect of SID to the intensity reaching the image receptor is inversely but A. TOTAL ABSORPTION
not proportion according to inverse square law due to the divergence of x-ray PHOTOELECTRIC EFFECT
beam
 2. CONES AND CYLINDERS
FACTORS: 3. VARIABLE LIGHT LOCALIZING APERTURE DIAPHRAGM
A T M COLLIMATOR
Atomic Thickness Mass 4. POSITIVE BEAM LIMITING DEVICE
number density AUTOMATIC COLLIMATION
ATOMIC NUMBER – number of protons inside the nucleus
- In a stable atom, the number of protons and the number of electrons are the

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same

THICKNESS
MASS DENSITY

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Increase thickness – increase absorption - Number of atoms in a given volume
Decrease thickness – decrease absorption - Compactness of tissue

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B. SCATTERING (COMPTON SCATTERING)

CONTROLS THE PRODUCTION OF SCATTER RADIATION

1. LOW KVP
2. SMALLER FIELD SIZE
BEAM RESTRICTING DEVICES
3. COMPRESSION
PRONE POSITION

REDUCTION OF SCATTER BEFORE IT REACHES THE IR

1. LOW KVP
2. SMALLER FIELD SIZE
BEAM RESTRICTING DEVICES
3. COMPRESSION
PRONE POSITION
U- GRID
Selectively absorbs scatter radiation
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4. GRID
PURPOSE: Increase contrast
5. AIR-GAP TECHNIQUE
DISADVANTAGE: High mAs
High patient dose
BEAM RESTRICTING DEVICES
- Invented by GUSTAV BUCKY (1913)
- Use to restrict or limit the radiation field size
- “GLITTERBLENDE” first checkerboard grid
- Invented by WILLIAM ROLLINS
GRID TYPES
TYPES:
1. STATIONARY GRIDS 2. MOVING GRID
1. APERTURE DIAPHRAGM
POTTER-BUCKY DIAPHRAGM
HOLLIS E. POTTER (1920)
GRID CONSTRUCTION

1. GRID/LEAD STRIP (High atomic number)

- Absorption of scatter radiation (grid clean-up)
2. INTERSPACE MATERIAL (Low atomic number)
GRID PROPERTIES
EXTRINSIC PROPERTIES:

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- Refers to the grid construction
GRID CUT-OFF

1. GRID RATIO

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2. GRID FREQUENCY – the number of grid strips per cm/inch
25 – 60 line pairs/cm

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80 – 200 line pairs/cm

INTRINSIC FACTOR
- Refers to grid performance

1. GRID SELECTIVITY – OFF

LEVEL OFF-CENTER
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2. CONTRAST IMPROVEMENT FACTOR

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3. BUCKY FACTOR

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 ADVANTAGE: increase Contrast
DISADVANTAGES:
Magnification
Increase Blur
Low Detail

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FILTRATION

Al Cu Tin Gd Ho

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13 29 50 64 67

TYPES:
1. INHERENT FILTER – found inside the tube

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- Examples: oil, Tube window(beryllium)
- 0.5 mm Al
2. ADDED FILTER – place after the XRT
- Examples: Port of the collimator (1.0mm Al)
Mirror (1.0 mm Al)
- 2.0 mm Al
IMAGE RECEPTOR
The receiver of transmitted/remnant x-rays

FOCUS
U-
UPSIDE DOWN
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Converts x-rays into visible images
Stores and records radiographic images

X-RAY FILMS
OFF-

- An image receptor used in conventional radiography

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- The receiver of transmitted/remnant x-rays
- Converts x-rays into visible images
- Stores and records radiographic images
TOPCOAT/SUPERCOAT/ OVERCOAT
- Protects the film from any mechanical damages such as scratches and
abrasions brought by rough handling

AIR GAP TECHNIQUE

EMULSION
- Heart of x-ray film
PARTS:
1. EMULSION BINDER
2. SILVER HALIDE CRYSTALS
ADHESIVE LAYER

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- Provides adhesion/contact between
emulsion and base layer - Ability of the film to respond to x-rays or light photons
BASE LAYER MATERIALS: - Refers to the sensitivity of film

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1896 1 X-RAY PLATES
GLASS PLATES
Use of glass
Fragile (breakable)
FILM CONTRAST
- Ability of the film to record different densities

FILM LATITUDE
CELLULOSE Extremely flammable
1914 2 - Ability of the film to record acceptable range of densities

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NITRATE Causes fires in the hospitals
TYPES OF FILM:
1. Accdg to screen:

1924 3 CELLULOSE
TRIACETATE
Not as flammable as Cellulose nitrate
DIRECT EXPOSURE FILM INDIRECT EXPOSURE FILM

2. According to construction
SINGLE-COATED EMULSION DOUBLE – COATED EMULSION
1950 4 MYLAR BASE

1960 5 POLYESTER

FILM MANUFACTURING
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Needs to be thick in order to be rigid

Molten polymer
3. According to sensitivity
Monochromatic
Ortochromatic
Panchromatic

