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Lauria M, Miller C, Singhrao K, Lewis J, Lin W, O'Connell D, Naumann L, Stiehl B, Santhanam A, Boyle P, Raldow AC, Goldin J, Barjaktarevic I, Low DA. Motion compensated cone-beam CT reconstruction using an a priorimotion model from CT simulation: a pilot study. Phys Med Biol 2024; 69:075022. [PMID: 38452385 DOI: 10.1088/1361-6560/ad311b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2023] [Accepted: 03/07/2024] [Indexed: 03/09/2024]
Abstract
Objective. To combat the motion artifacts present in traditional 4D-CBCT reconstruction, an iterative technique known as the motion-compensated simultaneous algebraic reconstruction technique (MC-SART) was previously developed. MC-SART employs a 4D-CBCT reconstruction to obtain an initial model, which suffers from a lack of sufficient projections in each bin. The purpose of this study is to demonstrate the feasibility of introducing a motion model acquired during CT simulation to MC-SART, coined model-based CBCT (MB-CBCT).Approach. For each of 5 patients, we acquired 5DCTs during simulation and pre-treatment CBCTs with a simultaneous breathing surrogate. We cross-calibrated the 5DCT and CBCT breathing waveforms by matching the diaphragms and employed the 5DCT motion model parameters for MC-SART. We introduced the Amplitude Reassignment Motion Modeling technique, which measures the ability of the model to control diaphragm sharpness by reassigning projection amplitudes with varying resolution. We evaluated the sharpness of tumors and compared them between MB-CBCT and 4D-CBCT. We quantified sharpness by fitting an error function across anatomical boundaries. Furthermore, we compared our MB-CBCT approach to the traditional MC-SART approach. We evaluated MB-CBCT's robustness over time by reconstructing multiple fractions for each patient and measuring consistency in tumor centroid locations between 4D-CBCT and MB-CBCT.Main results. We found that the diaphragm sharpness rose consistently with increasing amplitude resolution for 4/5 patients. We observed consistently high image quality across multiple fractions, and observed stable tumor centroids with an average 0.74 ± 0.31 mm difference between the 4D-CBCT and MB-CBCT. Overall, vast improvements over 3D-CBCT and 4D-CBCT were demonstrated by our MB-CBCT technique in terms of both diaphragm sharpness and overall image quality.Significance. This work is an important extension of the MC-SART technique. We demonstrated the ability ofa priori5DCT models to provide motion compensation for CBCT reconstruction. We showed improvements in image quality over both 4D-CBCT and the traditional MC-SART approach.
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Affiliation(s)
- Michael Lauria
- UCLA, Department of Radiation Oncology, Los Angeles, CA, United States of America
| | - Claudia Miller
- UCLA, Department of Radiation Oncology, Los Angeles, CA, United States of America
| | - Kamal Singhrao
- Brigham and Women's Hospital, Dana Farber Cancer Institute and Harvard Medical School, Department of Radiation Oncology, Boston, MA, United States of America
| | - John Lewis
- Cedars-Sinai Medical Center, Department of Radiation Oncology, Los Angeles, CA, United States of America
| | - Weicheng Lin
- UCLA, Department of Radiation Oncology, Los Angeles, CA, United States of America
| | - Dylan O'Connell
- UCLA, Department of Radiation Oncology, Los Angeles, CA, United States of America
| | - Louise Naumann
- UCLA, Department of Radiation Oncology, Los Angeles, CA, United States of America
| | - Bradley Stiehl
- Cedars-Sinai Medical Center, Department of Radiation Oncology, Los Angeles, CA, United States of America
| | - Anand Santhanam
- UCLA, Department of Radiation Oncology, Los Angeles, CA, United States of America
| | - Peter Boyle
- UCLA, Department of Radiation Oncology, Los Angeles, CA, United States of America
| | - Ann C Raldow
- UCLA, Department of Radiation Oncology, Los Angeles, CA, United States of America
| | - Jonathan Goldin
- UCLA, Department of Radiological Sciences, Los Angeles, CA, United States of America
| | - Igor Barjaktarevic
