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Section 2  M Vision Geometry Calibration  V Mc 062707 V Rjo062807
Section 2  M Vision Geometry Calibration  V Mc 062707 V Rjo062807
Section 2  M Vision Geometry Calibration  V Mc 062707 V Rjo062807
Section 2  M Vision Geometry Calibration  V Mc 062707 V Rjo062807
Section 2  M Vision Geometry Calibration  V Mc 062707 V Rjo062807
Section 2  M Vision Geometry Calibration  V Mc 062707 V Rjo062807
Section 2  M Vision Geometry Calibration  V Mc 062707 V Rjo062807
Section 2  M Vision Geometry Calibration  V Mc 062707 V Rjo062807
Section 2  M Vision Geometry Calibration  V Mc 062707 V Rjo062807
Section 2  M Vision Geometry Calibration  V Mc 062707 V Rjo062807
Section 2  M Vision Geometry Calibration  V Mc 062707 V Rjo062807
Section 2  M Vision Geometry Calibration  V Mc 062707 V Rjo062807
Section 2  M Vision Geometry Calibration  V Mc 062707 V Rjo062807
Section 2  M Vision Geometry Calibration  V Mc 062707 V Rjo062807
Section 2  M Vision Geometry Calibration  V Mc 062707 V Rjo062807
Section 2  M Vision Geometry Calibration  V Mc 062707 V Rjo062807
Section 2  M Vision Geometry Calibration  V Mc 062707 V Rjo062807
Section 2  M Vision Geometry Calibration  V Mc 062707 V Rjo062807
Section 2  M Vision Geometry Calibration  V Mc 062707 V Rjo062807
Section 2  M Vision Geometry Calibration  V Mc 062707 V Rjo062807
Section 2  M Vision Geometry Calibration  V Mc 062707 V Rjo062807
Section 2  M Vision Geometry Calibration  V Mc 062707 V Rjo062807
Section 2  M Vision Geometry Calibration  V Mc 062707 V Rjo062807
Section 2  M Vision Geometry Calibration  V Mc 062707 V Rjo062807
Section 2  M Vision Geometry Calibration  V Mc 062707 V Rjo062807
Section 2  M Vision Geometry Calibration  V Mc 062707 V Rjo062807
Section 2  M Vision Geometry Calibration  V Mc 062707 V Rjo062807
Section 2  M Vision Geometry Calibration  V Mc 062707 V Rjo062807
Section 2  M Vision Geometry Calibration  V Mc 062707 V Rjo062807
Section 2  M Vision Geometry Calibration  V Mc 062707 V Rjo062807
Section 2  M Vision Geometry Calibration  V Mc 062707 V Rjo062807
Section 2  M Vision Geometry Calibration  V Mc 062707 V Rjo062807
Section 2  M Vision Geometry Calibration  V Mc 062707 V Rjo062807
Section 2  M Vision Geometry Calibration  V Mc 062707 V Rjo062807
Section 2  M Vision Geometry Calibration  V Mc 062707 V Rjo062807
Section 2  M Vision Geometry Calibration  V Mc 062707 V Rjo062807
Section 2  M Vision Geometry Calibration  V Mc 062707 V Rjo062807
Section 2  M Vision Geometry Calibration  V Mc 062707 V Rjo062807
Section 2  M Vision Geometry Calibration  V Mc 062707 V Rjo062807
Section 2  M Vision Geometry Calibration  V Mc 062707 V Rjo062807
Section 2  M Vision Geometry Calibration  V Mc 062707 V Rjo062807
Section 2  M Vision Geometry Calibration  V Mc 062707 V Rjo062807
Section 2  M Vision Geometry Calibration  V Mc 062707 V Rjo062807
Section 2  M Vision Geometry Calibration  V Mc 062707 V Rjo062807
Section 2  M Vision Geometry Calibration  V Mc 062707 V Rjo062807
Section 2  M Vision Geometry Calibration  V Mc 062707 V Rjo062807
Section 2  M Vision Geometry Calibration  V Mc 062707 V Rjo062807
Section 2  M Vision Geometry Calibration  V Mc 062707 V Rjo062807
Section 2  M Vision Geometry Calibration  V Mc 062707 V Rjo062807
Section 2  M Vision Geometry Calibration  V Mc 062707 V Rjo062807
Section 2  M Vision Geometry Calibration  V Mc 062707 V Rjo062807
Section 2  M Vision Geometry Calibration  V Mc 062707 V Rjo062807
Section 2  M Vision Geometry Calibration  V Mc 062707 V Rjo062807
