Publications by authors named "Achkar S"

Article Synopsis
  • Dedicated brain imaging for cancer patients is rarely recommended unless symptoms arise, and brain metastases are often difficult to identify on non-enhanced CT (NE-CT).
  • This research aims to create a 3D Convolutional Neural Network (3D-CNN) using NE-CT scans to effectively distinguish between cancer patients with and without brain metastases.
  • The study utilized a dataset of 200 patients (100 with and 100 without brain abnormalities), achieving high accuracy (ACC of 0.983) and sensitivity (0.983) in detecting brain metastases, indicating the potential for a reliable diagnostic tool with further validation needed.
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  • AGuIX nanoparticles are gadolinium-based agents that serve as both MRI contrast agents and enhance the effectiveness of X-ray radiation therapy for cancer treatment.
  • A phase I trial tested the safety and optimal dosage of AGuIX in combination with conventional therapies for 12 patients with advanced cervical cancer, showing good tolerability and no severe side effects.
  • The treatment resulted in complete remission of the primary tumors in all but one patient, highlighting the potential of these nanoparticles to improve the precision of tumor targeting and enhance radiotherapy outcomes.
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  • This study compares various Deep Learning models for segmenting Gross Tumor Volume (GTV) in patients with locally advanced cervical cancer, emphasizing the need for improved segmentation methods in Radiotherapy.
  • Eight different models were trained using both 2D and 3D segmentation techniques, with the 2D-SegResNet model performing the best, achieving a high level of segmentation accuracy.
  • Additionally, a novel failure detection system using radiomic features was introduced, potentially aiding doctors in identifying segmentation errors and enhancing overall treatment planning.
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The last record of a rabies case caused by the dog-specific rabies virus (RABV) lineage in dogs or cats in São Paulo State was in 1998. From 2002 to 2021, 57 cases of rabies in these animals were reported, and the vast majority (51) were genetically characterized as belonging to the Desmodus rotundus/Artibeus lituratus RABV lineage. However, it is not currently possible to infer which of these bats is the source of infection by genome sequencing of RABV isolates.

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Rabies is worldwide zoonosis caused by Lyssavirus rabies (RABV) a RNA negative sense virus with low level of fidelity during replication cycle. Nucleoprotein of RABV is the most conserved between all five proteins of the virus and is the most used gene for phylogenetic and phylogeographic studies. Despite of rabies been very important in Public Health concern, it demands continuous prophylactic care for herbivores with economic interest, such as cattle and horses.

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Purpose: The objective of this work was to examine the benefit of an intensive locoregional treatment including an image guided adaptive brachytherapy (IGABT) among patients with cervical cancer and extrapelvic extension.

Methods And Materials: Medical records of consecutive patients with a metastatic cervical cancer and receiving external beam radiation therapy and IGABT boost in Gustave Roussy Institute as part of their first line of treatment were examined. Depending on tumor sites, patients received pelvic ± para-aortic external beam radiation therapy.

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Solitary large brain metastases (LBM) and high-grade gliomas (HGG) are sometimes hard to differentiate on MRI. The management differs significantly between these two entities, and non-invasive methods that help differentiate between them are eagerly needed to avoid potentially morbid biopsies and surgical procedures. We explore herein the performance and interpretability of an MRI-radiomics variational quantum neural network (QNN) using a quantum-annealing mutual-information (MI) feature selection approach.

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A growing body of scientific evidence indicates that exposure to low dose ionizing radiation (< 2 Gy) is associated with a higher risk of developing radio-induced cancer. Additionally, it has been shown to have significant impacts on both innate and adaptive immune responses. As a result, the evaluation of the low doses inevitably delivered outside the treatment fields (out-of-field dose) in photon radiotherapy is a topic that is regaining interest at a pivotal moment in radiotherapy.

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Radiation therapy has a fundamental role in the management of cancers. However, despite a constant improvement in radiotherapy techniques, the issue of radiation-induced side effects remains clinically relevant. Mechanisms of acute toxicity and late fibrosis are therefore important topics for translational research to improve the quality of life of patients treated with ionizing radiations.

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Article Synopsis
  • * Analysis involved reviewing medical records of 81 patients, assessing dosimetric parameters, and identifying prognostic factors related to survival and complications like fistula formation.
  • * Results showed a 42% recurrence rate after a median follow-up of about 28 months, with higher doses administered through IGABT linked to better overall survival outcomes.
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Image-guided adaptive brachytherapy (IGABT) is part of the standard of care for locally advanced cervical cancer (LACC). Access to IGABT is limited in many regions, thus leading to treatment care disparities. We report the experience of a referral network for women with LACC between radiotherapy facilities in Overseas France and Gustave Roussy.

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Globally, cervical cancers continue to be one of the leading causes of cancer-related deaths. The primary treatment of patients with early-stage disease includes surgery or radiation therapy with or without chemotherapy. The main challenge in treating these patients is to maintain a curative approach and limit treatment-related morbidity.

