Impact of Scattering Foil Composition on Electron Energy Distribution in a Clinical Linear Accelerator Modified for FLASH Radiotherapy: A Monte Carlo Study.

This study investigates how scattering foil materials and sampling holder placement affect electron energy distribution in electron beams from a modified medical linear accelerator for FLASH radiotherapy. We analyze electron energy spectra at various positions-ionization chamber, mirror, and jaw-to evaluate the impact of Cu, Pb-Cu, Pb, and Ta foils. Our findings show that close proximity to the source intensifies the dependence of electron energy distribution on foil material, enabling precise beam control through material selection.

Mechanisms of Action in FLASH Radiotherapy: A Comprehensive Review of Physicochemical and Biological Processes on Cancerous and Normal Cells.

The advent of FLASH radiotherapy (FLASH-RT) has brought forth a paradigm shift in cancer treatment, showcasing remarkable normal cell sparing effects with ultra-high dose rates (>40 Gy/s). This review delves into the multifaceted mechanisms underpinning the efficacy of FLASH effect, examining both physicochemical and biological hypotheses in cell biophysics. The physicochemical process encompasses oxygen depletion, reactive oxygen species, and free radical recombination.

FLASH Radiotherapy and the Use of Radiation Dosimeters.

Radiotherapy (RT) using ultra-high dose rate (UHDR) radiation, known as FLASH RT, has shown promising results in reducing normal tissue toxicity while maintaining tumor control. However, implementing FLASH RT in clinical settings presents technical challenges, including limited depth penetration and complex treatment planning. Monte Carlo (MC) simulation is a valuable tool for dose calculation in RT and has been investigated for optimizing FLASH RT.

Rethinking the Characterization of Nanoscale Field-Effect Transistors: A Universal Approach.

Standard methods for calculating transport parameters in nanoscale field-effect transistors (FETs), namely carrier concentration and mobility, require a linear connection between the gate voltage and channel conductance; however, this is often not the case. One reason often overlooked is that shifts in chemical and electric potential can partially compensate each other, commonly referred to as quantum capacitance. In nanoscale FETs, capacitance is often unmeasurable and an analytical formula is required, which assumes the conducting channel as metallic and common methods of determining threshold voltage no longer couple properly into transport equations.

Nonlinear Chemical Sensitivity Enhancement of Nanowires in the Ultralow Concentration Regime.

Much recent attention has been focused on the development of field-effect transistors based on low-dimensional nanostructures for the detection and manipulation of molecules. Because of their extraordinarily high charge sensitivity, InAs nanowires present an excellent material system in which to probe and study the behavior of molecules on their surfaces and elucidate the underlying mechanisms dictating the sensor response. So far, chemical sensors have relied on slow, activated processes restricting their applicability to high temperatures and macroscopic adsorbate coverages.