The works make the ‘present’ image from what is normally absent. The underlying structural principles of video frames and encoding are the bases of the developing picture. In this sense, the ‘now’ of a video image is multidimensional and variable; past, present and future are the simultaneous condition of a single moment (unlike film frames, which can be isolated as spatially and temporally dis...

Background: Small photon fields are increasingly used in modern radiotherapy especially in intensity modulated radiation therapy (IMRT) and stereotactic radiosurgery (SRS) treatments. Accurate beam profile and central axis depth doses measurements of such beams are complicated due to the electron disequilibrium. Hence the EBT2 (external beam therapy) Gafchromic film was used for dosimetry of sm...

The increased intricacy of Intensity-Modulated-Radiation-Therapy (IMRT) delivery has created the need for a high-resolution 3D-dosimetry (three-dimensional) system capable of measuring and verifying the complex delivery. Present clinical methods are inadequate being restricted to single points (e.g., ion-chambers) or to 2D planes (e.g., film), and are labor intensive. In this paper we show that...

Purpose. To assess differences in dose distribution of a vertebral body injected with bone cement as calculated by radiation treatment planning system (RTPS) and actual dose distribution. Methods. We prepared two water-equivalent phantoms with cement, and the other two phantoms without cement. The bulk density of the bone cement was imported into RTPS to reduce error from high CT values. A dose...

The purpose of this study was comparing dose-volume histogram (DVH)-based plan verification methods for volumetric modulated arc therapy (VMAT) pretreatment QA. We evaluated two 3D dose reconstruction systems: ArcCHECK-3DVH system (Sun Nuclear corp.) and Varian dynalog-based dose reconstruction (DBDR) system, developed in-house. Fifteen prostate cancer patients (67.6 Gy/26 Fr), four head and ne...

introduction intensity modulated radiation therapy (imrt) has made a significant progress in radiation therapy centers in recent years. in this method, each radiation beam is divided into many subfields that create a field with a modulated intensity. considering the complexity of this method, the quality control for imrt is a topic of interest for researchers. this article is about the various ...

background: small photon fields are increasingly used in modern radiotherapy especially in intensity modulated radiation therapy (imrt) and stereotactic radiosurgery (srs) treatments. accurate beam profile and central axis depth doses measurements of such beams are complicated due to the electron disequilibrium. hence the ebt2 (external beam therapy) gafchromic film was used for dosimetry of sm...

Radiographic or silver halide film is a well-established 2D dosimeter with an unquestioned spatial resolution. But its higher sensitivity to low-energy photons has to be taken into consideration. Metal compensators or physical modulators to deliver intensity modulated radiation therapy (IMRT) are known to change the beam energy spectrum and to produce scattered photons and contaminating electro...