SU-E-J-70: A Study of the Correlation of 3D Surface Matching and KV Imaging for Chestwall IMRT

Medical Physics
Hania Al-Hallaq, E Gerry

Abstract

We investigated the accuracy of surface matching compared to kV positioning of 10 post-mastectomy chestwall patients receiving inverse-planned, non-gated IMRT. During 130 treatment sessions, non-gated 3D surfaces were captured using AlignRT (v4.5) before and after table translations as indicated by kV imaging. Surfaces were compared to a reference generated from CT data. Pearson's correlations between 'indicated' AlignRT and kV shifts were studied for surface registration of user-defined regions-of-interest (ROIs): the entire surface ('all') and the chestwall ('cw'). In 21% of sessions, two consecutive surfaces of patients in identical positions were used to estimate variability. Finally, the 'implemented' shifts detected by AlignRT were calculated and compared to the absolute table translations. Correlations between 'indicated' AlignRT and kV shifts were higher for 'cw' than for 'all': r=0.65 (Anterior-Posterior), r=0.65 (Superior-Inferier), r=0.44 (Left-Right). Correlations exhibited large inter-patient variability; 60% had r<0.6 in at least 1 direction thereby resulting in ow correlation between 3D Euclidian shift distances (r=0.48). Correlations between 'cw' and kV increased (r>0.8) for 'implemented' table shifts; only 2 pa...Continue Reading

Related Concepts

Related Feeds

Aphasia

Aphasia affects the ability to process language, including formulation and comprehension of language and speech, as well as the ability to read or write. Here is the latest research on aphasia.