Section 2  M Vision Geometry Calibration  V Mc 062707 V Rjo062807
Section 2  M Vision Geometry Calibration  V Mc 062707 V Rjo062807
Section 2  M Vision Geometry Calibration  V Mc 062707 V Rjo062807
Section 2  M Vision Geometry Calibration  V Mc 062707 V Rjo062807
Section 2  M Vision Geometry Calibration  V Mc 062707 V Rjo062807
Section 2  M Vision Geometry Calibration  V Mc 062707 V Rjo062807
Section 2  M Vision Geometry Calibration  V Mc 062707 V Rjo062807
Section 2  M Vision Geometry Calibration  V Mc 062707 V Rjo062807
Section 2  M Vision Geometry Calibration  V Mc 062707 V Rjo062807
Section 2  M Vision Geometry Calibration  V Mc 062707 V Rjo062807
Section 2  M Vision Geometry Calibration  V Mc 062707 V Rjo062807
Section 2  M Vision Geometry Calibration  V Mc 062707 V Rjo062807
Section 2  M Vision Geometry Calibration  V Mc 062707 V Rjo062807
Section 2  M Vision Geometry Calibration  V Mc 062707 V Rjo062807
Section 2  M Vision Geometry Calibration  V Mc 062707 V Rjo062807
Section 2  M Vision Geometry Calibration  V Mc 062707 V Rjo062807
Section 2  M Vision Geometry Calibration  V Mc 062707 V Rjo062807
Section 2  M Vision Geometry Calibration  V Mc 062707 V Rjo062807
Section 2  M Vision Geometry Calibration  V Mc 062707 V Rjo062807
Section 2  M Vision Geometry Calibration  V Mc 062707 V Rjo062807
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Section 2 M Vision Geometry Calibration V Mc 062707 V Rjo062807

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    • 1. <ul><li>Section 2 </li></ul><ul><li>MVision Geometry Calibration </li></ul>MVision Physicist Self-Led Training 81 40 258 Rev. C Siemens Medical Solutions, Inc. Oncology Care Systems Group 4040 Nelson Avenue Concord, CA 95420 The reproduction, transmission or use of this document or its contents is not permitted without express written authority. Offenders will be liable for damages. All rights, including rights created by patent grant or registration of a utility modal or design, are reserved.
    • 2. Section 2: Table of Contents Geometry Calibration Phantom positioning Geometry Calibration field creation MVision Gain Field Creation Videos: MVision Gain Projection Matrices Phantom Positioning Geometry Calibration MVision Protocol Geometry Calibration Phantom MVision Image Reconstruction Overview Scale Factor Objectives
    • 3. Section 2: Table of Contents MVision Geometry Calibration (p. 50) Section 2 Quiz Geometry Calibration Phantom Setup (p. 40) Section 2 Review Videos : Fail to Pass Geometry Calibration MVision Geometry Calibration Video: Geometry Calibration MVision Protocol Geometry Calibration Results MVision Gain Geometry Calibration Window Labs : MVision Control Console Display
    • 4. Objectives <ul><li>At the completion of this section, you will be able to: </li></ul><ul><ul><li>Identify the fundamentals of MVision Geometry calibration </li></ul></ul><ul><ul><li>Understand the function of the Geometry Calibration Phantom </li></ul></ul><ul><ul><li>Describe the MVision Reconstruction Process </li></ul></ul><ul><ul><li>Describe the MVision Protocol parameters and how they influence the image quality </li></ul></ul><ul><ul><li>Perform the MVision gain calibration </li></ul></ul><ul><ul><li>Perform the MVision Geometry Calibration </li></ul></ul>
    • 5. Overview Figure 2.0 Geometry Calibration phantom
    • 6. Overview Figure 2.1 Projection image of the phantom
    • 7. Geometry Calibration Phantom Cradle Gantry Side Figure 2.2 Geometry Calibration Phantom Perspective View Shell
