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Sathya A, Goyal-Honavar A, Chacko AG, Jasper A, Chacko G, Devakumar D, Seelam JA, Sasidharan BK, Pavamani SP, Thomas HMT. Is radiomics a useful addition to magnetic resonance imaging in the preoperative classification of PitNETs? Acta Neurochir (Wien) 2024; 166:91. [PMID: 38376544 DOI: 10.1007/s00701-024-05977-4] [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] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2023] [Accepted: 01/18/2024] [Indexed: 02/21/2024]
Abstract
BACKGROUND The WHO 2021 introduced the term pituitary neuroendocrine tumours (PitNETs) for pituitary adenomas and incorporated transcription factors for subtyping, prompting the need for fresh diagnostic methods. Current biomarkers struggle to distinguish between high- and low-risk non-functioning PitNETs. We explored if radiomics can enhance preoperative decision-making. METHODS Pre-treatment magnetic resonance (MR) images of patients who underwent surgery between 2015 and 2019 with available WHO 2021 classification were used. The tumours were manually segmented on the T1w, T1-contrast enhanced, and T2w images using 3D Slicer. One hundred Pyradiomic features were extracted from each MR sequence. Models were built to classify (1) somatotroph and gonadotroph PitNETs and (2) high- and low-risk subtypes of non-functioning PitNETs. Feature were selected independently from the MR sequences and multi-sequence (combining data from more than one MR sequence) using Boruta and Pearson correlation. Support vector machine (SVM), logistic regression (LR), random forest (RF), and multi-layer perceptron (MLP) were the classifiers used. Data imbalance was addressed using the Synthetic Minority Oversampling TEchnique (SMOTE). Performance of the models were evaluated using area under the receiver operating curve (AUC), accuracy, sensitivity, and specificity. RESULTS A total of 222 PitNET patients (train, n = 149; test, n = 73) were enrolled in this retrospective study. Multi-sequence-based LR model discriminated best between somatotroph and gonadotroph PitNETs, with a test AUC of 0.84, accuracy of 0.74, specificity of 0.81, and sensitivity of 0.70. Multi-sequence-based MLP model perfomed best for the high- and low-risk non-functioning PitNETs, achieving a test AUC of 0.76, accuracy of 0.67, specificity of 0.72, and sensitivity of 0.66. CONCLUSIONS Utilizing pre-treatment MRI and radiomics holds promise for distinguishing high-risk from low-risk non-functioning PitNETs based on the latest WHO classification. This could assist neurosurgeons in making critical decisions regarding surgery or alternative management strategies for PitNETs after further clinical validation.
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Affiliation(s)
- Sathya A
- Quantitative Imaging Research and Artificial Intelligence Lab, Department of Radiation Oncology Unit II, Ida B Scudder Cancer Centre, Christian Medical College, Vellore, India
| | | | - Ari G Chacko
- Department of Neurosurgery, Christian Medical College, Vellore, India
| | - Anitha Jasper
- Department of Radiodiagnosis, Christian Medical College, Vellore, India
| | - Geeta Chacko
- Department of General Pathology, Christian Medical College, Vellore, India
| | - Devadhas Devakumar
- Department of Nuclear Medicine, Christian Medical College, Vellore, India
| | | | - Balu Krishna Sasidharan
- Quantitative Imaging Research and Artificial Intelligence Lab, Department of Radiation Oncology Unit II, Ida B Scudder Cancer Centre, Christian Medical College, Vellore, India
| | - Simon P Pavamani
- Quantitative Imaging Research and Artificial Intelligence Lab, Department of Radiation Oncology Unit II, Ida B Scudder Cancer Centre, Christian Medical College, Vellore, India
| | - Hannah Mary T Thomas
- Quantitative Imaging Research and Artificial Intelligence Lab, Department of Radiation Oncology Unit II, Ida B Scudder Cancer Centre, Christian Medical College, Vellore, India.
