Orin Green

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PURPOSE The first real-time-MRI-guided radiotherapy system has been installed in a clinic and it is being evaluated. Presence of magnetic field (MF) during radiation output calibration may have implications on ionization measurements and there is a possibility that standard calibration protocols may not be suitable for dose measurements for such devices. In(More)
PURPOSE MR based 3D gel has been proposed for radiation therapy dosimetry. However, access to MR scanner has been one of the limiting factors for its wide acceptance. Recent commercialization of an on-board MR-IGRT device (ViewRay) may render the availability issue less of a concern. This work reports our attempts to simulate MR based dose measurement(More)
In recent years, steady progress has been made towards the implementation of MRI in external beam radiation therapy for processes ranging from treatment simulation to in-room guidance. Novel procedures relying mostly on MR data are currently implemented in the clinic. This session will cover topics such as (a) commissioning and quality control of the MR(More)
The motion management in stereotactic body radiation therapy (SBRT) is a key to success for a SBRT program, and still an on-going challenging task. A major factor is that moving structures behave differently than standing structures when examined by imaging modalities, and thus require special considerations and employments. Understanding the motion effects(More)
PURPOSE To test the sensitivity of the quality assurance (QA) tools actively used on a clinical MR-IGRT system for potential delivery errors. METHODS Patient-specific QA procedures have been implemented for a commercially available Cobalt-60 MR-IGRT system. The QA tools utilized were a MR-compatible cylindrical diode-array detector (ArcCHECK) with a(More)
PURPOSE To characterize magnetic field effects on Optically Stimulated Luminescence Detectors (OSLDs) for use as an in-vivo dosimeter in an MRIGRT machine. METHODS Landauer OSLD nano-dots and the MicroStar II reader were used to measure and record OSLDs exposed in and on a solid water phantom in a 10.5 × 10.5 cm2 field, Co-60, 0.32-Tesla MR-IGRT machine -(More)
PURPOSE To determine if a MOSFET based in-vivo dosimetry system can be used for patients undergoing MR-IGRT. METHODS Standard and high sensitivity MOSFET detectors were used for in-field and out-of-field measurements respectively. The systems were benchmarked and calibrated against a calibrated ionization chamber on a standard 6 MV linear accelerator, and(More)
Lytro Immerge is the world's first professional Light Field solution for VR, providing true presence for live action VR through six degrees of freedom (6DoF) playback. Lytro's 6DoF playback allows the viewer to move around freely in the viewing experience, complete with parallax, view-dependent lighting, and perfect stereo in all directions no matter the(More)
PURPOSE The aims of this work are to describe the workflow and initial clinical experience treating patients with an MRI-guided radiotherapy (MRIGRT) system. METHODS Patient treatments with a novel MR-IGRT system started at our institution in mid-January. The system consists of an on-board 0.35-T MRI, with IMRT-capable delivery via doubly-focused MLCs on(More)
PURPOSE To quantify inter-fraction esophagus-variation. METHODS Computed tomography and daily on-treatment 0.3-T MRI data sets for 7 patients were analyzed using a novel Matlab-based (Mathworks, Natick, MA) rapid computational method. Rigid registration was performed from the cricoid to the gastro-esophageal junction. CT and MR-based contours were(More)