    • 8. Geometry Calibration Phantom Cradle Base Plate Figure 2.3 End and Side Views of the Phantom Small Tungsten Beads Large Tungsten Beads Level screw
    • 9. Geometry Calibration Phantom <ul><li>Phantom Physical Dimensions </li></ul>Table 2.0 108 Number of Ball Bearings 6 mm Diameter of the large Ball Bearings 3.2 mm Diameter of the small Ball Bearings 140 mm Diameter of the Phantom Cylinder Dimensions Physical Parameter
    • 10. Geometry Calibration <ul><li>Suggested Calibration Frequency: </li></ul><ul><ul><li>Every 6 months or when it is required </li></ul></ul><ul><li>Examples of when Geometry Calibration has to re-done: </li></ul><ul><ul><li>Every time Flat Panel mechanical alignment is performed </li></ul></ul><ul><ul><li>Adjustments to the LINAC mechanical isocenter are performed </li></ul></ul><ul><ul><li>XRETIC Calibration is performed </li></ul></ul>
    • 11. Geometry Calibration Figure 2.4 PROJECTION MATRICES PHANTOM MODEL: 3D INPUT PHANTOM IMAGES : 2D INPUT
    • 12. Geometry Calibration <ul><li>2D Projection Image Processing </li></ul><ul><ul><li>Each phantom projection image is processed to determine the ball bearing (bb’s) 2D position and size regarding the image coordinate system (u,v). </li></ul></ul>Figure 2.5 u V 0 0 0 0 0 0 0 1 0 0 0 1 0 1 0 0 1 1 0 0 0 1 1 1 1 1 0 1 0 0 0 1 1 0 1 0 1 0 0 0 0 0 1 1 1 0 0 1 1 0 1 1 1 0 0 0 1 0 0 1 1 1 0 1 0 1 1 0 1 1 0 0 0 0 1 0 1 1 0 01 0 0 1 0 1 0 1 0 1 1 1 1 0 0 1 0 1 1 1 0 1 1 1 1 1 1 1 Encoded ball bearing list from 2D projection images
    • 13. Geometry Calibration <ul><li>2D Projection Image Processing </li></ul><ul><ul><li>Each phantom projection image is processed to determine the ball bearing (bb’s) 2D position and size regarding the image coordinate system (u,v). </li></ul></ul>Figure 2.5 u V 0 0 0 0 0 0 0 1 0 0 0 1 0 1 0 0 1 1 0 0 0 1 1 1 1 1 0 1 0 0 0 1 1 0 1 0 1 0 0 0 0 0 1 1 1 0 0 1 1 0 1 1 1 0 0 0 1 0 0 1 1 1 0 1 0 1 1 0 1 1 0 0 0 0 1 0 1 1 0 01 0 0 1 0 1 0 1 0 1 1 1 1 0 0 1 0 1 1 1 0 1 1 1 1 1 1 1 Encoded ball bearing list from 2D projection images
    • 14. Geometry Calibration <ul><li>3D Phantom Model </li></ul><ul><ul><li>Phantom Model provides the 3D input used in the calculation of the projection matrices </li></ul></ul>Bead X,Y,Z Coordinates Bead Size Bead Type Bead ID Figure 2.6
    • 15. Geometry Calibration <ul><li>Coordinate System </li></ul>Figure 2.8 r Flat Panel Gantry X-ray Source Y Z X V u World (IEC) coordinate system 1 Gantry coordinate system 2 Camera coordinate system 3 X-ray receptor coordinate system 4 Pixelised Imaging coordinate system 5
    • 16. Geometry Calibration <ul><li>Coordinate System </li></ul>Figure 2.8 r Flat Panel Gantry X-ray Source Y Z X V u World (IEC) coordinate system 1 Gantry coordinate system 2 Camera coordinate system 3 X-ray receptor coordinate system 4 Pixelised Imaging coordinate system 5
    • 17. Projection Matrix <ul><li>Projection Matrix </li></ul><ul><ul><li>Has 12 coefficients representing geometrical parameters such as rotation angles and translation vectors </li></ul></ul><ul><ul><li>Provide the 3D (voxel) to 2D (pixel) geometrical mapping </li></ul></ul><ul><ul><li>Provides the input for the Backprojection step </li></ul></ul><ul><ul><li>Is computed for each MVision projection angle </li></ul></ul><ul><li>When computed: </li></ul><ul><ul><li>Allows 3D reconstruction of 2D MVision projection images </li></ul></ul><ul><ul><li>Can be used only in the LINAC where it was computed </li></ul></ul>
