The document discusses artificial intelligence applications in radiation oncology, including automatic delineation of organs-at-risk using deep learning models like OARNet. It also discusses radiomics approaches for clinical decision support and outcomes prediction using features extracted from medical images with techniques like spiculation quantification for lung cancer screening.
Artificial Intelligence in Radiation OncologyWookjin Choi
- The document discusses the use of artificial intelligence and radiomics in radiation oncology. It presents frameworks for radiomics analysis involving image registration, tumor segmentation, feature extraction, and predictive modeling.
- Specific applications discussed include using radiomics for lung cancer screening and prediction of tumor response. Radiomics features combined with machine learning models show improved performance over clinical guidelines for assessing lung nodule malignancy.
- Methods are also presented for quantifying tumor characteristics like spiculation through image analysis and extracting interpretable radiomics features. This can provide semantic information to radiologists for assessment.
Artificial Intelligence in Radiation OncologyWookjin Choi
This document discusses artificial intelligence applications in radiation oncology. It begins with acknowledgements and then outlines several AI applications including radiomics tools for lung cancer screening, tumor response prediction, and predicting aggressive lung adenocarcinoma subtypes. It also discusses using AI for automatic tumor delineation and quantification of delineation variability as well as local tumor morphological changes prediction and metabolic tumor volume changes. The document provides details on methods and results for several of these AI applications in radiation oncology.
This document discusses the use of stereotactic body radiation therapy (SBRT) for liver tumors. It provides details on common liver tumors including hepatocellular carcinoma and metastases. It describes SBRT as a treatment option for inoperable early stage tumors, as a bridge to transplant, and for intermediate or locally advanced stages. Key factors for patient selection and treatment planning such as tumor size, number and location, as well as liver function are summarized. The document also briefly discusses proton beam therapy and current clinical trials investigating SBRT for liver cancer.
A summary of recent innovations in radiation oncology focussing on the priniciples of different techniques and their application. An overview of clinical results has also been given
TBI is the radiotherapy technique to irradiate whole body before doing stem cell transplant. The main purpose of doing TBIB is to condition the immune system of body so that there will be maximum chance of transplant acceptance.
This document discusses image-guided radiation therapy (IGRT) and its evolution and applications. It begins by defining IGRT as external beam radiation therapy using imaging prior to each treatment fraction to verify patient positioning. IGRT allows for reduction of safety margins by compensating for set-up errors and organ motion. The document then reviews the history of IGRT from early portal imaging to modern cone-beam CT and other volumetric imaging techniques. It provides examples of IGRT protocols and clinical outcomes for sites such as prostate, lung, liver, and central nervous system tumors.
This document discusses various methods used to evaluate radiotherapy treatment plans, including physical and biological parameters. Physically, plans are evaluated using isodose curves, dose distribution statistics, differential and cumulative dose-volume histograms (DVHs). Target coverage should be within 95-100% of the prescribed dose. Biologically, tumor control probability (TCP) and normal tissue complication probability (NTCP) models are used. The therapeutic ratio and index compare the dose required for tumor control versus normal tissue complications. NTCP models include Lyman-Kutcher-Burman and critical element/volume models. Plan evaluation ensures target doses are adequate while respecting organ tolerance doses.
Artificial Intelligence in Radiation OncologyWookjin Choi
- The document discusses the use of artificial intelligence and radiomics in radiation oncology. It presents frameworks for radiomics analysis involving image registration, tumor segmentation, feature extraction, and predictive modeling.
- Specific applications discussed include using radiomics for lung cancer screening and prediction of tumor response. Radiomics features combined with machine learning models show improved performance over clinical guidelines for assessing lung nodule malignancy.
- Methods are also presented for quantifying tumor characteristics like spiculation through image analysis and extracting interpretable radiomics features. This can provide semantic information to radiologists for assessment.
Artificial Intelligence in Radiation OncologyWookjin Choi
This document discusses artificial intelligence applications in radiation oncology. It begins with acknowledgements and then outlines several AI applications including radiomics tools for lung cancer screening, tumor response prediction, and predicting aggressive lung adenocarcinoma subtypes. It also discusses using AI for automatic tumor delineation and quantification of delineation variability as well as local tumor morphological changes prediction and metabolic tumor volume changes. The document provides details on methods and results for several of these AI applications in radiation oncology.
This document discusses the use of stereotactic body radiation therapy (SBRT) for liver tumors. It provides details on common liver tumors including hepatocellular carcinoma and metastases. It describes SBRT as a treatment option for inoperable early stage tumors, as a bridge to transplant, and for intermediate or locally advanced stages. Key factors for patient selection and treatment planning such as tumor size, number and location, as well as liver function are summarized. The document also briefly discusses proton beam therapy and current clinical trials investigating SBRT for liver cancer.
A summary of recent innovations in radiation oncology focussing on the priniciples of different techniques and their application. An overview of clinical results has also been given
TBI is the radiotherapy technique to irradiate whole body before doing stem cell transplant. The main purpose of doing TBIB is to condition the immune system of body so that there will be maximum chance of transplant acceptance.
This document discusses image-guided radiation therapy (IGRT) and its evolution and applications. It begins by defining IGRT as external beam radiation therapy using imaging prior to each treatment fraction to verify patient positioning. IGRT allows for reduction of safety margins by compensating for set-up errors and organ motion. The document then reviews the history of IGRT from early portal imaging to modern cone-beam CT and other volumetric imaging techniques. It provides examples of IGRT protocols and clinical outcomes for sites such as prostate, lung, liver, and central nervous system tumors.
This document discusses various methods used to evaluate radiotherapy treatment plans, including physical and biological parameters. Physically, plans are evaluated using isodose curves, dose distribution statistics, differential and cumulative dose-volume histograms (DVHs). Target coverage should be within 95-100% of the prescribed dose. Biologically, tumor control probability (TCP) and normal tissue complication probability (NTCP) models are used. The therapeutic ratio and index compare the dose required for tumor control versus normal tissue complications. NTCP models include Lyman-Kutcher-Burman and critical element/volume models. Plan evaluation ensures target doses are adequate while respecting organ tolerance doses.
1.Aim of Radiotherapy
The goal of radiotherapy is to deliver a prescribed dose of radiation to the Target while sparing surrounding Healthy tissues to the largest extent possible
2.Organ Motion
Intra-fraction motion
during the fraction
Heartbeat
Swallowing
Coughing
Eye movement
Inter-fraction motion
- in between the fractions
Tumour change
Weight gain/loss
Positioning deviation
Breathing
Bowel and rectal filling
Bladder filling
Muscle relaxation/tension
3. Respiratory motion affects:
Respiratory motion affects all tumour sites in the thorax, abdomen and Pelvis. Tumours in the Lung, Liver, Pancreas, Oesophagus, Breast, Kidneys, prostate
Tumour displacement varies depending on the site and organ Location
Lung tumours can move several cm in any direction during irradiation
It is most prevalent and prominent in Lung cancers
4. Problems associated with respiratory motion during RT
Image acquisition limitations
Treatment planning limitations
Radiation delivery limitations
5. Methods to Account for Respiratory Motion
1. Motion encompassing methods
2. Respiratory gating methods
3. Breath hold methods
4. Forced shallow breathing with abdominal compression
5. Real-time tumor tracking methods
Summary:
The management of respiratory motion in radiation oncology is an evolving field
IGRT provides a solution for combating organ motion in radiotherapy
Delivering higher dose to tumor and less dose to normal tissue.
Limited clinical studies, needs to be studied further
IGRT – the future of radiotherapy
Stereotactic body radiotherapy (SBRT) delivers high-dose radiation to tumors in a small number of fractions using high precision. For prostate SBRT, the target and organs at risk are contoured on planning CT. A dose of 35-38Gy in 5 fractions is used as primary treatment for low risk prostate cancer. Rigid image guidance and intrafraction monitoring are important to minimize setup errors. ExacTrac X-ray positioning co-registers X-rays with digitally reconstructed radiographs and corrects for rotational and translational deviations, achieving sub-millimeter accuracy. This allows safe dose escalation for prostate SBRT.
Treatment verification systems in radiation therapyanju k.v.
This document discusses various techniques used for treatment verification in radiation therapy. It describes electronic portal imaging devices (EPID) which can be used for daily treatment localization and verification through portal images with little additional dose. Cone beam computed tomography (CBCT) is also discussed, which provides volumetric CT images with submillimeter resolution, allowing verification of patient positioning before treatment. Both EPID and CBCT help ensure the correct radiation dose is delivered to the intended target volume.
1. ICRU Report 83 provides guidelines for prescribing, recording, and reporting intensity-modulated radiation therapy (IMRT). It emphasizes using dose-volume histograms and statistics like median dose to describe dose distributions.
2. The report outlines three levels of prescribing and reporting with increasing complexity. Level 1 involves basic 2D dose distributions while Level 3 incorporates more advanced metrics like tumor control probability.
3. Key volumes discussed include gross tumor volume, clinical target volume, planning target volume, and organs at risk. The report standardized how to account for uncertainties and patient motion when defining these volumes.
Final ICRU 62 ( International commission on radiation units and measurements)DrAyush Garg
The document discusses recommendations from reports by the International Commission on Radiation Units and Measurements (ICRU) for defining volumes used in radiation therapy planning and reporting. ICRU Report 62 provides additional details on volumes such as the internal target volume (ITV) and planning organ at risk volume (PRV), and introduces metrics like the conformity index. It also further classifies organs at risk as serial, parallel or serial-parallel based on their radiosensitivity.
This document discusses various methods for managing tumor motion during radiotherapy treatment delivery, including gating, breath hold techniques, abdominal compression, and tumor tracking. It describes the basic workflow and advantages and disadvantages of each approach. Phase-based gating and breath hold methods can reduce margins and lower dose to nearby organs but require patient compliance. Tracking allows for treatment during respiration but increases imaging dose. The best solution depends on the individual clinical situation and tumor characteristics.
Advances in radiation oncology:Cancer careAjeet Gandhi
Radiation therapy has tremendous capacity for cancer cure. Advancement in last few decades have further enhanced its outcome. Global access would save many lives
RADIOTHERAPY TARGET DELINEATION IN BREAST CANCERKanhu Charan
This document discusses guidelines for target delineation in breast cancer radiotherapy, including contours for the chest wall, breast, lymph nodes, and organs at risk. It describes guidelines from organizations like EORTC, RTOG, TROG, and ESTRO for delineating targets like the supraclavicular fossa, internal mammary nodes, and three levels of axillary lymph nodes. It also discusses techniques like custom immobilization and image guidance that can help reduce planning target volume and guidelines for target volumes in post-mastectomy and breast-conserving settings.
This document discusses various modern radiation therapy techniques including IMRT, IGRT, MVCBCT, and KVCBCT. It provides background on 2D and 3D conformal radiation therapy. IMRT uses intensity modulated beams and inverse planning to improve dose distribution. IGRT uses imaging before and during treatment for precise targeting. MVCBCT and KVCBCT provide volumetric imaging using megavoltage and kilovoltage sources, with KVCBCT offering better soft tissue contrast. Errors in patient positioning can be detected and corrected using these image-guided techniques.
