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: 227  Home  EMail this page Print this page Decrease font size Default font size Increase font size 
TECHNICAL NOTE
Year : 2016  |  Volume : 41  |  Issue : 1  |  Page : 65-70

Respiratory gated radiotherapy-pretreatment patient specific quality assurance


1 Division of Radiation Oncology, Medanta Cancer Institute, Medanta - The Medicity, Gurgaon, Haryana, India
2 Department of Radiation Oncology, Nayati Healthcare and Research, Mathura, India
3 Department of Radiation Oncology, Royal Hospital, Muscat, Sultanate of Oman
4 Division of Medical Physics, Rajiv Gandhi Cancer Institute and Research Centre, New Delhi, India
5 Department of Medical Physics, Cancer Control Centre, Shuwaikh, Kuwait
6 Department of Physics, School of Advanced Sciences, VIT University, Vellore, Tamil Nadu, India

Correspondence Address:
Rajesh Thiyagarajan
Division of Radiation Oncology, Medanta Cancer Institute, Medanta - The Medicity, Sector - 38, Gurgaon, Haryana
India
Login to access the Email id

Source of Support: None, Conflict of Interest: None


DOI: 10.4103/0971-6203.177279

Rights and Permissions

Organ motions during inter-fraction and intra-fraction radiotherapy introduce errors in dose delivery, irradiating excess of normal tissue, and missing target volume. Lung and heart involuntary motions cause above inaccuracies and gated dose delivery try to overcome above effects. Present work attempts a novel method to verify dynamic dose delivery using a four-dimensional (4D) phantom. Three patients with mobile target are coached to maintain regular and reproducible breathing pattern. Appropriate intensity projection image set generated from 4D-computed tomography (4D-CT) is used for target delineation. Intensity modulated radiotherapy plans were generated on selected phase using CT simulator (Siemens AG, Germany) in conjunction with "Real-time position management" (Varian, USA) to acquire 4D-CT images. Verification plans were generated for both ion chamber and Gafchromic (EBT) film image sets. Gated verification plans were delivered on the phantom moving with patient respiratory pattern. We developed a MATLAB-based software to generate maximum intensity projection, minimum intensity projections, and average intensity projections, also a program to convert patient breathing pattern to phantom compatible format. Dynamic thorax quality assurance (QA) phantom (Computerized Imaging Reference Systems type) is used to perform the patient specific QA, which holds an ion chamber and film to measure delivered radiation intensity. Exposed EBT films are analyzed and compared with treatment planning system calculated dose. The ion chamber measured dose shows good agreement with planned dose within ± 0.5% (0.203 ± 0.57%). Gamma value evaluated from EBT film shows passing rates 92–99% (96.63 ± 3.84%) for 3% dose and 3 mm distance criteria. Respiratory gated treatment delivery accuracy is found to be within clinically acceptable level.


[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
    Viewed1643    
    Printed50    
    Emailed0    
    PDF Downloaded99    
    Comments [Add]    

Recommend this journal