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Thomas HMT, Wang HYC, Varghese AJ, Donovan EM, South CP, Saxby H, Nisbet A, Prakash V, Sasidharan BK, Pavamani SP, Devadhas D, Mathew M, Isiah RG, Evans PM. Reproducibility in Radiomics: A Comparison of Feature Extraction Methods and Two Independent Datasets. Appl Sci (Basel) 2024; 166:s00701-024-05977-4. [PMID: 38725869 PMCID: PMC7615943 DOI: 10.3390/app13127291] [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] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 05/12/2024]
Abstract
Radiomics involves the extraction of information from medical images that are not visible to the human eye. There is evidence that these features can be used for treatment stratification and outcome prediction. However, there is much discussion about the reproducibility of results between different studies. This paper studies the reproducibility of CT texture features used in radiomics, comparing two feature extraction implementations, namely the MATLAB toolkit and Pyradiomics, when applied to independent datasets of CT scans of patients: (i) the open access RIDER dataset containing a set of repeat CT scans taken 15 min apart for 31 patients (RIDER Scan 1 and Scan 2, respectively) treated for lung cancer; and (ii) the open access HN1 dataset containing 137 patients treated for head and neck cancer. Gross tumor volume (GTV), manually outlined by an experienced observer available on both datasets, was used. The 43 common radiomics features available in MATLAB and Pyradiomics were calculated using two intensity-level quantization methods with and without an intensity threshold. Cases were ranked for each feature for all combinations of quantization parameters, and the Spearman's rank coefficient, rs, calculated. Reproducibility was defined when a highly correlated feature in the RIDER dataset also correlated highly in the HN1 dataset, and vice versa. A total of 29 out of the 43 reported stable features were found to be highly reproducible between MATLAB and Pyradiomics implementations, having a consistently high correlation in rank ordering for RIDER Scan 1 and RIDER Scan 2 (rs > 0.8). 18/43 reported features were common in the RIDER and HN1 datasets, suggesting they may be agnostic to disease site. Useful radiomics features should be selected based on reproducibility. This study identified a set of features that meet this requirement and validated the methodology for evaluating reproducibility between datasets.
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Affiliation(s)
- Hannah Mary T. Thomas
- Department of Radiation Oncology, Christian Medical College Vellore, Vellore 632004, Tamil Nadu, India
| | - Helen Y. C. Wang
- Centre for Vision, Speech and Signal Processing, University of Surrey, Guildford GU2 7XH, UK
- Department of Medical Physics, Royal Surrey NHS Foundation Trust, Guildford GU2 7XX, UK
| | - Amal Joseph Varghese
- Department of Radiation Oncology, Christian Medical College Vellore, Vellore 632004, Tamil Nadu, India
| | - Ellen M. Donovan
- Centre for Vision, Speech and Signal Processing, University of Surrey, Guildford GU2 7XH, UK
| | - Chris P. South
- Department of Medical Physics, Royal Surrey NHS Foundation Trust, Guildford GU2 7XX, UK
| | - Helen Saxby
- St Luke’s Cancer Centre, Royal Surrey NHS Foundation Trust, Guildford GU2 7XX, UK
| | - Andrew Nisbet
- Department of Medical Physics and Biomedical Engineering, University College London, London WC1E 6BT, UK
| | - Vineet Prakash
- St Luke’s Cancer Centre, Royal Surrey NHS Foundation Trust, Guildford GU2 7XX, UK
| | - Balu Krishna Sasidharan
