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Her EJ, Haworth A, Reynolds HM, Sun Y, Kennedy A, Panettieri V, Bangert M, Williams S, Ebert MA. Voxel-level biological optimisation of prostate IMRT using patient-specific tumour location and clonogen density derived from mpMRI. Radiat Oncol 2020; 15:172. [PMID: 32660504 PMCID: PMC7805066 DOI: 10.1186/s13014-020-01568-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Accepted: 05/13/2020] [Indexed: 12/24/2022] Open
Abstract
AIMS This study aimed to develop a framework for optimising prostate intensity-modulated radiotherapy (IMRT) based on patient-specific tumour biology, derived from multiparametric MRI (mpMRI). The framework included a probabilistic treatment planning technique in the effort to yield dose distributions with an improved expected treatment outcome compared with uniform-dose planning approaches. METHODS IMRT plans were generated for five prostate cancer patients using two inverse planning methods: uniform-dose to the planning target volume and probabilistic biological optimisation for clinical target volume tumour control probability (TCP) maximisation. Patient-specific tumour location and clonogen density information were derived from mpMRI and geometric uncertainties were incorporated in the TCP calculation. Potential reduction in dose to sensitive structures was assessed by comparing dose metrics of uniform-dose plans with biologically-optimised plans of an equivalent level of expected tumour control. RESULTS The planning study demonstrated biological optimisation has the potential to reduce expected normal tissue toxicity without sacrificing local control by shaping the dose distribution to the spatial distribution of tumour characteristics. On average, biologically-optimised plans achieved 38.6% (p-value: < 0.01) and 51.2% (p-value: < 0.01) reduction in expected rectum and bladder equivalent uniform dose, respectively, when compared with uniform-dose planning. CONCLUSIONS It was concluded that varying the dose distribution within the prostate to take account for each patient's clonogen distribution was feasible. Lower doses to normal structures compared to uniform-dose plans was possible whilst providing robust plans against geometric uncertainties. Further validation in a larger cohort is warranted along with considerations for adaptive therapy and limiting urethral dose.
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Affiliation(s)
- E J Her
- School of Physics, Mathematics and Computing, University of Western Australia, Perth, Australia.
| | - A Haworth
- Institute of Medical Physics, University of Sydney, Sydney, Australia
| | - H M Reynolds
- The Sir Peter MacCallum Department of Oncology, University of Melbourne, Melbourne, Australia.,Department of Physical Sciences, Peter MacCallum Cancer Centre, Melbourne, Australia
| | - Y Sun
- The Sir Peter MacCallum Department of Oncology, University of Melbourne, Melbourne, Australia.,Department of Physical Sciences, Peter MacCallum Cancer Centre, Melbourne, Australia
| | - A Kennedy
- Department of Radiation Oncology, Sir Charles Gairdner Hospital, Perth, Australia
| | - V Panettieri
- Alfred Health Radiation Oncology, Melbourne, Australia
| | - M Bangert
- Department of Medical Physics in Radiation Oncology, German Cancer Research Center (DKFZ), Heidelberg, Germany.,Department of Medical Physics in Radiation Oncology, Heidelberg Institute for Radiation Oncology, Heidelberg, Germany
| | - S Williams
- The Sir Peter MacCallum Department of Oncology, University of Melbourne, Melbourne, Australia.,Division of Radiation Oncology and Cancer Imaging, Peter MacCallum Cancer Centre, Melbourne, Australia
| | - M A Ebert
- School of Physics, Mathematics and Computing, University of Western Australia, Perth, Australia.,Department of Radiation Oncology, Sir Charles Gairdner Hospital, Perth, Australia.,5D Clinics, Perth, Australia
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Watkins WT, Nourzadeh H, Siebers JV. Dose escalation in the definite target volume. Med Phys 2020; 47:3174-3183. [PMID: 32267535 PMCID: PMC8259326 DOI: 10.1002/mp.14164] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2019] [Revised: 03/10/2020] [Accepted: 03/13/2020] [Indexed: 12/25/2022] Open
Abstract
PURPOSE To introduce the definite target volume (DTV) and evaluate dosimetric consequences of boosting dose to this region of high clinical target volume (CTV)- and low organs at risk (OAR)-probability. METHODS This work defines the DTV via occupancy probability and via contraction of the CTV by margin M less any planning risk volume (PRV) volumes. The equivalence to within varying occupancy probability of the two methods is established for spherical target volumes. We estimate a margin for four radiation treatment sites based on modern images guided radiation therapy-literature utilizing repeat volumetric imaging. Based on margins and patient-specific DTV targets, the ability to dose escalate the DTV including the effects of spatial uncertainty was evaluated. We simulate delivery assuming violation of the underlying spatial uncertainty of 130%. RESULTS Contracting the planning target volume (PTV) by M and excluding PRV volumes, the