This document discusses Image Guided Radiation Therapy (IGRT). It begins by explaining that radiotherapy has traditionally used imaging for treatment planning and execution when the target is not on the surface. It then describes various IGRT technologies, dividing them into non-radiation based systems like ultrasound, cameras, electromagnetic tracking and MRI; and radiation based systems like EPID, CBCT, fan beam KVCT and MVCT. These systems provide improved target localization and allow for corrections. IGRT aims to reduce errors and improve precision of radiotherapy.
Treatment gap correction methods using bed formalism, radiobiologyRANJITH C P
1) Radiotherapy treatment interruptions can increase the risk of local tumor recurrence. Certain tumor types, like head and neck cancers, are particularly sensitive to interruptions.
2) Guidelines categorize patients based on sensitivity to interruptions. Category 1 patients should aim to avoid interruptions over 2 days.
3) Unscheduled interruptions can be managed by treating patients twice daily to compensate or adding extra fractions, while considering dose limits to normal tissues. Biological modeling can help determine equivalent doses when rescheduling treatment.
4D-CBCT (Symmetry) - a useful tool to verify and treat traditional ITV withou...Dr. Malhar Patel
4D-CBCT is latest software gadget in field of radiation oncology. It will calculate breathing movement during treatment of lung cancer and help in delineate the target better.
This presentation will convince you that even if you do not have 4D-CT simulation, you can confidently use 4D-CBCT at optimal level.
An overview of imrt, vmat optimization algorithmsRahim Gohar
This document discusses intensity-modulated radiation therapy (IMRT) and volumetric modulated arc therapy (VMAT) optimization algorithms, including direct machine parameter optimization (DVO), leaf motion calculation (LMC), progressive gradient optimization (PGO), and multi-resolution dose calculation (MRDC). It emphasizes that theoretical physicists developing these algorithms have revolutionized the field of radiation oncology by enabling more conformal radiation treatments.
Learn about the process of radiation therapy to treat soft tissue sarcoma, and how new radiation technology has improved treatment of the disease.
This presentation was given by Elizabeth H. Baldini, MD, MPH, radiation oncology director for the Center for Sarcoma and Bone Oncology at Dana-Farber Cancer Institute. It was originally presented as part of the "15 Years of GIST/Soft Tissue Sarcoma Symposium," held on Sept. 12, 2015 at Dana-Farber in Boston, Mass.
This document discusses radiosurgery for treating brain metastases. It begins by explaining that brain metastases originate from cancers elsewhere in the body that have spread to the brain, whereas primary brain tumors originate from brain cells. Radiosurgery is described as highly targeted radiation focused on a well-defined brain metastasis target, making it more appropriate than whole brain radiation or surgery for many cases. Several studies are summarized that show radiosurgery provides better local tumor control and longer survival compared to whole brain radiation for patients with 1-3 brain metastases. Optimal patient selection and dosing parameters are discussed to maximize the benefits of radiosurgery while minimizing side effects.
This document summarizes key considerations for intensity-modulated radiation therapy (IMRT) treatment planning and dosimetry. It discusses beam modeling, dose calculation, inverse planning, and quality assurance. Accurate modeling of beam penumbra, multileaf collimator characteristics, output factors for small fields, and dose calculation algorithms are essential for ensuring dosimetric accuracy. Proper target and organ-at-risk delineation and appropriate margins are also important for effective IMRT planning.
Artificial Intelligence in Radiation OncologyWookjin Choi
The document discusses artificial intelligence applications in radiation oncology. It begins with acknowledgements and then outlines topics including radiomics decision support tools, automatic delineation and variability analysis, and applications like lung cancer screening, tumor response prediction, and aggressive lung adenocarcinoma subtype prediction. Radiomics frameworks and deep learning models are presented. Results show potential for AI to provide quantitative imaging biomarkers and improve outcomes in areas like screening, treatment planning, and response assessment.
1.Aim of Radiotherapy
The goal of radiotherapy is to deliver a prescribed dose of radiation to the Target while sparing surrounding Healthy tissues to the largest extent possible
2.Organ Motion
Intra-fraction motion
during the fraction
Heartbeat
Swallowing
Coughing
Eye movement
Inter-fraction motion
- in between the fractions
Tumour change
Weight gain/loss
Positioning deviation
Breathing
Bowel and rectal filling
Bladder filling
Muscle relaxation/tension
3. Respiratory motion affects:
Respiratory motion affects all tumour sites in the thorax, abdomen and Pelvis. Tumours in the Lung, Liver, Pancreas, Oesophagus, Breast, Kidneys, prostate
Tumour displacement varies depending on the site and organ Location
Lung tumours can move several cm in any direction during irradiation
It is most prevalent and prominent in Lung cancers
4. Problems associated with respiratory motion during RT
Image acquisition limitations
Treatment planning limitations
Radiation delivery limitations
5. Methods to Account for Respiratory Motion
1. Motion encompassing methods
2. Respiratory gating methods
3. Breath hold methods
4. Forced shallow breathing with abdominal compression
5. Real-time tumor tracking methods
Summary:
The management of respiratory motion in radiation oncology is an evolving field
IGRT provides a solution for combating organ motion in radiotherapy
Delivering higher dose to tumor and less dose to normal tissue.
Limited clinical studies, needs to be studied further
IGRT – the future of radiotherapy
Stereotactic body radiotherapy (SBRT) delivers high-dose radiation to tumors in a small number of fractions using high precision. For prostate SBRT, the target and organs at risk are contoured on planning CT. A dose of 35-38Gy in 5 fractions is used as primary treatment for low risk prostate cancer. Rigid image guidance and intrafraction monitoring are important to minimize setup errors. ExacTrac X-ray positioning co-registers X-rays with digitally reconstructed radiographs and corrects for rotational and translational deviations, achieving sub-millimeter accuracy. This allows safe dose escalation for prostate SBRT.
Treatment verification systems in radiation therapyanju k.v.
This document discusses various techniques used for treatment verification in radiation therapy. It describes electronic portal imaging devices (EPID) which can be used for daily treatment localization and verification through portal images with little additional dose. Cone beam computed tomography (CBCT) is also discussed, which provides volumetric CT images with submillimeter resolution, allowing verification of patient positioning before treatment. Both EPID and CBCT help ensure the correct radiation dose is delivered to the intended target volume.
1. ICRU Report 83 provides guidelines for prescribing, recording, and reporting intensity-modulated radiation therapy (IMRT). It emphasizes using dose-volume histograms and statistics like median dose to describe dose distributions.
2. The report outlines three levels of prescribing and reporting with increasing complexity. Level 1 involves basic 2D dose distributions while Level 3 incorporates more advanced metrics like tumor control probability.
3. Key volumes discussed include gross tumor volume, clinical target volume, planning target volume, and organs at risk. The report standardized how to account for uncertainties and patient motion when defining these volumes.
Final ICRU 62 ( International commission on radiation units and measurements)DrAyush Garg
The document discusses recommendations from reports by the International Commission on Radiation Units and Measurements (ICRU) for defining volumes used in radiation therapy planning and reporting. ICRU Report 62 provides additional details on volumes such as the internal target volume (ITV) and planning organ at risk volume (PRV), and introduces metrics like the conformity index. It also further classifies organs at risk as serial, parallel or serial-parallel based on their radiosensitivity.
This document discusses various methods for managing tumor motion during radiotherapy treatment delivery, including gating, breath hold techniques, abdominal compression, and tumor tracking. It describes the basic workflow and advantages and disadvantages of each approach. Phase-based gating and breath hold methods can reduce margins and lower dose to nearby organs but require patient compliance. Tracking allows for treatment during respiration but increases imaging dose. The best solution depends on the individual clinical situation and tumor characteristics.
Advances in radiation oncology:Cancer careAjeet Gandhi
Radiation therapy has tremendous capacity for cancer cure. Advancement in last few decades have further enhanced its outcome. Global access would save many lives
RADIOTHERAPY TARGET DELINEATION IN BREAST CANCERKanhu Charan
This document discusses guidelines for target delineation in breast cancer radiotherapy, including contours for the chest wall, breast, lymph nodes, and organs at risk. It describes guidelines from organizations like EORTC, RTOG, TROG, and ESTRO for delineating targets like the supraclavicular fossa, internal mammary nodes, and three levels of axillary lymph nodes. It also discusses techniques like custom immobilization and image guidance that can help reduce planning target volume and guidelines for target volumes in post-mastectomy and breast-conserving settings.
This document discusses various modern radiation therapy techniques including IMRT, IGRT, MVCBCT, and KVCBCT. It provides background on 2D and 3D conformal radiation therapy. IMRT uses intensity modulated beams and inverse planning to improve dose distribution. IGRT uses imaging before and during treatment for precise targeting. MVCBCT and KVCBCT provide volumetric imaging using megavoltage and kilovoltage sources, with KVCBCT offering better soft tissue contrast. Errors in patient positioning can be detected and corrected using these image-guided techniques.
This document discusses Image Guided Radiation Therapy (IGRT). It begins by explaining that radiotherapy has traditionally used imaging for treatment planning and execution when the target is not on the surface. It then describes various IGRT technologies, dividing them into non-radiation based systems like ultrasound, cameras, electromagnetic tracking and MRI; and radiation based systems like EPID, CBCT, fan beam KVCT and MVCT. These systems provide improved target localization and allow for corrections. IGRT aims to reduce errors and improve precision of radiotherapy.
Treatment gap correction methods using bed formalism, radiobiologyRANJITH C P
1) Radiotherapy treatment interruptions can increase the risk of local tumor recurrence. Certain tumor types, like head and neck cancers, are particularly sensitive to interruptions.
2) Guidelines categorize patients based on sensitivity to interruptions. Category 1 patients should aim to avoid interruptions over 2 days.
3) Unscheduled interruptions can be managed by treating patients twice daily to compensate or adding extra fractions, while considering dose limits to normal tissues. Biological modeling can help determine equivalent doses when rescheduling treatment.
4D-CBCT (Symmetry) - a useful tool to verify and treat traditional ITV withou...Dr. Malhar Patel
4D-CBCT is latest software gadget in field of radiation oncology. It will calculate breathing movement during treatment of lung cancer and help in delineate the target better.
This presentation will convince you that even if you do not have 4D-CT simulation, you can confidently use 4D-CBCT at optimal level.
An overview of imrt, vmat optimization algorithmsRahim Gohar
This document discusses intensity-modulated radiation therapy (IMRT) and volumetric modulated arc therapy (VMAT) optimization algorithms, including direct machine parameter optimization (DVO), leaf motion calculation (LMC), progressive gradient optimization (PGO), and multi-resolution dose calculation (MRDC). It emphasizes that theoretical physicists developing these algorithms have revolutionized the field of radiation oncology by enabling more conformal radiation treatments.
Learn about the process of radiation therapy to treat soft tissue sarcoma, and how new radiation technology has improved treatment of the disease.
This presentation was given by Elizabeth H. Baldini, MD, MPH, radiation oncology director for the Center for Sarcoma and Bone Oncology at Dana-Farber Cancer Institute. It was originally presented as part of the "15 Years of GIST/Soft Tissue Sarcoma Symposium," held on Sept. 12, 2015 at Dana-Farber in Boston, Mass.
