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Brendlin AS, Dehdab R, Stenzl B, Mueck J, Ghibes P, Groezinger G, Kim J, Afat S, Artzner C. Novel Deep Learning Denoising Enhances Image Quality and Lowers Radiation Exposure in Interventional Bronchial Artery Embolization Cone Beam CT. Acad Radiol 2024; 31:2144-2155. [PMID: 37989681 DOI: 10.1016/j.acra.2023.11.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2023] [Revised: 10/23/2023] [Accepted: 11/01/2023] [Indexed: 11/23/2023]
Abstract
OBJECTIVES In interventional bronchial artery embolization (BAE), periprocedural cone beam CT (CBCT) improves guiding and localization. However, a trade-off exists between 6-second runs (high radiation dose and motion artifacts, but low noise) and 3-second runs (vice versa). This study aimed to determine the efficacy of an advanced deep learning denoising (DLD) technique in mitigating the trade-offs related to radiation dose and image quality during interventional BAE CBCT. MATERIALS AND METHODS This study included BMI-matched patients undergoing 6-second and 3-second BAE CBCT scans. The dose-area product values (DAP) were obtained. All datasets were reconstructed using standard weighted filtered back projection (OR) and a novel DLD software. Objective image metrics were derived from place-consistent regions of interest, including CT numbers of the Aorta and lung, noise, and contrast-to-noise ratio. Three blinded radiologists performed subjective assessments regarding image quality, sharpness, contrast, and motion artifacts on all dataset combinations in a forced-choice setup (-1 = inferior, 0 = equal; 1 = superior). The points were averaged per item for a total score. Statistical analysis ensued using a properly corrected mixed-effects model with post hoc pairwise comparisons. RESULTS Sixty patients were assessed in 30 matched pairs (age 64 ± 15 years; 10 female). The mean DAP for the 6 s and 3 s runs was 2199 ± 185 µGym² and 1227 ± 90 µGym², respectively. Neither low-dose imaging nor the reconstruction method introduced a significant HU shift (p ≥ 0.127). The 3 s-DLD presented the least noise and superior contrast-to-noise ratio (CNR) (p < 0.001). While subjective evaluation revealed no noticeable distinction between 6 s-DLD and 3 s-DLD in terms of quality (p ≥ 0.996), both outperformed the OR variants (p < 0.001). The 3 s datasets exhibited fewer motion artifacts than the 6 s datasets (p < 0.001). CONCLUSIONS DLD effectively mitigates the trade-off between radiation dose, image noise, and motion artifact burden in regular reconstructed BAE CBCT by enabling diagnostic scans with low radiation exposure and inherently low motion artifact burden at short examination times.
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Affiliation(s)
- Andreas S Brendlin
- Department of Diagnostic and Interventional Radiology, Eberhard-Karls University, Hoppe-Seyler-Str. 3, 72076 Tuebingen, Germany (A.S.B., R.D., B.S., J.M., P.G., G.G., S.A., C.A.).
| | - Reza Dehdab
- Department of Diagnostic and Interventional Radiology, Eberhard-Karls University, Hoppe-Seyler-Str. 3, 72076 Tuebingen, Germany (A.S.B., R.D., B.S., J.M., P.G., G.G., S.A., C.A.)
| | - Benedikt Stenzl
- Department of Diagnostic and Interventional Radiology, Eberhard-Karls University, Hoppe-Seyler-Str. 3, 72076 Tuebingen, Germany (A.S.B., R.D., B.S., J.M., P.G., G.G., S.A., C.A.)
| | - Jonas Mueck
- Department of Diagnostic and Interventional Radiology, Eberhard-Karls University, Hoppe-Seyler-Str. 3, 72076 Tuebingen, Germany (A.S.B., R.D., B.S., J.M., P.G., G.G., S.A., C.A.)
| | - Patrick Ghibes
- Department of Diagnostic and Interventional Radiology, Eberhard-Karls University, Hoppe-Seyler-Str. 3, 72076 Tuebingen, Germany (A.S.B., R.D., B.S., J.M., P.G., G.G., S.A., C.A.)
| | - Gerd Groezinger
- Department of Diagnostic and Interventional Radiology, Eberhard-Karls University, Hoppe-Seyler-Str. 3, 72076 Tuebingen, Germany (A.S.B., R.D., B.S., J.M., P.G., G.G., S.A., C.A.)
| | - Jonghyo Kim
- Department of Radiology, Seoul National University Hospital, 101 Daehak-ro, Jongno-gu, Seoul 03080, Republic of Korea (J.K.); ClariPi Inc., 11 Ihwajang 1-gil, Jongno-gu, Seoul 03088, Republic of Korea (J.K.)
| | - Saif Afat
- Department of Diagnostic and Interventional Radiology, Eberhard-Karls University, Hoppe-Seyler-Str. 3, 72076 Tuebingen, Germany (A.S.B., R.D., B.S., J.M., P.G., G.G., S.A., C.A.)
| | - Christoph Artzner
- Department of Diagnostic and Interventional Radiology, Eberhard-Karls University, Hoppe-Seyler-Str. 3, 72076 Tuebingen, Germany (A.S.B., R.D., B.S., J.M., P.G., G.G., S.A., C.A.)
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Santoso AP, Vinogradskiy Y, Robin TP, Goodman KA, Schefter TE, Miften M, Jones BL. Clinical and Dosimetric Impact of 2D kV Motion Monitoring and Intervention in Liver Stereotactic Body Radiation Therapy. Adv Radiat Oncol 2024; 9:101409. [PMID: 38298328 PMCID: PMC10828584 DOI: 10.1016/j.adro.2023.101409] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2023] [Accepted: 11/13/2023] [Indexed: 02/02/2024] Open
Abstract
Purpose Positional errors resulting from motion are a principal challenge across all disease sites in radiation therapy. This is particularly pertinent when treating lesions in the liver with stereotactic body radiation therapy (SBRT). To achieve dose escalation and margin reduction for liver SBRT, kV real-time imaging interventions may serve as a potential solution. In this study, we report results of a retrospective cohort of liver patients treated using real-time 2D kV-image guidance SBRT with emphasis on the impact of (1) clinical workflow, (2) treatment accuracy, and (3) tumor dose. Methods and Materials Data from 33 patients treated with 41 courses of liver SBRT were analyzed. During treatment, planar kV images orthogonal to the treatment beam were acquired to determine treatment interventions, namely treatment pauses (ie, adequacy of gating thresholds) or treatment shifts. Patients were shifted if internal markers were >3 mm, corresponding to the PTV margin used, from the expected reference condition. The frequency, duration, and nature of treatment interventions (ie, pause vs shift) were recorded, and the dosimetric impact associated with treatment shifts was estimated using a machine learning dosimetric model. Results Of all fractions delivered, 39% required intervention, which took on average 1.9 ± 1.6 minutes and occurred more frequently in treatments lasting longer than 7 minutes. The median realignment shift was 5.7 mm in size, and the effect of these shifts on minimum tumor dose in simulated clinical scenarios ranged from 0% to 50% of prescription dose per fraction. Conclusion Real-time kV-based imaging interventions for liver SBRT minimally affect clinical workflow and dosimetrically benefit patients. This potential solution for addressing positional errors from motion addresses concerns about target accuracy and may enable safe dose escalation and margin reduction in the context of liver SBRT.
