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...

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...

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...

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...

Background: To correct patient positioning errors (setup errors) during prostate cancer treatment using EPID and fiducial gold markers, to improve the accuracy of the dose delivery in these patients. Materials and Methods: Fifteen patients with localized prostate carcinoma after implantation of fiducial gold markers in their prostate gland underwent the five-field IMRT planning technique. The p...