Evaluating the Quality of Patient-Specific Deformable Image Registration in Adaptive Radiotherapy Using a Digitally Enhanced Head and Neck Phantom

Despite the availability of national and international guidelines, an accurate efficient, patient-specific, deformable image registration (DIR) validation methodology is not yet established, several groups have found incompatibility various digital phantoms with commercial systems. To evaluate quality computed tomography (CT) on-board cone-beam CT (CBCT) DIRs, a novel was developed tested on 10 head neck (HN) patients, using CBCT anthropomorphic HN phantom images, digitally reprocessed to include common organs at risk. Reference DVFs (refDVFs) were generated from clinical patient CT-CBCT fused images independent software. The artificially deformed, refDVFs, registered software, generating test DVF (testDVF) dataset. plans recalculated daily ‘deformed’ CTs, dose maps transferred patient-planning CT, both refDVF testDVF. spatial dosimetric errors quantified DIR performance evaluated established operative tolerance level. method showed ability quantify assess their impact voxel level could be applied patient-specific evaluation during adaptive radiotherapy in routine practice.