background: this study assessed the clinical usefulness of the solid phantom, which may compensate for the disadvantages of the water phantom, by comparing the radiological doses between the two depending on their depths. materials and methods: the experimental equipment used was a linear accelerator for medical use, water phantom, solid phantom, farmer type ion chamber and electrometer. the di...

background: electronic portal imaging devices (epids) play an important role in radiation therapy portal imaging, geometric and dosimetric verifications. a successful utilization of epids for imaging and dosimetric purposes requires a reliable quality control process routine to be carried out regularly. in this study, two in-house phantoms were developed and analyzed for implementation in a qua...

Purpose: In longitudinal oncological and brain PET/CT studies it is important to understand the repeatability of quantitative PET metrics in order to assess change in tracer uptake or binding. The present studies were performed in order to assess the aspects of PET/CT repeatability related to reconstruction settings, analysis methods, scan duration (or image noise) and position in the field of ...

Purpose Four-dimensional computed tomography (CT) images are typically used to quantify the necessary internal target volumes for thoracic and abdominal tumors. However, 4-dimensional CT is typically associated with excessive imaging dose to patients and the situation is exacerbated when using repeat 4-dimensional CT imaging on a weekly or daily basis throughout fractionated therapy. The aim of...

abtract background: in nuclear medicine, phantoms are mainly used to evaluate the overall performance of the imaging systems and practically there is no phantom exclusively designed for the evaluation of the software performance.  in this study the hoffman brain phantom was used for quantitative evaluation of reconstruction techniques. the phantom is modified to acquire tomographic and planar i...

Automatic tube current modulation (ATCM) systems are available for all CT manufacturers and are used for the majority of patients. Understanding how the systems work and their influence on patient dose and image quality is important for CT users, in order to gain the most effective use of the systems. In the present study, a new phantom was used for evaluating dose distribution and image qualit...

Introduction: In vitro dosimetric verification prior to patient treatment plays a key role in accurate and precision radiotherapy treatment delivery. Since the human body is a heterogeneous medium, the aim of this study was to design a heterogeneous pelvic phantom for radiotherapy quality assurance. Material and Methods: A pelvic phantom was ...

A table-top volumetric CT system has been implemented that is able to image a 5-cm-thick volume in one circular scan with no cone-beam artifacts. The prototype inverse-geometry CT (IGCT) scanner consists of a large-area, scanned x-ray source and a detector array that is smaller in the transverse direction. The IGCT geometry provides sufficient volumetric sampling because the source and detector...

Drawing regions of interest (ROIs) in positron emission tomography/computed tomography (PET/CT) scans of the National Electrical Manufacturers Association (NEMA) NU-2 Image Quality (IQ) phantom is a time-consuming process that allows for interuser variability in the measurements. In order to reduce operator effort and allow batch processing of IQ phantom images, we propose a fast, robust, autom...

Purpose: To investigate the feasibility of dual-modal on-board spectral-CT/CBCT imaging using a CZT photon-counting detector mounted on Linac by Monte Carlo simulations. Methods: In this proof-of-concept study, software platform Geant4 Application for Tomography Emission (GATE) and high-performance computing hardware were utilized to design validate novel spectral-CT conventional CBCT system si...