26
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Price R, Balter J, Kim J, Kadbi M, Zheng W, Chetty I, Glide-Hurst C. TH-CD-204-11: Three Dimensional Gradient Nonlinearity Distortion Corrections for 1.0T MR-SIM Patient Images. Med Phys 2015. [DOI: 10.1118/1.4926258] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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27
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Liu L, Cao Y, Fessler J, Balter J. SU-F-303-14: Investigation of a Pelvic Bone Shape Model in Support of Bone Classification for Synthetic CT Generation. Med Phys 2015. [DOI: 10.1118/1.4925241] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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28
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Cazoulat G, Owen D, Matuszak M, Balter J, Brock K. SU-E-J-91: Biomechanical Deformable Image Registration of Longitudinal Lung CT Images. Med Phys 2015. [DOI: 10.1118/1.4924178] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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29
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Chapman CH, Prisciandaro J, Maturen K, Balter J, Cao Y, Young L, Jolly S. MRI-Based Evaluation of Coverage of the Vaginal Cuff in Endometrial Brachytherapy: Are We Missing the Target? Brachytherapy 2015. [DOI: 10.1016/j.brachy.2015.02.209] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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30
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Chapman CH, Jolly S, Young L, Maturen K, Balter J, Owrangi A, Prisciandaro J. Assessing the Need for Dose Calculations to Organs at Risk Using MRI Planning in Vaginal Brachytherapy. Brachytherapy 2015. [DOI: 10.1016/j.brachy.2014.08.023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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31
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Liss A, Kapadia N, Marsh R, Rogers V, Balter J, Moran J, Frey K, Pierce L. Decreased Lung Perfusion Following Breast/Chest Wall Irradiation: Preliminary Results of a Prospective Clinical Trial. Int J Radiat Oncol Biol Phys 2014. [DOI: 10.1016/j.ijrobp.2014.05.172] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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32
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Chapman C, Jolly S, Young L, Maturen K, Balter J, Owrangi A, Prisciandaro J. Assessing the Need for Dose Calculations to Organs at Risk Using MRI Planning in Vaginal Brachytherapy. Int J Radiat Oncol Biol Phys 2014. [DOI: 10.1016/j.ijrobp.2014.05.1530] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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33
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Balter J, Hsu S, Vineberg K, Lawrence T, Feng M, Tsien C, Cao Y. Volumetric Arc Treatment Planning in the Brain Using MRI-Derived Synthetic CT Images. Int J Radiat Oncol Biol Phys 2014. [DOI: 10.1016/j.ijrobp.2014.05.750] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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34
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Matakos A, Balter J, Cao Y. Estimation of geometrically undistorted B(0) inhomogeneity maps. Phys Med Biol 2014; 59:4945-59. [PMID: 25109506 DOI: 10.1088/0031-9155/59/17/4945] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Geometric accuracy of MRI is one of the main concerns for its use as a sole image modality in precision radiation therapy (RT) planning. In a state-of-the-art scanner, system level geometric distortions are within acceptable levels for precision RT. However, subject-induced B0 inhomogeneity may vary substantially, especially in air-tissue interfaces. Recent studies have shown distortion levels of more than 2 mm near the sinus and ear canal are possible due to subject-induced field inhomogeneity. These distortions can be corrected with the use of accurate B0 inhomogeneity field maps. Most existing methods estimate these field maps from dual gradient-echo (GRE) images acquired at two different echo-times under the assumption that the GRE images are practically undistorted. However distortion that may exist in the GRE images can result in estimated field maps that are distorted in both geometry and intensity, leading to inaccurate correction of clinical images. This work proposes a method for estimating undistorted field maps from GRE acquisitions using an iterative joint estimation technique. The proposed method yields geometrically corrected GRE images and undistorted field maps that can also be used for the correction of images acquired by other sequences. The proposed method is validated through simulation, phantom experiments and applied to patient data. Our simulation results show that our method reduces the root-mean-squared error of the estimated field map from the ground truth by ten-fold compared to the distorted field map. Both the geometric distortion and the intensity corruption (artifact) in the images caused by the B0 field inhomogeneity are corrected almost completely. Our phantom experiment showed improvement in the geometric correction of approximately 1 mm at an air-water interface using the undistorted field map compared to using a distorted field map. The proposed method for undistorted field map estimation can lead to improved geometric distortion correction at air-tissue interfaces, especially in low readout-bandwidth acquisitions, thus making them suitable for clinical use in precision RT without increasing the treatment planning margin.
