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Zhang L, Yin FF, Lu K, Moore B, Han S, Cai J. Improving liver tumor image contrast and synthesizing novel tissue contrasts by adaptive multiparametric MRI fusion. PRECISION RADIATION ONCOLOGY 2022; 6:190-198. [PMID: 36590077 PMCID: PMC9797133 DOI: 10.1002/pro6.1167] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Accepted: 06/23/2022] [Indexed: 01/05/2023] Open
Abstract
Purpose Multiparametric MRI contains rich and complementary anatomical and functional information, which is often utilized separately. This study aims to propose an adaptive multiparametric MRI (mpMRI) fusion method and examine its capability in improving tumor contrast and synthesizing novel tissue contrasts among liver cancer patients. Methods An adaptive mpMRI fusion method was developed with five components: image pre-processing, fusion algorithm, database, adaptation rules, and fused MRI. Linear-weighted summation algorithm was used for fusion. Weight-driven and feature-driven adaptations were designed for different applications. A clinical-friendly graphic-user-interface (GUI) was developed in Matlab and used for mpMRI fusion. Twelve liver cancer patients and a digital human phantom were included in the study. Synthesis of novel image contrast and enhancement of image signal and contrast were examined in patient cases. Tumor contrast-to-noise ratio (CNR) and liver signal-to-noise ratio (SNR) were evaluated and compared before and after mpMRI fusion. Results The fusion platform was applicable in both XCAT phantom and patient cases. Novel image contrasts, including enhancement of soft-tissue boundary, vertebral body, tumor, and composition of multiple image features in a single image were achieved. Tumor CNR improved from -1.70 ± 2.57 to 4.88 ± 2.28 (p < 0.0001) for T1-w, from 3.39 ± 1.89 to 7.87 ± 3.47 (p < 0.01) for T2-w, and from 1.42 ± 1.66 to 7.69 ± 3.54 (p < 0.001) for T2/T1-w MRI. Liver SNR improved from 2.92 ± 2.39 to 9.96 ± 8.60 (p < 0.05) for DWI. The coefficient of variation (CV) of tumor CNR lowered from 1.57, 0.56, and 1.17 to 0.47, 0.44, and 0.46 for T1-w, T2-w and T2/T1-w MRI, respectively. Conclusion A multiparametric MRI fusion method was proposed and a prototype was developed. The method showed potential in improving clinically relevant features such as tumor contrast and liver signal. Synthesis of novel image contrasts including the composition of multiple image features into single image set was achieved.
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Affiliation(s)
- Lei Zhang
- Medical Physics Graduate Program, Duke University, Durham, North Carolina 27705, USA
- Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina 27710, USA
- Medical Physics Graduate Program, Duke Kunshan University, Kunshan, Jiangsu, 215316 China
| | - Fang-Fang Yin
- Medical Physics Graduate Program, Duke University, Durham, North Carolina 27705, USA
- Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina 27710, USA
- Medical Physics Graduate Program, Duke Kunshan University, Kunshan, Jiangsu, 215316 China
| | - Ke Lu
- Medical Physics Graduate Program, Duke University, Durham, North Carolina 27705, USA
- Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina 27710, USA
| | - Brittany Moore
- Medical Physics Graduate Program, Duke University, Durham, North Carolina 27705, USA
- Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina 27710, USA
| | - Silu Han
- Medical Physics Graduate Program, Duke University, Durham, North Carolina 27705, USA
- Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina 27710, USA
| | - Jing Cai
- Department of Health Technology and Informatics, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong
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Desai V, Bayouth J, Smilowitz J, Yadav P. A clinical validation of the MR-compatible Delta 4 QA system in a 0.35 tesla MR linear accelerator. J Appl Clin Med Phys 2021; 22:82-91. [PMID: 33666360 PMCID: PMC8035559 DOI: 10.1002/acm2.13216] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Revised: 01/21/2021] [Accepted: 02/15/2021] [Indexed: 12/27/2022] Open
Abstract
