Dose 2016

Dose to tissue?

External Beam

For

Against

• D

is the ‘natural’ quantity from MC

• D

w clinical experience (Ma et al?)

m,m

• To report D w

then if convert back to

• Dosimetry protocols • NTCP, TCP reported in dose to water • Uncertainties lower • Target is a ‘water’ cell in bone • Report both?

water – uncertainty in s w,m • Makes little difference for soft tissues • CT numbers converted using ICRU or ICRP but who is ‘standard?

Brachytherapy

• Mass energy absorption coeffs quite different between tissue types and water • D m,m and D w,m can be very different • Accurate dosimetry requires atomic composition • MC-D w,m good substitute for MC-D n.m for all energies and tissue types studied (Enger et al PMB 2012)