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Alekseychuk VO, Kupsch A, Plotzki D, Bellon C, Bruno G. Simulation-Assisted Augmentation of Missing Wedge and Region-of-Interest Computed Tomography Data. J Imaging 2023; 10:11. [PMID: 38248996 PMCID: PMC10817004 DOI: 10.3390/jimaging10010011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2023] [Revised: 12/19/2023] [Accepted: 12/22/2023] [Indexed: 01/23/2024] Open
Abstract
This study reports a strategy to use sophisticated, realistic X-ray Computed Tomography (CT) simulations to reduce Missing Wedge (MW) and Region-of-Interest (RoI) artifacts in FBP (Filtered Back-Projection) reconstructions. A 3D model of the object is used to simulate the projections that include the missing information inside the MW and outside the RoI. Such information augments the experimental projections, thereby drastically improving the reconstruction results. An X-ray CT dataset of a selected object is modified to mimic various degrees of RoI and MW problems. The results are evaluated in comparison to a standard FBP reconstruction of the complete dataset. In all cases, the reconstruction quality is significantly improved. Small inclusions present in the scanned object are better localized and quantified. The proposed method has the potential to improve the results of any CT reconstruction algorithm.
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Affiliation(s)
- Vladimir O. Alekseychuk
- Institute of Computer Vision & Remote Sensing, Technical University Berlin, Marchstr. 23, 10587 Berlin, Germany;
- Vision in X Industrial Imaging GmbH, Johann-Hittorf-Str. 8, 12489 Berlin, Germany
| | - Andreas Kupsch
- Bundesanstalt für Materialforschung und -Prüfung (BAM), Unter den Eichen 87, 12205 Berlin, Germany; (D.P.); (G.B.)
| | - David Plotzki
- Bundesanstalt für Materialforschung und -Prüfung (BAM), Unter den Eichen 87, 12205 Berlin, Germany; (D.P.); (G.B.)
- Felix Bloch Institute for Solid State Physics, University Leipzig, 04103 Leipzig, Germany
| | - Carsten Bellon
- Bundesanstalt für Materialforschung und -Prüfung (BAM), Unter den Eichen 87, 12205 Berlin, Germany; (D.P.); (G.B.)
| | - Giovanni Bruno
- Bundesanstalt für Materialforschung und -Prüfung (BAM), Unter den Eichen 87, 12205 Berlin, Germany; (D.P.); (G.B.)
- Institute of Physics and Astronomy, University Potsdam, Karl-Liebknecht-Str. 24–25, 14476 Potsdam, Germany
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Ihdayhid AR, Yeats B, Vernon M, Sathananthan J, Webb J, Leipsic J, Shetty S, Thourani VH, Yong G, De-Juan-Pardo E, Dasi LP. Computed Tomography-Guided Computational Modeling to Guide Treatment in Aortic Stenosis With Extremely Large Aortic Annulus. Struct Heart 2023; 7:100168. [PMID: 37273860 PMCID: PMC10236797 DOI: 10.1016/j.shj.2023.100168] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/24/2022] [Revised: 02/05/2023] [Accepted: 02/07/2023] [Indexed: 06/06/2023]
Affiliation(s)
- Abdul Rahman Ihdayhid
- Department of Cardiology, Fiona Stanley Hospital, Perth, Australia
- Harry Perkins Institute of Medical Research, Curtin University, Perth, Australia
| | - Breandan Yeats
- Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia, USA
| | - Michael Vernon
- T3mPLATE, Harry Perkins Institute of Medical Research, QEII Medical Centre and UWA Centre for Medical Research, The University of Western Australia, Perth, Australia
- School of Engineering, The University of Western Australia, Perth, Australia
| | | | - John Webb
- Centre for Cardiovascular Innovation, St. Paul’s Hospital, Vancouver, Canada
| | - Jonathon Leipsic
- Centre for Cardiovascular Innovation, St. Paul’s Hospital, Vancouver, Canada
| | - Sharad Shetty
- Department of Cardiology, Fiona Stanley Hospital, Perth, Australia
- Harry Perkins Institute of Medical Research, Curtin University, Perth, Australia
| | - Vinod H. Thourani
- Department of Cardiovascular Surgery, Marcus Valve Center, Piedmont Heart Institute, Atlanta, Georgia, USA
| | - Gerald Yong
- Department of Cardiology, Fiona Stanley Hospital, Perth, Australia
- Harry Perkins Institute of Medical Research, Curtin University, Perth, Australia
| | - Elena De-Juan-Pardo
- T3mPLATE, Harry Perkins Institute of Medical Research, QEII Medical Centre and UWA Centre for Medical Research, The University of Western Australia, Perth, Australia
- School of Engineering, The University of Western Australia, Perth, Australia
| | - Lakshmi P. Dasi
- Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia, USA
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Dove APH, Jaboin JJ, Block JJ, Shinohara ET, Kirschner AN. Academic patterns of practice regarding CT simulation scans and radiology review. J Med Imaging Radiat Sci 2022; 53:659-663. [PMID: 36216733 PMCID: PMC10230158 DOI: 10.1016/j.jmir.2022.09.015] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2022] [Revised: 08/25/2022] [Accepted: 09/20/2022] [Indexed: 11/29/2022]