PURPOSE To validate an MR-compatible version of the ScandiDos Delta4 Phantom+ on a 0.35T MR guided linear accelerator (MR-Linac) system and to determine the effect of plan complexity on the measurement results. METHODS/MATERIALS 36 clinical treatment plans originally delivered on a 0.35T MR linac system were re-planned on the Delta4 Phantom+ MR geometry following our clinical quality assurance (QA) protocol. The QA plans were then measured using the Delta4 Phantom+ MR and the global gamma pass rates were compared to previous results measured using a Sun Nuclear ArcCHECK-MR. Both 3%/3mm and 2%/2mm global gamma pass rates with a 20% dose threshold were recorded and compared. Plan complexity was quantified for each clinical plan investigated using 24 different plan metrics and each metric's correlation with the overall 2%/2mm global gamma pass rate was investigated using Pearson correlation coefficients. RESULTS Both systems demonstrated comparable levels of gamma pass rates at both the 3%/3mm and 2%/2mm level for all plan complexity metrics. Nine plan metrics including area, number of active MLCs, perimeter, edge metric, leaf segment variability, complete irradiation area outline, irregularity, leaf travel index, and unique opening index were moderately (|r| > 0.5) correlated with the Delta4 2%/2mm global gamma pass rates whereas those same metrics had weak correlation with the ArcCHECK-MR pass rates. Only the perimeter to area ratio and small aperture score (20 mm) metrics showed moderate correlation with the ArcCHECK-MR gamma pass rates. CONCLUSIONS The MR-compatible version of the ScandiDos Delta4 Phantom+ MR has been validated for clinical use on a 0.35T MR-Linac with results being comparable to an ArcCHECK-MR system in use clinically for almost five years. Most plan complexity metrics did not correlate with lower 2%/2mm gamma pass rates using the ArcCHECK-MR but several metrics were found to be moderately correlated with lower 2%/2mm global gamma pass rates for the Delta4 Phantom+ MR.
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Affiliation(s)
- Vimal Desai
- Department of Human OncologySchool of Medicine and Public HealthUniversity of Wisconsin‐MadisonMadisonWIUSA
| | - John Bayouth
- Department of Human OncologySchool of Medicine and Public HealthUniversity of Wisconsin‐MadisonMadisonWIUSA
| | - Jennifer Smilowitz
- Department of Human OncologySchool of Medicine and Public HealthUniversity of Wisconsin‐MadisonMadisonWIUSA
| | - Poonam Yadav
- Department of Human OncologySchool of Medicine and Public HealthUniversity of Wisconsin‐MadisonMadisonWIUSA
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Lee HJ, Kadbi M, Bosco G, Ibbott GS. Real-time volumetric relative dosimetry for magnetic resonance-image-guided radiation therapy (MR-IGRT). Phys Med Biol 2018; 63:045021. [PMID: 29384731 DOI: 10.1088/1361-6560/aaac22] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The integration of magnetic resonance imaging (MRI) with linear accelerators (linac) has enabled the use of 3D MR-visible gel dosimeters for real-time verification of volumetric dose distributions. Several iron-based radiochromic 3D gels were created in-house then imaged and irradiated in a pre-clinical 1.5 T-7 MV MR-Linac. MR images were acquired using a range of balanced-fast field echo (b-FFE) sequences during irradiation to assess the contrast and dose response in irradiated regions and to minimize the presence of MR artifacts. Out of four radiochromic 3D gel formulations, the FOX 3D gel was found to provide superior MR contrast in the irradiated regions. The FOX gels responded linearly with respect to real-time dose and the signal remained stable post-irradiation for at least 20 min. The response of the FOX gel also was found to be unaffected by the radiofrequency and gradient fields created by the b-FFE sequence during irradiation. A reusable version of the FOX gel was used for b-FFE sequence optimization to reduce artifacts by increasing the number of averages at the expense of temporal resolution. Regardless of the real-time MR sequence used, the FOX 3D gels responded linearly to dose with minimal magnetic field effects due to the strong 1.5 T field or gradient fields present during imaging. These gels can easily be made in-house using non-reusable and reusable formulations depending on the needs of the clinic, and the results of this study encourage further applications of 3D gels for MR-IGRT applications.
