Indian Journal of Cancer
Home  ICS  Feedback Subscribe Top cited articles Login 
Users Online :643
Small font sizeDefault font sizeIncrease font size
Navigate Here
 »   Next article
 »   Previous article
 »   Table of Contents

Resource Links
 »   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
    Viewed2902    
    Printed112    
    Emailed0    
    PDF Downloaded342    
    Comments [Add]    

Recommend this journal

 

 ORIGINAL ARTICLE
Year : 2016  |  Volume : 53  |  Issue : 1  |  Page : 166-173

Do technological advances in linear accelerators improve dosimetric outcomes in stereotaxy? A head-on comparison of seven linear accelerators using volumetric modulated arc therapy-based stereotactic planning


1 Department of Radiation Oncology, Fortis Memorial Research Institute, Gurgaon, Haryana; Department of Physics, GLA University, Mathura, Uttar Pradesh, India
2 Department of Mathematics, GLA University, Mathura, Uttar Pradesh, India
3 Department of Radiation Oncology, Fortis Memorial Research Institute, Gurgaon, Haryana, India

Correspondence Address:
B Sarkar
Department of Radiation Oncology, Fortis Memorial Research Institute, Gurgaon, Haryana; Department of Physics, GLA University, Mathura, Uttar Pradesh
India
Login to access the Email id

Source of Support: None, Conflict of Interest: None


DOI: 10.4103/0019-509X.180815

Rights and Permissions

Introduction: Linear accelerator (Linac) based stereotactic radiosurgery (SRS) and stereotactic radiotherapy (SRT) using volumetric modulated arc therapy (VMAT) has been used for treating small intracranial lesions. Recent development in the Linacs such as inbuilt micro multileaf collimator (MLC) and flattening filter free (FFF) beam are intended to provide a better dose conformity and faster delivery when using VMAT technique. This study was aimed to compare the dosimetric outcomes and monitor units (MUs) of the stereotactic treatment plans for different commercially available MLC models and beam profiles. Materials and Methods: Ten patients having 12 planning target volume (PTV)/gross target volume's (GTVs) who received the SRS/SRT treatment in our clinic using Axesse Linac (considered reference arm gold standard) were considered for this study. The test arms comprised of plans using Elekta Agility with FFF, Elekta Agility with the plane beam, Elekta APEX, Varian Millennium 120, Varian Millennium 120HD, and Elekta Synergy in Monaco treatment planning system. Planning constraints and calculation grid spacing were not altered in the test plans. To objectively evaluate the efficacy of MLC-beam model, the resultant dosimetric outcomes were subtracted from the reference arm parameters. Results: V95%, V100%, V105%, D1%, maximum dose, and mean dose of PTV/GTV showed a maximum inter MLC - beam model variation of 1.5% and 2% for PTV and GTV, respectively. Average PTV conformity index and heterogeneity index shows a variation in the range 0.56–0.63 and 1.08–1.11, respectively. Mean dose difference (excluding Axesse) for all organs varied between 1.1 cGy and 74.8 cGy (mean dose = 6.1 cGy standard deviation [SD] = 26.9 cGy) and 1.7 cGy–194.5 cGy (mean dose 16.1 cGy SD = 57.2 cGy) for single and multiple fraction, respectively. Conclusion: The dosimetry of VMAT-based SRS/SRT treatment plan had minimal dependence on MLC and beam model variations. All tested MLC and beam model could fulfil the desired PTV coverage and organs at risk dose constraints. The only notable difference was the halving of the MU for FFF beam as compared to the plane beam. This has the potential to reduce the total patient on couch time by 15% (approximately 2 min).






[FULL TEXT] [PDF]*


        
Print this article     Email this article

  Site Map | What's new | Copyright and Disclaimer
  Online since 1st April '07
  © 2007 - Indian Journal of Cancer | Published by Wolters Kluwer - Medknow