ORCID Profile
0000-0001-9848-2623
Current Organisation
Brigham and Women's Hospital
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Publisher: Wiley
Date: 08-01-2019
DOI: 10.1002/CNCR.31944
Publisher: SPIE
Date: 10-03-2020
DOI: 10.1117/12.2549625
Publisher: Elsevier BV
Date: 04-2020
Publisher: Cold Spring Harbor Laboratory
Date: 25-01-2022
DOI: 10.1101/2022.01.24.22269596
Abstract: Purpose: Tumor and target volume manual delineation remains a challenging task in head and neck cancer radiotherapy. The purpose of this study is to conduct a multi-institutional evaluation of manual delineations of gross tumor volume (GTV), high-risk clinical target volume (CTV), parotids, and submandibular glands on treatment simulation MR scans of oropharyngeal cancer (OPC) patients. Methods: Pre-treatment T1-weighted (T1w), T1-weighted with Gadolinium contrast (T1w+C) and T2-weighted (T2w) MRI scans were retrospectively collected for 4 OPC patients under an IRB-approved protocol. The scans were provided to twenty-six radiation oncologists from seven international cancer centers who participated in this delineation study. In addition, clinical history and physical examination findings along with a medical photographic image and radiological results were provided. The contours were compared using overlap and distance metrics using both STAPLE and pair-wise comparisons. Lastly, participants completed a brief questionnaire to assess personal experience and CTV delineation institutional practices. Results: Large variability was measured between observer delineations for both GTVs and CTVs. The mean Dice Similarity Coefficient values across all case delineations for GTVp, GTVn, CTVp, and CTVn where 0.77, 0.67, 0.77, and 0.69, respectively, for STAPLE comparison and 0.67, 0.60, 0.67, and 0.58, respectively, for pair-wise analysis. Normal tissue contours were defined more consistently when considering overlap and distance metrics. The median radiation oncology clinical experience was 7 years and the median experience delineating on MRI was 3.5 years. The GTV-to-CTV margin used was 10 mm for six of seven participant institutions. One institution used 8 mm and three delineators (from three different institutions) used a margin of 5 mm. Conclusion: The data from this study suggests that appropriate guidelines, contouring quality assurance sessions, and training are still needed for the adoption of MR-based treatment planning for head and neck cancers. Such efforts should play a critical role in reducing inter-observer delineation variation and ensure standardization of target design across clinical practices.
Publisher: Cold Spring Harbor Laboratory
Date: 13-10-2020
DOI: 10.1101/2020.10.09.20208827
Abstract: Osteoradionecrosis (ORN) is a major side-effect of radiation therapy in oropharyngeal cancer (OPC) patients. In this study, we demonstrate that early prediction of ORN is possible by analyzing the temporal evolution of mandibular subvolumes receiving radiation. For our analysis, we use computed tomography (CT) scans from 21 OPC patients treated with Intensity Modulated Radiation Therapy (IMRT) with subsequent radiographically-proven ≥ grade II ORN, at three different time points: pre-IMRT, 2-months, and 6-months post-IMRT. For each patient, radiomic features were extracted from a mandibular subvolume that developed ORN and a control subvolume that received the same dose but did not develop ORN. We used a Multivariate Functional Principal Component Analysis (MFPCA) approach to characterize the temporal trajectories of these features. The proposed MFPCA model performs the best at classifying ORN vs Control subvolumes with an area under curve (AUC) = 0.74 (95% confidence interval (C.I.): 0.61-0.90), significantly outperforming existing approaches such as a pre-IMRT features model or a delta model based on changes at intermediate time points, i.e. at 2- and 6-month follow-up. This suggests that temporal trajectories of radiomics features derived from sequential pre- and post-RT CT scans can provide markers that are correlates of RT-induced mandibular injury, and consequently aid in earlier management of ORN.
Publisher: Elsevier BV
Date: 04-2020
Publisher: Elsevier BV
Date: 09-2019
Location: United States of America
No related grants have been discovered for Hesham Elhalawani.