Abstract
OBJECTIVE Currently, there are no consensus guidelines about handling incidental radiological findings on radiotherapy planning CT simulation scans. Retrospective studies analyzing incidental findings on CT simulations show a small, but not insignificant, rate of both oncologic and non-oncologic findings. These findings may have medico-legal, financial, and clinical implications. Given a lack of guidelines, we obtained a formal survey of multiple academic institutions to evaluate how CT simulations are handled in regard to incidental findings. METHODS A formal survey was developed consisting of 12 questions related to institutional practices regarding CT simulation scans. From 7/18/21 to 8/27/21 and 5/6/22 to 5/24/22, the survey was administered electronically by REDCap to key personnel at Academic Radiation Oncology Programs identified through the American Society for Radiation Oncology (ASTRO) with inclusion criteria including an active ACGME approved Radiation Oncology residency program. RESULTS In total, 88 academic radiation oncology programs were surveyed with total of 45 responses (51%). 1 out of 45 departments who responded has formal guidelines regarding workup of incidental findings. There is variability about sending CT simulation scans for official radiology review if an incidental finding is identified. CONCLUSIONS Based on a measurable rate of incidental findings on radiotherapy planning CT simulations and their possible implications, our survey illustrates a likely need for consensus recommendations for handling such findings to improve patient care and safety.
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Affiliation(s)
- Austin P H Dove
- Department of Radiation Oncology, Vanderbilt University Medical Center, Nashville, TN, 37232, USA.
| | - Jerry J Jaboin
- Department of Radiation Oncology, The University of Oklahoma Health Sciences Center, Oklahoma City, OK, 73104, USA
| | - John J Block
- Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN, 37232, USA
| | - Eric T Shinohara
- Department of Radiation Oncology, Vanderbilt University Medical Center, Nashville, TN, 37232, USA
| | - Austin N Kirschner
- Department of Radiation Oncology, Vanderbilt University Medical Center, Nashville, TN, 37232, USA
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Polizzi M, Kim S, Rosu-Bubulac M. A comprehensive quality assurance procedure for 4D CT commissioning and periodic QA. J Appl Clin Med Phys 2022; 23:e13764. [PMID: 36057944 DOI: 10.1002/acm2.13764] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Revised: 06/21/2022] [Accepted: 08/04/2022] [Indexed: 11/11/2022] Open
Abstract
PURPOSE The 4D computed tomography (CT) simulation is an essential procedure for tumors exhibiting breathing-induced motion. However, to date there are no established guidelines to assess the characteristics of existing systems and to describe meaningful performance. We propose a commissioning quality assurance (QA) protocol consisting of measurements and acquisitions that assess the mechanical and computational operation for 4D CT with both phase and amplitude-based reconstructions, for regular and irregular respiratory patterns. METHODS The 4D CT scans of a QUASAR motion phantom were acquired for both regular and irregular breathing patterns. The hardware consisted of the Canon Aquilion Exceed LB CT scanner used in conjunction with the Anzai laser motion monitoring system. The nominal machine performance and reconstruction were demonstrated with measurements using regular breathing patterns. For irregular breathing patterns the performance was quantified through the analysis of the target motion in the superior and inferior directions, and the volume of the internal target volume (ITV). Acquisitions were performed using multiple pitches and the reconstructions were performed using both phase and amplitude-based binning. RESULTS The target was accurately captured during regular breathing. For the irregular breathing, the measured ITV exceeded the nominal ITV parameters in all scenarios, but all deviations were less than the reconstructed slice thickness. The mismatch between the nominal pitch and the actual breathing rate did not affect markedly the size of the ITV. Phase and normalized amplitude binning performed similarly. CONCLUSIONS We demonstrated a framework for measuring and quantifying the initial performance of 4D CT simulation scans that can also be applied during periodic QAs. The regular breathing provided confidence that the hardware and the software between the systems performs adequately. The irregular breathing data suggest that the system may be expected to capture in excess the target motion and geometry, but the deviation is expected to be within the slice thickness.
