Publications by authors named "Mohamed A Naser"

Magnetic resonance (MR)-guided radiation therapy (RT) is enhancing head and neck cancer (HNC) treatment through superior soft tissue contrast and longitudinal imaging capabilities. However, manual tumor segmentation remains a significant challenge, spurring interest in artificial intelligence (AI)-driven automation. To accelerate innovation in this field, we present the Head and Neck Tumor Segmentation for MR-Guided Applications (HNTS-MRG) 2024 Challenge, a satellite event of the 27th International Conference on Medical Image Computing and Computer Assisted Intervention.

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Background And Purpose: Prior work on adaptive organ-at-risk (OAR)-sparing radiation therapy has typically reported outcomes based on fixed-number or fixed-interval re-planning, which represent one-size-fits-all approaches and do not account for the variable progression of individual patients' toxicities. The purpose of this study was to determine the personalized optimal timing for re-planning in adaptive OAR-sparing radiation therapy, considering limited re-planning resources, for patients with head and neck cancer (HNC).

Materials And Methods: A novel Markov decision process (MDP) model was developed to determine optimal timing of re-planning based on the patient's expected toxicity, characterized by normal tissue complication probability (NTCP), for four toxicities.

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  • The study focuses on using radiomic features from contrast-enhanced CT scans to distinguish between osteoradionecrosis (ORN) and normal mandibular bone in head and neck cancer patients treated with radiotherapy.
  • Data from 150 patients was analyzed, with feature extraction performed using PyRadiomics and a Random Forest classifier used to identify key features, resulting in an accuracy of 88%.
  • The findings highlight specific radiomic features that can differentiate ORN from healthy tissue, paving the way for future research on early detection and intervention strategies.
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Background/objectives: Pain is a challenging multifaceted symptom reported by most cancer patients. This systematic review aims to explore applications of artificial intelligence/machine learning (AI/ML) in predicting pain-related outcomes and pain management in cancer.

Methods: A comprehensive search of Ovid MEDLINE, EMBASE and Web of Science databases was conducted using terms: "Cancer," "Pain," "Pain Management," "Analgesics," "Artificial Intelligence," "Machine Learning," and "Neural Networks" published up to September 7, 2023.

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Background: Radiotherapy is a core treatment modality for oropharyngeal cancer (OPC), where the primary gross tumor volume (GTVp) is manually segmented with high interobserver variability. This calls for reliable and trustworthy automated tools in clinician workflow. Therefore, accurate uncertainty quantification and its downstream utilization is critical.

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Background/purpose: The use of artificial intelligence (AI) in radiotherapy (RT) is expanding rapidly. However, there exists a notable lack of clinician trust in AI models, underscoring the need for effective uncertainty quantification (UQ) methods. The purpose of this study was to scope existing literature related to UQ in RT, identify areas of improvement, and determine future directions.

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  • The study investigates radiation induced carotid artery disease (RICAD) in survivors of oropharyngeal cancer, focusing on changes in carotid artery volume after unilateral radiotherapy for early tonsillar cancer.
  • Researchers analyzed pre- and post-therapy CT scans from disease-free patients to assess the effects of differing radiation doses on carotid artery volumes, aiming to identify early imaging markers for RICAD.
  • Results from 46 patients revealed significant volume decrease in irradiated carotid arteries but no clear dose-response relationship, suggesting the need for further research on factors influencing carotid artery changes post-radiation therapy.
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  • Radiation therapy is essential for treating head and neck squamous cell carcinoma but can negatively impact patients' long-term health and quality of life.
  • Researchers are investigating biomarkers, especially imaging biomarkers from MRI, to better predict how tumors respond to radiation therapy and to make treatments more personalized.
  • The study provides a valuable dataset of diffusion-weighted imaging (DWI) collected weekly during treatment, helping to analyze changes that can correlate with treatment response and patient outcomes.
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  • This study looked at how pain affects patients undergoing radiation therapy for oral cancer and tried to understand the different types of pain they experience over time.
  • Researchers checked medical records of 351 patients and found that pain levels increased from none to a score of 5 by the seventh week of treatment, with most people feeling pain in their mouth and throat.
  • The study showed that various factors like gender and weight changes could affect pain levels, suggesting that better pain management strategies are needed for patients during their treatment.
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Recent advancements in the field of biomedical engineering have underscored the pivotal role of biodegradable materials in addressing the challenges associated with tissue regeneration therapies. The spectrum of biodegradable materials presently encompasses ceramics, polymers, metals, and composites, each offering distinct advantages for the replacement or repair of compromised human tissues. Despite their utility, these biomaterials are not devoid of limitations, with issues such as suboptimal tissue integration, potential cytotoxicity, and mechanical mismatch (stress shielding) emerging as significant concerns.

