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MRI Co Viewray

Yu Gao, Fei Han, Ziwu Zhou, Minsong Cao, Tania Kaprealian, Mitchell Kamrava, Chenyang Wang, John Neylon, Daniel A Low, Yingli Yang, Peng Hu
PURPOSE: Monitoring tumor response during the course of treatment and adaptively modifying treatment plan based on tumor biological feedback may represent a new paradigm for radiotherapy. Diffusion MRI has shown great promises in assessing and predicting tumor response to radiotherapy. However, the conventional diffusion-weighted single-shot echo-planar-imaging (DW-ssEPI) technique suffers from limited resolution, severe distortion, and possibly inaccurate ADC at low field strength. The purpose of this work was to develop a reliable, accurate and distortion-free diffusion MRI technique that is practicable for longitudinal tumor response evaluation and adaptive radiotherapy on a 0...
October 2017: Medical Physics
F Reynoso, A Curcuru, O Green, S Mutic, I Das, L Santanam
PURPOSE: To investigate the effects of magnetic fields in radiochromic films (RCF). Magnetokinetic changes may affect crystal orientation and polymerization within active layer of RCF, these effects are investigated in Magnetic Resonance Image-guided Radiotherapy (MR-IGRT). METHODS: Gafchromic EBT2 RCF were irradiated in a 30×30×30 cm(3) solid water phantom using a ViewRay MRIdian Co-60 MRI guided radiotherapy system (B=0.35 T). Fifteen 20.3×25.4 cm(2) EBT2 film sheets were placed at three different depths (d=0...
June 2016: Medical Physics
X Qi, Y Yang, L Yang, D Low, K Sheng
PURPOSE: To report our initial experience of systematic monitoring treatment response using longitudinal diffusion MR images on a Co-60 MRI-guided radiotherapy system. METHODS: Four patients, including 2 head-and-necks, 1 sarcoma and 1 GBM treated on a 0.35 Tesla MRI-guided treatment system, were analyzed. For each patient, 3D TrueFISP MRIs were acquired during CT simulation and before each treatment for treatment planning and patient setup purposes respectively...
June 2016: Medical Physics
Francisco J Reynoso, Austen Curcuru, Olga Green, Sasa Mutic, Indra J Das, Lakshmi Santanam
PURPOSE: Magnetokinetic changes may affect crystal orientation and polymerization within the active layer of radiochromic film (RCF). This effect is investigated in a magnetic resonance image-guided radiotherapy unit within the context of film dosimetry. METHODS: Gafchromic EBT2 RCF was irradiated in a 30 × 30 × 30 cm(3) solid water phantom using a Co-60 MRI guided radiotherapy system (B = 0.35 T) under normal operating conditions, and under the exact conditions and setup without a magnetic field...
December 2016: Medical Physics
Camille E Noel, Parag J Parikh, Christopher R Spencer, Olga L Green, Yanle Hu, Sasa Mutic, Jeffrey R Olsen
BACKGROUND: Onboard magnetic resonance imaging (OB-MRI) for daily localization and adaptive radiotherapy has been under development by several groups. However, no clinical studies have evaluated whether OB-MRI improves visualization of the target and organs at risk (OARs) compared to standard onboard computed tomography (OB-CT). This study compared visualization of patient anatomy on images acquired on the MRI-(60)Co ViewRay system to those acquired with OB-CT. MATERIAL AND METHODS: Fourteen patients enrolled on a protocol approved by the Institutional Review Board (IRB) and undergoing image-guided radiotherapy for cancer in the thorax (n = 2), pelvis (n = 6), abdomen (n = 3) or head and neck (n = 3) were imaged with OB-MRI and OB-CT...
2015: Acta Oncologica
O Green, L Rankine, B Cai, L Santanam, R Kashani, A Sharma, L Senadheera, C Mahaffey, S Mutic
PURPOSE: To develop a methodology for commissioning the real-time tumor tracking and beam control capabilities of a magnetic resonance imaging radiation therapy (MR-IGRT) system. METHODS: The MRIdian (ViewRay, Inc., Oakwood Village, OH) MR-IGRT machine consists of a 0.35-T magnet and a three-head Co-60 delivery system capable of real-time sagittal plane acquisition at 4 frames per second (fps). After obtaining a volumetric MR image, a "target" is chosen by contouring an area of interest with different signal intensity than the surrounding medium...
June 2015: Medical Physics
D Thomas, D O'Connell, J Lamb, M Cao, Y Yang, N Agazaryan, P Lee, D Low
PURPOSE: To demonstrate real-time dose calculation of free-breathing MRI guided Co-60 treatments, using a motion model and Monte-Carlo dose calculation to accurately account for the interplay between irregular breathing motion and an IMRT delivery. METHODS: ViewRay Co-60 dose distributions were optimized on ITVs contoured from free-breathing CT images of lung cancer patients. Each treatment plan was separated into 0.25s segments, accounting for the MLC positions and beam angles at each time point...
