Presentation by Nityanand Gopalika on Digital Radiography Performance Study - paper presentaed at NDE 2003 conference.

1. Digital Radiography-
A Performance study for industrial application
V.Manoharan, Gopalika Nityanand, and Debasish Mishra
Industrial Imaging and Modeling Lab
Imaging Technologies
John F Welch Technology Center
Bangalore

2. Benefits of Digital Radiography
Productivity
1. Faster response
2. Elimination of chemical processing
3. Automated inspection
4. Elimination of retakes
Cost
• Elimination film and consumables
• ROI in two to three years
Quality
• Image processing and analysis
• Reduces operators fatigue
• Consistency
Advanced Application
• Volumetric CT for High Throughput
Productivity and cost benefits

3. System configurations under study
DXR-500 Digital Radiography system Detector and data acquisition systems
Model:DXR-500
Make: GE Inspection technologies
Type: a-Si based Indirect conversion
Scintillator:CsI
Pixel pitch:100 microns
No of pixels: 2304 X 1920
X-ray Source
Model: KA 160
Make:Kevex
Focal spot: 0.4,.25,.065,.01 mm
Max kV: 160 mA: 1
CsI needles structure
How it works?
Advanced medical technologies for Industrial applications

4. Performance study-Radiation exposure response
DXR-500 DR system
14000
12000
Signal(ADC)
10000
8000
6000
4000
2000 Min and Max exp ratio >12
0
0 5 10 15 20 25 30 35
Relative exposure
Comparative study Useful exposure range
Industrial X-ray film Min and Max exp ratio 2
Characteristics DXR-500 Digital Detector
( Medium speed) • Productivity:
In the order of few mR to get 1.3 R to get Optical
Speed
signal level of 12000 density of 2 • High Speed (mR vs R)
Useful minimum to
Useful minimum to • Minimized Rework
Dynamic range maximum exposure
maximum exposure ratio 12
ratio 2
• High Latitude Coverage
Typical Exposure ratio requirements • Advantages
X-ray tube Subject
• Less radiation field
Material Lattitude potential contrast • Micro focus (Faster response
Ti 3 to 20 mm 160 kV 12.7 enables high definition
Steel 1 to 10 mm 160 kV 7.28 radiography)
Detector characteristics suitable for industrial applications

5. Performance study-Noise response
• Poisson distributed noise
• Noise Quantum limited
• Averaging of frames reduces noise
Effect of no. of frames
1 frame
5 frames
Effect of no. of X-ray photons
1 Mas
10 frames
5 Mas 25 frames
Quantum limited Noise performance

6. Performance study-Spatial resolution
• Observation:
• System can be designed to match with
film MTF.
• Digital detector with mini/micro focal
tube outperforms film radiography
with large focal spots.
• DQE of DXR-500 is comparatively
good. (DQE is a better Image quality
metric than MTF)
System can be designed to meet IQ requirements

7. Performance study-IQI sensitivity
Mat. – Ti Mat. – Ti Mat. – SS Mat. – Al
Thick. – 25mm Thick. – 10mm Thick. – 10mm Thick. – 40 mm
Kvp – 120 Kvp – 120 Kvp – 140 Kvp – 120
mAs – 1.0 mAs – 1.0 mAs – 1.0 mAs – 1.0
FS – 0.4 mm FS – 0.4 mm FS – 0.4 mm FS – 0.4 mm
2-1T sensitivity over range of thickness

8. Performance study-Imaging
2-2T
Sensitivity Porosity
Lack of
penetration
Kvp – 125
mAs – 1.0
FS – 0.4 mm
Mat. – CS
Tech. - SWSI
Kvp – 125 Mat. – CS
mAs – 1.0 Tech. - DWDI
FS – 0.4 mm
Range of applications with 2-1T sensitivity

9. Performance study-Imaging
Object – IC
Kvp – 70
mAs – .5
FS – 10 microns
Mag. – 50X
Object – IC Object –ceramics
Kvp – 70 Kvp – 70
mAs – .5 mAs – .5
FS – 10 microns FS – 10 microns
Mag. – 50X Mag. – 50X
Enable high definition radiography

10. Performance study-Conclusion
• Faster response and wide dynamic range
• Quantum limited noise performance
• System can be designed to meet image quality requirements
• 2-1T sensitivity over range of thickness
• Range of applications with 2-1T sensitivity
• Enables high definition radiography