DTV ranged from 7.3 to 93.6 cc. In a brain treatment, DTV-Dmax increased to 66.8 Gy (145% of prescription isodose); in advanced lung DTV-Dmax increased to 122.2 Gy (204% of prescription isodose), in a pancreatic case DTV-Dmax was boosted up to 87.3 Gy (173% or prescription isodose), and in retroperitoneal sarcoma to 74.6 Gy (249% of prescription isodose). The high point doses were not associated with increased dose to OARs, even when considering the effects of spatial uncertainty. Simulated delivery at 130% of assumed spatial uncertainties revealed DTV-based planning can result in minor increases in OAR Dmean/Dmax of 2.7 ± 2.1 Gy/1.8 ± 2.2 Gy with duodenum Dmax > 110% of prescription isodose in the pancreatic case. These dose increases were consistent with simulation of clinical, homogenous PTV-dose distributions. CONCLUSION We have proposed and tested a method to deliver extremely high doses to subvolumes of target volumes in multiple treatment sites by defining a new target volume, the DTV. Based on simulated delivery, the method does not result in significant increases in dose to OARs if spatial uncertainty can be estimated.
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Affiliation(s)
- W. Tyler Watkins
- Department of Radiation Oncology, University of Virginia, Charlottesville, VA 22908, USA
| | - Hamidreza Nourzadeh
- Department of Radiation Oncology, University of Virginia, Charlottesville, VA 22908, USA
| | - Jeffrey V. Siebers
- Department of Radiation Oncology, University of Virginia, Charlottesville, VA 22908, USA
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Giżyńska MK, Kukołowicz PF, Heijmen BJM. Coping with interfraction time trends in tumor setup. Med Phys 2019; 47:331-341. [PMID: 31721232 PMCID: PMC7027586 DOI: 10.1002/mp.13919] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2019] [Revised: 10/24/2019] [Accepted: 10/29/2019] [Indexed: 11/29/2022] Open
Abstract
Purpose Interfraction tumor setup variations in radiotherapy are often reduced with image guidance procedures. Clinical target volume (CTV)–planning target volume (PTV) margins are then used to deal with residual errors. We have investigated characterization of setup errors in patient populations with explicit modelling of occurring interfraction time trends. Methods The core of a “trendline characterization” of observed setup errors in a population is a distribution of trendlines, each obtained by fitting a straight line through a patient's daily setup errors. Random errors are defined as daily deviations from the trendline. Monte Carlo simulations were performed to predict the impact of offline setup correction protocols on residual setup errors in patient populations with time trends. A novel CTV‐PTV margin recipe was derived that assumes that systematic underdosing of tumor edges in multiple consecutive fractions, as caused by trend motion, should preferentially be avoided. Similar to the well‐known approach by van Herk et al. for conventional error characterization (no explicit modelling of trends), only a predefined percentage of patients (generally 10%) was allowed to have nonrandom (systematic + trend) setup errors outside the margin. Additionally, a method was proposed to avoid erroneous results in Monte Carlo simulations with setup errors, related to decoupling of error sources in characterizations. The investigations were based on a database of daily measured setup errors in 835 prostate cancer patients that were treated with 39 fractions, and on Monte Carlo–generated patient populations with time trends. Results With conventional characterization of setup errors in patient populations with time trends, predicted standard deviations of residual systematic errors (Σres) after application of an offline correction protocol could be underestimated by more than 50%, potentially resulting in application of too small margins. With the new trendline characterization this was avoided. With the novel CTV‐PTV margin recipe with an allowed 10% of patients having nonrandom errors outside the margin, the observed percentage was 10.0% ± 0.2%. When using conventional characterization of errors and the van Herk margin recipe, on average 58.0% ± 24.3% of patients had errors outside the margin, while 10% was prescribed. For populations with no time trends, the novel recipe simplifies to the generally applied M=2.5Σ+0.7σ formula proposed by van Herk et al. Conclusions In populations with time trends in setup errors, the use of trendline characterizations in Monte Carlo simulations for establishment of residual errors after a setup correction protocol can avoid application of erroneous margins. The novel margin recipe can be used to accurately control the percentage of patients with nonrandom errors outside the margin. In case of daily image guidance of patients with multiple targets with differential motion, the recipe can be used to establish margins for the targets that are not the primary target for the image guidance (e.g., nodal regions). Probabilistic planning might be improved by using trendline characterization for modelling of setup errors. Population analyses of interfraction setup errors need to take into account potential time trends.
