268-269 / 1359
How many materials are needed?
• Du Plessis et al (MP 25(7) 1998)
– Combined 16 human tissues into 7 dosimetrically equivalent
subsets with constant elemental composition to give dose accuracy
of <1%.
– Needed further subdivision in bone and lung (57) by varying
density only
• W.Schneider (stoichiometric) calibrating H with mass density and
elemental weights
– Extended to 71 tissues
– Grouped into 24 bins
– Simplified using interpolation functions for 4 sections of calibration
curve+
• ‘Ctcreate’ from BEAMnrc
– 4 major tissue types (air, lung, soft tissue, bone)
– ICRU tissue composition used and mass density from linear
interpolation