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...

Introduction:  Stereotactic  radiosurgery  is  a  technique  for  the  treatment  of  intracranial  lesions  with  highly  collimated  x-ray  beam.  Linac-based  radiosurgery  is  currently  performed  by  two  techniques:  couch or pedestal mounted. In the first technique, a device is required to affix patient's head to a couch  and  moreover  to  translate  it  accurately.  Structure  of  suc...

background: closure of patent ductus arteriosus (pda), ventricular septal defect (vsd) and atrial septal defect (asd) can be done surgically or by device. this study was designed to compare the total cost of surgical or device closures of pda, asd or vsd for iranian patients. methods: this is a cross-sectional study, conducted from january 1, 2005 until january 1, 2006 in two large heart center...

Generation of frequency upshifted monochromatic radiation in the 100 GHz to FIR range by the interaction of a superluminous photoconducting front with an electrostatic “frozen wave” configuration in a semiconductor is reported. The interaction converts the energy contained in the “frozen wave” into monochromatic radiation, whose frequency depends on the energy in the laser pulse creating the su...

the existing studies of threshing process of combine harvesters adopt the assumption of constant mass, which is contradictory to the phenomenon of separation of grains and short stalks in actual threshing process. therefore, the characteristics of threshing and separation are not accurately described. aiming at this problem, this study established the tangential-longitudinal threshing and separ...