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Affiliation(s)
- Mitchell Polizzi
- Department of Radiation Oncology, Virginia Commonwealth University, Richmond, Virginia, USA
| | - Siyong Kim
- Department of Radiation Oncology, Virginia Commonwealth University, Richmond, Virginia, USA
| | - Mihaela Rosu-Bubulac
- Department of Radiation Oncology, Virginia Commonwealth University, Richmond, Virginia, USA
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Miller J, DiMaso L, Huang‐Vredevoogd J, Shah J, Lawless M. Characterization of size-specific effects during dual-energy CT material decomposition of non-iodine materials. J Appl Clin Med Phys 2021; 22:168-176. [PMID: 34783427 PMCID: PMC8664138 DOI: 10.1002/acm2.13471] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Revised: 10/05/2021] [Accepted: 10/20/2021] [Indexed: 12/11/2022] Open
Abstract
PURPOSE The dual-energy CT (DECT) LiverVNC application class in the Siemens Syngo.via software has been used to perform non-iodine material decompositions. However, the LiverVNC application is designed with an optional size-specific calibration based on iodine measurements. This work investigates the effects of this iodine-based size-specific calibration on non-iodine material decomposition and benchmarks alternative methods for size-specific calibrations. METHODS Calcium quantification was performed with split-filter and sequential-scanning DECT techniques on the Siemens SOMATOM Definition Edge CT scanner. Images were acquired of the Gammex MECT abdomen and head phantom containing calcium inserts with concentrations ranging from 50-300 mgCa/ml. Several workflows were explored investigating the effects of size-specific dual-energy ratios (DERs) and the beam hardening correction (BHC) function in the LiverVNC application. Effects of image noise were also investigated by varying CTDIvol and using iterative reconstruction (ADMIRE). RESULTS With the default BHC activated, Syngo.via underestimated the calcium concentrations in the abdomen for sequential-scanning acquisitions, leaving residual calcium in the virtual non-contrast images and underestimating calcium in the enhancement images for all DERs. Activation of the BHC with split-filter images resulted in a calcium over- or underestimation depending on the DER. With the BHC inactivated, the use of a single DER led to an under- or overestimate of calcium concentration depending on phantom size and DECT modality. Optimal results were found with BHC inactivated using size-specific DERs. CTDIvol levels and ADMIRE had no significant effect on results. CONCLUSION When performing non-iodine material decomposition in the LiverVNC application class, it is important to understand the implications of the BHC function and to account for patient size appropriately. The BHC in the LiverVNC application is specific to iodine and leads to inaccurate quantification of other materials. The inaccuracies can be overcome by deactivating the BHC function and using size-specific DERs, which provided the most accurate calcium quantification.
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Affiliation(s)
- Jessica Miller
- Department of Human OncologyUniversity of WisconsinMadisonWisconsinUSA
- Department of Medical PhysicsUniversity of WisconsinMadisonWisconsinUSA
| | - Lianna DiMaso
- Department of Human OncologyUniversity of WisconsinMadisonWisconsinUSA
| | - Jessie Huang‐Vredevoogd
- Department of Human OncologyUniversity of WisconsinMadisonWisconsinUSA
- Department of Medical PhysicsUniversity of WisconsinMadisonWisconsinUSA
| | - Jainil Shah
- Siemens Medical Solutions USA, Inc.MalvernPennsylvaniaUSA
| | - Michael Lawless
- Department of Human OncologyUniversity of WisconsinMadisonWisconsinUSA
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6
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Skinner L, Knopp R, Wang YC, Dubrowski P, Bush KK, Limmer A, Trakul N, Million L, Marquez CM, Yu AS. CT-less electron radiotherapy simulation and planning with a consumer 3D camera. J Appl Clin Med Phys 2021; 22:128-136. [PMID: 34042253 PMCID: PMC8292688 DOI: 10.1002/acm2.13283] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Revised: 04/15/2021] [Accepted: 04/20/2021] [Indexed: 11/17/2022] Open
Abstract
Purpose Electron radiation therapy dose distributions are affected by irregular body surface contours. This study investigates the feasibility of three‐dimensional (3D) cameras to substitute for the treatment planning computerized tomography (CT) scan by capturing the body surfaces to be treated for accurate electron beam dosimetry. Methods Dosimetry was compared for six electron beam treatments to the nose, toe, eye, and scalp using full CT scan, CT scan with Hounsfield Unit (HU) overridden to water (mimic 3D camera cases), and flat‐phantom techniques. Radiation dose was prescribed to a depth on the central axis per physician’s order, and the monitor units (MUs) were calculated. The 3D camera spatial accuracy was evaluated by comparing the 3D surface of a head phantom captured by a 3D camera and that generated with the CT scan in the treatment planning system. A clinical case is presented, and MUs were calculated using the 3D camera body contour with HU overridden to water. Results Across six cases the average change in MUs between the full CT and the 3Dwater (CT scan with HU overridden to water) calculations was 1.3% with a standard deviation of 1.0%. The corresponding hotspots had a mean difference of 0.4% and a standard deviation of 1.9%. The 3D camera captured surface of a head phantom was found to have a 0.59 mm standard deviation from the surface derived from the CT scan. In‐vivo dose measurements (213 ± 8 cGy) agreed with the 3D‐camera planned dose of 209 ± 6 cGy, compared to 192 ± 6 cGy for the flat‐phantom calculation (same MUs). Conclusions Electron beam dosimetry is affected by irregular body surfaces. 3D cameras can capture irregular body contours which allow accurate dosimetry of electron beam treatment as an alternative to costly CT scans with no extra exposure to radiation. Tools and workflow for clinical implementation are provided.