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Affiliation(s)
- Andrew P. Santoso
- Department of Radiation Oncology, University of Colorado School of Medicine, Aurora, Colorado
| | - Yevgeniy Vinogradskiy
- Department of Radiation Oncology, Thomas Jefferson University, Philadelphia, Pennsylvania
| | - Tyler P. Robin
- Department of Radiation Oncology, University of Colorado School of Medicine, Aurora, Colorado
| | - Karyn A. Goodman
- Department of Radiation Oncology, University of Colorado School of Medicine, Aurora, Colorado
- Department of Radiation Oncology, Icahn School of Medicine at Mount Sinai, New York, New York
| | - Tracey E. Schefter
- Department of Radiation Oncology, University of Colorado School of Medicine, Aurora, Colorado
| | - Moyed Miften
- Department of Radiation Oncology, University of Colorado School of Medicine, Aurora, Colorado
| | - Bernard L. Jones
- Department of Radiation Oncology, University of Colorado School of Medicine, Aurora, Colorado
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Dong Z, Yu S, Szmul A, Wang J, Qi J, Wu H, Li J, Lu Z, Zhang Y. Simulation of a new respiratory phase sorting method for 4D-imaging using optical surface information towards precision radiotherapy. Comput Biol Med 2023; 162:107073. [PMID: 37290392 PMCID: PMC10311359 DOI: 10.1016/j.compbiomed.2023.107073] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Revised: 05/09/2023] [Accepted: 05/27/2023] [Indexed: 06/10/2023]
Abstract
BACKGROUND Respiratory signal detection is critical for 4-dimensional (4D) imaging. This study proposes and evaluates a novel phase sorting method using optical surface imaging (OSI), aiming to improve the precision of radiotherapy. METHOD Based on 4D Extended Cardiac-Torso (XCAT) digital phantom, OSI in point cloud format was generated from the body segmentation, and image projections were simulated using the geometries of Varian 4D kV cone-beam-CT (CBCT). Respiratory signals were extracted respectively from the segmented diaphragm image (reference method) and OSI respectively, where Gaussian Mixture Model and Principal Component Analysis (PCA) were used for image registration and dimension reduction respectively. Breathing frequencies were compared using Fast-Fourier-Transform. Consistency of 4DCBCT images reconstructed using Maximum Likelihood Expectation Maximization algorithm was also evaluated quantitatively, where high consistency can be suggested by lower Root-Mean-Square-Error (RMSE), Structural-Similarity-Index (SSIM) value closer to 1, and larger Peak-Signal-To-Noise-Ratio (PSNR) respectively. RESULTS High consistency of breathing frequencies was observed between the diaphragm-based (0.232 Hz) and OSI-based (0.251 Hz) signals, with a slight discrepancy of 0.019Hz. Using end of expiration (EOE) and end of inspiration (EOI) phases as examples, the mean±1SD values of the 80 transverse, 100 coronal and 120 sagittal planes were 0.967, 0,972, 0.974 (SSIM); 1.657 ± 0.368, 1.464 ± 0.104, 1.479 ± 0.297 (RMSE); and 40.501 ± 1.737, 41.532 ± 1.464, 41.553 ± 1.910 (PSNR) for the EOE; and 0.969, 0.973, 0.973 (SSIM); 1.686 ± 0.278, 1.422 ± 0.089, 1.489 ± 0.238 (RMSE); and 40.535 ± 1.539, 41.605 ± 0.534, 41.401 ± 1.496 (PSNR) for EOI respectively. CONCLUSIONS This work proposed and evaluated a novel respiratory phase sorting approach for 4D imaging using optical surface signals, which can potentially be applied to precision radiotherapy. Its potential advantages were non-ionizing, non-invasive, non-contact, and more compatible with various anatomic regions and treatment/imaging systems.
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Affiliation(s)
- Zhengkun Dong
- Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education/Beijing), Department of Radiation Oncology, Peking University Cancer Hospital & Institute, Beijing, 100142, China; Institute of Medical Technology, Peking University Health Science Center, Beijing, 100191, China
| | - Shutong Yu
- Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education/Beijing), Department of Radiation Oncology, Peking University Cancer Hospital & Institute, Beijing, 100142, China; Institute of Medical Technology, Peking University Health Science Center, Beijing, 100191, China
| | - Adam Szmul
- Wellcome/EPSRC Centre for Interventional and Surgical Sciences, University College London, London, United Kingdom
| | - Jingyuan Wang
- Department of Biostatistics, School of Public Health, Peking University, Beijing, China
| | - Junfeng Qi
- Department of Engineering Physics, Tsinghua University, Beijing, 100084, China
| | - Hao Wu
- Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education/Beijing), Department of Radiation Oncology, Peking University Cancer Hospital & Institute, Beijing, 100142, China
| | - Junyu Li
- Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education/Beijing), Department of Radiation Oncology, Peking University Cancer Hospital & Institute, Beijing, 100142, China
| | - Zihong Lu
- Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education/Beijing), Department of Radiation Oncology, Peking University Cancer Hospital & Institute, Beijing, 100142, China
| | - Yibao Zhang
- Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education/Beijing), Department of Radiation Oncology, Peking University Cancer Hospital & Institute, Beijing, 100142, China.
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Ibad HA, de Cesar Netto C, Shakoor D, Sisniega A, Liu S, Siewerdsen JH, Carrino JA, Zbijewski W, Demehri S. Computed Tomography: State-of-the-Art Advancements in Musculoskeletal Imaging. Invest Radiol 2023; 58:99-110. [PMID: 35976763 PMCID: PMC9742155 DOI: 10.1097/rli.0000000000000908] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
ABSTRACT Although musculoskeletal magnetic resonance imaging (MRI) plays a dominant role in characterizing abnormalities, novel computed tomography (CT) techniques have found an emerging niche in several scenarios such as trauma, gout, and the characterization of pathologic biomechanical states during motion and weight-bearing. Recent developments and advancements in the field of musculoskeletal CT include 4-dimensional, cone-beam (CB), and dual-energy (DE) CT. Four-dimensional CT has the potential to quantify biomechanical derangements of peripheral joints in different joint positions to diagnose and characterize patellofemoral instability, scapholunate ligamentous injuries, and syndesmotic injuries. Cone-beam CT provides an opportunity to image peripheral joints during weight-bearing, augmenting the diagnosis and characterization of disease processes. Emerging CBCT technologies improved spatial resolution for osseous microstructures in the quantitative analysis of osteoarthritis-related subchondral bone changes, trauma, and fracture healing. Dual-energy CT-based material decomposition visualizes and quantifies monosodium urate crystals in gout, bone marrow edema in traumatic and nontraumatic fractures, and neoplastic disease. Recently, DE techniques have been applied to CBCT, contributing to increased image quality in contrast-enhanced arthrography, bone densitometry, and bone marrow imaging. This review describes 4-dimensional CT, CBCT, and DECT advances, current logistical limitations, and prospects for each technique.
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Affiliation(s)
- Hamza Ahmed Ibad
- The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Cesar de Cesar Netto
- Department of Orthopaedics and Rehabilitation, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Delaram Shakoor
- Department of Radiology and Biomedical Imaging, Yale School of Medicine, New Haven, CT, USA
| | - Alejandro Sisniega
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, USA
| | - Stephen Liu
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, USA
| | - Jeffrey H Siewerdsen
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, USA
| | - John A. Carrino
- Department of Radiology and Imaging, Hospital for Special Surgery, New York, NY, USA
| | - Wojciech Zbijewski
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, USA
| | - Shadpour Demehri
- The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, USA
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Khan M, Sandhu N, Naeem M, Ealden R, Pearson M, Ali A, Honey I, Webster A, Eaton D, Ntentas G. Implementation of a comprehensive set of optimised CBCT protocols and validation through imaging quality and dose audit. Br J Radiol 2022; 95:20220070. [PMID: 36000497 PMCID: PMC9793481 DOI: 10.1259/bjr.20220070] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
OBJECTIVES Cone-beam computed tomography (CBCT) for radiotherapy treatment verification has increased in frequency; therefore, it is crucial to optimise image quality and radiation dose to patients. The aim of this study was to implement optimised CBCT protocols for the Varian TrueBeams for most tumour sites in adult patients. METHODS A combination of patient size-specific CBCT protocols from the literature and developed in-house was used. Scans taken before and after optimisation were compared by senior radiographers and physicists to evaluate how changes affected image quality and clinical usability for online image registration. The change in dose for each new CBCT protocol was compared to the Varian default. A clinical audit was performed following implementation to evaluate the changes in imaging dose for all patients receiving a CBCT during that period. RESULTS Ten CBCT protocols were introduced including head and neck and patient-size-specific thorax and pelvis/abdomen protocols. Scans from 102 patients with images before and after optimisation were assessed, none of the scans showed image quality changes compromising clinical usability and for some image quality was improved. Between November 2020 and June 2021, 1185 patients had CBCTs using the new protocols. The imaging dose was reduced for 52% of patients, remained the same for 37% and increased for 12%. CONCLUSIONS This study showed that substantial dose reductions and image quality improvements can be achieved with simple changes in the default settings of the Varian TrueBeam CBCT without affecting the radiographers' confidence in online image registration. ADVANCES IN KNOWLEDGE This study represents a comprehensive assessment and optimisation of CBCT protocols for most sites, validated on a large cohort of patients.