INTENSIFYING SCREEN
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1. CRYSTAL PRODUCTION - Use to convert, amplify and intensify x-ray photons into light photons
2. RIPENING
3. MIXING
4. COATING
CHARACTERISTIC OF FILM
1. FILM SPEED
2. FILM CONTRAST
3. FILM LATITUDE
FILM SPEED
LAYERS: 1. GENERAL
1. PROTECTIVE ILLUMINATION
COATING WHITE LIGHT ILLUMINATION
2. PHOSPHOR 2. SAFELIGHT
3. REFLECTIVE ILLUMINATION
4. BASE

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INTENSIFYING SCREEN CHARACTERISTICS
1. SCREEN SPEED Distance from
WATT
2. CONVERSION EFFICIENCY Safelight to Bench Safelight to Floor

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3. RECORDED DETAIL
4. EFFECTIVE ATOMIC NUMBER
DETECTIVE QUANTUM EFFICIENCY
5. AFTERGLOW/LAG
6. MATCHING (SPECTRAL MATCHING)

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FILM PROCESSING
- Conversion of latent image into manifest image
DARKROOM - Conversion of invisible image into visible image
- A room devoid of all white light where film processing takes place - Conversion of exposed SHC into black metallic silver
STAGES:
GOOD CHARACTERISCTIC OF A DARKROOM
1. WETTING STAGE
LOCATION HUMIDITY 2. DEVELOPMENT STAGE
Near/adjacent to exposure room

SIZE
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8x8 ft- small size
9.5x15 ft – large size
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WALL
40-60% (psychrometer)

- 1.5 mm Pb
- 1/16 in Pb
3. RINSING STAGE
STOP BATH
4. FIXING STAGE
5. WASHING STAGE
6. DRYING STAGE
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- 2.5 – 3 m – ceiling height - 6 inches – concrete STAGE MANUAL AUTOMATIC
Light/ivory/pastel color – increase Wetting 15 sec ---------
reflectance of safelight Development 5 mins 22 sec
TEMPERATURE Rinse 30 sec --------
- Matte finish - absorbs white
- 18-24 deg C Fixing 15 mins 22 sec
li ht
- 20 deg C/ 68 deg F Wash 20 mins 26 sec
AIR MOVEMENT
Drying 30 mins 20 sec
- 15-25 ft/min
ROOM AIR CHANGES
ILLUMINATION
- 8-10 room air changes/hour
 BASE + FOG DENSITY
AUTOMATIC PROCESSING - Minimum or lowest density of the film
- The density of unexposed but processed film
1942 1956 1965 1987 BASE DENSITY
PAKO EASTMAN KODAK KONICA - The density provided by the addition of dye/tint into the base layer
40 mins processing KODAK

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FOG DENSITY
120 films/ hour First roller transport 90-sec processor Rapid processor - Density given by the inadvertinent/unwanted exposure of film by
Uses film hanger to system 45-sec processor
background and/or naturally occurring radioactive material during
transport the film
transport or storage

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RADIOGRAPHIC CONTRAST
SYSTEMS OF AUTOMATIC PROCESSOR o Variation of density in a radiograph.
1. Transport system o Radiographic contrast is the product of film contrast and subject contrast.
2. Replenishment system

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o Film Contrast– inherent film quality that result in recording high
3. Temperature control system contrast or low contrast radiograph
4. Recirculation system  Long Scale Contrast (Low Contrast) – there are small
5. Drying System differences between density of adjacent structures and many
6. Electrical system
densities are present.
7. Standby control system
 Short Scale of contrast (High Contrast ) –there is an evident
difference between and adjacent structures and few densities
RADIOGRAPHIC FILM QUALITY are present.
FACTORS:

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1. PHOTOGRAPHIC FACTORS – visibility of the image
CONTRAST RESOLUTION – ability to image similar tissue characteristics
A. DENSITY
B. CONTRAST
2. GEOMETRIC FACTORS – sharpness of the image
SPATIAL RESOLUTION–ability to image smaller objects
o Subject Contrast – difference in density of adjacent structure

FACTORS AFFECTING THE RADIOGRAPHIC CONTRAST

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Increased In: CONTRAST
A. DISTORTION PRIMARY FACTOR
B. DETAIL a) KVp Decreased
SECONDARY FACTORS
RADIOGRAPHIC DENSITY a) Grid Ratio Increased
- overall blackness of the radiograph b) OID Increased
- Exposure/ sensitization of x-ray film c) Beam Restriction/Collimation Increased
a. Must be EXPOSED d) Processing Time Decreased
b. Must be PROCESSED/DEVELOPED e) Processing Temperature Decreased
 f) Patient Thickness Decreased 3. HANDLING AND STORAGE ARTIFACTS
g) Field Size Decreased
h) Filtration Decreased
i) mAs No Changed
j) SID No Changed

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DISTORTION
- Misrepresentation of the image
TYPES:

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1. SIZE DISTORTION/MAGNIFICATION
- Enlargement or the increase of size of the image

2. SHAPE DISTORTION/ TRUE DISTORTION

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TYPES:
A. FORESHORTENING
- Caused by angulation of the part

B. ELONGATION
- Caused by angulation of the XRT
- Caused by angulation of the IR

DETAIL
- Sharpness of the image
UMBRA – true image
PENUMBRA – shadow of the image
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RADIOGRAPHIC ARTIFACTS
3 TYPES:
1. EXPOSURE ARTIFACTS
2. PROCESSING ARTIFACTS