1. Geometry Calibration for High Resolution Small Animal Imaging Vi-Hoa (Tim) Tran Thomas Jefferson National Accelerator Facilities

2. heavy duty rotation disk slider pinhole detector AOR parallel detector Gamma Cameras optical tracking CCD cameras Rotating SPECT Gantry

3. Geometry Calibration To determine the spatial relationship between the coordinate systems of the rotating detectors and the objects

4. AOR 360 degree acquisition pinhole detector parallel hole detector Calibration Phantom with 3 Point Sources Co-57

5. Pinhole Projections Over 360 Degrees axial motion (v) Transaxial motion (u) measured predicted Transaxial direction (u) Axial direction (V)

6. Bequé’s Calibration Model (2003) v u z y x z y x v u   The detector and object coordinate systems are not aligned

7. heavy duty rotation disk slider pinhole detector AOR ideal case: rigid body real case: flexing/rotation radial movement axial movement AOR z0z0 parallel hole detector A B C Normal ray A possible cause

8. A Model of Detector Motion Normal Ray z d f v z pinhole

9. Extension To Bequé’s Model g =  z.sin(  +ξ) sinusoidal axial motion

10. measured predicted w/ correction predicted w/o correction axial motion before and after correction

11. Improved tracking for both pinhole & parallel hole collimators

12. Summary  Prediction errors due to flexing gantry  Modeling of detector movement  Extension to Bequé’s calibration model  Prediction errors minimized