10. Characteristic Radiation in Tungsten Targets Shel l # of electrons Binding energy L Char M Char N Char O Char P Char Eff X-ray Energy K26957.466.768.969.469.569 L8129.311.51212.112 M1832.22.72.83 N3210.520.6 O120.10.080.1 P2

12. In a tungsten target, at any kVp less than 69.5 all x-rays are Brems. At 100 kVp, 85% of photons are Brems and 15% are characteristic Only 15 different energy levels are possible with characteristic production in tungsten tube.

21. Lecture 5: Patient Dose Management 21 determine energy of electrons  energy of X-ray photons determine number of electrons  number of X ray photons

22. Lecture 5: Patient Dose Management 22 X-ray tube Photons entering the human body will either penetrate, be absorbed, or produce scattered radiation

23. Lecture 5: Patient Dose Management 23 Image Contrast No object image is generated Object image is generated Object silhouette with no internal details

24. Where do X-rays come from ? Nucleus Electrons Atom of the target element Characteristic X-ray Bremsstrahlung