This document discusses radiosurgery for treating brain metastases. It begins by explaining that brain metastases originate from cancers elsewhere in the body that have spread to the brain, whereas primary brain tumors originate from brain cells. Radiosurgery is described as highly targeted radiation focused on a well-defined brain metastasis target, making it more appropriate than whole brain radiation or surgery for many cases. Several studies are summarized that show radiosurgery provides better local tumor control and longer survival compared to whole brain radiation for patients with 1-3 brain metastases. Optimal patient selection and dosing parameters are discussed to maximize the benefits of radiosurgery while minimizing side effects.
This document summarizes key considerations for intensity-modulated radiation therapy (IMRT) treatment planning and dosimetry. It discusses beam modeling, dose calculation, inverse planning, and quality assurance. Accurate modeling of beam penumbra, multileaf collimator characteristics, output factors for small fields, and dose calculation algorithms are essential for ensuring dosimetric accuracy. Proper target and organ-at-risk delineation and appropriate margins are also important for effective IMRT planning.
Artificial Intelligence in Radiation OncologyWookjin Choi
The document discusses artificial intelligence applications in radiation oncology. It begins with acknowledgements and then outlines topics including radiomics decision support tools, automatic delineation and variability analysis, and applications like lung cancer screening, tumor response prediction, and aggressive lung adenocarcinoma subtype prediction. Radiomics frameworks and deep learning models are presented. Results show potential for AI to provide quantitative imaging biomarkers and improve outcomes in areas like screening, treatment planning, and response assessment.
Pathomics Based Biomarkers, Tools, and Methodsimgcommcall
This document discusses pathomics-based biomarkers, tools, and methods for multi-scale integrative analysis in biomedical informatics. It summarizes several projects involving extracting quantitative features from pathology and radiology images using image segmentation and analysis techniques. These features are then linked to molecular data and clinical outcomes using statistical and machine learning methods to develop biomarkers. The tools and methods described aim to standardize and optimize feature extraction while accounting for uncertainties.
University of Toronto - Radiomics for Oncology - 2017Andre Dekker
This document contains the slides from a lecture on radiomics for oncology given by Andre Dekker. The lecture covers the rationale for radiomics, which is to use quantitative features extracted from medical images to help predict outcomes like tumor behavior, survival, and response to treatment using machine learning. The major workflow steps of radiomics are discussed, from image acquisition and feature extraction to modeling and validation. Key challenges like robust segmentation and feature reproducibility are also addressed. New directions for radiomics research include applications in preclinical studies, other modalities like PET and MRI, and linking radiomic features to genomic data. Overall, radiomics holds promise to help personalized medicine but large amounts of standardized data are still needed for proper validation of models.
Dekker trog - big data for radiation oncology - 2017Andre Dekker
- Big data in radiation oncology comes from clinical research, registries, and routine clinical data, but the latter has the most patients and features while also having the most missing data.
- Models are developed using a hypothesis-driven approach by learning from a training cohort and estimating performance in a validation cohort. Challenges include gaining trust in models, dealing with continuous changes, and addressing barriers to implementing shared decision making.
- Overall, big data and models can improve cancer care by better tailoring treatments to individual patients, but also require overcoming challenges through rapid learning and collaboration across institutions.
Interpretable Spiculation Quantification for Lung Cancer ScreeningWookjin Choi
Spiculations are spikes on the surface of pulmonary nodule and are important predictors of malignancy in lung cancer. In this work, we introduced an interpretable, parameter-free technique for quantifying this critical feature using the area distortion metric from the spherical conformal (angle-preserving) parameterization. The conformal factor in the spherical mapping formulation provides a direct measure of spiculation which can be used to detect spikes and compute spike heights for geometrically-complex spiculations. The use of the area distortion metric from conformal mapping has never been exploited before in this context. Based on the area distortion metric and the spiculation height, we introduced a novel spiculation score. A combination of our spiculation measures was found to be highly correlated (Spearman's rank correlation coefficient ρ = 0.48) with the radiologist's spiculation score. These measures were also used in the radiomics framework to achieve state-of-the-art malignancy prediction accuracy of 88.9% on a publicly available dataset.
Machine Learning and Deep Contemplation of DataJoel Saltz
Spatio temporal data analytics - Generation of Features
1) Sanity Checking and Data Cleaning, 2) Qualitative Exploration, 3) Descriptive Statistics, 4) Classification, 5) Identification of Interesting Phenomena, 6) Prediction, 7) Control and 8)
Save Data for Later (Compression).
Detailed example from Precision Medicine; Pathomics, Radiomics.
AI techniques are being explored to derive real-world evidence from routine medical imaging and reports. Image segmentation algorithms can identify tumors and organs in medical images. Natural language processing of radiology reports containing over 700,000 structured records dating back to 2009 has mapped patterns of metastatic disease and generated real-time survival curves for different cancers using only the uncurated data. Further development aims to uncover true response rates, map cancers of unknown primary back in time, and generate hypotheses for clinical trials to potentially expedite research. Addressing issues around data biases, identity, and social justice will be important to responsibly develop these techniques.
This document provides updates to the National Comprehensive Cancer Network (NCCN) Clinical Practice Guidelines for Soft Tissue Sarcoma. Key updates include:
1) Changing terms from "preoperative" to "neoadjuvant" and "postoperative" to "adjuvant".
2) Adding dermatofibrosarcoma protuberans without fibrosarcomatous transformation to special histologies for rhabdomyosarcoma.
3) Modifying imaging and biopsy recommendations.
4) Adding considerations for neoadjuvant radiation and systemic therapy.
5) Updating principles, treatment options, and footnotes across all algorithm pages.
American Association for Cancer Research Annual Meeting 2022
Analysis of images of routinely acquired tissue specimens promise to provide biomarkers that can be used to predict disease outcome and steer treatment, improve diagnostic reproducibility, and reveal new insights to further advance current human understanding of disease. The advent of AI and ubiquitous high-end computing are making it possible to carry out accurate whole slide image morphological and molecular tissue analyses at cellular and subcellular resolutions. AI methods are can enable exploration and discovery of novel diagnostic biomarkers grounded in prognostically predictive spatial and molecular patterns as well as quantitative assessments of predictive value and reproducibility of traditional morphological patterns employed in anatomic pathology. AI methods may be adapted to help steer treatment through integrative analysis of clinical information along with Pathology, Radiology and molecular data.
This document outlines a research proposal on medical image fusion. It discusses radiotherapy treatment planning which involves target volume delineation using fused images from modalities like PET, CT and MRI. The proposal discusses techniques for image decomposition, fusion and reconstruction. It reviews literature on various fusion methods like multi-resolution analysis, multi-scale geometric analysis and color based methods. It identifies research gaps in appropriate decomposition levels and contouring. The proposal discusses implementing a fusion method using soft computing techniques to differentiate between edge and non-edge regions.
The document describes the CyberKnife robotic radiosurgery system. It provides sub-millimeter accuracy for treating tumors throughout the body with precise radiation beams. Key features include its robotic ability to track and correct for tumor movement during treatment in real-time without needing invasive head/body frames. It has treated over 16,000 patients worldwide for conditions like brain, lung, prostate and spine tumors.
What are the Responsibilities of a Product Manager by Google PMProduct School
Main takeaways:
-Why Product Managers are critical for research organizations
-Find out what a Product Manager at DeepMind does
-Product Management at the complex intersection of AI and healthcare
Bridging the STEM gender gap through cultural inclusion and educational opportunity, this opportunity was granted to a selected set of women from UB to showcase their research.
Radiomics and Deep Learning for Lung Cancer ScreeningWookjin Choi
The document summarizes research on using radiomics and deep learning approaches for lung cancer screening. It describes:
1) Using radiomic features like shape, texture, and intensity from lung nodules on CT scans and an SVM-LASSO model to classify nodules with 87.9% sensitivity and 78.2% specificity, outperforming the Lung-RADS system.
2) A deep learning model developed for a Kaggle competition that achieved 67.4% accuracy on nodule classification but only ranked 99th due to overfitting issues without enough data.
3) Future work could integrate quantification of nodule characteristics like spiculation with plasma biomarkers to improve diagnostic accuracy.
The vital importance of imaging techniques in radiation oncology now extends beyond diagnostic evaluation and treatment planning. Radiotherapy requires input from imaging for treatment planning and execution, when the treatment target is not located on the surface and, inspection and visual confirmation are not feasible. Traditional radiotherapy practices incorporate use of anatomic surface landmarks as well as radiologic correlation with 2D imaging in the form of port films or fluoroscopic imaging. Targets to be irradiated and normal tissues to be spared are delineated on CT scans in the planning process. Recent technical advances have enabled the integration of various imaging modalities into the everyday practice of radiotherapy directly at the linear accelerator. IGRT seeks to address geometric uncertainties in dose placement for target and normal tissues. It has become a routine part of current RT practice. Safe application of IGRT technology requires additional training and careful integration into the clinical process. IGRT reveals changes in anatomy during treatment which challenges conventional practices. IGRT facilitates the precise application of specialized irradiation techniques with narrow safety margins to radiosensitive organs.
David Snead on The use of digital pathology in the primary diagnosis of histo...Cirdan
Recent developments in digital pathology enable the rapid scanning of microscope slides at high resolution, making the digitisation of histopathology slides for routine diagnosis purposes feasible. An important initial step in the wider adoption of this technology is the establishment of validation data assessing how effective pathologists are using digital workstations in comparison to conventional light microscopes and glass slides when examining cases for primary diagnosis. I will report on the first study sufficiently powered to demonstrate a statistically valid equivalent (i.e. non-inferior) performance of digital pathology (DP) against standard glass slide (GS) microscopy. This study examined a total of 3,017 cases were included, generating 10,138 slides, which when scanned resulted in a digital archive of 2.45 terabytes. As well as demonstrating non-inferiority of digital in comparison to glass slides the study was useful in establishing rules for slide scanning and identifying areas where digital pathology has limitations and needs to be used with caution.
Finally the presentation covers the impact adopting digital pathology will have on diagnostic laboratories, the economics of these changes and where these changes are most likely to benefit patients.
Similar to Artificial Intelligence in Radiation Oncology.pptx (20)
Deep Learning-based Histological SegmentationDifferentiates Cavitation Patte...Wookjin Choi
Unsupervised segmentation (unlabeled regions of interest, ROIs) and autoencoder (AE)-based classification were used to classify differences in cavitation patterns in knees and digits using the stained images (n=20-30 images/group).
Each image was divided into 256 x 256 pixel patches, and a convolutional neural network (CNN)-based unsupervised segmentation was used to identify ROIs. These patches were subsequently fed into a CNN-based AE whose latent space layer was connected to a classifier for input patch classification.
The AE was trained using the ROIs identified by the unsupervised segmentation, and the image classes were used to train the classifier. Whole image classifications were determined by maximum voting of the patch results and evaluated by accuracy.
Artificial Intelligence To Reduce Radiation-induced Cardiotoxicity In Lung Ca...Wookjin Choi
Traditionally, radiation-induced cardiotoxicity has been studied using cardiac radiation doses rather than functional imaging. We developed artificial intelligence (AI) models based on novel cardiac delta radiomics using pre- and post-treatment FDG-PET/CT scans to predict overall survival in lung cancer patients undergoing radiotherapy. We identified four clinically relevant delta radiomics features with the AI prediction models. The best model achieved an AUC of 0.91 on the training set and 0.87 on the test set. We are a pioneering group in AI for functional cardiac imaging. If validated, this approach will enable to use standard PET/CT scans as functional cardiac imaging with good predictive AUC for OS, as well as provide automated methods to provide functional cardiac information for clinical outcome prediction AI in lung cancer patients.