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Affiliation(s)
| | - Rick Knopp
- Stanford Radiation oncology, Palo Alto, CA, USA
| | | | | | - Karl K Bush
- Stanford Radiation oncology, Palo Alto, CA, USA
| | | | | | | | | | - Amy S Yu
- Stanford Radiation oncology, Palo Alto, CA, USA
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Sardaro A, Turi B, Bardoscia L, Ferrari C, Rubini G, Calabrese A, Ammirati F, Grillo A, Leo A, Lorusso F, Santorsola A, Stabile Ianora AA, Scardapane A. The Role of Multiparametric Magnetic Resonance in Volumetric Modulated Arc Radiation Therapy Planning for Prostate Cancer Recurrence After Radical Prostatectomy: A Pilot Study. Front Oncol 2021; 10:603994. [PMID: 33585223 PMCID: PMC7874055 DOI: 10.3389/fonc.2020.603994] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2020] [Accepted: 11/26/2020] [Indexed: 12/25/2022] Open
Abstract
Background and Purpose Volumetric modulated arc radiotherapy (RT) has become pivotal in the treatment of prostate cancer recurrence (RPC) to optimize dose distribution and minimize toxicity, thanks to the high-precision delineation of prostate bed contours and organs at risk (OARs) under multiparametric magnetic resonance (mpMRI) guidance. We aimed to assess the role of pre-treatment mpMRI in ensuring target volume coverage and normal tissue sparing. Material and Methods Patients with post-prostatectomy RPC eligible for salvage RT were prospectively recruited to this pilot study. Image registration between planning CT scan and T2w pre-treatment mpMRI was performed. Two sets of volumes were outlined, and DWI images/ADC maps were used to facilitate precise gross tumor volume (GTV) delineation on morphological MRI scans. Two rival plans (mpMRI-based or not) were drawn up. Results Ten patients with evidence of RPC after prostatectomy were eligible. Preliminary data showed lower mpMRI-based clinical target volumes than CT-based RT planning (p = 0.0003): median volume difference 17.5 cm3. There were no differences in the boost volume coverage nor the dose delivered to the femoral heads and penile bulb, but median rectal and bladder V70Gy was 4% less (p = 0.005 and p = 0.210, respectively) for mpMRI-based segmentation. Conclusions mpMRI provides high-precision target delineation and improves the accuracy of RT planning for post-prostatectomy RPC, ensures better volume coverage with better OARs sparing and allows non-homogeneous dose distribution, with an aggressive dose escalation to the GTV. Randomized phase III trials and wider datasets are needed to fully assess the role of mpMRI in optimizing therapeutic strategies.