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Affiliation(s)
- Marta K Giżyńska
- Medical Physics Department, Maria Sklodowska-Curie Institute - Oncology Center, 02-781, Warsaw, Poland.,Faculty of Physics, Department of Biomedical Physics, University of Warsaw, 02-093, Warsaw, Poland.,Department of Radiation Oncology, Erasmus MC University Medical Center Rotterdam, 3015GD, Rotterdam, Netherlands
| | - Paweł F Kukołowicz
- Medical Physics Department, Maria Sklodowska-Curie Institute - Oncology Center, 02-781, Warsaw, Poland
| | - Ben J M Heijmen
- Department of Radiation Oncology, Erasmus MC University Medical Center Rotterdam, 3015GD, Rotterdam, Netherlands
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Lens E, Kotte ANTJ, Patel A, Heerkens HD, Bal M, van Tienhoven G, Bel A, van der Horst A, Meijer GJ. Probabilistic treatment planning for pancreatic cancer treatment: prospective incorporation of respiratory motion shows only limited dosimetric benefit. Acta Oncol 2017; 56:398-404. [PMID: 27885864 DOI: 10.1080/0284186x.2016.1257863] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
BACKGROUND We introduced a probabilistic treatment planning approach that prospectively incorporates respiratory-induced motion in the treatment plan optimization. The aim of this study was to determine the potential dosimetric benefit by comparing this approach to the use of an internal target volume (ITV). MATERIAL AND METHOD We retrospectively compared the probabilistic respiratory motion-incorporated (RMI) approach to the ITV approach for 18 pancreatic cancer patients, for seven simulated respiratory amplitudes from 5 to 50 mm in the superior-inferior (SI) direction. For each plan, we assessed the target coverage (required: D98%≥95% of 50 Gy prescribed dose). For the RMI plans, we investigated whether target coverage was robust against daily variations in respiratory amplitude. We determined the distance between the clinical target volume and the 30 Gy isodose line (i.e. dose gradient steepness) in the SI direction. To investigate the clinical benefit of the RMI approach, we created for each patient an ITV and RMI treatment plan for the three-dimensional (3D) respiratory amplitudes observed on their pretreatment 4D computed tomography (4DCT). We determined Dmean, V30Gy, V40Gy and V50Gy for the duodenum. RESULTS All treatment plans yielded good target coverage. The RMI plans were robust against respiratory amplitude variations up to 10 mm, as D98% remained ≥95%. We observed steeper dose gradients compared to the ITV approach, with a mean decrease from 25.9 to 19.2 mm for a motion amplitude of 50 mm. For the 4DCT motion amplitudes, the RMI approach resulted in a mean decrease of 0.43 Gy, 1.1 cm3, 1.4 cm3 and 0.9 cm3 for the Dmean, V30Gy, V40Gy and V50Gy of the duodenum, respectively. CONCLUSION The probabilistic treatment planning approach yielded significantly steeper dose gradients and therefore significantly lower dose to surrounding healthy tissues than the ITV approach. However, the observed dosimetric gain for clinically observed respiratory motion amplitudes for this patient group was limited.