Novel Functional Radiomics for Prediction of Cardiac PET Avidity in Lung Canc...Wookjin Choi
Purpose/Objective(s)
Traditional methods of evaluating cardiotoxicity focus solely on radiation doses to the heart and do not incorporate functional imaging information. Functional imaging has great potential to improve the ability to provide early prediction for cardiotoxicity for lung cancer patients undergoing radiotherapy. FDG-based PET/CT imaging is routinely obtained as part of standard staging work up for lung cancer patients. Although FDG PET/CT scans are typically used to evaluate the tumor, imaging guidelines note that FDG PET/CT scans are an FDA-approved method to image for cardiac inflammation, and studies have noted that the PET cardiac signal can be predictive of clinical outcomes. The purpose of this work was to develop a radiomics model to predict clinical cardiac assessment of standard of care FDG PET/CT scans.
Materials/Methods
The study included 100 consecutive lung cancer patients treated with radiotherapy who underwent standard pre-treatment FDG-PET/CT staging scans. A clinician reviewed the PET/CT scans per clinical cardiac assessment guidelines and classified the cardiac uptake as: 0 = uniform diffuse, 1 = absent, 2 = heterogeneous, with event rates of 20%, 44%, and 35%, respectively. The heart was delineated and 200 novel functional radiomics features were selected to classify cardiac FDG uptake patterns. We divided the data into an 80% training set and a 20% test set to train and evaluate the classification models. Feature reduction was carried out using the Wilcoxon test (with Bonferroni adjusted p<0.05), hierarchical clustering, and Recursive Feature Elimination. Two automatic machine learning (AutoML) frameworks were used to determine classification models: a Random Forest Classifier (Tree-based Pipeline Optimization Tool, TPOT) and Linear Discriminant Analysis (AutoSklearn). 10-fold cross validation was carried out for training and the accuracy of the ability of the models to predict for clinical cardiac assessment is reported.
Results
Fifty-one independent radiomics features were reduced to 3 clinically pertinent features (PET 2D Skewness, PET Grey Level Co-occurrence Matrix Correlation, and PET Median) using feature reduction techniques. The model selected by TPOT showed 89.8% predictive accuracy in the cross validation of the training set and 85% predictive accuracy on the test set. The model selected by AutoSklearn showed 89.7% predictive accuracy in the cross validation of the training set and 80% predictive accuracy on the test set.
Conclusion
The novelty of this work is that it is the first study to develop and evaluate functional cardiac radiomic features from standard of care FDG PET/CT scans with the data showing good predictive accuracy with clinical imaging evaluation. If validated, the current work provides automated methods to provide functional cardiac information using standard of care imaging that can be used as an imaging biomarker for early clinical toxicity prediction for lung cancer patients.
Novel Deep Learning Segmentation Models for Accurate GTV and OAR Segmentation...Wookjin Choi
Purpose/Objective(s)
MR-guided adaptive radiotherapy (MRgART) improves target coverage and organ-at-risk (OAR) sparing in pancreatic cancer radiation therapy (RT). Inter-fractional changes in patients undergoing RT require time intensive re-delineation of gross tumor volume (GTV) and OARs prior to adaptive optimization. Accurate automatic segmentation has the potential to significantly improve efficiency of the adaptive workflow. We hypothesized that state-of-the-art deep learning (DL) segmentation models could adequately segment GTV and OARs in both planning and daily fractional MR scans.
Materials/Methods
The study included 21 patients with pancreatic cancer treated with MRgART (10 Gy x 5 fractions). The planning MR as well as all daily MR images and registrations were collected (6 image sets per patient and a total of 126 image sets). The planning MR and fraction 1-4 image sets were used as the training set (N = 105), while the test set (N = 21) comprised images for fraction 5, to simulate the last step of incremental learning from planning to final fraction. Evaluated contours included the GTV, Small Bowel, Large Bowel, Duodenum, Left and Right Kidney, Liver, Spinal Cord, and Stomach. To mimic clinical conditions, contour accuracy was evaluated within the ring structure surrounding the PTV, inside of which daily adaptive re-contouring is applied (2 cm expansion in the cradio-caudal direction, 3 cm expansion otherwise). We evaluated three DL model architectures: SegResNet, SegResNet 2D, and SwinUNETR to autosegment GTV and OARs. The segmentation models were trained on the training set using 5-fold cross-validation (CV) and quantitatively analyzed by comparing against clinically used contours with DICE scores. Qualitative analysis was performed by a radiation oncologist using a scoring scale: 1 = perfect, 2 = minor discrepancy, 3 = moderate discrepancy, and 4 = rejected.
Results
Overall, the DL segmentations were in acceptable agreement with clinical contours. The best performing model was the SwinUNETR model with overall training DICE = 0.88±0.06, test DICE = 0.78±0.11, and qualitative score of 1.6±0.8. The agreement between the DL model and clinical segmentation for the GTV was 0.79±0.08, with a qualitative score of 2.2±0.9
Conclusion
We report here the most comprehensive work on DL segmentation for pancreatic cancer MRgART, including quantitative and clinically-pertinent qualitative evaluations of 126 image sets and 3 DL architectures. Our data show good quantitative agreement between DL and clinical contours, and acceptable clinician evaluations for the majority of GTVs and OARs. The current work has great potential to significantly reduce a major bottleneck in the MRgART workflow for pancreatic cancer patients.
Novel Functional Delta-Radiomics for Predicting Overall Survival in Lung Canc...Wookjin Choi
AAPM2023_SU-300-IePD-F6-4
Purpose: Traditional methods of evaluating cardiotoxicity rely on cardiac radiation doses and do not incorporate functional imaging. Cardiac functional imaging can improve the ability to provide early prediction for clinical outcomes for lung cancer patients undergoing radiotherapy. FDG-based PET/CT imaging is routinely obtained for staging and disease assessment after treatment. Although FDG PET/CT scans are typically used to evaluate the tumor, studies have shown that the PET cardiac signal is predictive of clinical outcomes. Our study aimed to develop novel functional cardiac delta radiomics using pre and post-treatment FDG PET/CT scans to predict for overall survival (OS).
Methods: We conducted a study of 109 lung cancer patients who underwent standard FDG-PET/CT scans pre- and post-radiotherapy. Data from ACRIN 6668 (N=70) and an investigator-initiated lung cancer trial (N=39) for functional avoidance radiotherapy were used. The heart was delineated, and 200 cardiac CT and PET functional radiomics features were selected. Delta radiomics was calculated as the change between pre- and post-PET/CT. The data were divided into 80%/20% training/test set, and feature reduction was performed using Wilcoxon test, hierarchical clustering, and recursive feature elimination. A Gradient Boosting Classifier machine learning model evaluated the ability of the delta PET/CT cardiac radiomics to predict for OS using 10-fold cross-validation for training and area-under-the-curve (AUC) for model assessment.
Results: Median survival was 431 days (range 144 to 1640 days). 4 clinically relevant delta features were identified: pre-CT_Maximum, post-CT_Minimum, delta-CT_GLRM_Run_Variance, delta-PET_GLRM_Run_Entropy. The model showed an AUC of 0.91 on the training set and an AUC of 0.87 on the test set.
Conclusion: This is the first study to evaluate functional cardiac delta radiomic features from standard PET/CT scans with data showing good predictive AUC for OS. If validated, this work provides automated methods to provide functional cardiac information for clinical outcome prediction in lung cancer patients.
CIRDataset: A large-scale Dataset for Clinically-Interpretable lung nodule Ra...Wookjin Choi
The CIRDataset provides a large-scale dataset of 956 annotated lung nodules with segmentations and classifications of spiculations and lobulations, which are important radiomic features for assessing malignancy. It aims to address the lack of publicly available datasets capturing these subtle radiological features typically assessed by radiologists but often smoothed over by deep learning segmentation models. The dataset is accompanied by code, models, and a pipeline to enable the development of AI systems for joint nodule segmentation, classification of spiculations/lobulations, and malignancy prediction using an end-to-end deep learning approach.
Automatic motion tracking system for analysis of insect behaviorWookjin Choi
Undergraduate research.
We present a multi-object tracking system to track small insects such as ants and bees. Motion-based object tracking recognizes the movements of objects in videos using information extracted from the given video frames. We applied several computer vision techniques, such as blob detection and appearance matching, to track ants. Moreover, we discussed different object detection methodologies and investigated the various challenges of object detection, such as illumination variations and blob merge/split. The proposed system effectively tracked multiple objects in various environments.
Assessing the Dosimetric Links between Organ-At-Risk Delineation Variability ...Wookjin Choi
Purpose: To determine the relative dosimetric impact of delineation variability (DV) when inter-observer and inter-technique planning variability (PV), and setup variability (SV) with are considered.
Methods: 409 plans for a single head-and-neck patient from the 2017 Radiation Knowledge plan competition were used. Plans were created with Eclipse (N=227), Pinnacle (N=49), RayStation (N=25), Monaco (N=75), and TomoTherapy (N=33) with delivery techniques conventional linac IMRT (N=142), volumetric modulated arc therapy (VMAT, N=234), and helical TomoTherapy (N=33). All plans were optimized using a consistent set of target volumes and a single OAR structure set. Four additional OAR structure sets were contoured by radiation oncologists (N=2) and medical physics residents (N=2) who had completed head-and-neck contouring training. Probabilistic DVHs, dose-volume coverage maps (DVCM), which shows the probability of achieving a dose metric, were computed for each OAR on the following scenarios: SV alone (N=1000), SV+PV (N=1000*409), SV+DV (N=1000*5), SV+PV+DV (total variability [TV], N=1000*409*5). Analysis focused on the probability of exceeding the maximum dose constraint exceeded 5% for each OAR.
Results: The primary source of variability was PV, which was expected due to inter-observer planning abilities and preferences during the optimization planning process, even when all participants utilized the same constraints. The parotid had the most significant interquartile range (IQR) on the PV scenario. Conversely, adding SV, DV, and TV each reduced the IQR, showing a washing out effect on the DVCM.
Conclusion: Assessment of OAR sensitivity to DV will be highly sensitive to the specific planning technique and planner, likely requiring plan-specific assessment of in-tolerance delineation variations. Incorporation SV and DV variabilities in plan assessments washes out their relative impacts on maximum dose.
Simulation of Realistic Organ-At-Risk Delineation Variability in Head and Nec...Wookjin Choi
(Sunday, 7/14/2019) 4:00 PM - 5:00 PM
Room: 225BCD
Purpose: To simulate realistic manual delineation (MD) organ-at-risk (OAR) delineation variability (DV) the purpose of quantifying DV’s dosimetric impact.
