A benchmark for Monte Carlo simulations in gamma-ray spectrometry Part II: True coincidence summing correction factors.

The goal of this study is to provide a benchmark for the use of Monte Carlo simulation when applied to coincidence summing corrections. The examples are based on simple geometries: two types of germanium detectors and four kinds of sources, to mimic eight typical measurement conditions. The coincidence corrective factors are computed for four radionuclides.

Age-Related Changes in Corneal Epithelial Thickness Measured with an Ultrasound Pachymeter.

Background: There is increasing research on the aging process of the cornea and its effect on the corneal parameters measured objectively. Nevertheless, the association of corneal epithelial thickness (CET) with age has yet to be fully illustrated.

Purpose: We aimed to measure CET in healthy subjects to determine its age-related variation by using an ultrasound device.

Correlation between corneal thickness, keratometry, age, and differential pressure difference in healthy eyes.

To determine the use of differential pressure difference (DPD), in air-puff differential tonometry, as a potential biomechanical measure of the cornea and elucidate its relationship with the intraocular pressure (IOP), central corneal thickness, corneal curvature, and age. This study comprised 396 eyes from 198 patients and was conducted at Acibadem University, School of Medicine, Department of Ophthalmology, Istanbul, Turkey. The central corneal curvature and refraction of the eyes were measured using an Auto Kerato-Refractometer (KR-1; Topcon Corporation, Tokyo, Japan).

Intrauterine Cataract Diagnosis and Follow-up.

In this article, we report a 21-gestational-week fetus diagnosed with congenital cataract by ultrasonography. The parents decided to terminate the pregnancy and asked for examination of the fetus. An amniocentesis was performed for fetal karyotyping.

Intraocular Pressure Based on Dynamic Bidirectional Applanation and Air-puff Tonometry: A Comparative Study.

Aim: The aim of this study is to compare intraocular pressure (IOP) in healthy eyes measured via dynamic bidirectional applanation and air-puff tonometry, and to evaluate the effect of age, gender, the spherical equivalent (SE), mean keratometry (Kmean), corneal hysteresis (CH), and the corneal resistance factor (CRF) on IOP measurements.

Materials And Methods: IOP measured in 956 healthy eyes using the ocular response analyzer (ORA) and air-puff tonometer was compared in this cross-sectional retrospective study. Correlations between IOP, and age, gender, SE, Kmean, CH, and CRF were investigated using univariate and multivariate analyses.