    • 18. Projection Matrix <ul><li>The 2D points are related to the 3D points by the projection matrix P </li></ul>Figure 2.9 Projection matrix coefficients 2D Ball bearing position on the phantom projection images 3D Ball bearing position on the phantom model
    • 19. Projection Matrix <ul><li>Projection Matrix Naming Convention </li></ul><ul><ul><li>The projection matrices are stored in a single file named: </li></ul></ul><ul><ul><li>ProjectionMatrices_<SID>_<StartAngle>_<EndAngle>_<AngleInc>_<CW|CCW>_<BAD>.xml </li></ul></ul><ul><ul><li>Example filenames: </li></ul></ul><ul><ul><ul><li>ProjectionMatrices_1450_2700_1100_10_CW.xml (successful calibration) </li></ul></ul></ul><ul><ul><ul><li>ProjectionMatrices_1450_2700_1100_10_CW_BAD.xml (calibration failed) </li></ul></ul></ul>
    • 20. Projection Matrix <ul><li>Projection Matrix Naming Convention </li></ul><ul><ul><li>The projection matrices are stored in a single file named: </li></ul></ul><ul><ul><li>ProjectionMatrices_<SID>_<StartAngle>_<EndAngle>_<AngleInc>_<CW|CCW>_<BAD>.xml </li></ul></ul><ul><ul><li>Example filenames: </li></ul></ul><ul><ul><ul><li>ProjectionMatrices_1450_2700_1100_10_CW.xml (successful calibration) </li></ul></ul></ul><ul><ul><ul><li>ProjectionMatrices_1450_2700_1100_10_CW_BAD.xml (calibration failed) </li></ul></ul></ul>
    • 21. Projection Matrix <ul><li>Projection Matrices and Phantom Model Storage </li></ul>Figure 2.10
    • 22. Scale Factor <ul><li>A I 0 - MU Scale Factor is computed from the low MU MVision gain and used in the image reconstruction process </li></ul><ul><ul><li>Once determined is used to obtain non-attenuated beam data (I 0 ) for any MVision monitor unit setting </li></ul></ul><ul><li>The Scale Factor is computed as: </li></ul>Figure 2.11 non-attenuated beam Intensity from gain images Monitor units used to acquire gain images
    • 23. MVision Image Reconstruction <ul><li>Reconstruction Volume </li></ul><ul><ul><li>It is a cube made of voxels and centered at the machine isocenter </li></ul></ul><ul><ul><li>It is used for the backprojection algorithm as the template to reconstruct MVision images using the projection data </li></ul></ul>Figure 2.12
    • 24. MVision Image Reconstruction <ul><li>The backprojection process uses the projection matrices to reconstruct 3D MVision images </li></ul>Figure 2.13 Flat panel LINAC Radiation Source Reconstructed MVision Slice b) LINAC Radiation Source Reconstruction Volume a)
    • 25. MVision Image Reconstruction <ul><li>Backprojection Process </li></ul>Figure 2.14 X-ray source Projection Image Reconstruction Volume i(u,  ) - pixel intensity at u,v position u v
    • 26. MVision Image Reconstruction <ul><li>Backprojection Process </li></ul>Figure 2.14 X-ray source Projection Image Reconstruction Volume i(u,  ) - pixel intensity at u,v position u v
    • 27. MVision Image Reconstruction <ul><li>Image filtering is necessary in the Backprojection process </li></ul>Figure 2.15 e) Filtered Image 1 Projection a) 2 Projections b) 4 Projections c) 256 Projections d)
    • 28. MVision Gain <ul><li>Acquired like in a MVision acquisition </li></ul><ul><ul><li>Used to: </li></ul></ul><ul><ul><ul><li>Correct differences in the Flat Panel diodes behavior (as in 2D gain) </li></ul></ul></ul><ul><ul><ul><li>Applied to MVision imaging only </li></ul></ul></ul><ul><ul><ul><li>Compute a Scale Factor used in the image reconstruction process </li></ul></ul></ul><ul><ul><li>Suggested Calibration Frequency: Every 2 Weeks </li></ul></ul>
