Assessment of the Residual Error in Soft Tissue Setup in Patients Undergoing Partial Breast Irradiation: Results of a Prospective Study Using Cone-Beam Computed Tomography

In this initial study with a modest number of patients, the residual error in soft tissue was typically <5 mm, and with the field margins used, the resultant dosimetric consequences were modest. In patients immobilized in a customized cradle, setup using orthogonal kV images thus appears accurate and reproducible. The CBCT technique may have particular utility in patients with larger breast volumes or breast deformations. Further studies involving larger numbers of patients are needed to further assess the utility of CBCT.