June 2015: Medical Physics
J Lamb, M Kamrava, N Agazaryan, M Cao, D Low, D Thomas, Y Yang
PURPOSE: Even in the IMRT era, bowel toxicity and bone marrow irradiation remain concerns with pelvic irradiation. We examine the potential gain from an adaptive radiotherapy workflow for post-operative gynecological patients treated to pelvic targets including lymph nodes using MRI-guided Co-60 radiation therapy. METHODS: An adaptive workflow was developed with the intent of minimizing time overhead of adaptive planning. A pilot study was performed using retrospectively analyzed images from one patient's treatment...
June 2015: Medical Physics
H Omar Wooten, Olga Green, Min Yang, Todd DeWees, Rojano Kashani, Jeff Olsen, Jeff Michalski, Deshan Yang, Kari Tanderup, Yanle Hu, H Harold Li, Sasa Mutic
PURPOSE: This work describes a commercial treatment planning system, its technical features, and its capabilities for creating (60)Co intensity modulated radiation therapy (IMRT) treatment plans for a magnetic resonance image guidance radiation therapy (MR-IGRT) system. METHODS AND MATERIALS: The ViewRay treatment planning system (Oakwood Village, OH) was used to create (60)Co IMRT treatment plans for 33 cancer patients with disease in the abdominal, pelvic, thorax, and head and neck regions using physician-specified patient-specific target coverage and organ at risk (OAR) objectives...
July 15, 2015: International Journal of Radiation Oncology, Biology, Physics
Amar U Kishan, Minsong Cao, Pin-Chieh Wang, Argin G Mikaeilian, Stephen Tenn, Jean-Claude M Rwigema, Ke Sheng, Daniel A Low, Patrick A Kupelian, Michael L Steinberg, Percy Lee
PURPOSE: The purpose of this study was to investigate the dosimetric feasibility of liver stereotactic body radiation therapy (SBRT) using a teletherapy system equipped with 3 rotating (60)Co sources (tri-(60)Co system) and a built-in magnetic resonance imager (MRI). We hypothesized tumor size and location would be predictive of favorable dosimetry with tri-(60)Co SBRT. METHODS AND MATERIALS: The primary study population consisted of 11 patients treated with SBRT for malignant hepatic lesions whose linear accelerator (LINAC)-based SBRT plans met all mandatory Radiation Therapy Oncology Group (RTOG) 1112 organ-at-risk (OAR) constraints...
September 2015: Practical Radiation Oncology
Amar U Kishan, Minsong Cao, Argin G Mikaeilian, Daniel A Low, Patrick A Kupelian, Michael L Steinberg, Mitchell Kamrava
PURPOSE: The purpose of this study was to investigate the dosimetric differences of delivering preoperative intensity modulated radiation therapy (IMRT) to patients with soft tissue sarcomas of the extremity (ESTS) with a teletherapy system equipped with 3 rotating (60)Co sources and a built-in magnetic resonance imaging and with standard linear accelerator (LINAC)-based IMRT. METHODS AND MATERIALS: The primary study population consisted of 9 patients treated with preoperative radiation for ESTS between 2008 and 2014 with LINAC-based static field IMRT...
September 2015: Practical Radiation Oncology
H Harold Li, Vivian L Rodriguez, Olga L Green, Yanle Hu, Rojano Kashani, H Omar Wooten, Deshan Yang, Sasa Mutic
PURPOSE: This work describes a patient-specific dosimetry quality assurance (QA) program for intensity modulated radiation therapy (IMRT) using ViewRay, the first commercial magnetic resonance imaging-guided RT device. METHODS AND MATERIALS: The program consisted of: (1) a 1-dimensional multipoint ionization chamber measurement using a customized 15-cm(3) cube-shaped phantom; (2) 2-dimensional (2D) radiographic film measurement using a 30- × 30- × 20-cm(3) phantom with multiple inserted ionization chambers; (3) quasi-3D diode array (ArcCHECK) measurement with a centrally inserted ionization chamber; (4) 2D fluence verification using machine delivery log files; and (5) 3D Monte Carlo (MC) dose reconstruction with machine delivery files and phantom CT...
January 1, 2015: International Journal of Radiation Oncology, Biology, Physics
Sasa Mutic, James F Dempsey
A description of the first commercially available magnetic resonance imaging (MRI)-guided radiation therapy (RT) system is provided. The system consists of a split 0.35-T MR scanner straddling 3 (60)Co heads mounted on a ring gantry, each head equipped with independent doubly focused multileaf collimators. The MR and RT systems share a common isocenter, enabling simultaneous and continuous MRI during RT delivery. An on-couch adaptive RT treatment-planning system and integrated MRI-guided RT control system allow for rapid adaptive planning and beam delivery control based on the visualization of soft tissues...
July 2014: Seminars in Radiation Oncology
Daniel L Saenz, Bhudatt R Paliwal, John E Bayouth
ViewRay, a novel technology providing soft-tissue imaging during radiotherapy is investigated for treatment planning capabilities assessing treatment plan dose homogeneity and conformity compared with linear accelerator plans. ViewRay offers both adaptive radiotherapy and image guidance. The combination of cobalt-60 (Co-60) with 0.35 Tesla magnetic resonance imaging (MRI) allows for magnetic resonance (MR)-guided intensity-modulated radiation therapy (IMRT) delivery with multiple beams. This study investigated head and neck, lung, and prostate treatment plans to understand what is possible on ViewRay to narrow focus toward sites with optimal dosimetry...
April 2014: Journal of Medical Physics
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