Tanısal radyolojide görüntü kalitesi önemli bir rol oynamaktadır. Dijital görüntülemenin, görüntüleri sayısal olarak elde etme, işleme ve saklama gibi avantajları vardır. dedektörlerin geniş dinamik aralığa sahip olması, daha iyi kalitede görüntülerin edilmesine olanak sağlar. Ancak hasta dozunda artışa sebep olabilmektedir. Bu nedenle optimizasyonunun, doz ölçümleri ile beraber yürütülmesi ger...

In this study, dose rate distribution around a spherical 137Cs pellet source, from a low-dose-rate (LDR) Selectron remote afterloading system used in gynecological brachytherapy, has been determined using experimental and Monte Carlo simulation techniques. Monte Carlo simulations were performed using MCNP4C code, for a single pellet source in water medium and Plexiglas, and measurements were pe...

Show that the force between hemispheres in the left figure is the same as that between one such hemisphere and either a perfectly conducting plate, or a plate of infinite magnetic permeability. This problem was inspired by e-discussions with J. Castro Paredes. The force between two rectangular-prism permanent magnets has been deduced in [1]. For cylindrical magnets, see [2, 3], and for spheres,...

With interest in the potential of optical fibres as the basis of next-generation thermoluminescence dosimeters (TLDs), the development of suitable forms of material and their fabrication has become a fast-growing endeavour. Present study focuses on three types of Ge-doped optical fibres with different structural arrangements and/or shapes, namely conventional cylindrical fibre, capillary fibre,...

Polymer gel dosimetry undertaken on a multislice CT scanner provides an alternative method to conventional dosimetry measurements. Polymer gel dosimeters were used to measure CT radiation doses and compared to TLD and ionization chamber measurements in different diameter phantoms. CTDI was investigated for each of these phantoms for a range of mAs (100-400 mAs), tube voltage (100-135 kV) and no...

The early history of the esoteric phenomenon of thymineless death (TLD) is recounted, from the pioneering discovery by Seymour Cohen and Hazel Barner, through my graduate studies at Yale and postdoctoral research in Copenhagen. My principal contribution was the discovery that restricted synthesis of protein and RNA permits cultures of Escherichia coli to complete their DNA replication cycles wi...

The possibility to combine the track-etched CR-39 or Makrofol detectors with charcoal to increase the detector sensitivity was shown in the last years. Special requests are necessary in the case of a personal dosimeter when the detector must be active only during working activity. Regarding the combination of charcoal with TL detectors our preliminary investigations indicate that the TLD intens...

PURPOSE Thermoluminescent dosimeters are used routinely for dosimetric measurements of photon and electron fields. However, no work has been published characterizing TLDs for use in combined photon and electron fields. This work investigates the response of TLD-100 (LiF:Mg,Ti) in mixed fields of photon and electron beam qualities. METHODS TLDs were irradiated in a 6 MV photon beam, 6 MeV elec...

This paper deals with transmission theory of plane electromagnetic waves in free space and in cylindrical regions of arbitrary cross section. Transmission properties of such waves can be expressed very simply in the same terms as the properties of electric waves guided by a pair of parallel wires. The earlier parts of the paper are concerned with general theorems and the latter parts with their...

The method of lines (MOL), a semianalytical procedure, is well known to experts in computational techniques in electromagnetics. The range of applications of the method has increased dramatically in the past few years; nevertheless, there is no introductory paper to initiate a beginner to the method. This paper illustrates the application of the MOL to solve Laplace’s equation in rectangular an...