SPOT REGION OF INTEREST IMAGING: A NOVEL FUNCTIONALITY AIMED AT X-RAY DOSE REDUCTION IN NEUROINTERVENTIONAL PROCEDURES.

Aim Of The Study: The aim of this study was to describe a new functionality aimed at X-ray dose reduction, referred to as spot region of interest (Spot ROI) and to compare it with existing dose-saving functionalities, spot fluoroscopy (Spot F), and conventional collimation (CC).

Material And Methods: Dose area product, air kerma, and peak skin dose were measured for Spot ROI, Spot F, and CC in three different fields of view (FOVs) 20 × 20 cm, 15 × 15 cm, and 11 × 11 cm using an anthropomorphic head phantom RS-230T. The exposure sequence was 5 min of pulsed fluoroscopy (7.

Nonequilibrium Pair Breaking in Ba(Fe_{1-x}Co_{x})_{2}As_{2} Superconductors: Evidence for Formation of a Photoinduced Excitonic State.

Ultrafast terahertz (THz) pump-probe spectroscopy reveals an unusual out-of-equilibrium Cooper pair nonlinear dynamics and a nonequilibrium state driven by femtosecond (fs) photoexcitation of superconductivity (SC) in iron pnictides. Following fast SC quench via hot-phonon scattering, a second, abnormally slow (many hundreds of picoseconds), SC quench regime is observed prior to any recovery. Importantly, a nonlinear pump fluence dependence is identified for this remarkably long prebottleneck dynamics that are sensitive to both doping and temperature.

Flexible lateral isocenter: A novel mechanical functionality contributing to dose reduction in neurointerventional procedures.

Aim of the study A new functionality that enables vertical mobility of the lateral arm of a biplane angiographic machine is referred to as the flexible lateral isocenter. The aim of this study was to analyze the impact of the flexible lateral isocenter on the air-kerma rate under experimental conditions. Material and methods An anthropomorphic head-and-chest phantom with anteroposterior (AP) diameter of the chest varying from 22 cm to 30 cm simulated human bodies of different body constitutions.

Spot fluoroscopy: a novel innovative approach to reduce radiation dose in neurointerventional procedures.

Background Increased interest in radiation dose reduction in neurointerventional procedures has led to the development of a method called "spot fluoroscopy" (SF), which enables the operator to collimate a rectangular or square region of interest anywhere within the general field of view. This has potential advantages over conventional collimation, which is limited to symmetric collimation centered over the field of view. Purpose To evaluate the effect of SF on the radiation dose.

Ultrafast terahertz probes of interacting dark excitons in chirality-specific semiconducting single-walled carbon nanotubes.

Ultrafast terahertz spectroscopy accesses the dark excitonic ground state in resonantly excited (6,5) single-walled carbon nanotubes via internal, direct dipole-allowed transitions between the lowest-lying dark-bright pair state of ∼6  meV. An analytical model reproduces the response that enables the quantitative analysis of transient densities of dark excitons and e-h plasma, oscillator strength, transition energy renormalization, and dynamics. Nonequilibrium, yet stable, quasi-one-dimensional quantum states with dark excitonic correlations rapidly emerge even with increasing off-resonance photoexcitation and experience a unique crossover to complex phase-space filling of both dark and bright pair states, different from dense two- and three-dimensional excitons influenced by the thermalization, cooling, and ionization to free carriers.

Ultrafast observation of critical nematic fluctuations and giant magnetoelastic coupling in iron pnictides.

Many of the iron pnictides have strongly anisotropic normal-state characteristics, important for the exotic magnetic and superconducting behaviour these materials exhibit. Yet, the origin of the observed anisotropy is unclear. Electronically driven nematicity has been suggested, but distinguishing this as an independent degree of freedom from magnetic and structural orders is difficult, as these couple together to break the same tetragonal symmetry.

Femtosecond switching of magnetism via strongly correlated spin-charge quantum excitations.

The technological demand to push the gigahertz (10(9) hertz) switching speed limit of today's magnetic memory and logic devices into the terahertz (10(12) hertz) regime underlies the entire field of spin-electronics and integrated multi-functional devices. This challenge is met by all-optical magnetic switching based on coherent spin manipulation. By analogy to femtosecond chemistry and photosynthetic dynamics--in which photoproducts of chemical and biochemical reactions can be influenced by creating suitable superpositions of molecular states--femtosecond-laser-excited coherence between electronic states can switch magnetic order by 'suddenly' breaking the delicate balance between competing phases of correlated materials: for example, manganites exhibiting colossal magneto-resistance suitable for applications.

[Radiation exposure with 3D rotational angiography of the skull].

Purpose: Determination and comparison of radiation exposure for examinations of the skull with unsubtracted 3D Rotational Angiography (3D RA) and 2D Digital Subtraction Angiography (2D DSA).

Materials And Methods: Measurements were carried out with a skull of an Alderson phantom for 3D RA and for 2D DSA in p. a.

Proceedings of the Third International Symposium on Retinopathy of Prematurity: an update on ROP from the lab to the nursery (November 2003, Anaheim, California).

The Third International Symposium on Retinopathy of Prematurity (ROP) was convened with the aim of cross fertilizing the horizons of basic and clinical scientists with an interest in the pathogenesis and management of infants with ROP. Ten speakers in the clinical sciences and ten speakers in the basic sciences were recruited on the basis of their research to provide state of the art talks. The meeting was held November 9, 2003 immediately prior to the American Academy of Ophthalmology meeting; scholarships were provided for outreach to developing countries and young investigators.

Retinopathy of prematurity: the life of a lifetime disease.

Purpose: To provide information on retrolental fibroplasias (RLF), later known as retinopathy of prematurity.

Design: Review of the literature on the subject and a first-person account of what was then RLF by one of the authors (A.P.

Interval between onset of mild nonproliferative and proliferative retinopathy in type I diabetes.

Objective: To describe the interval between first appearance of mild nonproliferative diabetic retinopathy (NPDR) and first appearance of neovascularization (NV) in type I diabetes.

Setting: A longitudinal study of 269 patients followed up annually.

Participants: Participants had insulin-dependent diabetes and were free of proliferative diabetic retinopathy in both eyes at the baseline visit.

Clinically significant macular edema in type I diabetes. Incidence and risk factors.

Purpose: To examine incidence of and risk factors for clinically significant macular edema in persons with type I diabetes.

Methods: A group of 189 persons with type I diabetes, recruited from a summer camp for children with diabetes and from practices of local physicians, were participants in a longitudinal study with annual follow-up visits which included physical and ophthalmologic examinations and color stereo fundus photographs of each eye, centered on the disc and macula. Subjects were free of proliferative retinopathy at study baseline.

Elimination of preventable blindness from diabetes by the year 2000.

"Diabetes 2000" will parallel a major diabetic retinopathy public information campaign recently announced by the National Eye Institute. The NEI's National Eye Health Education Program (NEHEP), which targets both diabetic retinopathy and glaucoma, is fashioned along the lines of earlier federal initiatives against smoking and high blood pressure. By continuously updating our medical knowledge and skills related to this multisystem disorder, and by forging partnerships between physicians in the effective and efficient management of diabetic patients, we have a unique and important opportunity--we can reduce preventable blindness from diabetes by the year 2000.

The relationship of puberty to diabetic retinopathy.

The presence of background and preproliferative retinopathy in 70 patients with type I diabetes was correlated with their pubertal development. Pubertal status was assessed by pediatricians using the sexual maturity ratings of Tanner. In young diabetics with comparable disease duration (5 to 10 years), postpubertal children had a greater prevalence of retinopathy than those who were not sexually mature.