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Standard treatment of locally advanced gynecological cancers relies mainly on platinum-based concurrent chemoradiotherapy followed by brachytherapy. Current chemotherapeutic drugs are only transiently effective and patients with advanced disease often develop resistance and subsequently, distant metastases despite significant initial responses of the primary tumor. In addition, some patients still develop local failure or progression, suggesting that there is still a place for increasing the anti-tumor radiation effect.

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  • Peri-urethral cancers (PUC) are rare tumors, and brachytherapy (BT) is often preferred for treatment to avoid the complications of surgery while preserving the organ.
  • This study at Gustave Roussy reviewed the records of 44 female patients with PUC who received BT, revealing a median follow-up of 21.5 months, with an overall survival probability of 63%.
  • The research indicated an 80% local control rate with BT, although there was a significant risk of metastasis and noted instances of mild to moderate adverse effects in patients.
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Aim: To prospectively assess toxicities of curative-intent intensity-modulated conformal radiotherapy (IMRT) in patients with extremity soft tissue sarcomas (ESTS).

Methods: Data from 59 consecutive patients with ESTS between 2014 and 2019 were both retrospectively and prospectively analysed. Toxicity data were collected both by confidential mailed survey (39% completed) and medical charts, and graded according to CTCAE v5.

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Purpose: To examine clinical outcomes and quality of life of patients with anal squamous cell carcinoma treated with interstitial pulsed-dose-rate brachytherapy (PDR-BT) with a boost to residual tumor after external radiotherapy.

Material And Methods: Medical records of patients receiving a brachytherapy boost after radiotherapy for anal squamous cell carcinoma in our Institute between 2008 and 2019 were retrospectively reviewed. After receiving pelvic irradiation ± concurrent chemotherapy, patients received PDR-BT boost to residual tumor, in order to deliver a minimal total dose of 60 Gy.

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Article Synopsis
  • Cancer patients are more vulnerable to COVID-19, leading researchers to evaluate a combined screening approach of chest CT scans and RT-PCR tests at a cancer center during the pandemic's first wave in France.
  • From March 18 to May 1, 2020, 480 patients underwent chest CT screenings, with 313 also receiving RT-PCR tests; the cumulative incidence of COVID-19 was found to be 5.4%.
  • The study highlighted that chest CT was particularly useful for diagnosing cases where RT-PCR results were negative or not possible, showing a sensitivity of 82% and specificity of 98%, which allowed for necessary adaptations in radiation therapy treatment plans.
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Purpose: Glassy cell carcinoma (GCC) of the uterine cervix is a rare entity. This study aims at describing the clinical characteristics and outcomes of cervical GCC patients treated in a comprehensive cancer center.

Material And Methods: We retrospectively reported patients and tumors characteristics, therapeutic management, overall survival (OS), progression-free progression (PFS), relapse rates, and toxicities.

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In recent years, magnetic resonance imaging (MRI) has become one of the standard imaging tools to define the macroscopic gross tumor volume in locally advanced cervical cancer patients based on T2-weighted sequence. Recent data suggest that functional MRI could be used to potentially improve the delineation of target volumes based on physiologic features, defining radioresistant subvolumes that may require higher doses to achieve local cure. Functional imaging can be used to predict tumor biology and outcome, as well as for assessment of tumor response during radiotherapy.

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The direct-fluorescent antibody test (dFAT) is considered the "gold standard" assay to diagnose rabies. However, it is crucial to develop molecular techniques, such as RT-PCR and RT-qPCR, since many laboratories lack the needed supplies for performing complementary methods (viral isolation, for example). For this purpose, diagnostic techniques must be specific and sensitive to guarantee accuracy.

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Laboratory diagnosis of rabies in equines is essential for distinguishing the disease from other sources of encephalitis. Diagnosis by conventional techniques such as a direct fluorescent antibody test (dFAT) or viral isolation in mice or cell culture can be difficult, and the application of molecular biological methods may be necessary. We performed an indirect rapid immunohistochemistry test (iRIT) for the detection of the rabies virus (RABV) antigen in the central nervous system (CNS) of equines and compared the results with those of other diagnostic techniques.

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Purpose: Gantry collision is a concern in linac-based stereotactic radiosurgery (SRS). Without collision screening, the planner may compromise optimal planning, unnecessary re-planning delays can occur, and incomplete treatments may be delivered. To address these concerns, we developed a software for collision prediction based on simple machine measurements.

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The Th17 profile immune response is influenced by the presence of cytokines such as IL-1, IL-6, TGF-β, IL-17, and IL-23. We sought to characterize the Th17 profile in CNS samples from human rabies cases transmitted by dogs and examine its possible influence on disease pathogenesis. We observed a high expression of TGF-β, followed by IL-23, IL-17 and IL-6, and a low expression of IL-1β and IFN-γ.

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