Methods: Fourteen independent MD head-and-neck OAR structure sets (SS) were obtained from the ESTRO Falcon group. Seven OARs were available (BrainStem, Esophagus, OralCavity, Parotid_L, Parotid_R, SpinalCord, and Thyroid). A consensus MD SS was generated by the simultaneous truth and performance level estimation (STAPLE) method. MD DV was evaluated with respect to the STAPLE SS using the Dice coefficient and Hausdorff distance (HD) geometric similarity metrics. DVs were simulated using auto-delineation (AD)
methods: an average surface of standard deviation (ASSD) method, GrowCut segmentation, and a random walker (RW) segmentation. Each OAR AD was repeated five times with a different seed or variability level. Dice and HD were computed for each OAR AD with respect to the STAPLE SS. Dosimetric analysis was achieved by intercomparing dose-volume histograms (DVH) from a plan developed with a reference MD SS with DVHs for each MD and AD. DVH confidence bands are reported for MD and each AD method.
Results: The MD Dice was 0.7±0.2 (μ±σ). AD Dice values (ASSD, GrowCut, and RW) were 0.5±0.2, 0.7±0.2, and 0.8±0.1, respectively. HDs were 35.4±45.2, 27.3±19.1, 29.3±19.9, and 14.6±10.3. The simulated DV increased with increasing the seed standard deviations or variability level. The dosimetric effect was largest for MD DVs (larger OAR DVH confidence intervals and larger HD), even though the MD Dice was greater than the ASSD and GrowCut Dice values. GrowCut DV resulted in less dosimetric variation than RW, unlike the geometric indices.
Conclusion: We developed a framework to simulate DVs and demonstrated its feasibility. ADs were able to simulate different magnitudes of DVs, but did not replicate the dosimetric consequences of human delineation variability. The correlation between geometric similarity metrics and dosimetric consequences of DV is poor.
Quantitative image analysis for cancer diagnosis and radiation therapyWookjin Choi
1.Lung Cancer Screening
1.1.Deep learning (feasible but not interpretable)
1.2.Radiomics (concise model)
1.3.Spiculation quantification (interpretable feature)
2.PET/CT Tumor Response
2.1.Aggressive Lung ADC subtype prediction (helpful for surgeons)
2.2.Pathologic response prediction (accurate but not concise)
2.3.Local tumor morphological changes (accurate and interpretable)
Interpretable Spiculation Quantification for Lung Cancer ScreeningWookjin Choi
Spiculations are spikes on the surface of pulmonary nodule and are important predictors of malignancy in lung cancer. In this work, we introduced an interpretable, parameter-free technique for quantifying this critical feature using the area distortion metric from the spherical conformal (angle-preserving) parameterization. The conformal factor in the spherical mapping formulation provides a direct measure of spiculation which can be used to detect spikes and compute spike heights for geometrically-complex spiculations. The use of the area distortion metric from conformal mapping has never been exploited before in this context. Based on the area distortion metric and the spiculation height, we introduced a novel spiculation score. A combination of our spiculation measures was found to be highly correlated (Spearman's rank correlation coefficient ρ = 0.48) with the radiologist's spiculation score. These measures were also used in the radiomics framework to achieve state-of-the-art malignancy prediction accuracy of 88.9% on a publicly available dataset.
Quantitative Image Analysis for Cancer Diagnosis and Radiation TherapyWookjin Choi
1.Lung Cancer Screening
1.1.Deep learning (feasible but not interpretable)
1.2.Radiomics (concise model)
1.3.Spiculation quantification (interpretable feature)
2.PET/CT Tumor Response
2.1.Aggressive Lung ADC subtype prediction (helpful for surgeons)
2.2.Pathologic response prediction (accurate but not concise)
2.3.Local tumor morphological changes (accurate and interpretable)
Robust Normal Lung CT Texture Features for the Prediction of Radiation-Induce...Wookjin Choi
Abstract
Purpose: Normal lung CT texture features have been used for the prediction of radiation-induced lung disease (RILD) - pneumonitis and fibrosis. For these features to be clinically useful, they should be robust (relatively invariant or unbiased) to tumor size variations and not correlated (non-redundant) with the normal lung volume of interest, i.e., volume of the peri-tumoral region.
Methods: CT images of 14 lung cancer patients were studied. Different sizes of gross tumor volumes (GTVs) were simulated with spheres (diameters 10 to 60 mm) and placed in the lung contralateral to the tumor. 27 texture features [nine from intensity histogram, eight from the gray-level co-occurrence matrix (GLCM) and ten from the gray-level run-length matrix (GLRM)] were extracted from the peri-tumoral region (uniform 30 mm expansion around the GTV in the lung). The Bland-Altman analysis was applied to measure the normalized range of agreement (nRoA) for each feature when GTV size varied. A feature was considered as robust when its nRoA was less than the threshold (100%), which was chosen at the nRoA of the volume of the peri-tumoral region with modification based on the cumulative graph of features vs. nRoA. A feature was regarded as not correlated with the volume of the peri-tumoral region when their correlation was lower than 0.70.
Results: 16 of the 27 texture features were identified as robust. All intensity histogram features were robust except sum and kurtosis. All GLCM features were robust except cluster shade, cluster prominence, and Haralick's Correlation. Five GLRM features (two run emphasis and three high gray-level emphasis) were robust while the other five (two nonuniformity and three low gray-level emphasis) were unrobost. None of the robust features was correlated with the volume of the peri-tumoral region. No feature showed statistically significant differences (P<0.05) on GTV location (upper vs. lower lobe).
Conclusion: We identified 16 robust normal lung CT texture features that can be further examined for the prediction of RILD. Particularly, GLRM high gray-level emphasis features were robust and characterized the radiologic manifestations of pulmonary abnormalities.
Robust Normal Lung CT Texture Features for the Prediction of Radiation-Induce...Wookjin Choi
Abstract
Purpose/Objective(s)
Normal lung CT texture features have been used for the prediction of radiation-induced lung disease (RILD) - pneumonitis and fibrosis. For these features to be clinically useful, they need to be relatively invariant (robust) to tumor size and not correlated with normal lung volume.
Materials/Methods
The free-breathing CTs of 14 lung SBRT patients were studied. Different sizes of GTVs were simulated with spheres (diameters 10 to 60 mm) placed in the lung contralateral to the tumor. Twenty-seven texture features (9 from intensity histogram, 8 from the gray-level co-occurrence matrix [GLCM], and 10 from the gray-level run-length matrix [GLRM]) were extracted from [lung – GTV]. The Bland-Altman method was applied to measure the normalized range of agreement (nRoA) of each texture feature when GTV size varied. A feature was considered as robust when its nRoA was less than that of [lung – GTV] volume (8.8%) and regarded as not correlated when their absolute correlation coefficient was lower than 0.70.
Results
Eighteen texture features were identified as robust. All intensity histogram features were robust except sum and kurtosis. All GLCM features were robust except energy and Haralick's Correlation. Five GLRM features (two run emphasis and three high gray-level emphasis) were robust while the other five (two nonuniformity and three low gray-level emphasis) were nonrobust. Particularly, all three low gray-level emphasis features had extremely large nRoAs (∼30%), indicating huge variations when GTV size changed. None of the robust features was correlated with the normal lung [lung – GTV] volume, suggesting that they can provide additional information. Three nonrobust features (sum and two nonuniformity features) were highly correlated with the normal lung volume. None feature showed statistically significant differences (P < 0.05) with respect to GTV location (upper vs. lower lobe).
Conclusion
We identified 18 robust lung CT texture features which were invariant to varying tumor volumes. Particularly the three GLRM high gray-level emphasis features can characterize the radiologic manifestations of pulmonary abnormalities. Hence these features can be further examined for the prediction of the RILD.
Radiomics Analysis of Pulmonary Nodules in Low Dose CT for Early Detection of...Wookjin Choi
Purpose: To predict the histopathologic subtypes with poor surgery prognosis in early stage lung adenocarcinomas using CT and PET radiomics.
Methods: We retrospectively enrolled 53 patients with stage I lung adenocarcinoma who underwent both diagnostic CT and 18F-fluorodeoxyglucose (FDG) PET/CT before complete surgical resection of the tumors. Tumor segmentation was manually contoured by a physician on both the diagnostic CT and the attenuation CT of PET/CT.A total of 170 radiomics features were extracted on both PET and CT images to design predictive models for two histopathologic endpoints: (1) tumors with solid or micropapillary predominant subtype (aggressiveness), and (2) tumors with micropapillary component more than 5% (MIP5). We used least absolute shrinkage and selection operator (LASSO) as a model building method coupled with a class separability feature selection (CSFS) method. For an unbiased model estimate, a 10-fold cross validation approach was used. The area under the curve (AUC) and prediction accuracy were employed to evaluate the performance of the model. P-values were computed using Wilcoxon rank-sum test.
Results: Of the 53 patients, 9 and 15 had tumors with aggressiveness and MIP5, respectively. For both endpoints, LASSO models with two PET radiomics features achieved the best performance. For aggressiveness, the LASSO model with PET Cluster Shade and PET 2D Variance resulted in 77.6±2.3% accuracy and 0.71±0.02 AUC (P = 0.011). For MIP5, the LASSO model with PET Eccentricity and PET Cluster Shade resulted in 69.6±3.1% accuracy and 0.68±0.04 AUC (P=0.014). The PET Cluster Shade was commonly selected in both models. Cluster shade is a texture feature that measures the skewness of the co-occurrence matrix. Higher PET cluster shade predicted that the tumor was more aggressive and more likely MIP5.
Conclusion: We showed that PET/CT radiomics features can predict tumor aggressiveness.
Funding Support, Disclosures, and Conflict of Interest: This work was supported in part by the National Cancer Institute Grants R01CA172638.
Aggressive Lung Adenocarcinoma Subtype Prediction Using FDG-PET/CT RadiomicsWookjin Choi
Purpose: To predict the histopathologic subtypes with poor surgery prognosis in early stage lung adenocarcinomas using CT and PET radiomics.
Methods: We retrospectively enrolled 53 patients with stage I lung adenocarcinoma who underwent both diagnostic CT and 18F-fluorodeoxyglucose (FDG) PET/CT before complete surgical resection of the tumors. Tumor segmentation was manually contoured by a physician on both the diagnostic CT and the attenuation CT of PET/CT.A total of 170 radiomics features were extracted on both PET and CT images to design predictive models for two histopathologic endpoints: (1) tumors with solid or micropapillary predominant subtype (aggressiveness), and (2) tumors with micropapillary component more than 5% (MIP5). We used least absolute shrinkage and selection operator (LASSO) as a model building method coupled with a class separability feature selection (CSFS) method. For an unbiased model estimate, a 10-fold cross validation approach was used. The area under the curve (AUC) and prediction accuracy were employed to evaluate the performance of the model. P-values were computed using Wilcoxon rank-sum test.
Results: Of the 53 patients, 9 and 15 had tumors with aggressiveness and MIP5, respectively. For both endpoints, LASSO models with two PET radiomics features achieved the best performance. For aggressiveness, the LASSO model with PET Cluster Shade and PET 2D Variance resulted in 77.6±2.3% accuracy and 0.71±0.02 AUC (P = 0.011). For MIP5, the LASSO model with PET Eccentricity and PET Cluster Shade resulted in 69.6±3.1% accuracy and 0.68±0.04 AUC (P=0.014). The PET Cluster Shade was commonly selected in both models. Cluster shade is a texture feature that measures the skewness of the co-occurrence matrix. Higher PET cluster shade predicted that the tumor was more aggressive and more likely MIP5.
Conclusion: We showed that PET/CT radiomics features can predict tumor aggressiveness.
Funding Support, Disclosures, and Conflict of Interest: This work was supported in part by the National Cancer Institute Grants R01CA172638.