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Affiliation(s)
- Hannah J Lee
- Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, TX, United States of America. The University of Texas MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences, Houston, TX, United States of America. The University of Texas MD Anderson Cancer Center, 1400 Pressler Street, Houston, TX 77030, United States of America
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Mein S, Rankine L, Adamovics J, Li H, Oldham M. Development of a 3D remote dosimetry protocol compatible with MRgIMRT. Med Phys 2017; 44:6018-6028. [DOI: 10.1002/mp.12565] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2016] [Revised: 08/11/2017] [Accepted: 08/11/2017] [Indexed: 11/11/2022] Open
Affiliation(s)
- Stewart Mein
- Medical Physics Graduate Program; Duke University; Durham NC 27705 USA
| | - Leith Rankine
- Department of Radiation Oncology; The University of North Carolina; Chapel Hill NC 27599 USA
- Department of Radiation Oncology; Washington University School of Medicine; Saint Louis MO 63110 USA
| | - John Adamovics
- Department of Chemistry, Biochemistry & Physics; Rider University; Lawrenceville NY 08648 USA
| | - Harold Li
- Department of Radiation Oncology; Washington University School of Medicine; Saint Louis MO 63110 USA
| | - Mark Oldham
- Medical Physics Graduate Program; Duke University; Durham NC 27705 USA
- Department of Radiation Oncology; Duke University Medical Center; Durham NC 27710 USA
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Lee HJ, Roed Y, Venkataraman S, Carroll M, Ibbott GS. Investigation of magnetic field effects on the dose-response of 3D dosimeters for magnetic resonance - image guided radiation therapy applications. Radiother Oncol 2017; 125:426-432. [PMID: 28964533 DOI: 10.1016/j.radonc.2017.08.027] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2017] [Revised: 08/13/2017] [Accepted: 08/29/2017] [Indexed: 10/18/2022]
Abstract
BACKGROUND AND PURPOSE The strong magnetic field of integrated magnetic resonance imaging (MRI) and radiation treatment systems influences secondary electrons resulting in changes in dose deposition in three dimensions. To fill the need for volumetric dose quality assurance, we investigated the effects of strong magnetic fields on 3D dosimeters for MR-image-guided radiation therapy (MR-IGRT) applications. MATERIAL AND METHODS There are currently three main categories of 3D dosimeters, and the following were used in this study: radiochromic plastic (PRESAGE®), radiochromic gel (FOX), and polymer gel (BANG™). For the purposes of batch consistency, an electromagnet was used for same-day irradiations with and without a strong magnetic field (B0, 1.5T for PRESAGE® and FOX and 1.0T for BANG™). RESULTS For PRESAGE®, the percent difference in optical signal with and without B0 was 1.5% at the spectral peak of 632nm. For FOX, the optical signal percent difference was 1.6% at 440nm and 0.5% at 585nm. For BANG™, the percent difference in R2 MR signal was 0.7%. CONCLUSIONS The percent differences in responses with and without strong magnetic fields were minimal for all three 3D dosimeter systems. These 3D dosimeters therefore can be applied to MR-IGRT without requiring a correction factor.
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Affiliation(s)
- Hannah J Lee
- Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, USA; The University of Texas MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences, USA.
| | - Yvonne Roed
- Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, USA; Department of Physics, University of Houston, USA
| | - Sara Venkataraman
- Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, USA
| | - Mitchell Carroll
- Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, USA; The University of Texas MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences, USA
| | - Geoffrey S Ibbott
- Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, USA.
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