The effect of electron backscatter and charge build up in media on beam current transformer signal for ultra-high dose rate (FLASH) electron beam monitoring.

Beam current transformers (BCT) are promising detectors for real-time beam monitoring in ultra-high dose rate (UHDR) electron radiotherapy. However, previous studies have reported a significant sensitivity of the BCT signal to changes in source-to-surface distance (SSD), field size, and phantom material which have until now been attributed to the fluctuating levels of electrons backscattered within the BCT. The purpose of this study is to evaluate this hypothesis, with the goal of understanding and mitigating the variations in BCT signal due to changes in irradiation conditions.

Technical note: Consistency of IAEA's TRS-483 and AAPM's extended TG-51 protocols for clinical reference dosimetry of the CyberKnife M6 machine.

Background: While IAEA's TRS-483 code of practice is adapted for the calibration of CyberKnife machines, AAPM's TG-51 is still the protocol recommended by the manufacturer for their calibration. The differences between both protocols could lead to differences in absorbed dose to water during the calibration process.

Purpose: The aims of this work are to evaluate the difference resulting from the application of TG-51 (including the manufacturer's adaptations) and TRS-483 in terms of absorbed dose to water for a CyberKnife M6, and to evaluate the consistency of TRS-483.

Clinical Evaluation of In-House-Produced 3D-Printed Nasopharyngeal Swabs for COVID-19 Testing.

3D-printed alternatives to standard flocked swabs were rapidly developed to provide a response to the unprecedented and sudden need for an exponentially growing amount of diagnostic tools to fight the COVID-19 pandemic. In light of the anticipated shortage, a hospital-based 3D-printing platform was implemented in our institution for the production of swabs for nasopharyngeal and oropharyngeal sampling based on the freely available, open-source design provided to the community by University of South Florida's Health Radiology and Northwell Health System teams as a replacement for locally used commercial swabs. Validation of our 3D-printed swabs was performed with a head-to-head diagnostic accuracy study of the 3D-printed "Northwell model" with the cobas PCR Media swab sample kit.

Large-scale dosimetric assessment of Monte Carlo recalculated doses for lung robotic stereotactic body radiation therapy.

Owing to its short computation time and simplicity, the Ray-Tracing algorithm (RAT) has long been used to calculate dose distributions for the CyberKnife system. However, it is known that RAT fails to fully account for tissue heterogeneity and is therefore inaccurate in the lung. The aim of this study is to make a dosimetric assessment of 219 non-small cell lung cancer CyberKnife plans by recalculating their dose distributions using an independent Monte Carlo (MC) method.

On-chip combined radiotherapy and chemotherapy testing on soft-tissue sarcoma spheroids to study cell death using flow cytometry and clonogenic assay.

Radiotherapy (RT) and chemotherapy (CT) are the major therapeutics to treat cancer patients. Conventional in vitro 2D models are insufficient to study the combined effects of RT and CT towards optimized dose selection or drug screening. Soft-tissue sarcomas (STS) are rare cancers with profound social impacts as they affect patients of all ages.

The impacts of mid-treatment CBCT-guided patient repositioning on target coverage during lung VMAT.

Introduction: The purpose of this study is quantify intrafraction motion (IFM) during lung volumetric-modulated arc therapy (VMAT) and evaluate the impact of mid-treatment cone beam computed tomography (CBCT)-guided patient repositioning on target coverage.

Method: This analysis included lung tumours treated with VMAT to 50-60 Gy in 3-5 fractions. Treatment planning was based on four-dimensional CT scans from which internal tumour volumes (ITV) were derived.