Overview of CR and DR
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Transcript of Overview of CR and DR
23年 4月 19日 1
Overview of CR and DR
Gyeongsang National University Hospital Department of Diagnostic Radiology Radiation Technologist: You Dai In
23年 4月 19日 2
Direct Radiography (DR)
Overview of DR systemsCCD based systemsTFT + PhosphorTFT + Photoconductor
23年 4月 19日 3
Detector technology:CCD based systemsA. Lens Coupling B. Fiber optic coupling C. multiple detectors
A phosphor screen converts X-rays into visual light that is projected onto a CCD or onto a CCD-array
23年 4月 19日 4
CCD based systems
Company Imix Swissray TrexTechnology RED - Agfa
GOS:EuGOS:Tb4 CCD’s
CsI + FOP12 CCD’s
Application Chest General Mammo fullfield
Active Area 15.7”x15.7” 14” x 17” 8” x 10”
FDA clear. Yes yes no
MarketingStrategy
DealersDistributors
Directsales
OEM FisherLorad
• Mature technology• Mostly dedicated applications: mammography, chest• FDA approved except for mammography
23年 4月 19日 5
Detector technology:TFT + Phosphor
Photodiode convertsvisual photons into electrons
Electrons are stored oncapacity of switching element
Phosphor
Phosphor screenconverts X-ray photonsinto visual photons.
23年 4月 19日 6
TFT + PhosphorCompany Canon dpiX GE Trixell
Technology GOS:Tb GOS:Tb CsI:Tl CsI:Tl450µ
Application General General General,Mammo
General
Active Area 17”x17” 11.5”x15” 41x41cm19x23cm
15.7”x15.7”
FDA clear. yes OEM yes yesMarketingStrategy
OEMDirect Sales
OEM GE OEM
• GOS systems: available on the market• CsI systems: limited availability• FDA approved
23年 4月 19日 7
Detector technology:TFT + Photoconductor
Electrons migrate to surface electrode
Electrons are stored oncapacity of switching element
Charge transport in photoconductor
23年 4月 19日 8
TFT + PhotoconductorCompany dpiX Noranda Hologic Toshiba
Technology PbI2 100µ -Se 200µ -Se 500µ -Se 1000µApplication Mammo
FluoroMammo Spot General Fluoro
AngioActive Area 50x50mm2 90x90mm2 14” x 17” 7.5” x 9.5”FDA clear. Experimental Experimental Yes ExperimentalMarketingStrategy
OEM
Experimental except Hologics
23年 4月 19日 9
Weaknesses of TFT systems Low yield of TFT array fabrication Ghost images
Charge trapping in amorphous semiconductors
Clustering of Tl+ dopant in CsI needles Limited dynamic range (a- Se) due to high
dark current Image deformation beyond w>Nyquist due
to aliassing (a-Se) Electronic noise in low dose applications Detector damage at high dose (capacitor
overload)
23年 4月 19日 10
Principle of CR
I 0I 00I I00 I0I 00 I I I0I II
Laser
Storage phosphor plate
Rollers
Light guide
Galvanometer
Photomultiplier
Electrical Signal
Digitisation
A/DA/D
23年 4月 19日 11
Computed RadiographyCompany Agfa Fuji Kodak Konica Lumisys
Technology BaFBr BaFBr BaFBr BaFBr BaFBr(Agfa)
Application General General General, General GeneralActive Area 14”x17” 14”x17” 14”x17” 14”x17” 14”x17”FDA clear. yes yes yes yes yesMarketingStrategy
DirectSales
DirectSales
DirectSales
DirectSales
DirectSales
• Mature and robust technology• FDA approved and clinically accepted for all applications except mammography
23年 4月 19日 12
CR and DR: EconomicsFlat Panel Investment $250-300K for
one room $100K to replace damaged
detector
DR 20% higher productivity
6 pat./h x 2exp./pat. x 10h/day x 200 days/yr = 24 000 exp/yr
1 room = 24 000 exp./yr Amortisation 5 yrs = 120
000 exp. $350 000 / 120 000 exp. =
$2.90/exp.
CR Investment $150K for 3 to
4 rooms $1K to replace damaged
detector
CR productivity ~conventional
5 pat./h x 2exp./pat. x 10h/day x 200 days/yr = 20 000 exp/yr
3 rooms = 60 000 exp./yr Amortisation 5 yrs = 300
000 exp. $150 000 / 300 000 exp. =
$0.50/exp.
23年 4月 19日 13
CR/DR world market evolution 1996-
2005 19
96
1997
1998
1999
2000
2001
2002
2003
2004
2005
CR
DR
23年 4月 19日 14
Assumptions Penetration of digital acquisition in the x ray
rooms will evolve from 2.5% in 1999 to 11% in 2005
Within this digital segment, DR will substitute CR differently according to the application: Mobile: 100% retention of CR by 2005 Chest: 0% retention of CR General Rad high end: 70% retention of CR General Rad low end: 85% retention of CR
23年 4月 19日 15
CR and DRNew flat panel digital detectors are compact,
offer fast image acquisition and promise excellent image quality
DRFlat panel
CR
23年 4月 19日 16
Evolution of Digital Radiography Detector
23年 4月 19日 17
Innovation in Plate technology
Powder Phosphor BaFBr Needle Phosphor CsBr
“state of the art CR”more absorptionhigher sharpnesshigher image quality
23年 4月 19日 18
New CsBr:Eu PhosphorHigher image
quality Cubic crystal facilitates needle growth Equivalent specific X-ray absorption: ( =4.44 vs.
5.1 g/cm3)
Efficient stimulation with diode laser (stimulation 685 nm)
Efficient detection with PMT or CCD (emission 450 nm)
Excellent storage phosphor: Conversion efficiency > BaFBr:Eu
(more light / absorbed X-ray) Lower stimulation energy
Read-out requires 3 times less laser power
23年 4月 19日 19
DQE, 2,5 µGy (SC 400) 70 kV, 0.5mm Cu-Filter
0
0,2
0,4
0,6
0,8
0 1 2 3 4
Spatial frequency (Lp / mm)
DQE
CR "Needle IP", prototypemeasurement results
DR literature data (C. Chaussat etal., SPIE Med. Img. 1998)
CR, state of the art ("powder IP")
23年 4月 19日 20
Scanhead line scanner:Higher
throughput Fast acquisition (5s scan, 20s cycle) QE CCD > QE PMT Higher gain
Flying Spot Scanhead
Scan: pixel per pixel Scan: line per line Detector: Photomultiplier Detector: CCD
PhotoDetector
Fiber Optic Phosphor Image Plate
Galvo
Light Beam
Collimator
LaserScan-Head
SHT Phosphor Image Plate
23年 4月 19日 21
Scanhead - Scanning Principles
Front-StimulationFront-Stimulation
ADC StratusADC Stratus
Back-StimulationBack-Stimulation
CR PanelCR Panel
23年 4月 19日 22
Scanhead - 17” Front stimulation
23年 4月 19日 23
Scanhead - 17” Prototype(Back-Stimulation)
23年 4月 19日 24
Scanhead, the unifying technology
Scanhead Phosphor Image Plate
• simple• mature• robust• economic• multi-application
• fast• compact• integrated• higher image quality
CR
AGFA - Patent
(DR)
23年 4月 19日 25
Ideal DR System
23年 4月 19日 26
DR Detector Technologies
23年 4月 19日 27
CR and DR DQE
23年 4月 19日 28
DQE
23年 4月 19日 29
23年 4月 19日 30
Conclusions
The different technologies will coexist Best choice will depend on application CR potential is promising The difference between CR and DR
technology will become less relevant