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Affiliation(s)
- Angela Sardaro
- Interdisciplinary Department of Medicine, Section of Radiology and Radiation Oncology, University of Bari "Aldo Moro", Bari, Italy
| | - Barbara Turi
- Radiation Oncology Unit, Azienda Ospedaliero-Universitaria Policlinico, Bari, Italy
| | - Lilia Bardoscia
- Radiation Therapy Unit, Department of Oncology and Advanced Technology, Azienda USL-IRCCS di Reggio Emilia, Reggio Emilia, Italy
| | - Cristina Ferrari
- Nuclear Medicine Unit, Interdisciplinary Department of Medicine, University of Bari Aldo Moro, Bari, Italy
| | - Giuseppe Rubini
- Nuclear Medicine Unit, Interdisciplinary Department of Medicine, University of Bari Aldo Moro, Bari, Italy
| | - Angela Calabrese
- Department of Radiology, IRCCS Istituto Tumori "Giovanni Paolo II", Bari, Italy
| | - Federica Ammirati
- Interdisciplinary Department of Medicine, Section of Radiology and Radiation Oncology, University of Bari "Aldo Moro", Bari, Italy
| | - Antonietta Grillo
- Radiation Oncology Unit, Azienda Ospedaliero-Universitaria Policlinico, Bari, Italy
| | - Annamaria Leo
- Radiation Oncology Unit, Azienda Ospedaliero-Universitaria Policlinico, Bari, Italy
| | | | - Antonio Santorsola
- Radiation Oncology Unit, Azienda Ospedaliero-Universitaria Policlinico, Bari, Italy
| | - Antonio Amato Stabile Ianora
- Interdisciplinary Department of Medicine, Section of Radiology and Radiation Oncology, University of Bari "Aldo Moro", Bari, Italy
| | - Arnaldo Scardapane
- Interdisciplinary Department of Medicine, Section of Radiology and Radiation Oncology, University of Bari "Aldo Moro", Bari, Italy
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Godfrey DJ, Stephens SJ, Marin D, Moravan MJ, Salama JK, Palta M. Seeing is believing: A roadmap for implementing bolus-tracked multiphasic CT simulation for ablative radiotherapy of abdominal malignancies. J Radiosurg SBRT 2021; 7:253-255. [PMID: 33898090 PMCID: PMC8055236] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Accepted: 12/11/2020] [Indexed: 06/12/2023]
Affiliation(s)
- Devon J Godfrey
- Department of Radiation Oncology, Box 3085, Duke University, Durham, NC 27710, USA
- Radiation Oncology Service, Durham VA Medical Center, 508 Fulton St, Durham, NC 27705, USA
| | - Sarah Jo Stephens
- Department of Radiation Oncology, Box 3085, Duke University, Durham, NC 27710, USA
| | - Daniele Marin
- Department of Radiology, Box 3808, Duke University, Durham, NC 27710, USA
| | - Michael J Moravan
- Radiation Oncology Service, St. Louis VA Medical Center, 915 N Grand Blvd., St. Louis, MO 63106, USA
| | - Joseph K Salama
- Department of Radiation Oncology, Box 3085, Duke University, Durham, NC 27710, USA
- Radiation Oncology Service, Durham VA Medical Center, 508 Fulton St, Durham, NC 27705, USA
| | - Manisha Palta
- Department of Radiation Oncology, Box 3085, Duke University, Durham, NC 27710, USA
- Radiation Oncology Service, Durham VA Medical Center, 508 Fulton St, Durham, NC 27705, USA
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Robins M, Solomon J, Hoye J, Smith T, Zheng Y, Ebner L, Choudhury KR, Samei E. Interchangeability between real and three-dimensional simulated lung tumors in computed tomography: an interalgorithm volumetry study. J Med Imaging (Bellingham) 2019; 5:035504. [PMID: 30840716 DOI: 10.1117/1.jmi.5.3.035504] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Accepted: 08/27/2018] [Indexed: 12/17/2022] Open
Abstract
Using hybrid datasets consisting of patient-derived computed tomography (CT) images with digitally inserted computational tumors, we establish volumetric interchangeability between real and computational lung tumors in CT. Pathologically-confirmed malignancies from 30 thoracic patient cases from the RIDER database were modeled. Tumors were either isolated or attached to lung structures. Patient images were acquired on one of two CT scanner models (Lightspeed 16 or VCT; GE Healthcare) using standard chest protocol. Real tumors were segmented and used to inform the size and shape of simulated tumors. Simulated tumors developed in Duke Lesion Tool (Duke University) were inserted using a validated image-domain insertion program. Four readers performed volume measurements using three commercial segmentation tools. We compared the volume estimation performance of segmentation tools between real tumors in actual patient CT images and corresponding simulated tumors virtually inserted into the same patient images (i.e., hybrid datasets). Comparisons involved (1) direct assessment of measured volumes and the standard deviation between simulated and real tumors across readers and tools, respectively, (2) multivariate analysis, involving segmentation tools, readers, tumor shape, and attachment, and (3) effect of local tumor environment on volume measurement. Volume comparison showed consistent trends (9% volumetric difference) between real and simulated tumors across all segmentation tools, readers, shapes, and attachments. Across all cases, readers, and segmentation tools, an intraclass correlation coefficient = 0.99 indicates that simulated tumors correlated strongly with real tumors ( p = 0.95 ). In addition, the impact of the local tumor environment on tumor volume measurement was found to have a segmentation tool-related influence. Strong agreement between simulated tumors modeled in this study compared to their real counterparts suggests a high degree of similarity. This indicates that, volumetrically, simulated tumors embedded into patient CT data can serve as reasonable surrogates to real patient data.