Individually Optimized Contrast-Enhanced 4D-CT for Radiotherapy Simulation in...Wookjin Choi
Purpose/Objectives: To develop an individually optimized contrast-enhanced (CE) 4D-CT for radiotherapy simulation in pancreatic adenocarcinoma (PDA).
Materials/Methods: Ten PDA patients were enrolled and underwent three CT scans: a 4D-CT immediately following a CE 3D-CT, and an individually optimized CE 4D-CT using a test injection to estimate the peak contrast enhancement time and to optimize the delay time. Three physicians contoured the tumor and pancreatic tissues. We compared image quality scores, tumor volume, motion, image noise, tumor-to-pancreas contrast, and contrast-to- noise ratio (CNR) in the three CTs. We also evaluated inter-observer variations in contouring the tumor using simultaneous truth and performance level estimation (STAPLE).
Results: The average image quality scores for CE 3D-CT and CE 4D-CT were comparable (4.0 and 3.8, p=0.47), and both were significantly better than that for 4D-CT (2.6, p<0.001). The tumor-to- pancreas contrast in CE 3D-CT and CE 4D-CT were comparable (15.5 and 16.7 HU, p=0.71), and the later was significantly higher than that in 4D-CT (9.2 HU, p=0.03). Image noise in CE 3D-CT (12.5 HU) was significantly lower than that in CE 4D-CT (22.1 HU, p<0.001) and 4D-CT (19.4 HU, p=0.005). The CNR in CE 3D-CT and CE 4D-CT were comparable (1.4 and 0.8, p=0.23), and the former was significantly better than that in 4D-CT (0.6, p=0.04). The average tumor volume was smaller in CE 3D-CT (29.8 cm 3 ) and CE 4D-CT (22.8 cm 3 ) than in 4D-CT (42.0 cm 3 ), though the differences were not statistically significant. The tumor motion was comparable in 4D-CT and CE 4D-CT (7.2 and 6.2 mm, p=0.23). The inter-observer variations were comparable in CE 3D-CT and CE 4D-CT (Jaccard index 66.0% and 61.9%), and the former was significantly smaller than that of 4D-CT (55.6%, p=0.047).
Conclusions: The CE 4D-CT demonstrated largely comparable characteristics to the CE 3D-CT. It has high potential for simultaneously delineating the tumor and quantifying the tumor motion with a single scan.
Individually Optimized Contrast-Enhanced 4D-CT for Radiotherapy Simulation in...Wookjin Choi
To develop an individually optimized contrast-enhanced (CE) 4D-CT for radiotherapy simulation in pancreatic ductal adenocarcinomas (PDA).
http://scitation.aip.org/content/aapm/journal/medphys/43/6/10.1118/1.4958261
Integrating Ayurveda into Parkinson’s Management: A Holistic ApproachAyurveda ForAll
Explore the benefits of combining Ayurveda with conventional Parkinson's treatments. Learn how a holistic approach can manage symptoms, enhance well-being, and balance body energies. Discover the steps to safely integrate Ayurvedic practices into your Parkinson’s care plan, including expert guidance on diet, herbal remedies, and lifestyle modifications.
Histololgy of Female Reproductive System.pptxAyeshaZaid1
Dive into an in-depth exploration of the histological structure of female reproductive system with this comprehensive lecture. Presented by Dr. Ayesha Irfan, Assistant Professor of Anatomy, this presentation covers the Gross anatomy and functional histology of the female reproductive organs. Ideal for students, educators, and anyone interested in medical science, this lecture provides clear explanations, detailed diagrams, and valuable insights into female reproductive system. Enhance your knowledge and understanding of this essential aspect of human biology.
share - Lions, tigers, AI and health misinformation, oh my!.pptxTina Purnat
• Pitfalls and pivots needed to use AI effectively in public health
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Cell Therapy Expansion and Challenges in Autoimmune DiseaseHealth Advances
There is increasing confidence that cell therapies will soon play a role in the treatment of autoimmune disorders, but the extent of this impact remains to be seen. Early readouts on autologous CAR-Ts in lupus are encouraging, but manufacturing and cost limitations are likely to restrict access to highly refractory patients. Allogeneic CAR-Ts have the potential to broaden access to earlier lines of treatment due to their inherent cost benefits, however they will need to demonstrate comparable or improved efficacy to established modalities.
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Widespread adoption of cell therapies will not only require strong efficacy and safety data, but also adapted pricing and access strategies. At oncology-based price points, CAR-Ts are unlikely to achieve broad market access in autoimmune disorders, with eligible patient populations that are potentially orders of magnitude greater than the number of currently addressable cancer patients. Developers have made strides towards reducing cell therapy COGS while improving manufacturing efficiency, but payors will inevitably restrict access until more sustainable pricing is achieved.
Despite these headwinds, industry leaders and investors remain confident that cell therapies are poised to address significant unmet need in patients suffering from autoimmune disorders. However, the extent of this impact on the treatment landscape remains to be seen, as the industry rapidly approaches an inflection point.
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Muktapishti is a traditional Ayurvedic preparation made from Shoditha Mukta (Purified Pearl), is believed to help regulate thyroid function and reduce symptoms of hyperthyroidism due to its cooling and balancing properties. Clinical evidence on its efficacy remains limited, necessitating further research to validate its therapeutic benefits.
Osteoporosis - Definition , Evaluation and Management .pdfJim Jacob Roy
Osteoporosis is an increasing cause of morbidity among the elderly.
In this document , a brief outline of osteoporosis is given , including the risk factors of osteoporosis fractures , the indications for testing bone mineral density and the management of osteoporosis
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Artificial Intelligence in Radiation Oncology.pptx
1. Artificial Intelligence
in Radiation Oncology
Wookjin Choi, PhD
Assistant Professor of Radiation Oncology
Sidney Kimmel Medical College at Thomas Jefferson University
Wookjin.Choi@Jefferson.edu
Nov 4, 2022 @ KOSHIS
2. Acknowledgements
Memorial Sloan Kettering Cancer Center
• Wei Lu PhD
• Sadegh Riyahi, PhD
• Jung Hun Oh, PhD
• Saad Nadeem, PhD
• Eric Aliotta, PhD
• Joseph O. Deasy, PhD
• Andreas Rimner, MD
• Prasad Adusumilli, MD
Stony Brook University
• Allen Tannenbaum, PhD
University of Virginia School of Medicine
• Jeffrey Siebers, PhD
• Victor Gabriel Leandro Alves, PhD
University of Maryland School of Medicine
• Howard Zhang, PhD
• Wengen Chen, MD, PhD
• Charles White, MD
Thomas Jefferson University
• Yevgeniy Vinogradskiy, PhD
• Hamidreza Nourzadeh, PhD
• Adam P. Dicker, MD
2
NIH/NCI Grant R01 CA222216, R01 CA172638; NIH/NCI Cancer Center Support Grant P30 CA008748 and
5P30 CA056036; and ViewRay Technologies, Inc.
The ESTRO Falcon project team, Scott Kaylor of EduCase, Benjamin Nelms of Proknow for the multi-
delineator contour data presented in this work
3. Outline
• Introduction
• Auto Delineation and Variability Analysis
- OARNet
- CIRDataset
- …
• Radiomics - Clinical decision support and outcomes prediction
- Spiculation Quantification
- PathCNN
- …
• Summary
3
4. Outline
• Introduction
• Auto Delineation and Variability Analysis
- OARNet
- CIRDataset
- …
• Radiomics - Clinical decision support and outcomes prediction
- Spiculation Quantification
- PathCNN
- …
• Summary
4
5. What is AI?
5
Artificial intelligence (AI) is intelligence demonstrated by machines, as opposed
to the natural intelligence displayed by animals and humans.
Source: Nvidia
7. The Radiation Oncology Team
• Radiation Oncologist
- The doctor who prescribes and oversees the radiation therapy treatments
• Medical Physicist
- Ensures that treatment plans are properly tailored for each patient, and is
responsible for the calibration and accuracy of treatment equipment
• Dosimetrist
- Works with the radiation oncologist and medical physicist to calculate the
proper dose of radiation given to the tumor
• Radiation Therapist
- Administers the daily radiation under the doctor’s prescription and supervision
• Radiation Oncology Nurse
- Interacts with the patient and family at the time of consultation, throughout
the treatment process and during follow-up care
7
17. CIRDataset: A large-scale Dataset for Clinically-Interpretable lung
nodule Radiomics and malignancy prediction
17
Choi et al., MICCAI 2022 https://github.com/choilab-jefferson/CIR
19. Delineation Variability Quantification and Simulation
A framework for radiation therapy variability analysis
19
RT plan
Structure Set
CT Image
Dose Distribution
Structure Sets
DV simulation
ASSD
GrowCut
RW
Other delineators
SV analysis
DV analysis
Geometric
Dosimetric
Variability analysis
Human DV
Simulated
DV
Consensus SS
OARNet
Choi et al., AAPM, 2019.
20. Delineation Variability Quantification and Simulation (Results)
• DVH variability not predicted by geometric measures
• Large human variability
20
100%
50%
0%
100%
50%
0%
Human ASSD GrowCut RW
Right
Parotid
Left
Parotid
Choi, Nourzadeh et al., AAPM, 2019.
32. Spiculation Quantification for Lung Cancer
Screening
32
𝜖𝑖: = log
𝑗,𝑘 𝐴 ([𝜙(𝑣𝑖), 𝜙(𝑣𝑗), 𝜙(𝑣𝑘)])
𝑗,𝑘 𝐴 ([𝑣𝑖, 𝑣𝑗, 𝑣𝑘])
Area Distortion Map
Spherical Mapping
Malignant nodules Benign nodules
Early detection of lung cancer by LDCT can
reduce mortality
Known features correlated with PN malignancy
Size, growth rate (Lung-RADS)
Calcification, enhancement, solidity → texture
features
Boundary margins (spiculation, lobulation),
attachment → shape and appearance features
33. ACR Lung-RADS 1.0
Category Baseline Screening Malignancy
1 No PNs; PNs with calcification
Negative
<1% chance of malignancy
2
Solid/part-solid: <6 mm
GGN: <20 mm
Benign appearance
<1% chance of malignancy
3
Solid: ≥6 to <8 mm
Part-solid: ≥6 mm with solid component <6 mm
GGN: ≥20 mm
Probably benign
1-2% chance of malignancy
4A
Solid: ≥8 to <15 mm
Part-solid: ≥8 mm with solid component ≥6 and <8 mm
Suspicious
5-15% chance of malignancy
4B
Solid: ≥15 mm
Part-solid: Solid component ≥8 mm
>15% chance of malignancy
4X
Category 3 or 4 PNs with suspicious features (e.g., enlarged lymph
nodes) or suspicious imaging findings (e.g., spiculation)
>15% chance of malignancy
33
ACR: American College of Radiology
Lung-RADS: Lung CT Screening Reporting and Data System
34. ACR Lung-RADS 1.1
Category Baseline Screening Malignancy
1 No PNs; PNs with calcification
Negative
<1% chance of malignancy
2
Perifissural: <10mm (<524 mm3)
Solid: <6mm (<113 mm3) new < 4mm (<34 mm3)
part-solid: <6 mm total diameter (<113 mm3)
GGN: <30 mm (<14137 mm3)
Benign appearance
<1% chance of malignancy
3
Solid: ≥6 to <8 mm (≥113 to <268 mm3)
Part-solid: ≥6 mm total diameter (≥113 mm3) with solid component <6 mm
(<113 mm3)
GGN: ≥30 mm (≥14137 mm3)
Probably benign
1-2% chance of malignancy
4A
Solid: ≥8 to <15 mm (≥268 to <1767 mm3)
Part-solid: ≥ 6 mm (≥113 mm3) with solid component ≥6 mm to <8 mm
(≥113 to <268 mm3)
Endobronchial nodule
Suspicious
5-15% chance of malignancy
4B
Solid: ≥15 mm (≥1767 mm3)
Part-solid: a solid component ≥ 8 mm (≥268 mm3)
>15% chance of malignancy
4X
Category 3 or 4 PNs with suspicious features (e.g., enlarged lymph
nodes) or suspicious imaging findings (e.g., spiculation)
>15% chance of malignancy
34
ACR: American College of Radiology, Lung-RADS: Lung CT Screening Reporting and Data System
35. Spiculation Quantification (Results)
35
Number of Spiculations and Radiologists spiculation score (RS) for different pulmonary nodules
1 2 3 4 5
0 1 4 8 14
Choi et al. in CMPB 2021 https://github.com/choilab-jefferson/LungCancerScreeningRadiomics
38. Progression-free survival Prediction
after SBRT for early-stage NSCLC
38
Thor, Choi et al. ASTRO 2020
• 412 patients treated between 2006 and 2017
• PETs and CTs within three months prior to SBRT start.
