Journal of Medical Physics
 Home | Search | Ahead of print | Current Issue | Archives | Instructions | Subscription | Login  The official journal of Association of Medical Physicists of India      
 Users online: 99  Home  EMail this page Print this page Decrease font size Default font size Increase font size 
TECHNICAL NOTE
Year : 2017  |  Volume : 42  |  Issue : 2  |  Page : 90-95

The influence of acquisition mode on the dosimetric performance of an amorphous silicon electronic portal imaging device


1 Discipline of Medical Radiations, School of Medical Science, RMIT University, Melbourne, Victoria, Australia; Discipline of Sciences, School of Medical Physics, Umm Al.Qura University, Mecca, Saudi Arabia
2 Department of Physical Sciences, Peter MacCallum Cancer Centre, Melbourne, Victoria, Australia
3 Discipline of Medical Radiations, School of Medical Science, RMIT University; Department of Physical Sciences, Peter MacCallum Cancer Centre; Department of Medical Imaging and Radiation Sciences, Faculty of Medicine and Health Sciences, Monash University, Melbourne, Victoria, Australia
4 Department of Physical Sciences, Peter MacCallum Cancer Centre; The Sir Peter MacCallum Department of Oncology, The University of Melbourne, Melbourne, Victoria, Australia
5 Discipline of Medical Radiations, School of Medical Science, RMIT University, Melbourne, Victoria, Australia

Correspondence Address:
Omemh Bawazeer
211/50, Janfield Drive, Bundoora, Melbourne, Victoria

Login to access the Email id

Source of Support: None, Conflict of Interest: None


DOI: 10.4103/jmp.JMP_98_16

Rights and Permissions

Aims: This study investigates the impact of cine acquisition mode on the dosimetric characteristics of a Varian aS500 amorphous silicon electronic portal imaging device (a-Si EPID). Materials and Methods: The performance of an a-Si EPID operated in cine mode was assessed and compared to its performance when operated in an integrated mode and dose measurements using an ionization chamber. This study was conducted at different photon energies and the EPID performance was assessed as function of the delivered dose, dose rate, multileaf collimator speed, field size, phantom thickness, and intensity-modulated radiation therapy fields. Results: The worst nonlinearity was observed at low monitor unit (MU) settings < 100 MU with the highest dose per frame. The nonlinearity of response at a low MU setting was attributed due to the loss of four cine images during each delivery. The EPID response with changing dose rate for 10 MU delivered had similar results to its performance in an integrated mode and ionization chamber. Despite the nonlinearity of response with low MU delivered, EPID performance operated in cine and integrated acquisition modes had comparable responses within 2%. Conclusions: For EPID dosimetry application using cine mode, this study recommends the calibration of the EPID images to be undertaken at a large MU. There were no additional corrections that were required when the EPID operated in cine acquisition mode as compared to calibration in integrated mode.


[FULL TEXT] [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
 Related articles
 Citation Manager
 Access Statistics
 Reader Comments
 Email Alert *
 Add to My List *
 * Requires registration (Free)
 

 Article Access Statistics
    Viewed1054    
    Printed24    
    Emailed0    
    PDF Downloaded50    
    Comments [Add]    

Recommend this journal