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Affiliation(s)
- Marthony Robins
- Carl E. Ravin Advanced Imaging Laboratories, Durham, North Carolina, United States.,Duke University, Medical Physics Graduate Program, Durham, North Carolina, United States.,Duke University Medical Center, Department of Radiology, Durham, North Carolina, United States
| | - Justin Solomon
- Carl E. Ravin Advanced Imaging Laboratories, Durham, North Carolina, United States.,Duke University, Medical Physics Graduate Program, Durham, North Carolina, United States.,Duke University Medical Center, Department of Radiology, Durham, North Carolina, United States
| | - Jocelyn Hoye
- Carl E. Ravin Advanced Imaging Laboratories, Durham, North Carolina, United States.,Duke University, Medical Physics Graduate Program, Durham, North Carolina, United States.,Duke University Medical Center, Department of Radiology, Durham, North Carolina, United States
| | - Taylor Smith
- Carl E. Ravin Advanced Imaging Laboratories, Durham, North Carolina, United States.,Duke University, Medical Physics Graduate Program, Durham, North Carolina, United States.,Duke University Medical Center, Department of Radiology, Durham, North Carolina, United States
| | - Yuese Zheng
- Carl E. Ravin Advanced Imaging Laboratories, Durham, North Carolina, United States.,Duke University Medical Center, Department of Radiology, Durham, North Carolina, United States
| | - Lukas Ebner
- Duke University Medical Center, Department of Radiology, Durham, North Carolina, United States.,University of Bern, Department of Diagnostic, Interventional and Pediatric Radiology Inselspital, Bern, Switzerland
| | - Kingshuk Roy Choudhury
- Carl E. Ravin Advanced Imaging Laboratories, Durham, North Carolina, United States.,Duke University Medical Center, Department of Radiology, Durham, North Carolina, United States
| | - Ehsan Samei
- Carl E. Ravin Advanced Imaging Laboratories, Durham, North Carolina, United States.,Duke University, Medical Physics Graduate Program, Durham, North Carolina, United States.,Duke University Medical Center, Department of Radiology, Durham, North Carolina, United States
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10
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Robins M, Solomon J, Richards T, Samei E. 3D task-transfer function representation of the signal transfer properties of low-contrast lesions in FBP- and iterative-reconstructed CT. Med Phys 2018; 45:4977-4985. [PMID: 30231193 DOI: 10.1002/mp.13205] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Revised: 08/21/2018] [Accepted: 09/13/2018] [Indexed: 01/23/2023] Open
Abstract
PURPOSE The purpose of this study was to investigate how accurately the task-transfer function (TTF) models the signal transfer properties of low-contrast features in a non-linear commercial CT system. METHODS A cylindrical phantom containing 24 anthropomorphic "physical" lesions was 3D printed. Lesions had two sizes (523, 2145 mm3 ), and two nominal radio-densities (80 and 100 HU at 120 kV). CT images were acquired on a commercial CT system (Siemens Flash scanner) at four dose levels (CTDIvol , 32 cm phantom:1.5, 3.0, 6.0, 22.0 mGy) and reconstructed using FBP and IR kernels (B31f, B45f, I31f\2, I44f\2). Low-contrast rod inserts (in-plane) and a slanted edge (z-direction) were used to estimate 3D-TTFs. CAD versions of lesions were blurred by the 3D-TTFs, virtually superimposed into corresponding phantom images, and compared to the physical lesions in terms of (a) a 4AFC visual assessment, (b) edge gradient, (c) size, and (d) shape similarity. Assessments 2 and 3 were based on an equivalence criterion D ¯ ≥ COV ¯ to determine if the natural variability COV ¯ in the physical lesions was greater or equal to the difference D ¯ between physical and simulated. Shape similarity was quantified via Sorensen-Dice coefficient (SDC). Comparisons were done for each lesion and for all imaging conditions. RESULTS The readers detected simulated lesions at a rate of 37.9 ± 3.1% (25% implies random guessing). Lesion edge blur and volume differences D ¯ were on average less than physical lesions' natural variability COV ¯ . The SDC (average ± SD) was 0.80 ± 0.13 (max of 1 possible). CONCLUSIONS The visual appearance, edge blur, size, and shape of simulated lesions were similar to the physical lesions, which suggests 3D-TTF models the low-contrast signal transfer properties of this non-linear CT system reasonably well.