• The median prescription dose was 50Gy in 5 fractions.
39. Progression-free survival Prediction (Results)
• PET entropy, CT number of peaks,
CT major axis, and gender.
• The most frequently selected model
included PET entropy and CT
number of peaks
- The c-index in the validation
subset was 0.77
- The prediction-stratified survival
indicated a clear separation
between the observed HR and
LR
- e.g., a PFS of 60% was observed
at 12 months in HR vs. 22
months in LR.
39
Thor, Choi et al. ASTRO 2020
40. CIRDataset: A large-scale Dataset for Clinically-Interpretable lung
nodule Radiomics and malignancy prediction
40
Choi et al., MICCAI 2022 https://github.com/choilab-jefferson/CIR
41. 41
Training
Network AUC Accuracy Sensitivity Specificity F1
Mesh Only 0.885 80.25 54.84 93.04 65.03
Mesh+Encoder 0.899 80.71 55.76 93.27 65.94
Validation
Network AUC Accuracy Sensitivity Specificity F1
Mesh Only 0.881 80.37 53.06 92.11 61.90
Mesh+Encoder 0.808 75.46 42.86 89.47 51.2
Testing
LIDC-PM
N=72
Network AUC Accuracy Sensitivity Specificity F1
Mesh Only 0.790 70.83 56.10 90.32 68.66
Mesh+Encoder 0.813 79.17 70.73 90.32 79.45
Prediction Results
Testing
LUNGx
N=73
Network AUC Accuracy Sensitivity Specificity F1
Mesh Only 0.733 68.49 80.56 56.76 71.60
Mesh+Encoder 0.743 65.75 86.11 45.95 71.26
42. PathCNN: interpretable convolutional neural networks
for survival prediction and pathway analysis applied to glioblastoma
42
• CNNs have achieved great success
• A lack of interpretability remains a
key barrier
• Moreover, because biological array
data are generally represented in a
non-grid structured format
• PathCNN
An interpretable CNN model on
integrated multi-omics data using a
newly defined pathway image.
Oh, Choi et al. Bioinformatics 2021, joint first author Source code: https://github.com/mskspi/PathCNN.
43. PathCNN: interpretable CNNs (results)
43
Cancer PathCNN Logistic
regression SVM with RBF Neural network MiNet
GBM 0.755 ± 0.009 0.668 ± 0.039 0.685 ± 0.037 0.692 ± 0.030 0.690 ± 0.032
LGG 0.877 ± 0.007 0.816 ± 0.036 0.884 ± 0.017 0.791 ± 0.031 0.854 ± 0.027
LUAD 0.637 ± 0.014 0.581 ± 0.028 0.624 ± 0.034 0.573 ± 0.031 0.597 ± 0.042
KIRC 0.709 ± 0.009 0.654 ± 0.034 0.684 ± 0.027 0.702 ± 0.028 0.659 ± 0.030
Comparison of predictive performance with benchmark methods in terms of the area
under the curve (AUC: mean ± standard deviation) over 30 iterations of the 5-fold
cross validation
Note: AUCs for PathCNN were obtained with three principal components. Bold = Highest AUC for each dataset.
SVM, support vector machine; RBF, radial basis function; MiNet, Multi-omics Integrative Net; GBM, glioblastoma
multiforme; LGG, low-grade glioma; LUAD, lung adenocarcinoma; KIRC, kidney cancer.
Oh, Choi et al. Bioinformatics 2021, joint first author Source code: https://github.com/mskspi/PathCNN.
44. 44
A matrix of adjusted P-values. The row represents the 146 KEGG pathways ordered on pathway images. The
columns represent the first two principal components of each omics type. The red color indicates key
pathways with adjusted P-values < 0.001
45. Heart Toxicity Prediction using PET/CT
radiomics for Lung Radiotherapy (ongoing)
• Pre & Post
- PET/CT Radiomics
- Delta-radiomics between pre and post PET/CT
- 70 pts from ACRIN 6668/RTOG 0235, 39 pts from CU/BU
- Manual and auto heart contouring
• Pre only
- CT coronary artery calcium scoring
- PET/CT Radiomics
- Collected TJU 50 pts data and continue to collect more data
- Manual and auto heart contouring
45
46. Heart Toxicity Preliminary Results
46
Miller et al. Radiotheray and Oncology, 2022
Comparison of Overall Survival Data by SUVmean Change. The
median OS for patients with a negative SUVmean cardiac change
(dark grey) was 413 days and the median OS for patients with a
positive SUVmean cardiac change was 585 days (lightgrey).
Kaplan-Meier Analysis. Patients with a positive cardiac
SUVmean change (light grey) demonstrate a significantly
higher surviving fraction in comparison to those patients
with a negative cardiac SUVmean change (black).
47. Summary
• Introduction
• Auto Delineation and Variability Analysis
- OARNet: H&N OAR auto segmentation
- CIRDataset: volume segmentation and 3D mesh model generation
- Delineation Variability Analysis
- Auto contouring for Pancreatic Adenocarcinoma MRgRT
• Radiomics - Clinical decision support and outcomes prediction
- Spiculation Quantification
- CIRDataset: end-to-end model to predict PN malignancy
- PathCNN: Multiomics
- Heart Toxicity Prediction
• Summary
47
48. Selected Publications
1. Jung Hun Oh*, Wookjin Choi* et al., “PathCNN: interpretable convolutional neural networks for survival
prediction and pathway analysis applied to glioblastoma”, Bioinformatics, 2021, *joint first author
2. Wookjin Choi et al., “ Reproducible and Interpretable Spiculation Quantification for Lung Cancer Screening”,
Computer Methods and Programs in Biomedicine”, 2021
3. Noemi Garau, Wookjin Choi, et al., “ External validation of radiomics‐based predictive models in low‐dose CT
screening for early lung cancer diagnosis”, Medical Physics, 2020
4. Jiahui Wang, Wookjin Choi et al., “Prediction of anal cancer recurrence after chemoradiotherapy using
quantitative image features extracted from serial 18F-FDG PET/CT”, Frontiers in oncology, 2019
5. Wookjin Choi et al., “Radiomics analysis of pulmonary nodules in low-dose CT for early detection of lung cancer”,
Medical Physics, 2018
6. Sadegh Riyahi, Wookjin Choi, et al., “Quantifying local tumor morphological changes with Jacobian map for
prediction of pathologic tumor response to chemo-radiotherapy in locally advanced esophageal cancer”, Physics
in Medicine and Biology, 2018
7. Shan Tan, Laquan Li, Wookjin Choi, et al., “Adaptive region-growing with maximum curvature strategy for tumor
segmentation in 18F-FDG PET”, Physics in Medicine and Biology, 2017
8. Wookjin Choi et al., “Individually Optimized Contrast-Enhanced 4D-CT for Radiotherapy Simulation in Pancreatic
Ductal Adenocarcinoma”, Medical Physics, 2016
9. Wookjin Choi, Tae-Sun Choi, “Automated Pulmonary Nodule Detection based on Three-dimensional Shape-based
Feature Descriptor”, Computer Methods and Programs in Biomedicine, 2014
48
Complete list of publications: https://scholar.google.com/citations?user=iHgsGLUAAAAJ
49. Looking for a Post-Doctoral Research Fellow
Developing Interpretable Predictive Models for Radiation Therapy
• PI: Wookjin Choi, PhD - Wookjin.Choi@Jefferson.edu
• 2 Years
• Machine Learning/Deep Learning: Radiomics (PET/CT & MR) and Bioinformatics
• Computational Medical Physics: Development of Predictive Models and Automated
Workflows, and Improve Clinical Workflow
• Internal or Extramural Research Funding Opportunities
Qualifications
• Ph.D. in Computer Science, Electrical Engineering, Medical Physics, or related field
required
54. Long-term Future Works
• Comprehensive Framework for Cancer Imaging
- Multi-modal imaging
- Response prediction and evaluation (Pre, Mid, and Post)
- Longitudinal analysis of tumor change during treatment (MRgRT)
- Shape analysis (e.g., Spiculation)
- Deep learning models
• Automation of Clinical Workflow
- Big Data Analytics: EMR, PACS, ROIS, Genomics, etc.
- Provide an informatics platform for comprehensive cancer therapy
54
Editor's Notes
I would like to thank everyone who has helped me in the projects
How to generalize it
How to generalize it
Radiation has been an effective tool for treating cancer for more than 100 years
More than 60 percent of patients diagnosed with cancer will receive radiation therapy as part of their treatment
Radiation oncologists are cancer specialists who manage the care of cancer patients with radiation for either cure or palliation
Radiation therapy or radiotherapyis a therapy using ionizing radiation, generally provided as part of cancer treatment to control or kill malignant cells and normally delivered by a linear accelerator
Radiation therapy has multiple sources to be used for delivery.
Most radiation therapy treatments are delivered using photons which are either delivered with Gamma Rays (such as radioisotopes used in brachytherapy) and X-rays (generated by a linear accelerator)
Additional sources include particle beams such as protons, neutrons and electrons
Photons
Gamma Rays
Emitted from a nucleus of a radioactive atom
Cobalt treatment machine
Radioisotopes used in brachytherapy
X-rays
Generated by a linear accelerator when accelerated electrons hit a target
Particle Beams
Protons
Neutrons
Electrons
The radiation therapy treatment team works closely to ensure that patients are receiving safe, quality treatment.
a general overview of the radiation therapy workflow with brief descriptions of expected applications of artificial intelligence (AI) at each step.
The workflow begins with the decision to treat the patient with radiation therapy,
followed by a simulation appointment during which medical images are acquired for treatment planning.
Subsequently, the patient-specific treatment plan is created,
and then the plan is subjected to approval, review and quality assurance (QA) measures prior to delivery of radiation to the patient.
