purpose: to evaluate residual refractive errors after cataract surgery and its determinant factors at farabi eye hospital, tehran. methods: simple random sampling was done among cataract surgery scheduled patients over a 4 year period (2003-2006). exclusion criteria were uveitis, previous intraocular surgery and ocular trauma. after applying the exclusion criteria, 423 patients were studied. le...

The purpose of this study is to simulate random and systematic RapidArc delivery errors for external beam prostate radiotherapy plans in order to determine the dose sensitivity for each error type. Ten prostate plans were created with a single 360° arc. The DICOM files for these treatment plans were then imported into an in-house computer program that introduced delivery errors. Random and syst...

Error-correcting codes have contributed in a significant way for both the theoretical referred to as random errors, or else errors can appear in bursts of many errors each It was shown that long LDPC codes with iterative decoding achieve. LDPC codes provide good random error performance nearer to Shannon limit. iterations such errors can be corrected by concatenating LDPC codes with RS codes. b...

PURPOSE To investigate the impact of clinical target volume (CTV) shape and size on CTV to planning target volume (PTV) margin expansion. METHODS AND MATERIALS Using numerical integration methods, margins accounting for random errors and systematic errors were calculated for CTVs of different shapes and sizes. We use k(r-95) and k(s-95) to represent the coefficients, for random errors and sys...

We prove the following results concerning the list decoding of error-correcting codes: 1. We show that for any code with a relative distance of δ (over a large enough alphabet), the following result holds for random errors: With high probability, for a ρ 6 δ− ε fraction of random errors (for any ε > 0), the received word will have only the transmitted codeword in a Hamming ball of radius ρ arou...

PURPOSE The purpose of this study is to determine dose delivery errors that could result from random and systematic setup errors for head-and-neck patients treated using the simultaneous integrated boost (SIB)-intensity-modulated radiation therapy (IMRT) technique. METHODS AND MATERIALS Twenty-four patients who participated in an intramural Phase I/II parotid-sparing IMRT dose-escalation prot...

purpose : to determine the prevalence of refractive condition and its risk factors among students in mashhad . methods : a total of 2510 students representing a cross-sectional of the population of mashhad were sampled using random cluster sampling strategy. primary and middle school students underwent cycloplegic refraction. the refractive errors of high school students were measured using non...

Background & Aims: Administration of medications is an important part of treatment. Reporting of medication errors by nurses maintains patient safety and the lack of appropriate reporting can cause serious problems in health systems. The aim of this study was to determine the causes of medication errors and the barriers of error reporting from the viewpoints of nurses. Methods: This cross-secti...

research error in medical sciences studies and their control strategies khorami markaney a , yagmayee f , habibzadeh h received: 22 march, 2010 accepted: 11 july,. 2010 abstract background & aims: one of the important goals of research studies especially in medical sciences is accurate measurement of outcome occurrence. despite numerous efforts to reduce accuracy errors, they still occur. the a...