Advances in Film /
Screen Radiography
AgX Photodetector
Inorganic, digital
photoconductor
Robert E. Dickerson
1-4 µm pixel size
Senior Research Associate
Health Imaging
Eastman Kodak Company
©Eastman
Kodak Company, 2005
8/12/2005
©Eastman
Kodak Company, 2005
8/12/2005
AgX Photodetectors
AgX Photodetector
Light photons
produced by
intensifying screens
are captured by each
AgX crystal to
produce stable latent
image
4-30 photons needed
for stable latent image
Latent image formed
by exposure is
chemically amplified
by development to
yield viewable silver
image
Amplification factor
>109
©Eastman
Kodak Company, 2005
8/12/2005
©Eastman
Kodak Company, 2005
8/12/2005
1
Tabular vs Conventional, 3-D crystals
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Kodak Company, 2005
8/12/2005
Cubic Grain Microcrystals
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Kodak Company, 2005
8/12/2005
Non Commercialized Micro crystals
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Kodak Company, 2005
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X-Wing Fighter
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Kodak Company, 2005
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2
PACMAN
Opportunities for Improved
Film Design
Higher contrast by control of grain size
distribution and sensitivity
Higher resolution film/screen systems
Improved quantum sensitivities of silver
halide microcrystals
Novel coating structures to improve film
processing rates
New display properties
©Eastman
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Kodak Company, 2005
8/12/2005
Kodak Company, 2005
8/12/2005
KODAK MIN-R EV Film
New asymmetric coating structure, in conjunction with novel
emulsions, optimizes image quality from toe to shoulder of
the response and improves physical properties.
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een muls
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Total
©Eastman
Kodak Company, 2005
8/12/2005
Parenchymal Emulsion
Novel silver halide microcrystals in the
parenchymal emulsion contain shallow electron
trapping dopants. In conjunction with the
improved monodispersity of the grains, this allows
it to achieve high contrast with a sharp toe.
High contrast makes breast anatomy, including
abnormalities, more visible
Sharp toe might enable new optimization of
imaging chain and better visualization of
microcalcifications
©Eastman
Kodak Company, 2005
8/12/2005
3
Min-R EV 150
system vs.
system vs
KODAK
MIN-R
EVMin-R
1502000
Screen
KODAK
MIN-R
2000
Screen
6.5
High D-max and
shoulder contrast is
due to high opacity
grains and backside
emulsion
6.0
5.5
Density
Higher
5.0 contrast
4.5 to
is due
4.0
monodisperse
3.5
cubic
grains
Results in greater
overexposure latitude,
which is due to higher
upper scale contrast
3.0
2.5
Better2.0visualization
of breast
1.5
1.0
parenchyma
Sharp toe is due to novel emulsion technology
0.5
Images were exposed to a density of ~1.9 in the center
of the image
Images made with a GE DMR mammographic unit
Two imaging systems: MIN-R 2000 and MIN-R EV
Eight kVps: 25-32
Two anode/filter combinations: Mo/Mo and Rh/Rh
Two duplicate sets
0.0
0.0
0.5
1.0
1.5
2.0
Log E
X-ray Sensitometry
KODAK MIN-R
2000/2000 Screens
KODAK MIN-R EV & EV 150
Screens
©Eastman Kodak Company, 2005
Kodak
Company, 2005
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©Eastman
CDMAM Phantom, Type
3.4, used in the study
Gold disks range in
diameter from 60 µm to
2 mm, and in thickness
from 30 nm to 2 µm
Each square contains two
identical disks, one in the
center and one in a
randomly chosen corner
The task is to pick the
corner containing the disk
©Eastman
©Eastman
Kodak
Kodak
Company,
Company,2004
2005
8/12/2005
8/12/2005
2.5
Results
in whiter whites, more
“sparkle,” improved visibility
of microcalcifications
Total of 64 images
All processed in KODAK X-OMAT EX II Developer
and Replenisher
©Eastman
Kodak Company, 2005
8/12/2005
Score sheet from one
observer for MIN-R 2000
Film/Screen, 26 kVp,
Mo/Mo
Blue indicates that the
correct corner was
identified
Red indicates that the
wrong corner was identified
or that the observer said
they could no longer detect
the disks
©Eastman
©Eastman
Kodak
Kodak
Company,
Company,2004
2005
8/12/2005
8/12/2005
4
Summary
Phantom: CDMAM Phantom, Type 3.4
Results
System
kVp
Filtration
CDMAM
Detectability*
Exposure
Time (sec)
Relative
Mid-line
Dose
MIN-R 2000
MIN-R 2000
28
30
Mo/Mo
Rh/Rh
0
−2
1.92
0.60
1.0
0.4
MIN-R EV
MIN-R EV
28
30
Mo/Mo
Rh/Rh
+2
0
1.68
0.55
0.9
0.4
* Average relative column number
©Eastman
©Eastman
Kodak Company, 2005
8/12/2005
At 28 kVp, Mo/Mo, the MIN-R EV System will reduce the
mid-line dose by 10%, yet provide better detection of the
disks in the CDMAM Phantom than the MIN-R 2000
System
At 30 kVp, Rh/Rh, the MIN-R EV System will provide
similar detection of the disks in the CDMAM Phantom as a
MIN-R 2000 System but at 40% the mid-line dose
Kodak Company, 2005
8/12/2005
KODAK Hyper Speed G
Medical Film
(Provides improved
resolution and visually
adaptive contrast)
MIN-R EV Systems demonstrate simultaneously high
sharpness and low, high-frequency noise
©Eastman
Kodak Company, 2005
8/12/2005
Features oxidatively
enhanced, high quantum
efficiency AgX
microcrystal that provides
improved sensitivity
Because of the improved film properties (toe contrast, midscale contrast, speed) and improved screen properties
(improved MTF, speed)
KODAK Hyper Speed G Medical Film
Low Exposure Region
Imaging Layer
Hyper Speed G
0.30 logE faster
High Exposure Imaging Layer
+ Gradient Crossover Control
T-MAT G/RA
Support
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Kodak Company, 2005
8/12/2005
5
Radiographic Speed – Historical Timeline
1896: Paper used for media-based radiography. Calcium
tungstate intensifying screens discovered. Relative speeds
unknown (VERY low).