The patient then receives follow-up care.
AI has the potential to improve radiation therapy for patients with cancer by increasing efficiency for the staff involved, improving the quality of treatments, and providing additional clinical information and predictions of treatment response to assist and improve clinical decision-making.
Automatable tasks in radiation oncology for the modern clinic. The extent to which each skill set is used or task is performed in this figure is not indicated and may be dependent on each clinical practice. In order to group essential tasks performed during the treatment planning process, “Physical,” “Knowledge,” and “Social” skill domains were created and are indicated by green, magenta, and blue ellipses, respectively. Skills or tasks are indicated by circles within each colored domain and may be shared between domains. Based on works cited in this review, tasks which may be automated are within the “Automatable” domain.
(triangle: Monte Carlo; square: Inverse optimization/IMRT; circle: deep learning-based contouring). The curve depicts expectations by the target audience (those in radiation oncology and medical physics) as a function of time. Yellow, magenta, cyan, green, and blue portions of the curve denote “innovation trigger,” “peak of inflated expectations,” “trough of disillusionment,” “slope of enlightenment,” and “productivity plateau” regions, respectively.
10분
Objective: To auto-delineate organs-at-risk (OARs) in head and neck (H&N) CT image sets via a compact high-performance knowledge-based model.
Approach: A 3D deep learning model (OARnet) is developed and used to delineate 28 H&N OARs on CT images. OARnet utilizes a densely connected network to detect the OAR bounding-box, then delineates the OAR within the box. It reuses information from any layer to subsequent layers and uses skip connections to combine information from different dense block levels to progressively improve delineation accuracy. Training uses up to 28 expert manual delineated (MD) OARs from 165 CTs. Dice similarity coefficient (DSC) and the 95th percentile Hausdorff distance (HD95) with respect to MD is assessed for 70 other CTs. Mean, maximum, and root-mean-square dose differences with respect to MD are assessed for 56 of the 70 CTs. OARnet is compared with UaNet, AnatomyNet, and Multi-Atlas Segmentation (MAS). Wilcoxon signed-rank tests using 95% confidence intervals are used to assess significance.
Depiction of IRT architecture based on Voxel2Mesh. The standard UNet based voxel encoder/decoder (top) extracts features from the input CT volumes while the mesh decoder deforms an initial spherical mesh into increasing finer resolution meshes matching the target shape. The mesh deformation utilizes feature vectors sampled from the voxel decoder through the Learned Neighborhood (LN) Sampling technique and also performs adaptive unpooling with increased vertex counts in high curvature areas.
We extend the architecture by introducing extra mesh decoder layers for spiculation and lobulation classification. We also sample vertices (shape features) from the final mesh unpooling layer as input to Fully Connected malignancy prediction network. We optionally add deep voxel-features from the last voxel encoder layer to the malignancy prediction network.
A framework for radiation therapy variability analysis, human delineation variability (DV) and simulated DV generated by auto delineation (AD) methods were analyzed using geometric measurements and dosimetric consequence, as well as dosimetric consequences of setup variability also evaluated using RTRA. If multiple humans delineated SSs are not available, consensus SS will be generated by 10 ASSD delineated SSs (5 SSs with 2mm SD and 5 SSs with 5mm SD).
The MD Dice was 0.7±0.2 (μ±σ).
AD Dice values (ASSD, GrowCut, and RW) were 0.5±0.2, 0.7±0.2, and 0.8±0.1, respectively.
HDs were 35.4±45.2, 27.3±19.1, 29.3±19.9, and 14.6±10.3.
The simulated DV increased with increasing the seed standard deviations or variability level.
The dosimetric effect was largest for MD DVs (larger OAR DVH confidence intervals and larger HD), even though the MD Dice was greater than the ASSD and GrowCut Dice values.
GrowCut DV resulted in less dosimetric variation than RW, unlike the geometric indices.
5 Different
400 Plan
Elekta 1.5T ViewRay 0.35T
How to generalize it
20분
The pre-planning prediction of dosimetric tradeoffs to assist physicians, patients and payers alike to make better informed decisions about treatment modality and dose prescription [30], [31], [32].
The integration of dosimetric information with orthogonal data (e.g. genomics, diagnostic imaging, electronic medical records) to build accurate outcomes models of Tumor Control Probability (TCP) and Normal Tissue Complication Probability (NTCP). Although early research has shown this to be a promising approach, this area of decision support is not yet ready for routine clinical use [3], [5], [33], [34], [35], [36], [37].
Radiomics, which is a branch of medical imaging analytics that relies upon primary extraction of quantitative imaging features (e.g. texture) to predict various clinical phenomena.
I open sample automated workflow and essential components to public
I open sample automated workflow and essential components to public
I open sample automated workflow and essential components to public
I open sample automated workflow and essential components to public
I open sample automated workflow and essential components to public
I open sample automated workflow and essential components to public
Why spherical mapping because nodule has a spherical topology and we want to simplify its representation
First non-trivial eigenfunction of the Laplace-Beltrami operator
Conformal mapping from surface 𝑆 to unit sphere 𝒮 2 : 𝜙:𝑆→ 𝒮 2
Compute area distortion 𝜖 𝑖 to detect base ( 𝜖 𝑖 =0) and apex (max. negative 𝜖 𝑖 )
The Lung Imaging Reporting and Data System (Lung-RADS) was developed by the American College of Radiology (ACR) to standardize the screening of lung cancer on CT images.
As shown in the Table, the Lung-RADS categorization is mainly based on PN size (the average of the longest and shortest diameters on axial slice)
with some consideration to calcification, appearance type (solid, part-solid, and non-solid or ground glass nodule/GGN), and additional suspicious features.
We also performed Lung-RADS categorization based on the PN contour and the physician’s annotations.
To match the original LIDC-IDRI diagnosis, categories 3 and lower are labeled as benign and category 4 (4A, 4B, and 4X) as malignant.
The Lung Imaging Reporting and Data System (Lung-RADS) was developed by the American College of Radiology (ACR) to standardize the screening of lung cancer on CT images.
As shown in the Table, the Lung-RADS categorization is mainly based on PN size (the average of the longest and shortest diameters on axial slice)
with some consideration to calcification, appearance type (solid, part-solid, and non-solid or ground glass nodule/GGN), and additional suspicious features.
We also performed Lung-RADS categorization based on the PN contour and the physician’s annotations.
To match the original LIDC-IDRI diagnosis, categories 3 and lower are labeled as benign and category 4 (4A, 4B, and 4X) as malignant.
Spiculations are spikes on the surface of PN and are important predictors of malignancy in lung cancer
state of the art
Our spiculation measures improved the radiomics model for malignancy prediction
Model 9 is also mine
412 patients treated between 2006 and 2017 were included. Patients had to have PETs and CTs available within three months prior to SBRT start. The median prescription dose was 50Gy in 5 fractions. The planning-CT gross tumor volumes (GTVs) were propagated onto the pre-treatment PETs and CTs using b-spline deformable image registration. PET intensity features (90th percentile, entropy, maximum, mean, peak, robust mean absolute deviation, SD, valley) and CT shape features (compactness, diameter, elliptic axes, elongation, flatness, number of lobules/peaks/spicules, sphericity, surface area, surface to volume ratio, volume) were extracted. Data were split into training and hold-out validation subsets (n = 283, 123; 70%, 30%). In the training subset, the imaging features and six patient characteristics (age, gender, histology, performance status, prior surgery, tumor location) were tested for association with PFS using Cox Proportional Hazards regression with re-sampling (bootstrapping with 1000 samples). Significance was denoted at p≤0.0019 (corrected for 26 tests). A bootstrapped forward-stepwise multivariate analysis was undertaken including only non-strongly correlated predictors (Spearman’s rank, |Rs|<0.70). The most frequently selected model was explored in the validation subset in which model performance was assessed using the c-index and the prediction-stratified high and low risk tertiles (HR, LR) of the observed PFS were compared.
Results
Nineteen of the 20 identified candidate predictors were either PET or CT features (p-value range: 3E-9, 1.2E-3). The intra-imaging modality correlation between features was strong (median |Rs|: PET: 0.93; CT: 0.76) and only four features were passed on to multivariate analysis: PET entropy, CT number of peaks, CT major axis, and gender. The most frequently selected model included PET entropy and CT number of peaks; the c-index in the validation subset was 0.77 and the prediction-stratified survival indicated a clear separation between the observed HR and LR: e.g. a PFS of 60% was observed at 12 months in HR vs. 22 months in LR.
Conclusion
This PET and CT-based model identified the SUV distribution randomness (entropy) and spiculated tumor pattern on CTs as the most important features in predicting PFS in early stage NSCLC. The associated performance on the hold-out validation subset was good and its use has the potential to further improve the prediction of response to SBRT for this patient population. This model will be used to identify high-risk patients based on the predicted PFS in an upcoming phase II study on adjuvant immunotherapy.
Depiction of IRT architecture based on Voxel2Mesh. The standard UNet based voxel encoder/decoder (top) extracts features from the input CT volumes while the mesh decoder deforms an initial spherical mesh into increasing finer resolution meshes matching the target shape. The mesh deformation utilizes feature vectors sampled from the voxel decoder through the Learned Neighborhood (LN) Sampling technique and also performs adaptive unpooling with increased vertex counts in high curvature areas.
We extend the architecture by introducing extra mesh decoder layers for spiculation and lobulation classification. We also sample vertices (shape features) from the final mesh unpooling layer as input to Fully Connected malignancy prediction network. We optionally add deep voxel-features from the last voxel encoder layer to the malignancy prediction network.
To address these issues, we propose a novel method, called PathCNN, that constructs an interpretable CNN model on integrated multi-omics data using a newly defined pathway image.
PathCNN showed promising predictive performance in differentiating between long-term survival (LTS) and non-LTS when applied to glioblastoma multiforme (GBM). The adoption of a visualization tool coupled with statistical analysis enabled the identification of plausible pathways associated with survival in GBM.
In summary, PathCNN demonstrates that CNNs can be effectively applied to multi-omics data in an interpretable manner, resulting in promising predictive power while identifying key biological correlates of disease.
Motivation
Convolutional neural networks (CNNs) have achieved great success in the areas of image processing and computer vision, handling grid-structured inputs and efficiently capturing local dependencies through multiple levels of abstraction. However, a lack of interpretability remains a key barrier to the adoption of deep neural networks, particularly in predictive modeling of disease outcomes. Moreover, because biological array data are generally represented in a non-grid structured format, CNNs cannot be applied directly.
Results
To address these issues, we propose a novel method, called PathCNN, that constructs an interpretable CNN model on integrated multi-omics data using a newly defined pathway image. PathCNN showed promising predictive performance in differentiating between long-term survival (LTS) and non-LTS when applied to glioblastoma multiforme (GBM). The adoption of a visualization tool coupled with statistical analysis enabled the identification of plausible pathways associated with survival in GBM. In summary, PathCNN demonstrates that CNNs can be effectively applied to multi-omics data in an interpretable manner, resulting in promising predictive power while identifying key biological correlates of disease.
The cardiac SUVmean change was calculated as the post-treatment SUVmean minus the pretreatment SUVmean.
SUVmean cardiac change was predictive of OS with a HR of 0.811 (95% CI 0.68–0.96, p = 0.017).