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Affiliation(s)
- Eelco Lens
- Department of Radiation Oncology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Alexis N. T. J. Kotte
- Department of Radiotherapy, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Ajay Patel
- Department of Radiotherapy, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Hanne D. Heerkens
- Department of Radiotherapy, University Medical Center Utrecht, Utrecht, The Netherlands
| | | | - Geertjan van Tienhoven
- Department of Radiation Oncology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Arjan Bel
- Department of Radiation Oncology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Astrid van der Horst
- Department of Radiation Oncology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Gert J. Meijer
- Department of Radiotherapy, University Medical Center Utrecht, Utrecht, The Netherlands
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Abstract
We reviewed the literature on the use of margins in radiotherapy of patients with prostate cancer, focusing on different options for image guidance (IG) and technical issues. The search in PubMed database was limited to include studies that involved external beam radiotherapy of the intact prostate. Post-prostatectomy studies, brachytherapy and particle therapy were excluded. Each article was characterized according to the IG strategy used: positioning on external marks using room lasers, bone anatomy and soft tissue match, usage of fiducial markers, electromagnetic tracking and adapted delivery. A lack of uniformity in margin selection among institutions was evident from the review. In general, introduction of pre- and in-treatment IG was associated with smaller planning target volume (PTV) margins, but there was a lack of definitive experimental/clinical studies providing robust information on selection of exact PTV values. In addition, there is a lack of comparative research regarding the cost-benefit ratio of the different strategies: insertion of fiducial markers or electromagnetic transponders facilitates prostate gland localization but at a price of invasive procedure; frequent pre-treatment imaging increases patient in-room time, dose and labour; online plan adaptation should improve radiation delivery accuracy but requires fast and precise computation. Finally, optimal protocols for quality assurance procedures need to be established.
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Affiliation(s)
- Slav Yartsev
- 1 London Regional Cancer Program, London Health Sciences Centre, London, ON, Canada.,2 Departments of Oncology and Medical Biophysics, Western University, London, ON, Canada
| | - Glenn Bauman
- 1 London Regional Cancer Program, London Health Sciences Centre, London, ON, Canada.,2 Departments of Oncology and Medical Biophysics, Western University, London, ON, Canada
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Sá AC, Peres A, Pereira M, Coelho CM, Monsanto F, Macedo A, Lamas A. Evaluating deviations in prostatectomy patients treated with IMRT. Rep Pract Oncol Radiother 2016; 21:266-70. [DOI: 10.1016/j.rpor.2015.11.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2015] [Accepted: 11/30/2015] [Indexed: 10/22/2022] Open
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Tilly D, Ahnesjö A. Fast dose algorithm for generation of dose coverage probability for robustness analysis of fractionated radiotherapy. Phys Med Biol 2015; 60:5439-54. [DOI: 10.1088/0031-9155/60/14/5439] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Watkins WT, Moore JA, Gordon J, Hugo GD, Siebers JV. Multiple anatomy optimization of accumulated dose. Med Phys 2014; 41:111705. [PMID: 25370619 DOI: 10.1118/1.4896104] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
PURPOSE To investigate the potential advantages of multiple anatomy optimization (MAO) for lung cancer radiation therapy compared to the internal target volume (ITV) approach. METHODS MAO aims to optimize a single fluence to be delivered under free-breathing conditions such that the accumulated dose meets the plan objectives, where accumulated dose is defined as the sum of deformably mapped doses computed on each phase of a single four dimensional computed tomography (4DCT) dataset. Phantom and patient simulation studies were carried out to investigate potential advantages of MAO compared to ITV planning. Through simulated delivery of the ITV- and MAO-plans, target dose variations were also investigated. RESULTS By optimizing the accumulated dose, MAO shows the potential to ensure dose to the moving target meets plan objectives while simultaneously reducing dose to organs at risk (OARs) compared with ITV planning. While consistently superior to the ITV approach, MAO resulted in equivalent OAR dosimetry at planning objective dose levels to within 2% volume in 14/30 plans and to within 3% volume in 19/30 plans for each lung V20, esophagus V25, and heart V30. Despite large variations in per-fraction respiratory phase weights in simulated deliveries at high dose rates (e.g., treating 4/10 phases during single fraction beams) the cumulative clinical target volume (CTV) dose after 30 fractions and per-fraction dose were constant independent of planning technique. In one case considered, however, per-phase CTV dose varied from 74% to 117% of prescription implying the level of ITV-dose heterogeneity may not be appropriate with conventional, free-breathing delivery. CONCLUSIONS MAO incorporates 4DCT information in an optimized dose distribution and can achieve a superior plan in terms of accumulated dose to the moving target and OAR sparing compared to ITV-plans. An appropriate level of dose heterogeneity in MAO plans must be further investigated.