- Department of Radiation Oncology, Christian Medical College Vellore, Vellore 632004, Tamil Nadu, India
| | - Simon Pradeep Pavamani
- Department of Radiation Oncology, Christian Medical College Vellore, Vellore 632004, Tamil Nadu, India
| | - Devakumar Devadhas
- Department of Nuclear Medicine, Christian Medical College Vellore, Vellore 632004, Tamil Nadu, India
| | - Manu Mathew
- Department of Radiation Oncology, Christian Medical College Vellore, Vellore 632004, Tamil Nadu, India
| | - Rajesh Gunasingam Isiah
- Department of Radiation Oncology, Christian Medical College Vellore, Vellore 632004, Tamil Nadu, India
| | - Philip M. Evans
- Centre for Vision, Speech and Signal Processing, University of Surrey, Guildford GU2 7XH, UK
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John NO, Irodi A, Thomas HMT, Abraham V, Sasidharan BK, John S, Pavamani SP. Utility of Mid-treatment DWI in Selecting Pathological Responders to Neoadjuvant Chemoradiotherapy in Locally Advanced Esophageal Cancer. J Gastrointest Cancer 2023; 54:447-455. [PMID: 35347663 DOI: 10.1007/s12029-022-00818-y] [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] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/06/2022] [Indexed: 12/24/2022]
Abstract
PURPOSE Pathological complete response correlates with better clinical outcomes in locally advanced esophageal cancer (LA-EC). However, there is lack of prognostic markers to identify patients in the current setting of neoadjuvant chemoradiotherapy (NACRT) followed by surgery. This study evaluates the utility of mid-treatment diffusion-weighted imaging (DWI) in identifying pathological responders of NACRT. METHODS Twenty-four patients with LA-EC on NACRT were prospectively recruited and underwent three MRI (baseline, mid-treatment, end-of-RT) scans. DWI-derived apparent diffusion coefficient (ADC) mean and minimum were used as a surrogate to evaluate the treatment response, and its correlation to pathological response was assessed. RESULTS Mid-treatment ADC mean was significantly higher among patients with pathological response compared to non-responders (p = 0.011). ADC difference (ΔADC) between baseline and mid-treatment correlated with tumor response (p = 0.007). ADC at other time points did not correlate to pathological response. CONCLUSION In this study, mid-treatment ADC values show potential to be a surrogate for tumor response in NACRT. However, larger trials are required to establish DW-MRI as a definite biomarker for tumor response.
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Affiliation(s)
- Neenu Oliver John
- Department of Radiation Oncology, Ida B. Scudder Cancer Centre, Christian Medical College, Tamil Nadu, Vellore, 632004, India
| | - Aparna Irodi
- Division of Clinical Radiology, Department of Radiodiagnosis, Christian Medical College, Tamil Nadu, Vellore, 632004, India
| | - Hannah Mary T Thomas
- Department of Radiation Oncology, Ida B. Scudder Cancer Centre, Christian Medical College, Tamil Nadu, Vellore, 632004, India
| | - Vijay Abraham
- Department of Surgery, Christian Medical College, Tamil Nadu, Vellore, 632004, India
- Department of Upper GI Surgery, The Queen Elizabeth Hospital, Woodville South, Adelaide, 5011, Australia
| | - Balu Krishna Sasidharan
- Department of Radiation Oncology, Ida B. Scudder Cancer Centre, Christian Medical College, Tamil Nadu, Vellore, 632004, India
| | - Subhashini John
- Department of Radiation Oncology, Ida B. Scudder Cancer Centre, Christian Medical College, Tamil Nadu, Vellore, 632004, India
| | - Simon P Pavamani
- Department of Radiation Oncology, Ida B. Scudder Cancer Centre, Christian Medical College, Tamil Nadu, Vellore, 632004, India.