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Affiliation(s)
- Marina Khan
- Department of Radiotherapy, Guy’s & St Thomas’ NHS Foundation Trust, London, UK
| | - Navneet Sandhu
- Department of Medical Physics, Guy’s & St Thomas’ NHS Foundation Trust, London, UK
| | - Marium Naeem
- Department of Medical Physics, Guy’s & St Thomas’ NHS Foundation Trust, London, UK
| | - Rebecca Ealden
- Department of Medical Physics, Guy’s & St Thomas’ NHS Foundation Trust, London, UK
| | - Michael Pearson
- Department of Medical Physics, Guy’s & St Thomas’ NHS Foundation Trust, London, UK
| | - Abdirzak Ali
- Department of Radiotherapy, Guy’s & St Thomas’ NHS Foundation Trust, London, UK
| | - Ian Honey
- Department of Medical Physics, Guy’s & St Thomas’ NHS Foundation Trust, London, UK
| | - Amanda Webster
- Department of Radiotherapy, University College Hospital, London, UK
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El Naqa I, Pogue BW, Zhang R, Oraiqat I, Parodi K. Image guidance for FLASH radiotherapy. Med Phys 2022; 49:4109-4122. [PMID: 35396707 PMCID: PMC9844128 DOI: 10.1002/mp.15662] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Revised: 03/10/2022] [Accepted: 03/30/2022] [Indexed: 01/19/2023] Open
Abstract
FLASH radiotherapy (FLASH-RT) is an emerging ultra-high dose (>40 Gy/s) delivery that promises to improve the therapeutic potential by limiting toxicities compared to conventional RT while maintaining similar tumor eradication efficacy. Image guidance is an essential component of modern RT that should be harnessed to meet the special emerging needs of FLASH-RT and its associated high risks in planning and delivering of such ultra-high doses in short period of times. Hence, this contribution will elaborate on the imaging requirements and possible solutions in the entire chain of FLASH-RT treatment, from the planning, through the setup and delivery with online in vivo imaging and dosimetry, up to the assessment of biological mechanisms and treatment response. In patient setup and delivery, higher temporal sampling than in conventional RT should ensure that the short treatment is delivered precisely to the targeted region. Additionally, conventional imaging tools such as cone-beam computed tomography will continue to play an important role in improving patient setup prior to delivery, while techniques based on magnetic resonance imaging or positron emission tomography may be extremely valuable for either linear accelerator (Linac) or particle FLASH therapy, to monitor and track anatomical changes during delivery. In either planning or assessing outcomes, quantitative functional imaging could supplement conventional imaging for more accurate utilization of the biological window of the FLASH effect, selecting for or verifying things such as tissue oxygen and existing or transient hypoxia on the relevant timescales of FLASH-RT delivery. Perhaps most importantly at this time, these tools might help improve the understanding of the biological mechanisms of FLASH-RT response in tumor and normal tissues. The high dose deposition of FLASH provides an opportunity to utilize pulse-to-pulse imaging tools such as Cherenkov or radiation acoustic emission imaging. These could provide individual pulse mapping or assessing the 3D dose delivery superficially or at tissue depth, respectively. In summary, the most promising components of modern RT should be used for safer application of FLASH-RT, and new promising developments could be advanced to cope with its novel demands but also exploit new opportunities in connection with the unique nature of pulsed delivery at unprecedented dose rates, opening a new era of biological image guidance and ultrafast, pulse-based in vivo dosimetry.
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Affiliation(s)
- Issam El Naqa
- Department of Machine Learning, Moffitt Cancer Center, Tampa, FL 33612, USA,Corresponding Author:
| | - Brian W. Pogue
- Thayer School of Engineering, Dartmouth College, Hanover, NH 03755, USA,Department of Medical Physics, University of Wisconsin-Madison, WI 53705, USA
| | - Rongxiao Zhang
- Giesel School of Medicine, Dartmouth College, Hanover, NH 03755, USA
| | - Ibrahim Oraiqat
- Department of Machine Learning, Moffitt Cancer Center, Tampa, FL 33612, USA
| | - Katia Parodi
- Department of Medical Physics, Ludwig-Maximilians-Universität München, Am Coulombwall 1, Garching 85748, Germany
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Dong G, Zhang C, Deng L, Zhu Y, Dai J, Song L, Meng R, Niu T, Liang X, Xie Y. A deep unsupervised learning framework for the 4D CBCT artifact correction. Phys Med Biol 2022; 67. [DOI: 10.1088/1361-6560/ac55a5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Accepted: 02/16/2022] [Indexed: 11/11/2022]
Abstract
Abstract
Objective. Four-dimensional cone-beam computed tomography (4D CBCT) has unique advantages in moving target localization, tracking and therapeutic dose accumulation in adaptive radiotherapy. However, the severe fringe artifacts and noise degradation caused by 4D CBCT reconstruction restrict its clinical application. We propose a novel deep unsupervised learning model to generate the high-quality 4D CBCT from the poor-quality 4D CBCT. Approach. The proposed model uses a contrastive loss function to preserve the anatomical structure in the corrected image. To preserve the relationship between the input and output image, we use a multilayer, patch-based method rather than operate on entire images. Furthermore, we draw negatives from within the input 4D CBCT rather than from the rest of the dataset. Main results. The results showed that the streak and motion artifacts were significantly suppressed. The spatial resolution of the pulmonary vessels and microstructure were also improved. To demonstrate the results in the different directions, we make the animation to show the different views of the predicted correction image in the supplementary animation. Significance. The proposed method can be integrated into any 4D CBCT reconstruction method and maybe a practical way to enhance the image quality of the 4D CBCT.
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Li Y, Wu W, He R, Lu Y, Zhang Y, Wang L, Zhang X. Using 4DCBCT simulation and guidance to evaluate inter-fractional tumor variance during SABR for lung tumor within the lower lobe. Sci Rep 2021; 11:19976. [PMID: 34620950 PMCID: PMC8497481 DOI: 10.1038/s41598-021-99489-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Accepted: 09/23/2021] [Indexed: 12/25/2022] Open
Abstract
Inter-fractional tumor variance would lead to insufficient dosage or overdose in tumor region during lung cancer radiotherapy. However, previous works have not considered influence of inter-fractional tumor amplitude variance at treatment position due to lack of effective evaluation method during radiotherapy, especially for lung tumor within the lower lobe. Our objective was to investigate inter-fractional tumor baseline shift and amplitude variance due to respiratory motion with 4DCBCT simulation and guidance during stereotactic ablative body radiotherapy (SABR) for lung tumor. Subject included 19 patients with lung tumor within the lower lobe. 4DCBCT-simulated images at treatment position were acquired sequentially to determine internal tumor volume (ITV) and reference tumor motion at simulation process. Compared with reference tumor motion, 95 4DCBCT-guided images were acquired during each treatment to evaluate inter-fractional tumor baseline shift and amplitude variance, which were − 0.0 ± 1.3 mm and − 0.2 ± 1.4 mm in left–right(LR) direction, 0.9 ± 2.3 mm and 0.4 ± 2.9 mm in superior-inferior (SI) direction, 0.1 ± 1.5 mm and − 0.4 ± 2.0 mm in anterior–posterior (AP) direction. ITV margin were 3.5 mm, 7.5 mm and 5.3 mm in LR, SI and AP directions with van Herk’s (Int J Radiat Oncol Biol Phys 52(5):1407–1422, 2002) formula. 4DCBCT simulation and guidance is a reliable method to evaluate inter-fractional tumor variance during SABR for lung tumor within the lower lobe. ITV margin of 3.5 mm, 7.5 mm and 5.3 mm in LR, SI and AP directions would ensure greater tumor coverage during SABR for lung tumor within the lower lobe.
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Affiliation(s)
- Yi Li
- Department of Radiation Oncology, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, 710061, China
| | - Wenjing Wu
- Department of Radiological Health, Xi'an Center for Disease Control and Prevention, Xi'an, 710054, China.
| | - Ruixin He
- Department of Radiation Oncology, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, 710061, China
| | - Yongkai Lu
- Department of Radiation Oncology, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, 710061, China
| | - Yuemei Zhang
- Department of Radiation Oncology, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, 710061, China
| | - Long Wang
- Department of Radiation Oncology, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, 710061, China
| | - Xiaozhi Zhang
- Department of Radiation Oncology, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, 710061, China.
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Dumas M, Laugeman E, Sevak P, Snyder KC, Mao W, Chetty IJ, Ajlouni M, Wen N. Technical Note: Comparison of the internal target volume (ITV) contours and dose calculations on 4DCT, average CBCT, and 4DCBCT imaging for lung stereotactic body radiation therapy (SBRT). J Appl Clin Med Phys 2020; 21:288-294. [PMID: 33044040 PMCID: PMC7700943 DOI: 10.1002/acm2.13041] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2019] [Revised: 07/22/2020] [Accepted: 09/15/2020] [Indexed: 11/15/2022] Open
Abstract
PURPOSE To investigate the differences between internal target volumes (ITVs) contoured on the simulation 4DCT and daily 4DCBCT images for lung cancer patients treated with stereotactic body radiotherapy (SBRT) and determine the dose delivered on 4D planning technique. METHODS For nine patients, 4DCBCTs were acquired before each fraction to assess tumor motion. An ITV was contoured on each phase of the 4DCBCT and a union of the 10 ITVs was used to create a composite ITV. Another ITV was drawn on the average 3DCBCT (avgCBCT) to compare with current clinical practice. The Dice coefficient, Hausdorff distance, and center of mass (COM) were averaged over four fractions to compare the ITVs contoured on the 4DCT, avgCBCT, and 4DCBCT for each patient. Planning was done on the average CT, and using the online registration, plans were calculated on each phase of the 4DCBCT and on the avgCBCT. Plan dose calculations were tested by measuring ion chamber dose in the CIRS lung phantom. RESULTS The Dice coefficients were similar for all three comparisons: avgCBCT-to-4DCBCT (0.7 ± 0.1), 4DCT-to-avgCBCT (0.7 ± 0.1), and 4DCT-to-4DCBCT (0.7 ± 0.1); while the mean COM differences were also comparable (2.6 ± 2.2mm, 2.3 ± 1.4mm, and 3.1 ± 1.1mm, respectively). The Hausdorff distances for the comparisons with 4DCBCT (8.2 ± 2.9mm and 8.1 ± 3.2mm) were larger than the comparison without (6.5 ± 2.5mm). The differences in ITV D95% between the treatment plan and avgCBCT calculations were 4.3 ± 3.0% and -0.5 ± 4.6%, between treatment plan and 4DCBCT plans, respectively, while the ITV V100% coverages were 99.0 ± 1.9% and 93.1 ± 8.0% for avgCBCT and 4DCBCT, respectively. CONCLUSION There is great potential for 4DCBCT to evaluate the extent of tumor motion before treatment, but image quality challenges the clinician to consistently delineate lung target volumes.
