Publications by authors named "Ivaylo B Mihaylov"

Background: Immune checkpoint inhibitor (ICI) therapy is first-line treatment for many advanced non-small cell lung cancer (aNSCLC) patients. Predicting response could help guide selection of intensified or alternative anti-cancer regimens. We hypothesized that radiomics and laboratory variables predictive of ICI response in a murine model would also predict response in aNSCLC patients.

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Background: Primary sinonasal mucosal melanoma (SNMM) is a rare, aggressive histology usually diagnosed at advanced stages and associated with poor prognosis. Evidence regarding etiology, diagnosis, and treatment mainly derives from case reports, retrospective series, and national databases. In the treatment of metastatic melanoma, anti-CTLA-4 and anti-PD-1 checkpoint blockade increased 5-year overall survival from ~10% (prior to 2011) to ~50% (between 2011 and 2016).

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Article Synopsis
  • The study explores how combining radiotherapy and immune checkpoint inhibitors can boost tumor responses while examining the potential side effect of lung inflammation caused by these treatments.
  • Researchers tested this by using a mouse model with Lewis lung carcinoma, monitoring tumor response and lung inflammation through imaging and blood analysis.
  • The results identified specific imaging features that could predict lung inflammation, providing a foundation for developing models that help manage risks associated with this combined cancer therapy.
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Purpose: Immunotherapy (IT) and radiotherapy (RT) can act synergistically, enhancing antitumor response beyond what either treatment can achieve separately. Anecdotal reports suggest that these results are in part due to the induction of an abscopal effect on non-irradiated lesions. Systematic data on incidence of the abscopal effect are scarce, while the existence and the identification of predictive signatures or this phenomenon are lacking.

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Purpose: To describe in detail a dataset consisting of longitudinal fan-beam computed tomography (CT) imaging to visualize anatomical changes in head-and-neck squamous cell carcinoma (HNSCC) patients throughout radiotherapy (RT) treatment course.

Acquisition And Validation Methods: This dataset consists of CT images from 31 HNSCC patients who underwent volumetric modulated arc therapy (VMAT). Patients had three CT scans acquired throughout the duration of the radiation treatment course.

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Purpose: The voxels in a CT data sets contain density information. Besides its use in dose calculation density has no other application in modern radiotherapy treatment planning. This work introduces the use of density information by integral dose minimization in radiotherapy treatment planning for head-and-neck squamous cell carcinoma (HNSCC).

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Purpose: Inverse planning is trial-and-error iterative process. This work introduces a fully automated inverse optimization approach, where the treatment plan is closely tailored to the unique patient anatomy. The auto-optimization is applied to pancreatic stereotactic body radiotherapy (SBRT).

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Purpose: The purpose of this work is to apply a novel inverse optimization approach, based on utilization of quantitative imaging information in the optimization function, to prostate carcinoma.

Materials And Methods: This new inverse optimization algorithm relies upon quantitative information derived from computed tomography (CT) imaging studies. The Hounsfield numbers of the CT voxels are converted to physical density, which in turn is used to calculate voxel mass and the corresponding integral dose, by summation over the product of dose and mass in each dose voxel.

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Purpose: Medical images are more than pictures. They contain additional quantitative information which can be interrogated, quantified, and utilized. Besides anatomical information computed tomography (CT) imaging data provide electron density information.

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Purpose: To introduce the concept of dose-mass-based inverse optimization for radiotherapy applications.

Materials And Methods: Mathematical derivation of the dose-mass-based formalism is presented. This mathematical representation is compared to the most commonly used dose-volume-based formulation used in inverse optimization.

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Purpose: To introduce the concept of energy minimization-based inverse optimization for external beam radiotherapy.

Materials And Methods: Mathematical formulation of energy minimization-based inverse optimization is presented. This mathematical representation is compared to the most commonly used dose-volume based formulation used in inverse optimization.

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Volumetric-modulated arc technique (VMAT) is an efficient form of IMRT delivery. It is advantageous over conventional IMRT in terms of treatment delivery time. This study investigates the relation between the number of segments and plan quality in VMAT optimization for a single modulated arc.

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Article Synopsis
  • This study investigates how carbon fiber couches affect radiation doses delivered to the skin during volumetric modulated arc therapy (VMAT) for cancer treatment, specifically looking to identify ways to reduce this skin dose.
  • By analyzing treatment plans for ten patients (five lung and five prostate), the researchers compared VMAT plans that used different photon energy levels and measured the skin doses associated with each plan, noting significant differences in doses as high as 34%.
  • The results suggest that using mixed energy VMAT plans can substantially decrease skin doses compared to using only lower energy photons, indicating potential benefits in sparing skin during hypofractionated treatments.
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Purpose: To investigate the potential benefits achievable with biological optimization for modulated volumetric arc (VMAT) treatments of prostate carcinoma.

Methods And Materials: Fifteen prostate patient plans were studied retrospectively. For each case, planning target volume, rectum, and bladder were considered.

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Purpose: To evaluate incidental doses to benign lung tissue for patients with minimally moving lung lesions treated with respiratory gating.

Methods And Materials: Seventeen lung patient plans were studied retrospectively. Tumor motion was less than 5 mm in all cases.

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Purpose: To quantify the skin doses resulting from the use of carbon fiber couches (CFCs) for patient support.

Materials And Methods: BrainLab's CFC was evaluated for five prostate patients and five lung patients. For each patient PTV, organs at risk (OARs), and a 0.

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