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Varghese AJ, Gouthamchand V, Sasidharan BK, Wee L, Sidhique SK, Rao JP, Dekker A, Hoebers F, Devakumar D, Irodi A, Balasingh TP, Godson HF, Joel T, Mathew M, Gunasingam Isiah R, Pavamani SP, Thomas HMT. Multi-centre radiomics for prediction of recurrence following radical radiotherapy for head and neck cancers: Consequences of feature selection, machine learning classifiers and batch-effect harmonization. Phys Imaging Radiat Oncol 2023; 26:100450. [PMID: 37260438 PMCID: PMC10227455 DOI: 10.1016/j.phro.2023.100450] [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] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Revised: 05/01/2023] [Accepted: 05/02/2023] [Indexed: 06/02/2023] Open
Abstract
Background and purpose Radiomics models trained with limited single institution data are often not reproducible and generalisable. We developed radiomics models that predict loco-regional recurrence within two years of radiotherapy with private and public datasets and their combinations, to simulate small and multi-institutional studies and study the responsiveness of the models to feature selection, machine learning algorithms, centre-effect harmonization and increased dataset sizes. Materials and methods 562 patients histologically confirmed and treated for locally advanced head-and-neck cancer (LA-HNC) from two public and two private datasets; one private dataset exclusively reserved for validation. Clinical contours of primary tumours were not recontoured and were used for Pyradiomics based feature extraction. ComBat harmonization was applied, and LASSO-Logistic Regression (LR) and Support Vector Machine (SVM) models were built. 95% confidence interval (CI) of 1000 bootstrapped area-under-the-Receiver-operating-curves (AUC) provided predictive performance. Responsiveness of the models' performance to the choice of feature selection methods, ComBat harmonization, machine learning classifier, single and pooled data was evaluated. Results LASSO and SelectKBest selected 14 and 16 features, respectively; three were overlapping. Without ComBat, the LR and SVM models for three institutional data showed AUCs (CI) of 0.513 (0.481-0.559) and 0.632 (0.586-0.665), respectively. Performances following ComBat revealed AUCs of 0.559 (0.536-0.590) and 0.662 (0.606-0.690), respectively. Compared to single cohort AUCs (0.562-0.629), SVM models from pooled data performed significantly better at AUC = 0.680. Conclusions Multi-institutional retrospective data accentuates the existing variabilities that affect radiomics. Carefully designed prospective, multi-institutional studies and data sharing are necessary for clinically relevant head-and-neck cancer prognostication models.
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Affiliation(s)
- Amal Joseph Varghese
- Department of Radiation Oncology, Christian Medical College, Vellore, Tamil Nadu, India
| | - Varsha Gouthamchand
- Department of Radiation Oncology (Maastro), GROW School for Oncology and Reproduction, Maastricht University Medical Centre+, Maastricht, The Netherlands
| | | | - Leonard Wee
- Department of Radiation Oncology (Maastro), GROW School for Oncology and Reproduction, Maastricht University Medical Centre+, Maastricht, The Netherlands
| | - Sharief K Sidhique
- Department of Radiation Oncology, Christian Medical College, Vellore, Tamil Nadu, India
| | | | - Andre Dekker
- Department of Radiation Oncology (Maastro), GROW School for Oncology and Reproduction, Maastricht University Medical Centre+, Maastricht, The Netherlands
| | - Frank Hoebers
- Department of Radiation Oncology (Maastro), GROW School for Oncology and Reproduction, Maastricht University Medical Centre+, Maastricht, The Netherlands
| | - Devadhas Devakumar
- Department of Nuclear Medicine, Christian Medical College, Vellore, Tamil Nadu, India
| | - Aparna Irodi
- Department of Radiology, Christian Medical College, Vellore, Tamil Nadu, India
| | | | - Henry Finlay Godson
- Department of Radiation Oncology, Christian Medical College, Vellore, Tamil Nadu, India
| | - T Joel