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Affiliation(s)
- Michael Dumas
- Department of Radiation OncologyHenry Ford Health SystemDetroitMIUSA
| | - Eric Laugeman
- Department of Radiation OncologyWashington UniversitySt. LouisMOUSA
| | - Parag Sevak
- Department of Radiation OncologyColumbus Regional HealthColumbusINUSA
| | - Karen C. Snyder
- Department of Radiation OncologyHenry Ford Health SystemDetroitMIUSA
| | - Weihua Mao
- Department of Radiation OncologyHenry Ford Health SystemDetroitMIUSA
| | - Indrin J. Chetty
- Department of Radiation OncologyHenry Ford Health SystemDetroitMIUSA
| | - Munther Ajlouni
- Department of Radiation OncologyHenry Ford Health SystemDetroitMIUSA
| | - Ning Wen
- Department of Radiation OncologyHenry Ford Health SystemDetroitMIUSA
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Madesta F, Sentker T, Gauer T, Werner R. Self‐contained deep learning‐based boosting of 4D cone‐beam CT reconstruction. Med Phys 2020; 47:5619-5631. [DOI: 10.1002/mp.14441] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2020] [Revised: 06/02/2020] [Accepted: 07/16/2020] [Indexed: 12/25/2022] Open
Affiliation(s)
- Frederic Madesta
- Department of Computational Neuroscience University Medical Center Hamburg‐Eppendorf Hamburg20246 Germany
| | - Thilo Sentker
- Department of Computational Neuroscience University Medical Center Hamburg‐Eppendorf Hamburg20246 Germany
- Department of Radiotherapy and Radio‐Oncology University Medical Center Hamburg‐Eppendorf Hamburg20246 Germany
| | - Tobias Gauer
- Department of Radiotherapy and Radio‐Oncology University Medical Center Hamburg‐Eppendorf Hamburg20246 Germany
| | - René Werner
- Department of Computational Neuroscience University Medical Center Hamburg‐Eppendorf Hamburg20246 Germany
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11
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Vergalasova I, Cai J. A modern review of the uncertainties in volumetric imaging of respiratory-induced target motion in lung radiotherapy. Med Phys 2020; 47:e988-e1008. [PMID: 32506452 DOI: 10.1002/mp.14312] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2019] [Revised: 05/15/2020] [Accepted: 05/26/2020] [Indexed: 12/25/2022] Open
Abstract
Radiotherapy has become a critical component for the treatment of all stages and types of lung cancer, often times being the primary gateway to a cure. However, given that radiation can cause harmful side effects depending on how much surrounding healthy tissue is exposed, treatment of the lung can be particularly challenging due to the presence of moving targets. Careful implementation of every step in the radiotherapy process is absolutely integral for attaining optimal clinical outcomes. With the advent and now widespread use of stereotactic body radiation therapy (SBRT), where extremely large doses are delivered, accurate, and precise dose targeting is especially vital to achieve an optimal risk to benefit ratio. This has largely become possible due to the rapid development of image-guided technology. Although imaging is critical to the success of radiotherapy, it can often be plagued with uncertainties due to respiratory-induced target motion. There has and continues to be an immense research effort aimed at acknowledging and addressing these uncertainties to further our abilities to more precisely target radiation treatment. Thus, the goal of this article is to provide a detailed review of the prevailing uncertainties that remain to be investigated across the different imaging modalities, as well as to highlight the more modern solutions to imaging motion and their role in addressing the current challenges.
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Affiliation(s)
- Irina Vergalasova
- Department of Radiation Oncology, Rutgers Cancer Institute of New Jersey, Rutgers University, New Brunswick, NJ, USA
| | - Jing Cai
- Department of Health Technology and Informatics, The Hong Kong Polytechnic University, Kowloon, Hong Kong
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12
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Kadoya N, Nemoto H, Kajikawa T, Nakajima Y, Kanai T, Ieko Y, Ikeda R, Sato K, Dobashi S, Takeda K, Jingu K. Evaluation of four-dimensional cone beam computed tomography ventilation images acquired with two different linear accelerators at various gantry speeds using a deformable lung phantom. Phys Med 2020; 77:75-83. [PMID: 32795891 DOI: 10.1016/j.ejmp.2020.07.030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/10/2020] [Revised: 06/24/2020] [Accepted: 07/26/2020] [Indexed: 10/23/2022] Open
Abstract
We evaluated four-dimensional cone beam computed tomography (4D-CBCT) ventilation images (VICBCT) acquired with two different linear accelerator systems at various gantry speeds using a deformable lung phantom. The 4D-CT and 4D-CBCT scans were performed using a computed tomography (CT) scanner, an X-ray volume imaging system (Elekta XVI) mounted in Versa HD, and an On-Board Imager (OBI) system mounted in TrueBeam. Intensity-based deformable image registration (DIR) was performed between peak-exhale and peak-inhale images. VICBCT- and 4D-CT-based ventilation images (VICT) were derived by DIR using two metrics: one based on the Jacobian determinant and one on changes in the Hounsfield unit (HU). Three different DIR regularization values (λ) were used for VICBCT. Correlations between the VICBCT and VICT values were evaluated using voxel-wise Spearman's rank correlation coefficient (r). In case of both metrics, the Jacobian-based VICBCT with a gantry speed of 0.6 deg/sec in Versa HD showed the highest correlation for all the gantry speeds (e.g., λ = 0.05 and r = 0.68). Thus, the r value of the Jacobian-based VICBCT was greater or equal to that of the HU-based VICBCT. In addition, the ventilation accuracy of VICBCT increased at low gantry speeds. Thus, the image quality of VICBCT was affected by the change in gantry speed in both the imaging systems. Additionally, DIR regularization considerably influenced VICBCT in both the imaging systems. Our results have the potential to assist in designing CBCT protocols, incorporating VICBCT imaging into the functional avoidance planning process.
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Affiliation(s)
- Noriyuki Kadoya
- Department of Radiation Oncology, Tohoku University Graduate School of Medicine, Sendai, Japan.
| | - Hikaru Nemoto
- Department of Radiation Oncology, Tohoku University Graduate School of Medicine, Sendai, Japan; Department of Radiotherapy, Tokyo Metropolitan Cancer and Infectious Diseases Center Komagome Hospital, Tokyo, Japan
| | - Tomohiro Kajikawa
- Department of Radiation Oncology, Tohoku University Graduate School of Medicine, Sendai, Japan; Department of Radiology, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Yujiro Nakajima
- Department of Radiation Oncology, Tohoku University Graduate School of Medicine, Sendai, Japan; Department of Radiotherapy, Tokyo Metropolitan Cancer and Infectious Diseases Center Komagome Hospital, Tokyo, Japan
| | - Takayuki Kanai
- Department of Radiation Oncology, Yamagata University Faculty of Medicine, Yamagata, Japan
| | - Yoshiro Ieko
- Department of Radiation Oncology, Tohoku University Graduate School of Medicine, Sendai, Japan; Department of Radiation Oncology, Iwate Medical University School of Medicine, Iwate, Japan
| | - Ryutaro Ikeda
- Department of Radiation Oncology, Tohoku University Graduate School of Medicine, Sendai, Japan; Department of Radiology, Japanese Red Cross Ishinomaki Hospital, Ishinomaki, Japan
| | - Kiyokazu Sato
- Radiation Technology, Tohoku University Hospital, Sendai, Japan
| | - Suguru Dobashi
- Department of Radiological Technology, School of Health Sciences, Faculty of Medicine, Tohoku University, Sendai, Japan
| | - Ken Takeda
- Department of Radiological Technology, School of Health Sciences, Faculty of Medicine, Tohoku University, Sendai, Japan
| | - Keiichi Jingu
- Department of Radiation Oncology, Tohoku University Graduate School of Medicine, Sendai, Japan
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Yuasa Y, Shiinoki T, Onizuka R, Fujimoto K. Estimation of effective imaging dose and excess absolute risk of secondary cancer incidence for four-dimensional cone-beam computed tomography acquisition. J Appl Clin Med Phys 2019; 20:57-68. [PMID: 31593377 PMCID: PMC6839364 DOI: 10.1002/acm2.12741] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2019] [Revised: 09/02/2019] [Accepted: 09/15/2019] [Indexed: 12/25/2022] Open
Abstract
This study was conducted to estimate the organ equivalent dose and effective imaging dose for four-dimensional cone-beam computed tomography (4D-CBCT) using a Monte Carlo simulation, and to evaluate the excess absolute risk (EAR) of secondary cancer incidence. The EGSnrc/BEAMnrc were used to simulate the on-board imager (OBI) from the TrueBeam linear accelerator. Specifically, the OBI was modeled based on the percent depth dose and the off-center ratio was measured using a three-dimensional (3D) water phantom. For clinical cases, 15 lung and liver cancer patients were simulated using the EGSnrc/DOSXYZnrc. The mean absorbed doses to the lung, stomach, bone marrow, esophagus, liver, thyroid, bone surface, skin, adrenal glands, gallbladder, heart, intestine, kidney, pancreas and spleen, were quantified using a treatment planning system, and the equivalent doses to each organ were calculated. Subsequently, the effective dose was calculated as the weighted sum of the equivalent dose, and the EAR of the secondary cancer incidence was determined for each organ with the use of the biologic effects of ionizing radiation (BEIR) VII model. The effective doses were 3.9 ± 0.5, 15.7 ± 2.0, and 7.3 ± 0.9 mSv, for the lung, and 4.2 ± 0.6, 16.7 ± 2.4, and 7.8 ± 1.1 mSv, for the liver in the respective cases of the 3D-CBCT (thorax, pelvis) and 4D-CBCT modes. The lung EARs for males and females were 7.3 and 10.7 cases per million person-years, whereas the liver EARs were 9.9 and 4.5 cases per million person-years. The EAR increased with increasing time since radiation exposure. In clinical studies, we should use 4D-CBCT based on consideration of the effective dose and EAR of secondary cancer incidence.
