Experimental determination of depth-scaling factors and central axis depth dose for clinical electron beams

Electron beam central axis depth dose measurements.

Central axis depth dose measurements were made by the Radiological Physics Center on over 70 electron-producing machines used in radiation therapy. These data were consistent for each machine model and nominal energy. However, the data show that depth dose relations can vary significantly among different machine models for electron beams having the same nominal energy. Analysis shows that both ...

An analytical expression for central axis depth-dose of electrons.

Determination of Percentage Depth Dose (Pdd) of Pagat Gel Dosimeter By Electron Beams

Background: The purpose of this study was to determine the percentage depth dose (PDD) of PAGAT normoxic polymer gel dosimeter by electron beams using MRI technique for a standard clinically used Co-60 therapy unit and an electa linear accelerator. Materials and Methods: Using MRI, the formulation to give the maximum change in the transverse relaxation rate R2(1/T2) was determined to be 4.5% N,...

Experimental Evaluation of Depth Dose by Exit Surface Diode Dosimeters for Off-Axis Wedged Fields in Radiation Therapy

Introduction Evaluation of the delivered dose of externally wedged photon beams by external diode dosimeters during the treatment process requires the estimation of exit surface dose correction factors in various wedge angles and field sizes. Materials and Methods A system of absorbed dose evaluation, using p-type diode dosimeters placed on the exit surface of a phantom, was characterized for e...

New formula for Calculation of Cobalt-60 Percent Depth Dose

Introduction:  On  the  basis  of  percent  depth  dose  (PDD)  calculation,  the  application  of  dosimetry  in  radiotherapy  has  an  important  role  to  play  in  reducing  the  chance  of  tumor  recurrence. The aim of this study is to introduce a new formula for calculating the centeral axis  percent depth doses of Cobalt-60 beam.   Materials and Methods: In the present study, based on ...