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Affiliation(s)
- W Tyler Watkins
- Department of Radiation Oncology, University of Virginia, Charlottesville, Virginia 22908 and Department of Radiation Oncology, Virginia Commonwealth University, Richmond, Virginia 23298
| | - Joseph A Moore
- Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University, Baltimore, Maryland 21231 and Department of Radiation Oncology, Virginia Commonwealth University, Richmond, Virginia 23298
| | - James Gordon
- Henry Ford Health System, Detroit, Michigan 48202 and Department of Radiation Oncology, Virginia Commonwealth University, Richmond, Virginia 23298
| | - Geoffrey D Hugo
- Department of Radiation Oncology, Virginia Commonwealth University, Richmond, Virginia 23298
| | - Jeffrey V Siebers
- Department of Radiation Oncology, University of Virginia, Charlottesville, Virginia 22908 and Department of Radiation Oncology, Virginia Commonwealth University, Richmond, Virginia 23298
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Fontanarosa D, van der Laan HP, Witte M, Shakirin G, Roelofs E, Langendijk JA, Lambin P, van Herk M. An in silico comparison between margin-based and probabilistic target-planning approaches in head and neck cancer patients. Radiother Oncol 2013; 109:430-6. [DOI: 10.1016/j.radonc.2013.07.012] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2012] [Revised: 07/12/2013] [Accepted: 07/24/2013] [Indexed: 10/26/2022]
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Bohoslavsky R, Witte MG, Janssen TM, van Herk M. Probabilistic objective functions for margin-less IMRT planning. Phys Med Biol 2013; 58:3563-80. [PMID: 23640114 DOI: 10.1088/0031-9155/58/11/3563] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Sharma M, Weiss E, Siebers JV. Dose deformation-invariance in adaptive prostate radiation therapy: implication for treatment simulations. Radiother Oncol 2012. [PMID: 23200409 DOI: 10.1016/j.radonc.2012.10.011] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
PURPOSE To investigate dose deformation-invariance in adaptive prostate radiation treatment. METHODS A 19 patient prostate cancer-cohort with 8-13 CTs/patient is used. The 79.2 Gy plans are developed on the reference image using seven 6 and 18 MV intensity-modulated beams with identical RTOG 0126 objectives. Dose on the subsequent images is evaluated in two ways: (A1) Dose is recalculated on each image. (A2) The initially planned dose distribution is copied to each image. A2 assumes dose-invariance in the accelerator-coordinate-system. Effects of patient miss-alignment are simulated by 27 per-patient image shifts; 0 and ±10 mm in left-right, anterior-posterior and superior-inferior directions. The per-voxel dose differences for each patient image, total accumulated patient dose, and dose-volume metrics (CTV-D98 and -D90, bladder- and rectum-D50, -D35, -D25 and -D15) are used to compare A1 and A2. RESULTS The per-voxel mean percent difference in A1 and A2 dose over all patient images at 6 MV is (0.01±1.56)% and at 18 MV is (0.00±0.96)%. For 6 MV and 18 MV plans, the root-mean-square-percentage-error (RMSPE) in A2 over all patient image shifts are CTV-D98=0.94 and 0.55, CTV-D90=0.92 and 0.55, rectum-D50, -D35, -D25 and -D15=1.00, 0.96, 0.86, 0.80 and 0.84, 0.96, 0.92, 1.05; and bladder-D50, -D35, -D25, -D15=1.07, 0.88, 0.78, 0.72 and 1.61, 0.93, 0.67, 0.51. The dose differences are not correlated to the dice-similarity coefficients; with respective correlation-coefficients for CTV, rectum and bladder being -0.17, -0.17 and 0.081. CONCLUSIONS Assumption of shift- and deformation-invariant dose distributions on an average introduces <2% error in evaluated dose-volume metrics for 6 and 18 MV IMRT prostate plans. Use of invariant dose distributions has a potential to reduce online re-planning time and permit pre-planning based on tissue deformation models.
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Affiliation(s)
- Manju Sharma
- Virginia Commonwealth University, Richmond, VA 23298, United States.
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