background: the assessment of rbe quantity in the treatment of cancer tumors with proton beams in treatment planning systems (tps) is of high significance. given the significance of the issue and the studies conducted in the literature, this quantity is fixed and is taken as equal to 1.1. objective: the main objective of this study was to assess rbe quantity of proton beams and their variations...

A hybrid integration of nanoplasmonic antennas with silicon nitride waveguides enables miniaturized chips for surface-enhanced Raman spectroscopy at visible and near-infrared wavelengths. This integration can result in high-throughput SERS assays on low sampling volumes. However, current fabrication methods are complex and rely on electron-beam lithography, thereby obstructing the full use of a...

Using in situ transmission electron microscopy, we demonstrated that gold nanoparticles are unified via "oriented attachment" assisted either by nanoparticle rotation or grain boundary migration at the attachment interface. We also observed that the combined nanoparticle changes shape with stable facet planes via surface diffusion, along with recrystallization.

introduction: in clinical electron beams, most of bremsstrahlung radiation is produced by various linac head structures. this bremsstrahlung radiation dose is influenced by the geometry and construction of every component of the linac treatment head structures. thus, it can be expected that the amount of the contaminated photon dose due to bremsstrahlung radiation varies among different linacs,...

background: hadron therapy for malignant tumor is becoming increasingly popular. there are many factors which effect on implementation of a proper treatment planning. the purpose of this work is to investigate the inhomogeneity effects as affecting factor on proton range, full width at half maximum (fwhm) and 20% position of penumbra (p20) by mcnpx code. materials and methods: an inhomogeneous ...

The bacterial action of gentamicin and that of a mixture of gentamicin and 15-nm colloidal-gold particles on Escherichia coli K12 was examined by the agar-well-diffusion method, enumeration of colony-forming units, and turbidimetry. Addition of gentamicin to colloidal gold changed the gold color and extinction spectrum. Within the experimental errors, there were no significant differences in an...

BACKGROUND AND PURPOSE To investigate combining unmodulated electron beams with intensity-modulated radiation therapy to improve dose distributions for superficial head and neck cancers, and to compare mixed beam plans with helical tomotherapy. MATERIALS AND METHODS Mixed beam and helical tomotherapy dose plans were developed for two patients with parotid gland tumors and two patients with na...

Background: Reliable estimation of radiation-absorbed dose is necessary to evaluate the benefits and the risks of radiopharmaceuticals used for diagnostic or therapeutic purposes in nuclear medicine. Materiel and Methods: This study included 47 patients treated with iodine-131 for Graves’ disease. A comparative study between Geant4 Monte Carlo simulation and MIRD formalism was carried out to ev...