BACKGROUND AND AIM: Digital panoramic X-ray images can be captured using photostimulable phosphors or solid-state detectors (i.e. charge-coupled devices and Flat-Panels). The first category is defined as computed radiography (CR) or semi-direct radiography. The second technology that uses solid-state detectors is known as direct digital radiography (DDR). Both of these technologies have their o...

We give digital analogues of classical theorems of topology for continuous functions defined on spheres, for digital simple closed curves. In particular, we show the following: 1) A digital simple closed curve S of more than 4 points is not contractible, i.e., its identity map is not nullhomotopic in S ; 2) Let X and Y be digital simple closed curves, each symmetric with respect to the origin, ...

Introduction: Paediatric patients deserve special attention because of the higher radiation risks compared with adults. The main purpose of this study is to determine patient dose and diagnostic reference level for Paediatric through Entrance Surface Dose (ESD) calculations in common X-ray examination and to establish Paediatric national DRLs in digital radiography in Iran. <...

In this paper we introduce a notion of digital implicit surface in arbitrary dimensions. The digital implicit surface is the result of a morphology inspired digitization of an implicit surface {x ∈ R : f(x) = 0} which is the boundary of a given closed subset of R, {x ∈ R : f(x) ≤ 0}. Under some constraints, the digital implicit surface has some interesting properties, such as k-tunnel freeness,...

OBJECTIVE To determine the film-retake rates and causes in digital radiography comparison to conventional X-rays method. STUDY DESIGN Comparative study. PLACE AND DURATION OF STUDY Radiology Department, Aga Khan University Hospital, Karachi, from January 2004 to December 2006. PATIENTS AND METHODS X-rays of different body parts, conducted during the year 2004, with conventional radiograph...