Advanced Brachytherapy Physics - Vienna 2016

Linear attenuation coefficient

Describes attenuation of a photon beam Torikoshi et al :  ) ( 4 E    

 ) , ( ZEG ZEFZ

) , (

e

• ρ e

= ρZ/A*N A

= electron density

• Z effective atomic number = • F ( E,Z ) and G ( E,Z ) are the photoelectric absorption and scattering terms (Rayleigh and Compton) of μ

For polychromatic x-rays:       ji e j

 ) ,

( 4

ZEG ZEFZ ji

( ) , 

ji

i

x-ray spectra represented by weights ω i

at E i

Torikoshi et al, Phys. Med. Biol. 2003; 48: 673-685. Tsunoo T, et al , NSS Conference Record, IEEE, 2004; 6: 3764-3768