1. FRED project Absorbing Pore Inside Scattering Media Märta Lewander Lund 17 June 2008

2. June 2008 Märta Lewander Background – human sinuses

3. June 2008 Märta Lewander 1. How much light gets through to the detector  The number of rays 2. How many of the detected photons carry a signal imprint  The number of rays that are detected that have passed through the sinus 3. How large is the mean absorption imprint  The length the rays have through the sinus interrogating distance Want to know

4. June 2008 Märta Lewander Model Incident Light Tissue Detected Light Sinus Approaces 1.Specified paths 2.History file 3.History script

5. June 2008 Märta Lewander Approach 1 - Paths Specify different paths -Not through sinus -1 time through sinus -2 times through sinus -... Problem: Still do not know the interrogation distance Path: Unique sequence of surfaces

6. June 2008 Märta Lewander Approach 2 – History file Advanced Raytrace FRED saves the positions at the different surfaces Saved in a file Raytrace Generated according to history file That ends up on detector

7. June 2008 Märta Lewander Approach 2 – History file

8. June 2008 Märta Lewander Approach 2 – Problem Detected Light Incident Light Problem: Need to use simplification

9. June 2008 Märta Lewander Approach 3 – History script Script Advanced raytrace nr of hits = 1 Stores the positions and the pathlength at the different surfaces Saved in a file

10. June 2008 Märta Lewander Approach 3 – History script

11. June 2008 Märta Lewander Approach 3 – Problem Problem - All the stored rays at a specific surace get new ID number - The before entity stored is always another surface  Approach 2 with simplification

12. June 2008 Märta Lewander Full scale model Simulation time: 3 h and 53 minutes Rays at start:3 141 549 rays Rays traced:10 918 133 rays Number of rays that hit the detector:1160 rays

13. June 2008 Märta Lewander Full scale model

14. June 2008 Märta Lewander Full scale model Intorragation path 50.6 mm

15. June 2008 Märta Lewander Conclusions + Easy to learn the basics nice interface many good functions -Hard to learn Frustrating when you can not output everything Time consuming

16. June 2008 Märta Lewander

17. June 2008 Märta Lewander Detection geometries Orbital – Frontal bonePalate - Cheek boneCheek – Cheek bone