Po‐Poster ‐ 15: Conversion of kV‐CT Numbers to electron density of human tissues in vivo: Validation using megavoltage CT scanning on a tomotherapy machine

Abstract

In radiotherapy planning, the calibration of CT number in terms of electron density (electrons per cm3) is essential for dose computations in heterogeneous tissue. For electron density of soft tissues with low atomic numbers (6 < Z 100), empirical methods based on phantom experiments with bone‐substitute materials have been performed to produce an approximate bone calibration curve. This approach was first validated for in‐vivo tissues by plotting kV‐CT numbers against the electron density measured independently by Compton‐scatter imaging. With the advent of megavoltage (MV) CT scanning on tomotherapy machines, we now have a similar opportunity for the measurement of electron densities in v..