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Affiliation(s)
- Yuki Yuasa
- Department of Radiation OncologyGraduate School of MedicineYamaguchi UniversityUbeYamaguchiJapan
| | - Takehiro Shiinoki
- Department of Radiation OncologyGraduate School of MedicineYamaguchi UniversityUbeYamaguchiJapan
| | - Ryota Onizuka
- Department of Radiological TechnologyYamaguchi University HospitalUbeYamaguchiJapan
| | - Koya Fujimoto
- Department of Radiation OncologyGraduate School of MedicineYamaguchi UniversityUbeYamaguchiJapan
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14
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Wu RY, Liu AY, Williamson TD, Yang J, Wisdom PG, Zhu XR, Frank SJ, Fuller CD, Gunn GB, Gao S. Quantifying the accuracy of deformable image registration for cone-beam computed tomography with a physical phantom. J Appl Clin Med Phys 2019; 20:92-100. [PMID: 31541526 PMCID: PMC6806467 DOI: 10.1002/acm2.12717] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Revised: 08/16/2019] [Accepted: 08/21/2019] [Indexed: 01/31/2023] Open
Abstract
PURPOSE Kilo-voltage cone-beam computed tomography (CBCT) is widely used for patient alignment, contour propagation, and adaptive treatment planning in radiation therapy. In this study, we evaluated the accuracy of deformable image registration (DIR) for CBCT under various imaging protocols with different noise and patient dose levels. METHODS A physical phantom previously developed to facilitate end-to-end testing of the DIR accuracy was used with Varian Velocity v4.0 software to evaluate the performance of image registration from CT to CT, CBCT to CT, and CBCT to CBCT. The phantom is acrylic and includes several inserts that simulate different tissue shapes and properties. Deformations and anatomic changes were simulated by changing the rotations of both the phantom and the inserts. CT images (from a head and neck protocol) and CBCT images (from pelvis, head and "Image Gently" protocols) were obtained with different image noise and dose levels. Large inserts were filled with Mobil DTE oil to simulate soft tissue, and small inserts were filled with bone materials. All inserts were contoured before the DIR process to provide a ground truth contour size and shape for comparison. After the DIR process, all deformed contours were compared with the originals using Dice similarity coefficient (DSC) and mean distance to agreement (MDA). Both large and small volume of interests (VOIs) for DIR volume selection were tested by simulating a DIR process that included whole patient image volume and clinical target volumes (CTV) only (for CTVs propagation). RESULTS For cross-modality DIR registration (CT to CBCT), the DSC were >0.8 and the MDA were <3 mm for CBCT pelvis, and CBCT head protocols. For CBCT to CBCT and CT to CT, the DIR accuracy was improved relative to the cross-modality tests. For smaller VOIs, the DSC were >0.8 and MDA <2 mm for all modalities. CONCLUSIONS The accuracy of DIR depends on the quality of the CBCT image at different dose and noise levels.
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Affiliation(s)
- Richard Y. Wu
- Department of Radiation PhysicsThe University of Texas MD Anderson Cancer CenterHoustonTXUSA
| | - Amy Y. Liu
- Department of Radiation PhysicsThe University of Texas MD Anderson Cancer CenterHoustonTXUSA
| | - Tyler D. Williamson
- Department of Radiation PhysicsThe University of Texas MD Anderson Cancer CenterHoustonTXUSA
| | - Jinzhong Yang
- Department of Radiation PhysicsThe University of Texas MD Anderson Cancer CenterHoustonTXUSA
| | - Paul G. Wisdom
- Department of Radiation PhysicsThe University of Texas MD Anderson Cancer CenterHoustonTXUSA
| | - Xiaorong R. Zhu
- Department of Radiation PhysicsThe University of Texas MD Anderson Cancer CenterHoustonTXUSA
| | - Steven J. Frank
- Department of Radiation OncologyThe University of Texas MD Anderson Cancer CenterHoustonTXUSA
| | - Clifton D. Fuller
- Department of Radiation OncologyThe University of Texas MD Anderson Cancer CenterHoustonTXUSA
| | - Gary B. Gunn
- Department of Radiation OncologyThe University of Texas MD Anderson Cancer CenterHoustonTXUSA
| | - Song Gao
- Department of Radiation PhysicsThe University of Texas MD Anderson Cancer CenterHoustonTXUSA
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Chen Y, Yin FF, Jiang Z, Ren L. Daily edge deformation prediction using an unsupervised convolutional neural network model for low dose prior contour based total variation CBCT reconstruction (PCTV-CNN). Biomed Phys Eng Express 2019; 5:065013. [PMID: 32587754 PMCID: PMC7316357 DOI: 10.1088/2057-1976/ab446b] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
PURPOSE Previously we developed a PCTV method to enhance the edge sharpness for low-dose CBCT reconstruction. However, the iterative deformable registration method used for deforming edges from planning-CT to on-board CBCT is time-consuming and user-dependent. This study aims to automate and accelerate PCTV reconstruction by developing an unsupervised CNN model to bypass the conventional deformable registration. METHODS The new method uses unsupervised CNN model for deformation prediction and PCTV reconstruction. An unsupervised CNN model with a u-net structure was used to predict deformation vector fields (DVF) to generate on-board contours for PCTV reconstruction. Paired 3D image volumes of prior CT and on-board CBCT are inputs and DVF are predicted without the need of ground truths. The model was initially trained on brain MRI images, and then fine-tuned using our lung SBRT data. This method was evaluated using lung SBRT patient data. In the intra-patient study, the first n-1 day's CBCTs are used for CNN training to predict nth day edge information (n = 2, 3, 4, 5). 45 half-fan projections covering 360˚ from nth day CBCT is used for reconstruction. In the inter-patient study, the 10 patient images including CT and first day's CBCT are used for training. Results from Edge-preserving (EPTV), PCTV and PCTV-CNN are compared. RESULTS The cross-correlations of the predicted edge map and the ground truth were on average 0.88 for both intra-patient and inter-patient studies. PCTV-CNN achieved comparable image quality as PCTV while automating the registration process and reducing the registration time from 1-2 min to 1.4 s. CONCLUSION It is feasible to use an unsupervised CNN to predict daily deformation of on-board edge information for PCTV based low-dose CBCT reconstruction. PCTV-CNN has a great potential for enhancing the edge sharpness with high efficiency for low-dose CBCT to improve the precision of on-board target localization and adaptive radiotherapy.