- Department of Radiation Oncology, Christian Medical College, Vellore, Tamil Nadu, India
| | - Manu Mathew
- Department of Radiation Oncology, Christian Medical College, Vellore, Tamil Nadu, India
| | | | | | - Hannah Mary T Thomas
- Department of Radiation Oncology, Christian Medical College, Vellore, Tamil Nadu, India
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Devakumar D, Sunny G, Sasidharan BK, Bowen SR, Nadaraj A, Jeyseelan L, Mathew M, Irodi A, Isiah R, Pavamani S, John S, T Thomas HM. Framework for Machine Learning of CT and PET Radiomics to Predict Local Failure after Radiotherapy in Locally Advanced Head and Neck Cancers. J Med Phys 2021; 46:181-188. [PMID: 34703102 PMCID: PMC8491314 DOI: 10.4103/jmp.jmp_6_21] [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] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2021] [Revised: 06/07/2021] [Accepted: 06/07/2021] [Indexed: 01/06/2023] Open
Abstract
Context: Cancer Radiomics is an emerging field in medical imaging and refers to the process of converting routine radiological images that are typically qualitatively interpreted to quantifiable descriptions of the tumor phenotypes and when combined with statistical analytics can improve the accuracy of clinical outcome prediction models. However, to understand the radiomic features and their correlation to molecular changes in the tumor, first, there is a need for the development of robust image analysis methods, software tools and statistical prediction models which is often limited in low- and middle-income countries (LMIC). Aims: The aim is to build a framework for machine learning of radiomic features of planning computed tomography (CT) and positron emission tomography (PET) using open source radiomics and data analytics platforms to make it widely accessible to clinical groups. The framework is tested in a small cohort to predict local disease failure following radiation treatment for head-and-neck cancer (HNC). The predictors were also compared with the existing Aerts HNC radiomics signature. Settings and Design: Retrospective analysis of patients with locally advanced HNC between 2017 and 2018 and 31 patients with both pre- and post-radiation CT and evaluation PET were selected. Subjects and Methods: Tumor volumes were delineated on baseline PET using the semi-automatic adaptive-threshold algorithm and propagated to CT; PyRadiomics features (total of 110 under shape/intensity/texture classes) were extracted. Two feature-selection methods were tested for model stability. Models were built based on least absolute shrinkage and selection operator-logistic and Ridge regression of the top pretreatment radiomic features and compared to Aerts' HNC-signature. Average model performance across all internal validation test folds was summarized by the area under the receiver operator curve (ROC). Results: Both feature selection methods selected CT features MCC (GLCM), SumEntropy (GLCM) and Sphericity (Shape) that could predict the binary failure status in the cross-validated group and achieved an AUC >0.7. However, models using Aerts' signature features (Energy, Compactness, GLRLM-GrayLevelNonUniformity and GrayLevelNonUniformity-HLH wavelet) could not achieve a clear separation between outcomes (AUC = 0.51–0.54). Conclusions: Radiomics pipeline included open-source workflows which makes it adoptable in LMIC countries. Additional independent validation of data is crucial for the implementation of radiomic models for clinical risk stratification.
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Affiliation(s)
- Devadhas Devakumar
- Department of Nuclear Medicine, Christian Medical College, Vellore, Tamil Nadu, India
| | - Goutham Sunny
- Department of Radiation Oncology, Christian Medical College, Vellore, Tamil Nadu, India.,Department of Radiation Oncology, Baptist Cancer Centre, Bangalore Baptist Hospital, Bengaluru, Karnataka, India
| | | | - Stephen R Bowen
- Department of Radiation Oncology, School of Medicine, University of Washington, Seattle, WA 98195, USA
| | - Ambily Nadaraj
- Department of Clinical Epidemiology, Christian Medical College, Vellore, Tamil Nadu, India
| | - L Jeyseelan