    • 29. MVision Gain <ul><ul><li>Two MVision Gain fields are delivered in free air </li></ul></ul><ul><ul><ul><li>High MU Gain used on MVision Geometry Calibration projection data </li></ul></ul></ul><ul><ul><ul><li>Low MU Gain for regular MVision projection data </li></ul></ul></ul><ul><ul><li>Two hundred gain images are acquired and averaged </li></ul></ul><ul><ul><li>Two MVision Gain files are created </li></ul></ul><ul><ul><ul><li>The software “knows” whether to save the gain as “High MU MVision Gain” or “Low MU MVision Gain” </li></ul></ul></ul>
    • 30. MVision Gain <ul><li>Gain Storage location </li></ul>Figure 2.16
    • 31. MVision Gain Field Creation <ul><li>Log in on the Practice Database and Service Software </li></ul><ul><li>Under the Service Patient, the Site ‘Calibration Other’ on TxDelivery task card is selected </li></ul>Figure 2.17
    • 32. MVision Gain Field Creation <ul><li>Gain is selected as type of MVision field </li></ul>Figure 2.18
    • 33. MVision Gain Field Creation <ul><li>The Table eccentric is set to either 90 ˚ or 270 ˚ to prevent field override message </li></ul>Figure 2.19
    • 34. MVision Gain Field Creation <ul><li>MVision protocol selection </li></ul><ul><ul><li>The 8MU or 15MU protocol is used for low MU gain </li></ul></ul><ul><ul><li>The 60MU protocol is used for High MU gain </li></ul></ul>Figure 2.20
    • 35. MVision Protocol <ul><li>Used to set the MVision acquisition and reconstruction parameters </li></ul><ul><ul><li>Protocol creation application is launched from Coherence RTT </li></ul></ul><ul><ul><li>Acquisition Parameters </li></ul></ul><ul><ul><ul><li>Only the Monitor Units can be edited/changed </li></ul></ul></ul><ul><ul><ul><li>Arc Angle, Gantry direction, Sampling and SID are fixed </li></ul></ul></ul><ul><ul><li>Reconstruction Parameters </li></ul></ul><ul><ul><ul><li>Slice Size (pixels) </li></ul></ul></ul><ul><ul><ul><li>Slice thickness (mm) </li></ul></ul></ul><ul><ul><ul><li>Kernels (filters) </li></ul></ul></ul>
    • 36. MVision Protocol <ul><li>Creating a MVision Protocol </li></ul><ul><li>User must be logged on the Service Software prior to create/modify MVision protocols </li></ul>Figure 2.21 Cone Beam Protocol icon
    • 37. MVision Protocol <ul><li>Protocol configuration </li></ul>Figure 2.22 Reconstruction Kernel Smoothing-Pelvis (Default) Protocol Monitor Units Slice Size (pixels) 128 x 128 256 x 256 (default) 512 x 512 Slice Thickness (default 1mm) MVision protocol name
    • 38. MVision Protocol <ul><li>Effect of the Slice Size on the image quality </li></ul>Figure 2.23
    • 39. MVision Protocol <ul><li>Effect of the Slice Thickness on the image quality </li></ul>Figure 2.24
    • 40. MVision Protocol <ul><li>Effect of the Kernels on the image quality </li></ul>Figure 2.25
    • 41. MVision Protocol <ul><li>Effect of the Kernels on the image quality </li></ul>Figure 2.26
    • 42. MVision Protocol <ul><li>Effect of the Kernels on the image quality </li></ul>Figure 2.27
    • 43. MVision Protocol <ul><li>Effect of the amount of monitor units on the image quality </li></ul>Figure 2.28
    • 44. MVision Protocol <ul><li>Effect of the amount of monitor units on the image quality </li></ul>Figure 2.29
    • 45. MPR Thickness <ul><li>Effect of the Mutiplanar Reformat Thickness (MPR) on the image quality </li></ul>Figure 2.30
    • 46. Phantom Positioning <ul><li>The Geometry Calibration Phantom is aligned with the room lasers </li></ul>Figure 2.31 a) c) b)
    • 47. <ul><li>Video: </li></ul><ul><li>Geometry Calibration </li></ul><ul><li>Phantom Positioning </li></ul>
