abstractbackground: delivering the radiation dose to the target volume and minimizing the dose to normal tissues are the main objectives in radiotherapy. the aim of our study is to enhance the contrast of the portal image to increase the accuracy of delineation of the organs in the irradiation field.   methods: the software was written based on local enhancement of the pixel values in image mat...

abstractbackground: although electronic portal imaging devices (epids) have originally developed for positioning verification, they can also be used for dosimetric purposes. in the current work, the dose response of minimum detectable thickness of a scanning liquid filled ion chamber epid, slic-epid, and the variation of transmitted dose with the shift of inhomogeneity inside of phantom was als...

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...

Objective(s): In this study, we aimed to describe the characteristics of portal vein tumor thrombosis (PVTT), complicating hepatocellular carcinoma (HCC) in contrast-enhanced FDG PET/CT scan. Methods: In this retrospective study, 9 HCC patients with FDG-avid PVTT were diagnosed by contrast-enhanced fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT), which is a comb...

objective(s): in this study, we aimed to describe the characteristics of portal vein tumor thrombosis (pvtt), complicating hepatocellular carcinoma (hcc) in contrast-enhanced fdg pet/ct scan. methods: in this retrospective study, 9 hcc patients with fdg-avid pvtt were diagnosed by contrast-enhanced fluorodeoxyglucose positron emission tomography/computed tomography (fdg pet/ct), which is a comb...

background: in order to assign appropriate planning target volume (ptv) margins, each centre should measure the patient positioning deviations for their set-up techniques. at the royal marsden hospital, uk, a conformal shell (cast) system is used when a stereotactic frame is not suitable. in this paper, we report on a series of measurements with the aim of obtaining the systematic and random co...

Portal imaging is the acquisition of images with a radiotherapy beam. Imaging theory suggests that the quality of portal images could be much higher if the efficiency of the imaging media in detecting radiation could be improved. Introduction of new media (films and electronic portal imaging devices) has confirmed this by markedly increasing the quality of portal images. Images from these devic...

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...

Previously we have shown that our routine portal imaging (PI) of the craniofacial region in pediatric brain tumor patients contributed an additional 2%-3% of the prescribed dose and up to 200 cGy to the planning target volume (PTV) and nearby organs at risk (OARs). The purpose of this study is to quantify the reduction in dose to PTV and OARs from portal imaging (PI) of the craniofacial region ...