- Department of Clinical Epidemiology, Christian Medical College, Vellore, Tamil Nadu, India
| | - Manu Mathew
- Department of Radiation Oncology, Christian Medical College, Vellore, Tamil Nadu, India
| | - Aparna Irodi
- Department of Radiology, Christian Medical College, Vellore, Tamil Nadu, India
| | - Rajesh Isiah
- Department of Radiation Oncology, Christian Medical College, Vellore, Tamil Nadu, India
| | - Simon Pavamani
- Department of Radiation Oncology, Christian Medical College, Vellore, Tamil Nadu, India
| | - Subhashini John
- Department of Radiation Oncology, Christian Medical College, Vellore, Tamil Nadu, India
| | - Hannah Mary T Thomas
- Department of Radiation Oncology, Christian Medical College, Vellore, Tamil Nadu, India
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Thomas HMT, Zeng J, Lee, Jr HJ, Sasidharan BK, Kinahan PE, Miyaoka RS, Vesselle HJ, Rengan R, Bowen SR. Comparison of regional lung perfusion response on longitudinal MAA SPECT/CT in lung cancer patients treated with and without functional tissue-avoidance radiation therapy. Br J Radiol 2019; 92:20190174. [PMID: 31364397 PMCID: PMC6849661 DOI: 10.1259/bjr.20190174] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2019] [Revised: 06/28/2019] [Accepted: 07/23/2019] [Indexed: 12/25/2022] Open
Abstract
OBJECTIVE The effect of functional lung avoidance planning on radiation dose-dependent changes in regional lung perfusion is unknown. We characterized dose-perfusion response on longitudinal perfusion single photon emission computed tomography (SPECT)/CT in two cohorts of lung cancer patients treated with and without functional lung avoidance techniques. METHODS The study included 28 primary lung cancer patients: 20 from interventional (NCT02773238) (FLARE-RT) and eight from observational (NCT01982123) (LUNG-RT) clinical trials. FLARE-RT treatment plans included perfused lung dose constraints while LUNG-RT plans adhered to clinical standards. Pre- and 3 month post-treatment macro-aggregated albumin (MAA) SPECT/CT scans were rigidly co-registered to planning four-dimensional CT scans. Tumour-subtracted lung dose was converted to EQD2 and sorted into 5 Gy bins. Mean dose and percent change between pre/post-RT MAA-SPECT uptake (%ΔPERF), normalized to total tumour-subtracted lung uptake, were calculated in each binned dose region. Perfusion frequency histograms of pre/post-RT MAA-SPECT were analyzed. Dose-response data were parameterized by sigmoid logistic functions to estimate maximum perfusion increase (%ΔPERFmaxincrease), maximum perfusion decrease (%ΔPERFmaxdecrease), dose midpoint (Dmid), and dose-response slope (k). RESULTS Differences in MAA perfusion frequency distribution shape between time points were observed in 11/20 (55%) FLARE-RT and 2/8 (25%) LUNG-RT patients (p < 0.05). FLARE-RT dose response was characterized by >10% perfusion increase in the 0-5 Gy dose bin for 8/20 patients (%ΔPERFmaxincrease = 10-40%), which was not observed in any LUNG-RT patients (p = 0.03). The dose midpoint Dmid at which relative perfusion declined by 50% trended higher in FLARE-RT compared to LUNG-RT cohorts (35 GyEQD2 vs 21 GyEQD2, p = 0.09), while the dose-response slope k was similar between FLARE-RT and LUNG-RT cohorts (3.1-3.2, p = 0.86). CONCLUSION Functional lung avoidance planning may promote increased post-treatment perfusion in low dose regions for select patients, though inter-patient variability remains high in unbalanced cohorts. These preliminary findings form testable hypotheses that warrant subsequent validation in larger cohorts within randomized or case-matched control investigations. ADVANCES IN KNOWLEDGE This novel preliminary study reports differences in dose-response relationships between patients receiving functional lung avoidance radiation therapy (FLARE-RT) and those receiving conventionally planned radiation therapy (LUNG-RT). Following further validation and testing of these effects in larger patient populations, individualized estimation of regional lung perfusion dose-response may help refine future risk-adaptive strategies to minimize lung function deficits and toxicity incidence.