    • 48. Geometry Calibration Field Creation <ul><li>Geometry Calibration is selected as type of MVision field </li></ul>Figure 2.32
    • 49. Geometry Calibration Field Creation <ul><li>The 60MU protocol is selected for the Geometry Calibration </li></ul>Figure 2.33
    • 50. MVision Control Console Display Figure 2.34
    • 51. Geometry Calibration Window <ul><li>The Geometry Calibration is a sub task under the Calibration task card </li></ul>Figure 2.35 Acquired Projection Images are displayed here Images that have a valid Projection Matrix after interpolation are displayed here Images that have an invalid Projection Matrices are displayed here Images that have Valid Projection Matrices are displayed here
    • 52. Geometry Calibration Results <ul><li>Successful Calibration display </li></ul>Figure 2.36 Dog Ear
    • 53. Geometry Calibration Results <ul><li>Successful Calibration display </li></ul>Figure 2.37
    • 54. Geometry Calibration Results <ul><li>Calibration Fails due Invalid projection matrices </li></ul>Figure 2.38
    • 55. <ul><li>Video: </li></ul><ul><li>Geometry Calibration </li></ul>
    • 56. Troubleshooting <ul><li>Errors during Geometry Calibration </li></ul><ul><li>Geometry Calibration failed due missing projection </li></ul>Figure 2.39
    • 57. Troubleshooting <ul><li>Errors during Geometry Calibration </li></ul><ul><ul><li>Mismatch between expected and actual gantry position </li></ul></ul><ul><ul><li>Gantry position and delivered dose of a projection image were not received by the control console </li></ul></ul>Figure 2.40
    • 58. Troubleshooting <ul><li>Geometry Calibration not performed </li></ul>Figure 2.41
    • 59. Troubleshooting <ul><li>Fail to Pass the Geometry Calibration </li></ul><ul><li>Phantom misalignment: </li></ul><ul><ul><li>Align the phantom properly and re-acquire the images </li></ul></ul><ul><li>Wrong Phantom Orientation: </li></ul><ul><ul><li>Align the phantom with label “Gantry Side” toward the Gantry </li></ul></ul><ul><li>Phantom position in the table: </li></ul><ul><ul><li>Place the phantom following the recommendations in the Lab 4 MVision Geometry Calibration </li></ul></ul><ul><li>Object in the Image: </li></ul><ul><ul><li>Make sure there is no object other than the phantom in the beam path </li></ul></ul><ul><li>Wrong MVision Protocol: </li></ul><ul><ul><li>MVision calibration images should be acquired using the 60MU protocol </li></ul></ul>
    • 60. Section 2 Review <ul><li>Now that you have completed this section, you will be able to: </li></ul><ul><ul><li>Identify the fundamentals of MVision Geometry calibration </li></ul></ul><ul><ul><li>Understand the function of the Geometry Calibration Phantom </li></ul></ul><ul><ul><li>Describe the MVision Reconstruction Process </li></ul></ul><ul><ul><li>Describe the MVision Protocol parameter and how they influence the image quality </li></ul></ul><ul><ul><li>Perform the MVision gain calibration </li></ul></ul><ul><ul><li>Perform the MVision Geometry Calibration </li></ul></ul>
    • 61. Section 2 Quiz
    • 62. 1) The MVision Geometry Calibration is required in order to: <ul><li>Correct flat panel sag </li></ul><ul><li>Map the geometry between a 3D object and its 2D projections </li></ul><ul><li>Correct image offset caused by flat panel sag </li></ul><ul><li>A and C are correct </li></ul>