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Introduction: We prospectively evaluated morphologic and functional changes in the carotid arteries of patients treated with unilateral neck radiation therapy (RT) for head and neck cancer.

Methods: Bilateral carotid artery duplex studies were performed at 0, 3, 6, 12, 18 months and 2, 3, 4, and 5 years following RT. Intima media thickness (IMT); global and regional circumferential, as well as radial strain, arterial elasticity, stiffness, and distensibility were calculated.

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Background: Acute pain is a common and debilitating symptom experienced by oral cavity and oropharyngeal cancer (OC/OPC) patients undergoing radiation therapy (RT). Uncontrolled pain can result in opioid overuse and increased risks of long-term opioid dependence. The specific aim of this exploratory analysis was the prediction of severe acute pain and opioid use in the acute on-treatment setting, to develop risk-stratification models for pragmatic clinical trials.

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Background/objective: Pain is a challenging multifaceted symptom reported by most cancer patients, resulting in a substantial burden on both patients and healthcare systems. This systematic review aims to explore applications of artificial intelligence/machine learning (AI/ML) in predicting pain-related outcomes and supporting decision-making processes in pain management in cancer.

Methods: A comprehensive search of Ovid MEDLINE, EMBASE and Web of Science databases was conducted using terms including "Cancer", "Pain", "Pain Management", "Analgesics", "Opioids", "Artificial Intelligence", "Machine Learning", "Deep Learning", and "Neural Networks" published up to September 7, 2023.

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  • The study aimed to enhance segmentation accuracy in head and neck cancer radiotherapy by optimizing a specific type of MRI sequence known as SPAIR for use with a 1.5T MR-Linac.
  • After testing several sequences, three viable SPAIR sequences were analyzed for various metrics, leading to the identification of a top-performing sequence for better delineation of tumors and lymph nodes.
  • Ultimately, the research provided an optimized imaging sequence for Unity MR-Linac users and established a new pathway for objectively assessing image quality in MRI, which can benefit future protocols.
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Radiation therapy (RT) is a crucial treatment for head and neck squamous cell carcinoma (HNSCC), however it can have adverse effects on patients' long-term function and quality of life. Biomarkers that can predict tumor response to RT are being explored to personalize treatment and improve outcomes. While tissue and blood biomarkers have limitations, imaging biomarkers derived from magnetic resonance imaging (MRI) offer detailed information.

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Purpose: Identify Oropharyngeal cancer (OPC) patients at high-risk of developing long-term severe radiation-associated symptoms using dose volume histograms for organs-at-risk, via unsupervised clustering.

Material And Methods: All patients were treated using radiation therapy for OPC. Dose-volume histograms of organs-at-risk were extracted from patients' treatment plans.

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  • This study focuses on improving the delivery of cancer treatment by evaluating autosegmentation methods that outline key organs at risk (OARs) in head and neck cancer patients using low-resolution MRIs from a specific machine known as the MR-linac.
  • Researchers investigated 20 autosegmentation approaches, including both population-based methods and deep learning techniques, comparing their effectiveness in accurately identifying OARs against established ground truth contours.
  • Results showed varying performance across methods, with additional dosimetric analysis performed on the best and worst methods, highlighting the importance of accurate dose reconstruction for effective patient treatment.
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  • The study aimed to evaluate changes in the apparent diffusion coefficient (ADC) of head and neck squamous cell carcinoma (HNSCC) patients during radiation therapy, using diffusion-weighted imaging to predict tumor response and outcomes.
  • A group of 30 HNSCC patients underwent weekly MRI scans, measuring various ADC parameters over six weeks to analyze correlations with treatment response and recurrence.
  • Results showed a significant increase in ADC values during treatment, especially for primary tumors achieving complete remission, with a specific ADC threshold identified as a predictor for successful outcomes.
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Background: Demand for head and neck cancer (HNC) radiotherapy data in algorithmic development has prompted increased image dataset sharing. Medical images must comply with data protection requirements so that re-use is enabled without disclosing patient identifiers. Defacing, i.

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Background: Oropharyngeal cancer (OPC) is a widespread disease, with radiotherapy being a core treatment modality. Manual segmentation of the primary gross tumor volume (GTVp) is currently employed for OPC radiotherapy planning, but is subject to significant interobserver variability. Deep learning (DL) approaches have shown promise in automating GTVp segmentation, but comparative (auto)confidence metrics of these models predictions has not been well-explored.

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Importance: Extranodal extension (pENE) is a critical prognostic factor in oropharyngeal cancer (OPC) that drives therapeutic disposition. Determination of pENE from radiological imaging has been associated with high inter-observer variability. However, the impact of clinician specialty on human observer performance of imaging-detected extranodal extension (iENE) remains poorly understood.

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