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Affiliation(s)
- Yingxuan Chen
- Medical Physics Graduate Program, Duke University, 2424 Erwin Road Suite 101, Durham, NC 27705, United States of America
| | - Fang-Fang Yin
- Medical Physics Graduate Program, Duke University, 2424 Erwin Road Suite 101, Durham, NC 27705, United States of America
- Department of Radiation Oncology, Duke University Medical Center, DUMC Box 3295, Durham, North Carolina, 27710, United States of America
- Medical Physics Graduate Program, Duke Kunshan University, Kunshan, Jiangsu, 215316, People's Republic of China
| | - Zhuoran Jiang
- Department of Radiation Oncology, Duke University Medical Center, DUMC Box 3295, Durham, North Carolina, 27710, United States of America
| | - Lei Ren
- Medical Physics Graduate Program, Duke University, 2424 Erwin Road Suite 101, Durham, NC 27705, United States of America
- Department of Radiation Oncology, Duke University Medical Center, DUMC Box 3295, Durham, North Carolina, 27710, United States of America
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16
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Chen Y, Yin FF, Zhang Y, Zhang Y, Ren L. Low dose cone-beam computed tomography reconstruction via hybrid prior contour based total variation regularization (hybrid-PCTV). Quant Imaging Med Surg 2019; 9:1214-1228. [PMID: 31448208 DOI: 10.21037/qims.2019.06.02] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Background Previously, we developed a prior contour based total variation (PCTV) method to use edge information derived from prior images for edge enhancement in low-dose cone-beam computed tomography (CBCT) reconstruction. However, the accuracy of edge enhancement in PCTV is affected by the deformable registration errors and anatomical changes from prior to on-board images. In this study, we develop a hybrid-PCTV method to address this limitation to enhance the robustness and accuracy of the PCTV method. Methods Planning-CT is used as prior images and deformably registered with on-board CBCT reconstructed by the edge preserving TV (EPTV) method. Edges derived from planning CT are deformed based on the registered deformation vector fields to generate on-board edges for edge enhancement in PCTV reconstruction. Reference CBCT is reconstructed from the simulated projections of the deformed planning-CT. Image similarity map is then calculated between reference and on-board CBCT using structural similarity index (SSIM) method to estimate local registration accuracy. The hybrid-PCTV method enhances the edge information based on a weighted edge map that combines edges from both PCTV and EPTV methods. Higher weighting is given to PCTV edges at regions with high registration accuracy and to EPTV edges at regions with low registration accuracy. The hybrid-PCTV method was evaluated using both digital extended-cardiac-torso (XCAT) phantom and lung patient data. In XCAT study, breathing amplitude change, tumor shrinkage and new tumor were simulated from CT to CBCT. In the patient study, both simulated and real projections of lung patients were used for reconstruction. Results were compared with both EPTV and PCTV methods. Results EPTV led to blurring bony structures due to missing edge information, and PCTV led to blurring tumor edges due to inaccurate edge information caused by errors in the deformable registration. In contrast, hybrid-PCTV enhanced edges of both bone and tumor. In XCAT study using 30 half-fan CBCT projections, compared with ground truth, relative errors (REs) were 1.3%, 1.1% and 0.9% and edge cross-correlation were 0.66, 0.68 and 0.71 for EPTV, PCTV and hybrid-PCTV, respectively. Moreover, in the lung patient data, hybrid-PCTV avoided the wrong edge enhancement in the PCTV method while maintaining enhancements of the correct edges. Conclusions Hybrid-PCTV further improved the robustness and accuracy of PCTV by accounting for uncertainties in deformable registration and anatomical changes between prior and onboard images. The accurate edge enhancement in hybrid-PCTV will be valuable for target localization in radiation therapy.
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Affiliation(s)
- Yingxuan Chen
- Medical Physics Graduate Program, Duke University, Durham, NC, USA
| | - Fang-Fang Yin
- Medical Physics Graduate Program, Duke University, Durham, NC, USA.,Department of Radiation Oncology, Duke University Medical Center, Durham, NC, USA.,Medical Physics Graduate Program, Duke Kunshan University, Kunshan 215316, China
| | - Yawei Zhang
- Department of Radiation Oncology, Duke University Medical Center, Durham, NC, USA
| | - You Zhang
- Medical Physics Graduate Program, Duke University, Durham, NC, USA
| | - Lei Ren
- Medical Physics Graduate Program, Duke University, Durham, NC, USA.,Department of Radiation Oncology, Duke University Medical Center, Durham, NC, USA
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Zhang Y, Yin FF, Ren L. First clinical retrospective investigation of limited projection CBCT for lung tumor localization in patients receiving SBRT treatment. Phys Med Biol 2019; 64:10NT01. [PMID: 31018195 DOI: 10.1088/1361-6560/ab1c0c] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
To clinically investigate the limited-projection CBCT (LP-CBCT) technology for daily positioning of patients receiving breath-hold lung SBRT radiation treatment and to investigate the feasibility of reconstructing fast 4D-CBCT from 1 min 3D-CBCT scan. Eleven patients who underwent breath-hold lung SBRT radiation treatment were scanned daily with on-board full-projection CBCT (CBCT) using half-fan scan. A subset of the CBCT projections and the prior planning CT were used to estimate the LP-CBCT images using the weighted free-form deformation method. The limited projections are clusteringly sampled within fifteen sub-angles in 360° in order to simulate the fast 1 min scan for 4D-CBCT. The estimated LP-CBCTs were rigidly registered to the planning CT to determine the clinical shifts needed for patient setup corrections, which were compared with shifts determined by the CBCT for evaluation. Both manual and automatic registrations were performed in order to compare the systematic registration errors. Fifty CBCT volumes were obtained from the eleven patients in fifty fractions for this pilot clinical study. For the CBCT images, the mean (±standard deviation) shifts between CBCT and planning CT from manual registration in left-right (LR), anterior-posterior (AP), and superior-inferior (SI) directions are 1.1 ± 1.2 mm, 2.1 ± 1.9 mm, 5.2 ± 3.6 mm, respectively. The mean deviation difference between shifts determined by CBCT and LP-CBCT images are 0.3 ± 0.5 mm, 0.5 ± 0.8 mm, 0.4 ± 0.3 mm, in LR, AP, and SI directions, respectively. The mean vector length of CBCT shift for all fractions is 6.1 ± 3.6 mm, and the mean vector length difference between CBCT and LP-CBCT for all fractions studied is 1.0 ± 0.9 mm. The automatic registrations yield similar results as manual registrations. The pilot clinical study shows that LP-CBCT localization offers comparable accuracy to CBCT localization for daily tumor positioning while reducing the projection number to 1/10 for patients receiving breath hold lung radiation treatment. The cluster projection sampling in this study also shows the feasibility of reconstructing fast 4D-CBCT from 1 min 3D-CBCT scan.
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Affiliation(s)
- Yawei Zhang
- Department of Radiation Oncology, Duke University Medical Center, DUMC Box 3295, Durham, NC 27710, United States of America
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Mao W, Liu C, Gardner SJ, Siddiqui F, Snyder KC, Kumarasiri A, Zhao B, Kim J, Wen NW, Movsas B, Chetty IJ. Evaluation and Clinical Application of a Commercially Available Iterative Reconstruction Algorithm for CBCT-Based IGRT. Technol Cancer Res Treat 2019; 18:1533033818823054. [PMID: 30803367 PMCID: PMC6373994 DOI: 10.1177/1533033818823054] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
Purpose: We have quantitatively evaluated the image quality of a new commercially available iterative cone-beam computed tomography reconstruction algorithm over standard cone-beam computed tomography image reconstruction results. Methods: This iterative cone-beam computed tomography reconstruction pipeline uses a finite element solver (AcurosCTS)-based scatter correction and a statistical (iterative) reconstruction in addition to a standard kernel-based correction followed by filtered back-projection-based Feldkamp-Davis-Kress cone-beam computed tomography reconstruction. Standard full-fan half-rotation Head, half-fan full-rotation Head, and standard Pelvis cone-beam computed tomography protocols have been investigated to scan a quality assurance phantom via the following image quality metrics: uniformity, HU constancy, spatial resolution, low contrast detection, noise level, and contrast-to-noise ratio. An anthropomorphic head phantom was scanned for verification of noise reduction. Clinical patient image data sets for 5 head/neck patients and 5 prostate patients were qualitatively evaluated. Results: Quality assurance phantom study results showed that relative to filtered back-projection-based cone-beam computed tomography, noise was reduced from 28.8 ± 0.3 HU to a range between 18.3 ± 0.2 and 5.9 ± 0.2 HU for Full-Fan Head scans, from 14.4 ± 0.2 HU to a range between 12.8 ± 0.3 and 5.2 ± 0.3 HU for Half-Fan Head scans, and from 6.2 ± 0.1 HU to a range between 3.8 ± 0.1 and 2.0 ± 0.2 HU for Pelvis scans, with the iterative cone-beam computed tomography algorithm. Spatial resolution was marginally improved while results for uniformity and HU constancy were similar. For the head phantom study, noise was reduced from 43.6 HU to a range between 24.8 and 13.0 HU for a Full-Fan Head and from 35.1 HU to a range between 22.9 and 14.0 HU for a Half-Fan Head scan. The patient data study showed that artifacts due to photon starvation and streak artifacts were all reduced, and image noise in specified target regions were reduced to 62% ± 15% for 10 patients. Conclusion: Noise and contrast-to-noise ratio image quality characteristics were significantly improved using the iterative cone-beam computed tomography reconstruction algorithm relative to the filtered back-projection-based cone-beam computed tomography method. These improvements will enhance the accuracy of cone-beam computed tomography-based image-guided applications.
