Journal of Medical Physics
 Home | Search | Ahead of print | Current Issue | Archives | Instructions | Subscription | Login  The official journal of AMPI, IOMP and AFOMP      
 Users online: 803  Home  EMail this page Print this page Decrease font size Default font size Increase font size 
Year : 1999  |  Volume : 24  |  Issue : 1  |  Page : 21-24

Effect Of Shielding On Virtual Source Position For Electron Beams From A Clinic-1800 Linear Accelerator



Correspondence Address:
M Ravikumar


Login to access the Email id

Source of Support: None, Conflict of Interest: None


Rights and PermissionsRights and Permissions

In the present study, the virtual point source positions were determined for field sizes defined by standard electron cones and cerroband field inserts for various electron energies. Ionometric measurements were carried out with a0.6 cm3 Farmer type ion chamber at dm= in a polystyrene phantoms. The virtual source positions obtained by inverse square law method were observed to change with the beam energies and the applicator sizes. It was also observed that the Virtual Source-to-Surface Distances O/SSD) are greater for the field sizes defined by the cerroband inserts in the standard 20 cm x 20 cm applicator for all energies. These observed variations in virtual source positions are due to the change in electron scatter for different energies and beam sizes. When the cerroband cut-outs are introduced close to the chamber, the scattering conditions are likely to get altered, resulting in change in the virtual source position.


[PDF]*
Print this article     Email this article
 Next article
 Previous article
 Table of Contents

 Similar in PUBMED
   Search Pubmed for
   Search in Google Scholar for
 Citation Manager
 Access Statistics
 Reader Comments
 Email Alert *
 Add to My List *
 * Requires registration (Free)
 

 Article Access Statistics
    Viewed548    
    Printed44    
    Emailed1    
    PDF Downloaded127    
    Comments [Add]    

Recommend this journal