PURPOSE To isolate focal rod electroretinograms (ERGs) from the dark-adapted human eye. METHODS In two normal volunteers, dark-adapted focal rod ERGs were recorded from the peripheral retina in response to 30 degree diameter blue flashes of varying retinal illuminance and from different retinal regions in response to 10 degree diameter bright blue flashes. Dark-adapted focal rod ERGs also wer...

Introduction: The aim of the present study was to determine burn intensity in retinal laser photocoagulation based on laser parameters; wavelength, power, beam size and pulse duration, using Optical Coherence Tomography (OCT), fundus camera, physical eye model and computer simulation in a clinical study.Materials and Methods: Participants were 10 adult patients between 50-80 years with prolifer...

introduction: with the rapid increase in use of lasers in medical treatments, it is important to understand the mechanisms of heat transfer in biological tissues in order to minimize damage to the tissues resulting from extra heat applied. the aim of this study is to investigate the temperature distribution in living biological tissues when laser irradiation is used in a treatment. methods:  in...

Arrays of wavelength scale scatterers are a promising platform for designing optical elements with a compact footprint. The large number of degrees of freedom in this system allows for unique and plentiful functionalities. However, the many variables also create a complex design problem. While intuitive forward design methods work for simple optical elements, they often fail to produce complica...

Stimulated emission depletion (STED) microscopy usually employs a scanning excitation beam that is superimposed by a donut-shaped STED beam for keeping the fluorophores at the periphery of the excitation spot dark. Here, we introduce a simple birefringent device that produces a donut-shaped focal spot with suitable polarization for STED, while leaving the excitation spot virtually intact. The d...

A laminated beam-spot camera of length 20 cm and effective cross-sectional area 2.5 cm × 3 cm was designed and constructed for the measurement of X-ray beam-spot sizes on different models of Siemens accelerators. With the accelerator gantry at 180° and camera positioned on an accessory tray holder, an XV film placed in contact with the camera at the distal end of it detected those X-rays that w...

Flat-panel cone-beam CT (CBCT) has been applied clinically in a number of high-resolution applications. Increasing geometric magnification can potentially improve resolution, but also increases blur due to an extended x-ray focal-spot. We present a shift-variant focal-spot blur model and incorporate it into a model-based iterative-reconstruction algorithm. We apply this algorithm to simulation ...

In this contribution we present numerical simulations of full impact of the Super Proton Synchrotron (SPS) beam with a solid tungsten cylindrical target that is facially irradiated. The beam comprises of 288 bunches and each bunch is made of 1.15 × 10 450 GeV protons. The bunch length is 0.5 ns and two neighboring bunches are separated by 25 ns so that the total duration of the beam is about 7 ...

Introduction For various therapeutic applications, focused ultrasound (FUS) is used in either thermal mode or in mechanical mode. Mechanical mode FUS has been used for temporary blood brain barrier disruption and for targeted drug delivery. Monitoring of such treatments remains a technical challenge since there should be no significant temperature increase in the focal spot, unlike in case of t...