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Affiliation(s)
- Weihua Mao
- 1 Department of Radiation Oncology, Henry Ford Health System, Detroit, MI, USA
| | - Chang Liu
- 1 Department of Radiation Oncology, Henry Ford Health System, Detroit, MI, USA
| | - Stephen J Gardner
- 1 Department of Radiation Oncology, Henry Ford Health System, Detroit, MI, USA
| | - Farzan Siddiqui
- 1 Department of Radiation Oncology, Henry Ford Health System, Detroit, MI, USA
| | - Karen C Snyder
- 1 Department of Radiation Oncology, Henry Ford Health System, Detroit, MI, USA
| | - Akila Kumarasiri
- 1 Department of Radiation Oncology, Henry Ford Health System, Detroit, MI, USA
| | - Bo Zhao
- 1 Department of Radiation Oncology, Henry Ford Health System, Detroit, MI, USA
| | - Joshua Kim
- 1 Department of Radiation Oncology, Henry Ford Health System, Detroit, MI, USA
| | - Ning Winston Wen
- 1 Department of Radiation Oncology, Henry Ford Health System, Detroit, MI, USA
| | - Benjamin Movsas
- 1 Department of Radiation Oncology, Henry Ford Health System, Detroit, MI, USA
| | - Indrin J Chetty
- 1 Department of Radiation Oncology, Henry Ford Health System, Detroit, MI, USA
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Quantitative evaluation of 4D Cone beam CT scans with reduced scan time in lung cancer patients. Radiother Oncol 2019; 136:64-70. [PMID: 31015131 PMCID: PMC6598855 DOI: 10.1016/j.radonc.2019.03.027] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2018] [Revised: 03/26/2019] [Accepted: 03/27/2019] [Indexed: 11/21/2022]
Abstract
Fast (2 min) 4D CBCT can be simulated accurately from long (4 min) scans. Registration was accurate for 96.6% of simulated 2 min scans. Acquired 2 min scan registration was accurate in 6/8 patients. 2 min 4D CBCT produces sufficient image quality for IGRT in lung cancer patients.
Purpose Image guided radiotherapy (IGRT) based on respiration correlated cone-beam CT (4D-CBCT) provides accurate tumour localisation in lung cancer patients by taking into account respiratory motion when deriving setup correction. However, 4D-CBCT scan times are typically longer than for acquisition of 3D-CBCT scans, e.g. 4 min. This work aims to quantitatively evaluate the effect of reduced scan times on 4D-CBCT image quality and registration accuracy in lung cancer patients. Methods and materials Scan times down to 1 min were simulated by retaining only projection images corresponding to every second, third or fourth respiratory cycle in forty-four 4D-CBCTs from 15 lung cancer patients. In addition twenty 2-minute scans were acquired for 12 lung cancer patients. Image quality was quantified by assessing registration accuracy in the shorter scan times, comparing to the 4-minute scan registration result where available as reference. Results Use of 2-minute scans had little impact on registration accuracy or ability to detect tumour motion: automatic registration accuracy was within 2 mm in 6/8 scans analysed with 2-minute acquisitions, and 96.6% of registration discrepancies were within 2 mm for the simulated scans. When the scan time simulated was below 2 min, automatic registration results still agreed within 2 mm for 84.7% of scans, however visual image quality was considerably degraded. Conclusion A 4D-CBCT acquisition time of 2 min produces scans of sufficient image quality for IGRT in most lung cancer patients, as demonstrated quantitatively by assessing the impact on automatic registration accuracy in simulated and real acquisitions.
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Mao W, Gardner SJ, Snyder KC, Wen NW, Zhong H, Li H, Jackson P, Shah M, Chetty IJ. On the improvement of CBCT image quality for soft tissue-based SRS localization. J Appl Clin Med Phys 2018; 19:177-184. [PMID: 30294838 PMCID: PMC6236842 DOI: 10.1002/acm2.12470] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2018] [Revised: 08/10/2018] [Accepted: 09/11/2018] [Indexed: 12/02/2022] Open
Abstract
Purpose We explore the optimal cone‐beam CT (CBCT) acquisition parameters to improve CBCT image quality to enhance intracranial stereotactic radiosurgery (SRS) localization and also assess the imaging dose levels associated with each imaging protocol. Methods Twenty‐six CBCT acquisition protocols were generated on an Edge® linear accelerator (Varian Medical Systems, Palo Alto, CA) with different x‐ray tube current and potential settings, gantry rotation trajectories, and gantry rotation speeds. To assess image quality, images of the Catphan 504 phantom were analyzed to evaluate the following image quality metrics: uniformity, HU constancy, spatial resolution, low contrast detection, noise level, and contrast‐to‐noise ratio (CNR). To evaluate the imaging dose for each protocol, the cone‐beam dose index (CBDI) was measured. To validate the phantom results, further analysis was performed with an anthropomorphic head phantom as well as image data acquired for a clinical SRS patient. Results The Catphan data indicates that adjusting acquisition parameters had direct effects on the image noise level, low contrast detection, and CNR, but had minimal effects on uniformity, HU constancy, and spatial resolution. The noise level was reduced from 34.5 ± 0.3 to 18.5 ± 0.2 HU with a four‐fold reduction in gantry speed, and to 18.7 ± 0.2 HU with a four‐fold increase in tube current. Overall, the noise level was found to be proportional to inverse square root of imaging dose, and imaging dose was proportional to the product of total tube current‐time product and the cube of the x‐ray potential. Analysis of the anthropomorphic head phantom data and clinical SRS imaging data also indicates that noise is reduced with imaging dose increase. Conclusions Our results indicate that optimization of the imaging protocol, and thereby an increase in the imaging dose, is warranted for improved soft‐tissue visualization for intracranial SRS.
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Affiliation(s)
- Weihua Mao
- Henry Ford Health System, Detroit, MI, USA
| | | | | | | | | | - Haisen Li
- Henry Ford Health System, Detroit, MI, USA
| | | | - Mira Shah
- Henry Ford Health System, Detroit, MI, USA
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Chen Y, Yin FF, Zhang Y, Zhang Y, Ren L. Low dose CBCT reconstruction via prior contour based total variation (PCTV) regularization: a feasibility study. Phys Med Biol 2018. [PMID: 29537385 DOI: 10.1088/1361-6560/aab68d] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
PURPOSE compressed sensing reconstruction using total variation (TV) tends to over-smooth the edge information by uniformly penalizing the image gradient. The goal of this study is to develop a novel prior contour based TV (PCTV) method to enhance the edge information in compressed sensing reconstruction for CBCT. METHODS the edge information is extracted from prior planning-CT via edge detection. Prior CT is first registered with on-board CBCT reconstructed with TV method through rigid or deformable registration. The edge contours in prior-CT is then mapped to CBCT and used as the weight map for TV regularization to enhance edge information in CBCT reconstruction. The PCTV method was evaluated using extended-cardiac-torso (XCAT) phantom, physical CatPhan phantom and brain patient data. Results were compared with both TV and edge preserving TV (EPTV) methods which are commonly used for limited projection CBCT reconstruction. Relative error was used to calculate pixel value difference and edge cross correlation was defined as the similarity of edge information between reconstructed images and ground truth in the quantitative evaluation. RESULTS compared to TV and EPTV, PCTV enhanced the edge information of bone, lung vessels and tumor in XCAT reconstruction and complex bony structures in brain patient CBCT. In XCAT study using 45 half-fan CBCT projections, compared with ground truth, relative errors were 1.5%, 0.7% and 0.3% and edge cross correlations were 0.66, 0.72 and 0.78 for TV, EPTV and PCTV, respectively. PCTV is more robust to the projection number reduction. Edge enhancement was reduced slightly with noisy projections but PCTV was still superior to other methods. PCTV can maintain resolution while reducing the noise in the low mAs CatPhan reconstruction. Low contrast edges were preserved better with PCTV compared with TV and EPTV. CONCLUSION PCTV preserved edge information as well as reduced streak artifacts and noise in low dose CBCT reconstruction. PCTV is superior to TV and EPTV methods in edge enhancement, which can potentially improve the localization accuracy in radiation therapy.
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Affiliation(s)
- Yingxuan Chen
- Medical Physics Graduate Program, Duke University, 2424 Erwin Road Suite 101, Durham, NC 27705, United States of America
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Shimohigashi Y, Araki F, Maruyama M, Yonemura K, Nakaguchi Y, Kai Y, Toya R. Image quality of four-dimensional cone-beam computed tomography obtained at various gantry rotation speeds for liver stereotactic body radiation therapy with fiducial markers. Phys Med 2017; 45:19-24. [PMID: 29472086 DOI: 10.1016/j.ejmp.2017.11.020] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/05/2017] [Revised: 11/24/2017] [Accepted: 11/26/2017] [Indexed: 11/25/2022] Open
Abstract
In this study, qualities of 4D cone-beam CT (CBCT) images obtained using various gantry rotation speeds (GRSs) for liver stereotactic body radiation therapy (SBRT) with fiducial markers were quantitatively evaluated. Abdominal phantom containing a fiducial marker was moved along a sinusoidal waveform, and 4D-CBCT images were acquired with GRSs of 50-200° min-1. We obtained the 4D-CBCT projection data from six patients who underwent liver SBRT and generated 4D-CBCT images at GRSs of 67-200° min-1, by varying the number of projection data points. The image quality was evaluated based on the signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and structural similarity index (SSIM). The fiducial marker positions with different GRSs were compared with the setup values and a reference position in the phantom and clinical studies, respectively. The root mean square errors (RMSEs) were calculated relative to the reference positions. In the phantom study, the mean SNR, CNR, and SSIM decreased from 37.6 to 10.1, from 39.8 to 10.1, and from 0.9 to 0.7, respectively, as the GRS increased from 50 to 200° min-1. The fiducial marker positions were within 2.0 mm at all GRSs. Similarly, in the clinical study, the mean SNR, CNR, and SSIM decreased from 50.4 to 13.7, from 24.2 to 6.0, and from 0.92 to 0.73, respectively. The mean RMSEs were 2.0, 2.1, and 3.6 mm for the GRSs of 67, 100, and 200° min-1, respectively. We conclude that GRSs of 67 and 85° min-1 yield images of acceptable quality for 4D-CBCT in liver SBRT with fiducial markers.