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Affiliation(s)
- Marthony Robins
- Carl E. Ravin Advanced Imaging Laboratories, Department of Radiology, Medical Physics Graduate Program, Duke University Medical Center, Durham, NC, 27705, USA
| | - Justin Solomon
- Clinical Imaging Physics Group, Medical Physics Graduate Program, Duke University Medical Center, Durham, NC, 27705, USA
| | - Taylor Richards
- Carl E. Ravin Advanced Imaging Laboratories, Department of Radiology, Medical Physics Graduate Program, Duke University Medical Center, Durham, NC, 27705, USA
| | - Ehsan Samei
- Clinical Imaging Physics Group, Carl E. Ravin Advanced Imaging Laboratories, Department of Radiology, Departments of Physics, Biomedical Engineering, and Electrical and Computer Engineering, Medical Physics Graduate Program, Duke University Medical Center, Durham, NC, 27705, USA
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11
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Mekdash H, Shahine B, Jalbout W, Chehab C, Abdel Khalek H, Youssef B. A simple technique for an accurate shielding of the lungs during total body irradiation. Tech Innov Patient Support Radiat Oncol 2017; 3-4:13-18. [PMID: 32095561 PMCID: PMC7033769 DOI: 10.1016/j.tipsro.2017.07.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2017] [Revised: 06/08/2017] [Accepted: 07/10/2017] [Indexed: 11/20/2022] Open
Abstract
A total body irradiation technique based on CT simulation was newly introduced. This technique succeeded in reducing the length of the overall treatment session. This new technique reduced patient discomfort while ensuring accurate shielding of the lungs.
Purpose During total body irradiation (TBI), customized shielding blocks are positioned in front of the lungs to reduce radiation dose. The difficulty is to accurately position the blocks to cover the entire lungs. A new technique based on Computed Tomography (CT) simulation was developed to determine the exact position of lung blocks prior to treatment in order to decrease overall treatment time and reduce patient discomfort. Material/Methods Patients were CT simulated and lungs were contoured using a treatment planning system. Anteroposterior/posteroanterior (AP/PA) fields were designed with MLC aperture conforming to lung contours. The fields were used to represent the extent of the lungs, which was subsequently marked on the patient’s skin. The lung blocks were positioned with their shadow matching the lungs’ marks. Their position was radiographically verified prior to the delivery of each beam. To evaluate the efficiency of this technique, the treatment session time and the number of repeated attempts to correctly position the shielding blocks was recorded for each beam. Exact treatment times for patients treated with the old technique were not available and were hence approximated based on previous experience. Results We succeeded in positioning the shielding blocks from the first attempt in 10/12 beams. The position of the shielding blocks was adjusted only one time prior to treatment in 2/12 beams. These results are compared to an average of 3 attempts per beam for each patient using the conventional technique of trial and error. The average time of a treatment session was 29 min with a maximum of 41 min versus approximately 60 min in past treatments and a maximum of 120 min. Conclusion This new technique succeeded in reducing the length of the overall treatment session of the conventional TBI procedure and hence reduced patient discomfort while ensuring accurate shielding of the lungs.
