ID: 18137 Title: Treatment of Multiple Brain Metastases Using Stereotactic Radiosurgery with Single-Isocenter Volumetric Modulated Arc Therapy: Comparison with Conventional Dynamic Conformal Arc and Static Beam Stereotactic Radiosurgery Purpose: To investigate the treatment of multiple brain metastases using stereotactic radiosurgery with single-isocenter volumetric modulated arc therapy (VMAT)...

The purpose of this study was to compare the single-isocenter, four-field hybrid IMRT with the two-isocenter techniques to treat the whole breast and supraclavicular fields and to investigate the intrafraction motions in both techniques in the superior direction. Fifteen breast cancer patients who underwent lumpectomy and adjuvant radiation to the whole breast and supraclavicular (SCV) fossa at...

The purpose of this study was to evaluate patient setup in head and neck IMRT using daily portal imaging. At our institution, orthogonal digital portal images are taken daily to check patient positioning prior to head and neck IMRT treatment. Isocenter misalignments are corrected using a couch shift (3mm action level). Therapists also compare the DRRs and portal images looking at points more di...

BACKGROUND Linac-based stereotactic radiosurgery or fractionated stereotactic radiotherapy (SRS/FSRT) of multiple brain lesions using volumetric modulated arc therapy (VMAT) is typically performed by a multiple-isocenter approach, i.e. one isocenter per lesion, which is time-demanding for the need of independent setup verifications of each isocenter. Here, we present our initial experience with...

Radiosurgical treatment of cranial or extracranial targets demands accurate positioning of the isocenter at the beam and table isocenter, and immobilization of the target during treatment. For spinal radiosurgery, the standard approach involves matching of cone-beam CT (CBCT) in-room images with the planning CT (pCT) to determine translation and yaw corrections. The purpose of this study was to...

The aim of this study is to provide a practical approach to the planning technique and evaluation of plan quality for the multi-lesion, single-isocenter stereotactic ablative radiotherapy (SABR) of the lung. Eleven patients with two or more lung lesions underwent single-isocenter volumetric-modulated arc therapy (VMAT) radiosurgery or IMRS. All plans were normalized to the target maximum dose. ...

In Winston-Lutz (WL) tests, the isocenter of a linear accelerator (linac) is determined as the intersection of radiation central axes (CAX) from multiple gantry, collimator, and couch angles. It is well known that the CAX can wobble due to mechanical imperfections of the linac. Previous studies suggested that the wobble varies with gantry and collimator angles. Therefore, the isocenter determin...

direction (blue) introduce a phase shift from echo to echo that increases with the distance form the isocenter. (b, c) Schematic example for acquiring three ROIs with two of them (ROIs B and C) overlapping with a conventional projection (dashed gray). With the phase shifts introduced by the blip gradients in the slice direction, the projection direction (dashed blue) is tilted by an angle that ...

There have been several manual, semi-automatic and fully-automatic methods proposed for verification of the position of mechanical isocenter as part of comprehensive quality assurance programs required for linear accelerator-based stereotactic radiosurgery/radiotherapy (SRS/SRT) treatments. In this paper, a systematic review has been carried out to discuss the present methods for isocenter veri...

In this work, the suitability and performance of a mouse-size MOSFET (Mousefet) phantom is investigated for routine quality assurance (QA) of the small animal radiation research platform (SARRP). This Mousefet phantom is a simple construction consisting of five micro-MOSFETS custom integrated in a quincunx pattern within a tissue-equivalent phantom, allowing repeat/multiple QA tasks to be quick...