An augmented correlation framework for the estimation of tumour translational and rotational motion during external beam radiotherapy treatments using intermittent monoscopic X-ray imaging and an external respiratory signal.

An augmented correlation framework for the estimation of tumour translational and rotational motion during external beam radiotherapy treatments using intermittent monoscopic X-ray imaging and an external respiratory signal.
Phys Med Biol. 2018 Sep 05;:
Authors: Nguyen DT, Booth JT, Caillet V, Hardcastle N, Briggs A, Haddad C, Eade T, O'Brien RT, Keall PJ
Abstract
Increasing evidence shows that intrafraction tumour motion monitoring must include both six degrees of freedom (6DoF): 3D translations and 3D rotations. Existing real- time algorithms for 6DoF target motion estimation requires continuous intrafraction fluoroscopic imaging at high frequency, thereby exposing patients to additional high imaging dose. This paper presents the first method capable of 6DoF motion monitoring using intermittent 2D kV imaging and a continuous external respiratory signal.
 Method: Our approach is to optimise a state-augmented linear correlation model between an external signal and internal 6DoF motion. In standard treatments, the model can be built using information obtained during pre-treatment CBCT. Real-time 6DoF tumor motion can then be estimated using just the external signal. Intermittent intrafraction kV images are used to update the model parameters, accounting for changes in correlation and baseline shifts.
 The method was evaluated in silico using data from 6 lung SABR patients, with the internal tumour motion recorded with ...

Source: Physics in Medicine and Biology - September 5, 2018 Category: Physics Authors: Nguyen DT, Booth JT, Caillet V, Hardcastle N, Briggs A, Haddad C, Eade T, O'Brien RT, Keall PJ Tags: Phys Med Biol Source Type: research