Comprehensive MRI simulation methodology using a dedicated MRI scanner in radiation oncology for external beam radiation treatment planning

Medical Physics - Tập 42 Số 1 - Trang 28-39 - 2015
E.S. Paulson1, Bradley A. Erickson2, Chris Schultz2, X. Allen Li2
1Department of Radiation Oncology, Medical College of Wisconsin, Milwaukee, Wisconsin 53226 and Department of Radiology, Medical College of Wisconsin, Milwaukee, Wisconsin 53226
2Department of Radiation Oncology, Medical College of Wisconsin, Milwaukee, Wisconsin 53226

Tóm tắt

Purpose:The use of magnetic resonance imaging (MRI) in radiation oncology is expanding rapidly, and more clinics are integrating MRI into their radiation therapy workflows. However, radiation therapy presents a new set of challenges and places additional constraints on MRI compared to diagnostic radiology that, if not properly addressed, can undermine the advantages MRI offers for radiation treatment planning (RTP). The authors introduce here strategies to manage several challenges of using MRI for virtual simulation in external beam RTP.Methods:A total of 810 clinical MRI simulation exams were performed using a dedicated MRI scanner for external beam RTP of brain, breast, cervix, head and neck, liver, pancreas, prostate, and sarcoma cancers. Patients were imaged in treatment position using MRI‐optimal immobilization devices. Radiofrequency (RF) coil configurations and scan protocols were optimized based on RTP constraints. Off‐resonance and gradient nonlinearity‐induced geometric distortions were minimized or corrected prior to using images for RTP. A multidisciplinary MRI simulation guide, along with window width and level presets, was created to standardize use of MR images during RTP. A quality assurance program was implemented to maintain accuracy and repeatability of MRI simulation exams.Results:The combination of a large bore scanner, high field strength, and circumferentially wrapped, flexible phased array RF receive coils permitted acquisition of thin slice images with high contrast‐to‐noise ratio (CNR) and image intensity uniformity, while simultaneously accommodating patient setup and immobilization devices. Postprocessing corrections and alternative acquisition methods were required to reduce or correct off‐resonance and gradient nonlinearity induced geometric distortions.Conclusions:The methodology described herein contains practical strategies the authors have implemented through lessons learned performing clinical MRI simulation exams. In their experience, these strategies provide robust, high fidelity, high contrast MR images suitable for external beam RTP.

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Tài liệu tham khảo

10.1088/0031‐9155/53/12/R01

10.4103/0971‐6203.44472

10.1053/j.semradonc.2003.10.003

10.1148/radiology.199.3.8638017

10.1259/bjr/41321492

10.1016/j.ijrobp.2009.01.065

10.1118/1.4758068

10.1002/mrm.24459

10.7785/tcrt.2012.500342

10.1118/1.4889702

10.1259/bjr/26802977

10.1016/j.media.2005.09.004

10.1148/radiology.198.1.8539406

10.1007/PL00002385

American Association of Physicists in Medicine (AAPM). Comprehensive QA for radiation oncology: Report of AAPM Radiation Therapy Committee Task Group 40, 1994, Med. Phys., 31, 581

10.1002/(SICI)1097‐0193(1999)8:2/3<80::AID‐HBM2>3.0.CO;2‐C

10.1118/1.3180107

10.1016/j.radonc.2013.10.004

10.1118/1.3182289

10.1002/mrm.20288

10.1120/jacmp.v11i1.2961

10.1118/1.3613192

10.1118/1.3560418

10.1118/1.4818656

10.1155/2014/485067

10.1259/bjr/70617164

American College of Radiology (ACR) “MR accreditation program phantom test guidance” (2005).

American Association of Physicists in Medicine, 2010, AAPM Report 100: Acceptance Testing and Quality Assurance Procedures for Magnetic Resonance Imaging Facilities

10.1016/j.ijrobp.2009.01.014

10.1016/j.ijrobp.2009.06.031

10.1002/mrm.20863

10.1088/0031‐9155/58/3/465

10.1002/mrm.22407

10.1177/0284185113498535

10.1016/j.neuroimage.2009.06.039

10.1118/1.2335487

10.1118/1.3578928

10.1016/j.ijrobp.2011.11.056

10.1088/0031‐9155/58/23/8419

Zhang T., 2013, Fast pediatric 3D free breathing abdominal dynamic contrast enhanced MRI with high spatiotemporal resolution, J. Magn. Reson. Imaging

Celicanin Z., 2014, Simultaneous acquisition of image and navigator slices using CAIPIRINHA for 4D MRI, Magn. Reson. Med.

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Medical Physics

Tập 42 Số 1

28-39

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