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Affiliation(s)
- Yoshinobu Shimohigashi
- Department of Radiological Technology, Kumamoto University Hospital, Kumamoto, Japan; Graduate School of Health Sciences, Kumamoto University, Kumamoto, Japan.
| | - Fujio Araki
- Department of Health Sciences, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan
| | - Masato Maruyama
- Department of Radiological Technology, Kumamoto University Hospital, Kumamoto, Japan
| | - Keisuke Yonemura
- Department of Radiological Technology, Kumamoto University Hospital, Kumamoto, Japan
| | - Yuji Nakaguchi
- Department of Radiological Technology, Kumamoto University Hospital, Kumamoto, Japan
| | - Yudai Kai
- Department of Radiological Technology, Kumamoto University Hospital, Kumamoto, Japan
| | - Ryo Toya
- Department of Radiation Oncology, Kumamoto University Hospital, Kumamoto, Japan
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Yuasa Y, Shiinoki T, Fujimoto K, Hanazawa H, Uehara T, Koike M, Shibuya K. Effect of gantry speed on accuracy of extracted target motion trajectories and image quality in 4D-CBCT: phantom study. Biomed Phys Eng Express 2017. [DOI: 10.1088/2057-1976/aa8ade] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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Nakano M, Haga A, Kotoku J, Magome T, Masutani Y, Hanaoka S, Kida S, Nakagawa K. Cone-beam CT reconstruction for non-periodic organ motion using time-ordered chain graph model. Radiat Oncol 2017; 12:145. [PMID: 28870227 PMCID: PMC5584034 DOI: 10.1186/s13014-017-0879-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2017] [Accepted: 08/23/2017] [Indexed: 11/22/2022] Open
Abstract
Purpose The purpose of this study is to introduce the new concept of a four-dimensional (4D) cone-beam computed tomography (CBCT) reconstruction approach for non-periodic organ motion in cooperation with the time-ordered chain graph model (TCGM) and to compare it with previously developed methods such as total variation-based compressed sensing (TVCS) and prior-image constrained compressed sensing (PICCS). Materials and Methods Our proposed reconstruction is based on a model including the constraint originating from the images of neighboring time phases. Namely, the reconstructed time-series images depend on each other in this TCGM scheme, and the time-ordered images are concurrently reconstructed in the iterative reconstruction approach. In this study, iterative reconstruction with the TCGM was carried out with 90° projection ranges. The images reconstructed by the TCGM were compared with the images reconstructed by TVCS (200° projection ranges) and PICCS (90° projection ranges). Two kinds of projection data sets–an elliptic-cylindrical digital phantom and two clinical patients’ data–were used. For the digital phantom, an air sphere was contained and virtually moved along the longitudinal axis by 3 cm/30 s and 3 cm/60 s; the temporal resolution was evaluated by measuring the penumbral width of the air sphere. The clinical feasibility of the non-periodic time-ordered 4D CBCT image reconstruction was examined with the patient data in the pelvic region. Results In the evaluation of the digital-phantom reconstruction, the penumbral widths of the TCGM yielded the narrowest result; the results obtained by PICCS and TCGM using 90° projection ranges were 2.8% and 18.2% for 3 cm/30 s, and 5.0% and 23.1% for 3 cm/60 s narrower than that of TVCS using 200° projection ranges. This suggests that the TCGM has a better temporal resolution, whereas PICCS seems similar to TVCS. These reconstruction methods were also compared using patients’ projection data sets. Although all three reconstruction results showed motion related to rectal gas or stool, the result obtained by the TCGM was visibly clearer with less blurring. Conclusion The TCGM is a feasible approach to visualize non-periodic organ motion. The digital-phantom results demonstrated that the proposed method provides 4D image series with a better temporal resolution compared to TVCS and PICCS. The clinical patients’ results also showed that the present method enables us to visualize motion related to rectal gas and flatus in the rectum.
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Affiliation(s)
- Masahiro Nakano
- Department of Radiology, The University of Tokyo Hospital, Bunkyo-ku, Tokyo, 113-8655, Japan.,Department of Radiation Oncology, The Cancer Institute Hospital, Japanese Foundation for Cancer Research, Koto-ku, Tokyo, 135-8550, Japan
| | - Akihiro Haga
- Department of Radiology, The University of Tokyo Hospital, Bunkyo-ku, Tokyo, 113-8655, Japan.
| | - Jun'ichi Kotoku
- Faculty of Medical Technology, Teikyo University, Itabashi-ku, Tokyo, 173-8605, Japan
| | - Taiki Magome
- Faculty of Health Sciences, Komazawa University, Setagaya-ku, Tokyo, 154-8525, Japan
| | - Yoshitaka Masutani
- Faculty of Information Science, Hiroshima-City University, Hiroshima, 731-3194, Japan
| | - Shouhei Hanaoka
- Department of Radiology, The University of Tokyo Hospital, Bunkyo-ku, Tokyo, 113-8655, Japan
| | - Satoshi Kida
- School of Medicine, Gunma University, Maebashi, 371-8511, Japan
| | - Keiichi Nakagawa
- Department of Radiology, The University of Tokyo Hospital, Bunkyo-ku, Tokyo, 113-8655, Japan
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Harris W, Zhang Y, Yin FF, Ren L. Estimating 4D-CBCT from prior information and extremely limited angle projections using structural PCA and weighted free-form deformation for lung radiotherapy. Med Phys 2017; 44:1089-1104. [PMID: 28079267 DOI: 10.1002/mp.12102] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2016] [Revised: 11/18/2016] [Accepted: 01/04/2017] [Indexed: 12/25/2022] Open
Abstract
PURPOSE To investigate the feasibility of using structural-based principal component analysis (PCA) motion-modeling and weighted free-form deformation to estimate on-board 4D-CBCT using prior information and extremely limited angle projections for potential 4D target verification of lung radiotherapy. METHODS A technique for lung 4D-CBCT reconstruction has been previously developed using a deformation field map (DFM)-based strategy. In the previous method, each phase of the 4D-CBCT was generated by deforming a prior CT volume. The DFM was solved by a motion model extracted by a global PCA and free-form deformation (GMM-FD) technique, using a data fidelity constraint and deformation energy minimization. In this study, a new structural PCA method was developed to build a structural motion model (SMM) by accounting for potential relative motion pattern changes between different anatomical structures from simulation to treatment. The motion model extracted from planning 4DCT was divided into two structures: tumor and body excluding tumor, and the parameters of both structures were optimized together. Weighted free-form deformation (WFD) was employed afterwards to introduce flexibility in adjusting the weightings of different structures in the data fidelity constraint based on clinical interests. XCAT (computerized patient model) simulation with a 30 mm diameter lesion was simulated with various anatomical and respiratory changes from planning 4D-CT to on-board volume to evaluate the method. The estimation accuracy was evaluated by the volume percent difference (VPD)/center-of-mass-shift (COMS) between lesions in the estimated and "ground-truth" on-board 4D-CBCT. Different on-board projection acquisition scenarios and projection noise levels were simulated to investigate their effects on the estimation accuracy. The method was also evaluated against three lung patients. RESULTS The SMM-WFD method achieved substantially better accuracy than the GMM-FD method for CBCT estimation using extremely small scan angles or projections. Using orthogonal 15° scanning angles, the VPD/COMS were 3.47 ± 2.94% and 0.23 ± 0.22 mm for SMM-WFD and 25.23 ± 19.01% and 2.58 ± 2.54 mm for GMM-FD among all eight XCAT scenarios. Compared to GMM-FD, SMM-WFD was more robust against reduction of the scanning angles down to orthogonal 10° with VPD/COMS of 6.21 ± 5.61% and 0.39 ± 0.49 mm, and more robust against reduction of projection numbers down to only 8 projections in total for both orthogonal-view 30° and orthogonal-view 15° scan angles. SMM-WFD method was also more robust than the GMM-FD method against increasing levels of noise in the projection images. Additionally, the SMM-WFD technique provided better tumor estimation for all three lung patients compared to the GMM-FD technique. CONCLUSION Compared to the GMM-FD technique, the SMM-WFD technique can substantially improve the 4D-CBCT estimation accuracy using extremely small scan angles and low number of projections to provide fast low dose 4D target verification.
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Affiliation(s)
- Wendy Harris
- Medical Physics Graduate Program, Duke University, Durham, NC, 27705, USA
| | - You Zhang
- Medical Physics Graduate Program, Duke University, Durham, NC, 27705, USA
| | - Fang-Fang Yin
- Medical Physics Graduate Program, Duke University, Durham, NC, 27705, USA.,Department of Radiation Oncology, Duke University Medical Center, Durham, NC, 27710, USA
| | - Lei Ren
- 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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