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Jenkins C, Xing L, Yu A. Using a handheld stereo depth camera to overcome limited field-of-view in simulation imaging for radiation therapy treatment planning. Med Phys 2017; 44:1857-1864. [PMID: 28295413 DOI: 10.1002/mp.12207] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2016] [Revised: 03/03/2017] [Accepted: 03/03/2017] [Indexed: 11/11/2022] Open
Abstract
PURPOSE A correct body contour is essential for reliable treatment planning in radiation therapy. While modern medical imaging technologies provide highly accurate patient modeling, there are times when a patient's anatomy cannot be fully captured or there is a lack of easy access to computed tomography (CT) simulation. Here, we provide a practical solution to the surface contour truncation problem by using a handheld stereo depth camera (HSDC) to obtain the missing surface anatomy and a surface-surface image registration to stich the surface data into the CT dataset for treatment planning. METHODS For a subject with truncated simulation CT images, a HSDC is used to capture the surface information of the truncated anatomy. A mesh surface model is created using a software tool provided by the camera manufacturer. A surface-to-surface registration technique is used to merge the mesh model with the CT and fill in the missing surface information thereby obtaining a complete surface model of the subject. To evaluate the accuracy of the proposed approach, experiments were performed with the following steps. First, we selected three previously treated patients and fabricated a phantom mimicking each patient using the corresponding CT images and a 3D printer. Second, we removed part of the CT images of each patient to create hypothetical cases with image truncations. Next, a HSDC was used to image the 3D-printed phantoms and the HSDC-derived surface models were registered with the hypothetically truncated CT images. The contours obtained using the approach were then compared with the ground truth contours derived from the original simulation CT without image truncation. The distance between the two contours was calculated in order to evaluate the accuracy of the method. Finally, the dosimetric impact of the approach is assessed by comparing the volume within the 95% isodose line and global maximum dose (Dmax ) computed based on the two surface contours for the breast case that exhibited the largest contour variation in the treated breast. RESULTS A systematic strategy of using a 3D HSDC to compensate for missing surface information caused by the truncation of CT images was established. Our study showed that the proposed technique was able to reliably provide the full contours for treatment planning in the case of severe CT image truncation(s). The root-mean-square error for the registration between the aligned HDSC surface model and the ground truth data was found to be 2.1 mm. The average distance between the two models was 0.4 ± 1.7 mm (mean ± SD). Maximum deviations occurred in areas of high concavity or when the skin was close to the couch. The breast tissue covered by 95% isodose line decreased by 3% and Dmax increased by 0.2% with the use of the HSDC model. CONCLUSIONS The use of HSDC for obtaining missing surface data during simulation has a number of advantages, such as, ease of use, low cost, and no additional ionizing radiation. It may provide a clinically practical solution to deal with the longstanding problem of CT image truncations in radiation therapy treatment planning.
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Affiliation(s)
- Cesare Jenkins
- Departments of Radiation Oncology, Stanford University, Stanford, CA, 94305, USA.,Departments of Mechanical Engineering, Stanford University, Stanford, CA, 94305, USA
| | - Lei Xing
- Departments of Radiation Oncology, Stanford University, Stanford, CA, 94305, USA
| | - Amy Yu
- Departments of Radiation Oncology, Stanford University, Stanford, CA, 94305, USA
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Heydarheydari S, Farshchian N, Haghparast A. Influence of the contrast agents on treatment planning dose calculations of prostate and rectal cancers. Rep Pract Oncol Radiother 2016; 21:441-6. [PMID: 27489514 DOI: 10.1016/j.rpor.2016.04.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2016] [Revised: 03/07/2016] [Accepted: 04/13/2016] [Indexed: 01/22/2023] Open
Abstract
AIM The aim of the present study is to quantify differences in dose calculations caused by using CA and determine if the resulting differences are clinically significant. BACKGROUND The influence of contrast agents (CA) on radiation dose calculations must be taken into account in treatment planning. MATERIALS AND METHODS Eleven patients with pelvic cancers were included in this study and two sets of CTs were taken for each patient (without and with CA) in the same position and coordinates. Both sets of images were transferred to the DosiSoft ISOgray treatment planning system for contouring and calculating the dose distribution and monitor units (MUs) with Collapsed Cone and Superposition algorithms, respectively. All plans were generated on pre-contrast CT and subsequently copied to the post-contrast CT. Radiation dose calculations from the two sets of CTs were compared using a paired sample t-test. RESULTS The results showed a statistically insignificant difference between pre- and post-contrast CT treatment plans for target volume and OARs (p > 0.05), except bladder organ in the prostate region (p < 0.05) but the relative mean dose and MU differences were less than 2% in any patient for 18 MV photon beam. CONCLUSIONS Treatment planning on contrasted images generally showed a lower radiation dose to both target volume and OARs than plans on non-contrasted images. The results of this research showed that the small radiation dose differences between the plans for the CT scans with and without CA seem to be clinically insignificant; therefore, contrast-enhanced CT can be used for both target delineation and treatment planning of prostate and rectal cancers.
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Affiliation(s)
- Sahel Heydarheydari
- Department of Biomedical Physics and Engineering, Faculty of Medicine, Kermanshah University of Medical Sciences, Kermanshah, Iran
| | - Negin Farshchian
- Department of Radiation Oncology, Faculty of Medicine, Kermanshah University of Medical Sciences, Kermanshah, Iran
| | - Abbas Haghparast
- Department of Biomedical Physics and Engineering, Faculty of Medicine, Kermanshah University of Medical Sciences, Kermanshah, Iran
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