- UCLA, Department of Pulmonary and Critical Care Medicine, Los Angeles, CA, United States of America
| | - Daniel A Low
- UCLA, Department of Radiation Oncology, Los Angeles, CA, United States of America
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Lauria M, Stiehl B, Santhanam A, O’Connell D, Naumann L, McNitt-Gray M, Raldow A, Goldin J, Barjaktarevic I, Low DA. An analysis of the regional heterogeneity in tissue elasticity in lung cancer patients with COPD. Front Med (Lausanne) 2023; 10:1151867. [PMID: 37840998 PMCID: PMC10575648 DOI: 10.3389/fmed.2023.1151867] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Accepted: 09/08/2023] [Indexed: 10/17/2023] Open
Abstract
Purpose Recent advancements in obtaining image-based biomarkers from CT images have enabled lung function characterization, which could aid in lung interventional planning. However, the regional heterogeneity in these biomarkers has not been well documented, yet it is critical to several procedures for lung cancer and COPD. The purpose of this paper is to analyze the interlobar and intralobar heterogeneity of tissue elasticity and study their relationship with COPD severity. Methods We retrospectively analyzed a set of 23 lung cancer patients for this study, 14 of whom had COPD. For each patient, we employed a 5DCT scanning protocol to obtain end-exhalation and end-inhalation images and semi-automatically segmented the lobes. We calculated tissue elasticity using a biomechanical property estimation model. To obtain a measure of lobar elasticity, we calculated the mean of the voxel-wise elasticity values within each lobe. To analyze interlobar heterogeneity, we defined an index that represented the properties of the least elastic lobe as compared to the rest of the lobes, termed the Elasticity Heterogeneity Index (EHI). An index of 0 indicated total homogeneity, and higher indices indicated higher heterogeneity. Additionally, we measured intralobar heterogeneity by calculating the coefficient of variation of elasticity within each lobe. Results The mean EHI was 0.223 ± 0.183. The mean coefficient of variation of the elasticity distributions was 51.1% ± 16.6%. For mild COPD patients, the interlobar heterogeneity was low compared to the other categories. For moderate-to-severe COPD patients, the interlobar and intralobar heterogeneities were highest, showing significant differences from the other groups. Conclusion We observed a high level of lung tissue heterogeneity to occur between and within the lobes in all COPD severity cases, especially in moderate-to-severe cases. Heterogeneity results demonstrate the value of a regional, function-guided approach like elasticity for procedures such as surgical decision making and treatment planning.
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Affiliation(s)
- Michael Lauria
- Department of Radiation Oncology, University of California, Los Angeles, Los Angeles, CA, United States
| | - Bradley Stiehl
- Department of Radiation Oncology, University of California, Los Angeles, Los Angeles, CA, United States
| | - Anand Santhanam
- Department of Radiation Oncology, University of California, Los Angeles, Los Angeles, CA, United States
| | - Dylan O’Connell
- Department of Radiation Oncology, University of California, Los Angeles, Los Angeles, CA, United States
| | - Louise Naumann
- Department of Radiation Oncology, University of California, Los Angeles, Los Angeles, CA, United States
| | - Michael McNitt-Gray
- Department of Radiological Sciences, University of California, Los Angeles, Los Angeles, CA, United States
| | - Ann Raldow
- Department of Radiation Oncology, University of California, Los Angeles, Los Angeles, CA, United States
| | - Jonathan Goldin
- Department of Radiological Sciences, University of California, Los Angeles, Los Angeles, CA, United States
| | - Igor Barjaktarevic
- Division of Pulmonary and Critical Care Medicine, University of California, Los Angeles, Los Angeles, CA, United States
| | - Daniel A. Low
- Department of Radiation Oncology, University of California, Los Angeles, Los Angeles, CA, United States
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