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9 real negative results, null findings, and replication failures in Medical physics. Medical radiology. Nuclear medicine · Negative / Null Result Report. Search the index →

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Negative / Null Result ReportOpen accessMedical physics. Medical radiology. Nuclear medicine

Anesthetic Oxygen Use and Sex Are Critical Factors in the FLASH Sparing Effect

Armin D. Tavakkoli, BA, Megan A. Clark, BE, Alireza Kheirollah, PhD et al. · 2024 · Advances in Radiation Oncology

Purpose: Ultra High Dose-Rate (UHDR) radiation has been reported to spare normal tissue, compared with Conventional Dose-Rate (CDR) radiation. However, important work remains to be done to improve the reproducibility of the FLASH effect. A better understanding of the biologic factors that modulate the FLASH effect may shed light on the mechanism of FLASH sparing. Here, we evaluated whether sex and/or the use of 100% oxygen as a carrier gas during irradiation contribute to the variability of the FLASH effect. Methods and Materials: C57BL/6 mice (24 male, 24 female) were anesthetized using isofl

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Negative / Null Result ReportOpen accessMedical physics. Medical radiology. Nuclear medicine

The in vivo study on the radiobiologic effect of prolonged delivery time to tumor control in C57BL mice implanted with Lewis lung cancer

Zhu Guo-Pei, Lu Jiade, Xiong Xiao-Peng et al. · 2011 · Radiation Oncology

Abstract Background High-precision radiation therapy techniques such as IMRT or sterotactic radiosurgery, delivers more complex treatment fields than conventional techniques. The increased complexity causes longer dose delivery times for each fraction. The purpose of this work is to explore the radiobiologic effect of prolonged fraction delivery time on tumor response and survival in vivo. Methods 1-cm-diameter Lewis lung cancer tumors growing in the legs of C57BL mice were used. To evaluate effect of dose delivery prolongation, 18 Gy was divided into different subfractions. 48 mice were rando

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Negative / Null Result ReportOpen accessMedical physics. Medical radiology. Nuclear medicine

Clinical outcome and safety of selective renal artery embolization using permanent occlusive agents for acute renal bleeding

Mohamed S. Alwarraky, Mohamed M. Abdallah, Mohamed S. Elgharbawy · 2020 · The Egyptian Journal of Radiology and Nuclear Medicine

Abstract Background To evaluate how far is selective renal artery embolization (RAE) using permanent agents effective in treating acute renal artery bleeding. We retrospectively reviewed the medical records of patients (n = 45) with renal bleeding who were managed by selective RAE using coils, N-butyl-cyanoacrylate glue (NBCA glue), and polyvinyl alcohol (PVA). Data retrieved included the cause, number, and type of the bleeding lesions as well as the results of the embolization for 1 year after RAE. Clinical success was the primary outcome while re-bleeding and complications were the secondary

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Negative / Null Result ReportOpen accessMedical physics. Medical radiology. Nuclear medicine

Intra-fractional geometric and dose/volume metric variations of magnetic resonance imaging-guided stereotactic radiotherapy of prostate bed after radical prostatectomy

Yu Gao, Stephanie Yoon, Ting Martin Ma et al. · 2024 · Physics and Imaging in Radiation Oncology

Background and purpose: Magnetic Resonance Imaging (MRI)-guided Stereotactic body radiotherapy (SBRT) treatment to prostate bed after radical prostatectomy has garnered growing interests. The aim of this study is to evaluate intra-fractional anatomic and dose/volume metric variations for patients receiving this treatment. Materials and methods: Nineteen patients who received 30–34 Gy in 5 fractions on a 0.35T MR-Linac were included. Pre- and post-treatment MRIs were acquired for each fraction (total of 75 fractions). The Clinical Target Volume (CTV), bladder, rectum, and rectal wall were conto

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Negative / Null Result ReportOpen accessMedical physics. Medical radiology. Nuclear medicine

Comparison of the Main Staging Systems for Assessing the Severity of Lung Injury in Patients with COVID-19 and Evaluation of Their Predictive Value

