Motion Analysis of Target during Stereotactic Radiotherapy of Lung Tumors

Abstract

Volumetric modulated arc therapy (VMAT) is a rotational intensity-modulated radiotherapy (IMRT) technique capable of acquiring projection images for cone-beam computed tomography (CBCT). CBCT during treatment is expected to evaluate the actual tumor position and dose distribution. The goal of our research is to establish a new method of verification during treatment in stereotactic body radiotherapy. In this study, we evaluated the movement of the target “in treatment” using kilo volts X-ray beams for diagnosis (kV-CBCT) and mega volts X-ray beams for treatment (MV-CBCT). One patient with lung tumor underwent CT scans for radiotherapy planning and was treated by VMAT while acquiring projection images for kV and MV-CBCT. The datasets were reconstructed from the projection images using in-house programs. The position of the target in kV and MV-CBCT were detected using radiotherapy planning system and the movement of the targets between kV and MV-CBCT was similar. We have successfully evaluated the movement of the target “in treatment” using kV and MV-CBCT.