Modulation Transfer Function (image blur)
Screen / Film
Speed
MTF (cycles/mm)
2
4
8
400
100% 100% 100%
800
175% 250% 270%
1912: Glass plate radiography. VERY low speed.
1918-1970s: Double-emulsion films, calcium tungstate screens
improved, relative system speeds 25-200.
1970s – present: Rare earth screens and appropriate films
commercialized, relative system speeds 100-400 (A few small
niche markets use faster systems).
2004: Hyper-speed systems, relative system speeds 400-1600
(with greatly improved high-frequency NEQ and DQE).
©Eastman
Screen / Film
Speed
MTF (cycles/mm)
2
4
8
LANEX Regular /
T-MAT G
400
100% 100% 100%
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Kodak Company, 2005
8/12/2005
1300
90%
95%
100%
Kodak Company, 2005
8/12/2005
Modulation Transfer Function (image blur)
GE Digital
Radiography
Computed
Radiography
X-SIGHT /
Hyper Speed G
LANEX Fast /
Hyper Speed G
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Kodak Company, 2005
8/12/2005
INSIGHT Skeletal
Medium /
Hyper Speed G
LANEX Fine /
Hyper Speed G
LANEX Regular /
T-MAT G
How Hyper Speed Works, cont.
MTF benefit can be utilized in two basic ways:
1. Provide improved image quality (better visibility
of fine detail) at current system speeds.
400
250% 500% 750%
OR
200
300% 600% 900%
2. Provide clinically acceptable, high image quality
at 2X current system speeds, exchanging potential
200-400
150%
60%
NA
200-400
90%
60%
NA
image quality for radiation dose reduction.
©Eastman
Kodak Company, 2005
8/12/2005
6
Benefits of High-Speed Systems
What does this mean?
Mammographic – MTF at 200200-300 speed
X-SIGHT – MTF at 800 speed
LANEX Regular/TRegular/T-MAT – MTF at 1300 speed
©Eastman
Higher image quality from stopping motion
grids, body motion
Opportunity to reduce Kv
Smaller focal spot
Magnification
Increased tube life
Reduced radiation dose to radiology staff
©Eastman
Kodak Company, 2005
8/12/2005
Kodak Company, 2005
8/12/2005
Visually Adaptive Contrast
The human visual system loses it’s ability to distinguish
differences in density as an image gets darker.
Visually Adaptive Contrast
Visually adaptive contrast puts the contrast where the eyes need it.
Visually Adaptive Contrast
This means that lesion detection is less likely if the lesion
appears in a darker area of the radiograph.
More
Lesion Detectability
Film Contrast
Lesion Detectability
Lesion Detection vs Density
More
Lower
Less
Less
Light
Light
©Eastman
Higher
Kodak Company, 2005
8/12/2005
Film Density
Film Density
Dark
Dark
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Kodak Company, 2005
8/12/2005
7
KODAK X-SIGHT L/RA Film
Visually Adaptive Contrast
Local contrast comparison with other of Kodak’s latitude systems
X-RAY SENSITOMETRY
SPEED MATCHED AT D = 1.20
4.0
T-MAT L/RA &
LANEX Regular
X-SIGHT L/RA &
X-SIGHT
XLA+ & TRIMATIC
Regular
3.5
3.0
Gamma
2.5
2.0
1.5
1.0
0.5
0.0
0.0
0.5
1.0
1.5
2.0
Summary
New film/screen system allows for
significantly reduced X-ray dose at improved
MTF (image blur).
Significant improvements in system MTF are
possible at equivalent X-ray doses
New film/screen system provide opportunities
for dose reduction as result of higher system
speed while maintaining high image quality
2.5
log10 Relative Exposure
©Eastman
Kodak Company, 2005
8/12/2005
©Eastman
Kodak Company, 2005
8/12/2005
Conclusion
Improved film/screen systems continue to
be developed.
Opportunities for improved image quality
and processability still exist.
New systems provide possibilities for
lower-dose radiology at high image quality.
©Eastman
Kodak Company, 2005
8/12/2005
©Eastman
Kodak Company, 2005
8/12/2005
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