Fast intra-fractional image-guidance with 6D positioning correction reduces delivery uncertainty for stereotactic radiosurgery and radiotherapy.

The purpose of this study is to analyze intra-fractional positioning uncertainty for stereotactic radiotherapy and radiosurgery of cranial tumors. Specifically, we wish to determine the use of intra-fractional image guided patient positioning verification is necessary during delivery of "frameless" stereotactic radiotherapy and radiosurgery (SRT/SRS) and non-coplanar radiation beams, and if positioning uncertainty is associated with overall treatment time. Orthogonal radiographic treatment verification data was extracted for 288 patients and 1344 fractions, and were analyzed with respect to 3D translational and angular corrections once during treatment delivery of SRT/SRS.

Interfractional changes in tumour volume and position during entire radiotherapy courses for lung cancer with respiratory gating and image guidance.

Introduction: With the purpose of implementing gated radiotherapy for lung cancer patients, this study investigated the interfraction variations in tumour size and internal displacement over entire treatment courses. To explore the potential of image guided radiotherapy (IGRT) the variations were measured using a set-up strategy based on imaging of bony landmarks and compared to a strategy using in room lasers, skin tattoos and cupper landmarks.

Materials And Methods: During their six week treatment course of 60Gy in 2Gy fractions, ten patients underwent 3 respiratory gated CT scans.