Use of AlignRT System During Stereotactic Radiosurgery

Overview

This prospective study evaluated whether the AlignRT surface-guided radiotherapy system improves patient positioning accuracy during stereotactic radiosurgery (SRS) for brain metastases compared with standard manual positioning. Twenty adults scheduled for single-fraction SRS were positioned twice before treatment. Participants were first positioned using the standard manual method with delta couch shift and were then positioned automatically using the AlignRT system. After each positioning method, a partial cone-beam computed tomography (CBCT) scan was performed to measure residual setup deviations in three translational and three rotational directions. The primary objective was to compare the average setup deviations between the two positioning methods and determine whether AlignRT provided more accurate patient positioning. The additional positioning and imaging procedure prolonged the treatment visit by up to 15 minutes and involved a low additional imaging dose.

This was a prospective, single-group clinical study conducted at the Institute of Oncology Ljubljana. The study included adult patients with brain metastases who were scheduled to receive single-fraction stereotactic radiosurgery using the TrueBeam STx linear accelerator. Each participant underwent two positioning procedures before treatment. Standard manual positioning was performed using the delta couch shift function, followed by partial CBCT verification. The participant was then positioned automatically using the AlignRT surface-guided radiotherapy system, followed by a second partial CBCT verification. Residual positioning deviations were recorded in three translational directions (vertical, longitudinal, and lateral) and three rotational directions (rotation, pitch, and roll). The average deviations obtained after manual positioning were compared with those obtained after AlignRT-guided positioning. Additional analyses considered participant age and sex. Positioning data were obtained from the ARIA information system and analyzed using Microsoft Excel and IBM SPSS. A total of 20 participants completed the study. No additional follow-up was required after completion of the positioning measurements.