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Affiliation(s)
- Hannah Mary T Thomas
- Department of Radiation Oncology, University of Washington School of Medicine, Seattle, USA
| | - Jing Zeng
- Department of Radiation Oncology, University of Washington School of Medicine, Seattle, USA
| | - Howard J Lee, Jr
- Department of Radiation Oncology, University of Washington School of Medicine, Seattle, USA
| | | | - Paul E Kinahan
- Department of Radiology, University of Washington School of Medicine, Seattle, USA
| | - Robert S Miyaoka
- Department of Radiology, University of Washington School of Medicine, Seattle, USA
| | - Hubert J. Vesselle
- Department of Radiology, University of Washington School of Medicine, Seattle, USA
| | - Ramesh Rengan
- Department of Radiation Oncology, University of Washington School of Medicine, Seattle, USA
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T Thomas HM, Devakumar D, Sasidharan B, Bowen SR, Heck DK, James Jebaseelan Samuel E. Hybrid positron emission tomography segmentation of heterogeneous lung tumors using 3D Slicer: improved GrowCut algorithm with threshold initialization. J Med Imaging (Bellingham) 2017; 4:011009. [PMID: 28149920 DOI: 10.1117/1.jmi.4.1.011009] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [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: 06/10/2016] [Accepted: 12/20/2016] [Indexed: 12/25/2022] Open
Abstract
This paper presents an improved GrowCut (IGC), a positron emission tomography-based segmentation algorithm, and tests its clinical applicability. Contrary to the traditional method that requires the user to provide the initial seeds, the IGC algorithm starts with a threshold-based estimate of the tumor and a three-dimensional morphologically grown shell around the tumor as the foreground and background seeds, respectively. The repeatability of IGC from the same observer at multiple time points was compared with the traditional GrowCut algorithm. The algorithm was tested in 11 nonsmall cell lung cancer lesions and validated against the clinician-defined manual contour and compared against the clinically used 25% of the maximum standardized uptake value [SUV-(max)], 40% [Formula: see text], and adaptive threshold methods. The time to edit IGC-defined functional volume to arrive at the gross tumor volume (GTV) was compared with that of manual contouring. The repeatability of the IGC algorithm was very high compared with the traditional GrowCut ([Formula: see text]) and demonstrated higher agreement with the manual contour with respect to threshold-based methods. Compared with manual contouring, editing the IGC achieved the GTV in significantly less time ([Formula: see text]). The IGC algorithm offers a highly repeatable functional volume and serves as an effective initial guess that can well minimize the time spent on labor-intensive manual contouring.
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Affiliation(s)
- Hannah Mary T Thomas
- VIT University , School of Advanced Sciences, Department of Physics, Vellore, Tamil Nadu 632004, India
| | - Devadhas Devakumar
- Christian Medical College , Department of Nuclear Medicine, Vellore, Tamil Nadu 632004, India
| | - Balukrishna Sasidharan
- Christian Medical College , Department of Radiation Oncology, Vellore, Tamil Nadu 632004, India
| | - Stephen R Bowen
- University of Washington , School of Medicine, Departments of Radiology and Radiation Oncology, Seattle, Washington 98195, United States
| | - Danie Kingslin Heck
- Christian Medical College , Department of Nuclear Medicine, Vellore, Tamil Nadu 632004, India
| | - E James Jebaseelan Samuel
- VIT University , School of Advanced Sciences, Department of Physics, Vellore, Tamil Nadu 632004, India
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Thomas HMT, Balukrishna S, Devakumar D, Muthuswamy P, Samuel EJJ. Can positron emission tomography be more than a diagnostic tool? A survey on clinical practice among radiation oncologists in India. Indian J Cancer 2014; 51:145-9. [PMID: 25104197 DOI: 10.4103/0019-509x.138247] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
AIM The purpose of the survey was to understand the role of positron emission tomography (PET) in clinical radiotherapy practice among the radiation oncologists' in India. SETTINGS AND DESIGN An online questionnaire was developed to survey the oncologists on their use of PET, viewing protocols, contouring techniques practiced, the barriers on the use of PET and the need for training in use of PET in radiotherapy. The questionnaire was sent to about 500 oncologists and 76 completed responses were received. RESULTS The survey shows that radiation oncologists use PET largely to assess treatment response and staging but limitedly use it for radiotherapy treatment planning. Only manual contouring and fixed threshold based delineation techniques (e.g. 40% maximum standard uptake value [SUV max ] or SUV 2.5) are used. Cost is the major barrier in the wider use of PET, followed by limited availability of FDG radionuclide tracer. Limited or no training was available for the use of PET. CONCLUSIONS Our survey revealed the vast difference between literature suggestions and actual clinical practice on the use of PET in radiotherapy. Additional training and standardization of protocols for use of PET in radiotherapy is essential for fully utilizing the capability of PET.
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Affiliation(s)
- H M T Thomas
- Photonics, Nuclear and Medical Physics Division, School of Advanced Sciences, Vellore, Tamil Nadu, India
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