16. Optimization of protection in fluoroscopy: Part 2 (652 KB)
Z Y Image Optimization in Fluoroscopy - umich.edu
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X Y Z Image Optimization in Fluoroscopy Phil Rauch Henry Ford Health Systems Detroit, MI
Transcript of Z Y Image Optimization in Fluoroscopy - umich.edu
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Image Optimization in Fluoroscopy
Phil RauchHenry Ford Health Systems
Detroit, MI
2Dep art ment of Radiology – Division of Ph ysi cs and Engineering
Henry Ford Health System
3Dep art ment of Radiology – Division of Ph ysi cs and Engineering
Image Optimization in Fluoroscopy
!Contrast to noise
Key Considerations
!Temporal fidelity!Dynamic Range Rendering!Visual Perception!Skin Dose
4Dep art ment of Radiology – Division of Ph ysi cs and Engineering
Exposure ON-time
• Under control of the interventionalist
• Once procedure begins it generally does not end until the intervention is complete
• May result in fluoroscopy time measured in hours
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address these effects, or……
The Challenge for Medical Physics
T.R. Koenig, M.D.,Ph.D.; L.K. Wagner, Ph.D.; F. A. Mettler, M.D. and D. Wolff, M.D.Radiation Injury to the Skin Caused by Fluoroscopic Procedures: Lessons on Radiation ManagementScientific Exhibit Cum Laude - RSNA 2000
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The Challenge for MP’s…… prospectively understand and optimize these …...
PatientDose
X-ray tubekVp
Beam Filtration
Image Quality
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Fluoroscopic Radiation Capture/Conversion
Indirect Conversion FPDIndirect Conversion FPDIndirect Conversion FPDIndirect Conversion FPD
8Dep art ment of Radiology – Division of Ph ysi cs and Engineering2005 AAPM M eeting-Phil Rau ch
Dynamic Range Rendering
9Dep art ment of Radiology – Division of Ph ysi cs and Engineering2005 AAPM M eeting-Phil Rau ch
Is Contrast Required?
Native Subtracted
10Dep art ment of Radiology – Division of Ph ysi cs and Engineering2005 AAPM M eeting-Phil Rau ch
Is Contrast Required?
Native Subtracted
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Imaging Task #5What’s wrong with this image?
Continuous Fluoro Pulsed Fluoro
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Sharpness
Continuous Fluoro Pulsed Fluoro
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How Much Dose?
Fluoroscopy – 0.036 µGy/pulse Acquisition Frame – 3.6 µGy/frame
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X-ray Tube Potential
Attenuator: 20 cm water
EERD: 90 µR/sec
SEER: 5 R/min
SEER: 2.5 R/min
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Tube
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l (kV
p)Does patient dose depend on detector dose?
15Dep art ment of Radiology – Division of Ph ysi cs and Engineering
X-ray Tube PotentialDoes patient dose depend on detector dose?
Attenuator: 20 cm water
EERD: 90 µR/sec
SEER: 5 R/min
SEER: 2.5 R/min
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Tube
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Dose Per Pulse
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Dose Per Pulse
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Dose Per Pulse
GI Fluoroscopic Power Curve
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Normal Mode
Mag. 1 Mode
Mag. 2 Mode
Fluoroscopic Power Curve (High Level vs Normal / 0.2 mm Cu Attenuator)
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High Level - 2nd Footswitch Pos.
Low Le vel - 2nd Footswitch Pos.High Level - 1st Footswitch Pos.
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Image Quality
!Contrast to Noise Ratio vs KVpLow attenuation region (high signal), 0.2 mm CuLow attenuation region(high signal), 0.4 mm CuHigh attenuation region(low signal), 0.2 mm CuHigh attenuation region(low signal), 0.4 mm Cu
The British Jour nal of Radiolog y, 77 (2004), 479–487[Constant EERD]
21Dep art ment of Radiology – Division of Ph ysi cs and Engineering
Fluoro kVp & beam filtrationFluoroscopic Power Curves
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Fluoro Power Curve with Cu:Autofilter (70 kV Plateau), 3kW,32 nGy/pulse, 10R
Fluoro Power Curve with Cu:Autofilter (70 kV Plateau), 3kW,32 nGy/pulse, 20R
0.9 mm Cu0.6 mm Cu
0.3 mm Cu
0.2 mm Cu
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Human Visual Perception
!To help reduce missed findings, medical images should be associated with a specific task
!The imaging modality selected should be that which optimizes the success of the imaging task
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Imaging Task #3
!This task is intended to test your ability to interpret a moving image and focus on a specific task
!For this task, assume the tolerance for error is zero
!You will be assigned to a team!Each team will have a different task
to perform using the same image
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Imaging Task #3
25Dep art ment of Radiology – Division of Ph ysi cs and Engineering
Final Imaging Task
Why is there an extra square?
How can this be true?
Below the four parts
are re-ordered
The four parts are
exactly the same as
those used above
Thank youPhil Rauch
