New findings on clinical experience on surface-guided radiotherapy for frameless non-coplanar stereotactic radiosurgery treatments.

Purpose: The aim of this study was to assess the accuracy of a surface-guided radiotherapy (SGRT) system for setup and intra-fraction motion control in frameless non-coplanar stereotactic radiosurgery (fSRS) using actual patient data immobilized with two different types of open-faced masks and employing a novel SGRT systems settings.

Methods And Materials: Forty-four SRS patients were immobilized with two types of open-faced masks. Sixty lesions were treated, involving the analysis of 68 cone-beam scans (CBCT), 157 megavoltage (MV) images, and 521 SGRT monitoring sessions.

A retrospective tomotherapy image-guidance study: analysis of more than 9,000 MVCT scans for ten different tumor sites.

The purpose of this study was to quantify the systematic and random errors for various disease sites when daily MVCT scans are acquired, and to analyze alterna- tive off-line verification protocols (OVP) with respect to the patient setup accuracy achieved. Alignment data from 389 patients (9,418 fractions) treated at ten differ- ent anatomic sites with daily image-guidance (IG) on a helical tomotherapy unit were analyzed. Moreover, six OVP were retrospectively evaluated.

Correction factors for A1SL ionization chamber dosimetry in TomoTherapy: machine-specific, plan-class, and clinical fields.

Purpose: Recently, an international working group on nonstandard fields presented a new formalism for ionization chamber reference dosimetry of small and nonstandard fields [Alfonso et al., Med. Phys.