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Brock K, Lee C, Lockhart C, Balter J, Ten HR, Eisbruch A. SU-E-CAMPUS-J-02: Implementation of Routine Clinical Daily Dose Evaluation for Patient Specific Quality Control. Med Phys 2014. [DOI: 10.1118/1.4889022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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36
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Matakos A, Balter J, Cao Y. WE-G-18C-01: Novel Method for Geometrically Undistorted B0 Inhomogeneity Field Map Estimation and Image Correction. Med Phys 2014. [DOI: 10.1118/1.4889520] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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37
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Stanescu T, Balter J, Nyholm T, Lagendijk J. TU-A-BRF-01: MR Guided Radiation Therapy. Med Phys 2014. [DOI: 10.1118/1.4889233] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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38
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Hsu S, Cao Y, Jolly S, Balter J. SU-C-17A-01: MRI-Based Radiotherapy Treatment Planning In Pelvis. Med Phys 2014. [DOI: 10.1118/1.4889728] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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39
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Owrangi A, Jolly S, Balter J, Cao Y, Young L, Zhu T, Prisciandaro J. SU-E-T-366: Clinical Implementation of MR-Guided Vaginal Cylinder Brachytherapy. Med Phys 2014. [DOI: 10.1118/1.4888699] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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40
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Balter J, Eisbruch A. In Reply to Ren et al. Int J Radiat Oncol Biol Phys 2014; 88:1214. [DOI: 10.1016/j.ijrobp.2014.01.028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2014] [Accepted: 01/18/2014] [Indexed: 11/24/2022]
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41
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Matakos A, Balter J, Cao Y. OC-0084: Iterative correction of subject-dependent B0 inhomogeneity field maps for geometric distortion correction. Radiother Oncol 2014. [DOI: 10.1016/s0167-8140(15)30189-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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42
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Hsu S, Cao Y, Balter J. TH-C-141-01: Differentiation of Air From Bone Using MRI for Radiation Therapy and PET-MRI Reconstruction. Med Phys 2013. [DOI: 10.1118/1.4815769] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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43
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Molineu A, Miller R, Clements J, Balter J. WE-E-105-01: Managing and Leading Others: Practical Advice for Medical Physicists. Med Phys 2013. [DOI: 10.1118/1.4815577] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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44
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Wang H, Feng M, Frey K, Balter J, Haken RT, Lawrence T, Cao Y. Hepatic Function Model Based Upon HIDA SPECT and Dose for Physiological Adaptive RT. Pract Radiat Oncol 2013; 3:S2. [DOI: 10.1016/j.prro.2013.01.010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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45
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Wang H, Balter J, Cao Y. Patient-induced susceptibility effect on geometric distortion of clinical brain MRI for radiation treatment planning on a 3T scanner. Phys Med Biol 2013; 58:465-77. [PMID: 23302471 DOI: 10.1088/0031-9155/58/3/465] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Concerns about the geometric accuracy of MRI in radiation therapy (RT) have been present since its invention. Although modern scanners typically have system levels of geometric accuracy that meet requirements of RT, subject-specific distortion is variable, and methods to in vivo assess and control patient-induced geometric distortion are not yet resolved. This study investigated the nature and magnitude of the subject-induced susceptibility effect on geometric distortions in clinical brain MRI, and tested the feasibility of in vivo quality control using field inhomogeneity mapping. For 19 consecutive patients scanned on a dedicated 3T MR scanner, B0 field inhomogeneity maps were acquired and analyzed to determine subject-induced distortions. For 3D T1 weighted images frequency-encoded with a bandwidth of 180 Hz/pixel, 86.9% of the estimated displacements were <0.5 mm, 97.4% <1 mm, and only 0.1% of displacements > 2 mm. The maximum displacement was <4 mm. The greatest distortions were observed at the interfaces with air at the sinuses. Displacements decayed to less than 1 mm over a distance of 8 mm. Metal surgical wires generated smaller distortions, with an averaged maximum displacement of 0.76 mm. Repeat acquisition of the field maps in 17 patients revealed a within-subject standard deviation of 0.25 ppm, equivalent to 0.22 mm displacement in the frequency-encoding direction in the 3D T1 weighted images. Susceptibility-induced voxel displacements in the brain are generally small, but should be monitored for precision RT. These effects are manageable at 3T and lower fields, and the methods applied can be used to monitor for potential local errors in individual patients, as well as to correct for local distortions as needed.
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Cao Y, Hsu S, Flammang A, Balter J. MRCT: Synthetic CT Imaging for Radiation Oncology Using Magnetic Resonance Images. Int J Radiat Oncol Biol Phys 2012. [DOI: 10.1016/j.ijrobp.2012.07.1981] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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47
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Hsu S, Cao Y, Balter J. MO-G-BRA-02: Investigation of a Method for Generating Synthetic CT Models from MRI Scans for Radiation Therapy. Med Phys 2012. [DOI: 10.1118/1.4735847] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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48
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Wang H, Feng M, Frey K, Balter J, Haken RT, Lawrence T, Cao Y. WE-A-217A-04: Hepatic Function Estimated from HIDA SPECT for Assessment of Liver Response to Radiation Therapy. Med Phys 2012. [DOI: 10.1118/1.4736062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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49
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Thomas A, Hollister S, Balter J. SU-C-218-05: A CFD-Based Approach to Validating Flow in a Prototype Dynamic Perfusion Phantom for Dynamic Contrast Fnhanced (DCE) Imaging. Med Phys 2012. [DOI: 10.1118/1.4734653] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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50
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Kim J, Matuszak M, Saitou K, Balter J. MO-F-BRA-01: A Biomechanical Constraint for Intensity-Driven Deformable Alignment of Skeletal Components in the Head and Neck Region. Med Phys 2012; 39:3874-3875. [DOI: 10.1118/1.4735820] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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