Y. S. Kudryavtsev, M. M. Beregov, A. B. Berdalin et al. · 2021 · Вестник рентгенологии и радиологии

Objective: to compare the results of staging the severity of viral pneumonia in patients with COVID-19 based on the results of chest computed tomography (CT) using the empirical visual scale CT 0–4 and chest CT severity score (CT-SS) point scale, as well as to assess their prognostic value.Material and methods. Chest CT scans and anamnestic data in patients hospitalized to a non-specialized center repurposed for the treatment of new coronavirus infection, were analyzed. Chest CT analysis was performed by two radiologists using CT 0–4 and CT-SS scales.Results. The time course of changes in the

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Negative / Null Result ReportOpen accessMedical physics. Medical radiology. Nuclear medicine

Dosimetric Comparison and Plan Evaluation of Different Dose Computing Algorithms for Different Radiotherapy Techniques in Head and Neck Tumors

Bharath Pandu, KHANNA D, Mohandass P et al. · 2022 · Iranian Journal of Medical Physics

Introduction: The study aims to compare target coverage and critical structure dose difference between various dose computing algorithms with small segment dose calculation in Intensity Modulated Radiation Therapy (IMRT) and large segment dose calculation in 3-Dimensional Conformal Radiation Therapy (3DCRT) treatment plan for Head and Neck (H&N) tumor.Material and Methods: For the present study, thirty-eight H&N cancer patients were selected retrospectively. Twenty-seven patients were planned with IMRT plan using Monte Carlo (MC) algorithm and eleven patients with 3DCRT plan using Collapsed Co

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Negative / Null Result ReportOpen accessMedical physics. Medical radiology. Nuclear medicine

Phase I and II trial on infusional 5-fluorouracil and gefitinib in combination with preoperative radiotherapy in rectal cancer: 10-years median follow-up

Maria Antonietta Gambacorta, Antonino De Paoli, Marco Lupattelli et al. · 2018 · Clinical and Translational Radiation Oncology

Purpose: The aim of this study is to evaluate the long term survival of the addition of gefitinib to chemoradiotherapy (CRT) in locally advanced rectal cancer (LARC). Methods and materials: This previously published multicentre, open-label, phase I-II study, enrolled patients (pts) with LARC to receive CRT with concurrent 5-fluorouracil continuous intravenous infusion and a dose escalation of orally administered gefitinib, followed 6–8 weeks later by surgery. An intra-operative radiotherapy boost of 10 Gy was planned. Adjuvant chemotherapy was administrated in ypN1-2 pts. After a median f/u of

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Negative / Null Result ReportOpen accessMedical physics. Medical radiology. Nuclear medicine

Single-institution analysis of the prevalence, indications and outcomes of end-of-life radiotherapy

Sebastian M. Christ, Markus Schettle, Annina Seiler et al. · 2021 · Clinical and Translational Radiation Oncology

Background: Radiotherapy plays an important role for symptom control in advanced stage cancer patients. Yet patients need to be carefully selected, and its use and benefits must be weighed against time spent under treatment and patient priorities in the last phase of life. In this study, we assess prevalence, indications and outcomes of radiotherapy close to death. Methods: We screened all radiotherapy treatments performed at the Department of Radiation Oncology of the University Hospital Zurich between January 2010 and December 2019 to identify those which occurred near patients’ end-of-life.

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Negative / Null Result ReportOpen accessMedical physics. Medical radiology. Nuclear medicine

Safety and efficacy of self-expandable metallic stent combined with 125I brachytherapy for the treatment of malignant obstructive jaundice

Ye Sheng, Xiaobo Fu, Guobao Wang et al. · 2023 · Cancer Imaging

Abstract Background Several previous studies demonstrated that the combination of self-expandable metallic stents (SEMS) and 125I seed implantation might prolong stent patency and obtain survival benefits for malignant obstructive jaundice (MOJ) patients. However, these studies rarely mentioned a comparison between CT-guided intratumoral 125I seed implantation and intraluminal 125I seed strand insertion combined with stenting for the management of MOJ. This study aimed to further evaluate the safety and efficacy of SEMS combined with 125I brachytherapy in the management of unresectable MOJ. Me

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