    • 63. 2) In order to perform the Geometry Calibration one should: <ul><li>Place the Geometry Calibration phantom at the LINAC isocenter </li></ul><ul><li>Acquire MVision projection images of the phantom </li></ul><ul><li>Calibrate the XRETIC </li></ul><ul><li>A and B are correct </li></ul><ul><li>A, B and C are correct </li></ul>
    • 64. 3) The Geometry Calibration phantom model and the phantom projection images provide the input necessary to: <ul><li>Reconstruct the MVision images </li></ul><ul><li>Find out the LINAC isocenter coordinates </li></ul><ul><li>Compute the projection matrices </li></ul><ul><li>A and C are correct </li></ul>
    • 65. 4) With regards the projection matrices it is correct to state that : <ul><li>Provide voxel to pixel geometrical mapping </li></ul><ul><li>Do not depend on the flat panel alignment </li></ul><ul><li>Disable 3D reconstruction </li></ul><ul><li>All the above </li></ul>
    • 66. 5) In the MVision Protocol configuration window the protocol parameters that can be changed are: <ul><li>Monitor units, SID and Kernels </li></ul><ul><li>Kernels, Slice Size and Slice Thickness </li></ul><ul><li>Arc length, SID and Slice Size </li></ul><ul><li>Matrix size, monitor units and sampling </li></ul><ul><li>A and D are correct </li></ul>
    • 67. 6) Increasing a slice size of a MVision image will cause the image spatial resolution, image noise and low contrast resolution respectively to: <ul><li>Increase, decrease, decrease </li></ul><ul><li>Decrease, increase, decrease </li></ul><ul><li>Increase, increase, decrease </li></ul><ul><li>Decrease, decrease, increase </li></ul>
    • 68. 7) A 5mm increase in the MVision slice thickness will: <ul><li>Increase reconstruction time </li></ul><ul><li>Reconstruct images 5mm thick </li></ul><ul><li>Decrease image spatial resolution </li></ul><ul><li>Reconstruct images every 5mm </li></ul><ul><li>All the above is correct </li></ul>
    • 69. <ul><li>Smoothing Head-Neck kernel and 5mm MPR </li></ul><ul><li>1mm MPR and Smoothing kernel </li></ul><ul><li>Edge Enhancing Head Neck kernel and 2mm MPR </li></ul><ul><li>1mm MPR and Edge Preserving kernel </li></ul>8) A Head and Neck patient of standard size will be imaged with MVision. The Kernel and MPR combination that will provide better soft tissue contrast and less cupping artifact:
    • 70. 9)Overall an increase on the monitor in a MVision acquisition will: <ul><li>Increase the acquisition time and image noise </li></ul><ul><li>Decrease image noise and increase soft tissue contrast </li></ul><ul><li>Increase the visibility of high density objects </li></ul><ul><li>A and C are correct </li></ul>
    • 71. 10) Regarding the Geometry Calibration which one of the following is correct: <ul><li>The 60MU protocol should be used </li></ul><ul><li>Phantom alignment is critical to get accurate projection matrices </li></ul><ul><li>Image reconstruction is not possible without Geometry calibration </li></ul><ul><li>A and C are correct </li></ul>
    • 72. 11) Which of the following is correct about the MVision gain calibration: <ul><li>Is acquired in the same way as the 2D gains </li></ul><ul><li>Should always be acquired at 15MU </li></ul><ul><li>Table should be moved out of the beam path </li></ul><ul><li>The 200 gain images are averaged </li></ul><ul><li>C and D are correct </li></ul>
    • 73. Answer Key <ul><li>B </li></ul><ul><li>D </li></ul><ul><li>C </li></ul><ul><li>A </li></ul><ul><li>B </li></ul><ul><li>C </li></ul><ul><li>C </li></ul><ul><li>A </li></ul><ul><li>B </li></ul><ul><li>D </li></ul><ul><li>E </li></ul>

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