Journal of Medical Physics
TECHNICAL NOTE
Year
: 2018  |  Volume : 43  |  Issue : 2  |  Page : 119--128

Validation of delivery consistency for intensity-modulated radiation therapy and volumetric-modulated arc therapy plans


Wui Ann Woon1, Paul B Ravindran2, Piyasiri Ekayanake4, Yivonne Yih Fang Lim3 
1 Department of Radiation Oncology, The Brunei Cancer Center; Applied Physics Program, Faculty of Science, Universiti Brunei Darussalam, Bandar Seri Begawan, Brunei Darussalam
2 Applied Physics Program, Faculty of Science, Universiti Brunei Darussalam, Bandar Seri Begawan, Brunei Darussalam; Department of Radiation Oncology, Christian Medical College and Hospital, Vellore, Tamil Nadu, India
3 Department of Radiation Oncology, The Brunei Cancer Center, Bandar Seri Begawan, Brunei Darussalam

Correspondence Address:
Mr. Wui Ann Woon
Department of Radiation Oncology, The Brunei Cancer Center, Bandar Seri Begawan, BG3122
Brunei Darussalam

The delivery consistency of a Varian Edge linear accelerator over the entire course of treatment for nasopharynx carcinoma (NPC) and prostate cancer intensity-modulated radiation therapy (IMRT) and volumetric-modulated arc therapy (VMAT) treatment plans was investigated using four different approaches. Three NPCs and three prostate plans were delivered in 34 and 29 consecutive days, respectively, using a Varian Edge equipped with a 120 high-definition (HD) multileaf collimator (MLC). All deliveries were measured with an electronic portal imaging device (EPID), and MapCheck2 and ArcCheck commercial systems with gamma analysis used to compare the results of all daily measurements against the pretreatment patient-specific quality assurance. The daily log files generated were also assessed for differences between the actual and planned doses using an in-house program to replace the original values in the DICOM plan files with the delivered parameter values from the log file, and then exporting the plans back to the treatment planning system for reconstruction of the actual dose delivered. The trajectory log file and EPID methods showed very good agreement, with minimal deviations between the daily delivered and reference doses. However, comparisons of the MapCheck2 and ArcCheck with the EPID revealed statistically significant differences (P < 0.001, one-tailed) with greater daily fluctuations, raising concerns over the performance, and reliability of the MapCheck2 and ArcCheck systems when being used to identify IMRT and VMAT plans with poor dosimetric accuracy. We conclude that the Varian Edge linear accelerator equipped with a 120 HD MLC can consistently deliver IMRT and VMAT plans over the entire treatment course.


How to cite this article:
Woon WA, Ravindran PB, Ekayanake P, Lim YY. Validation of delivery consistency for intensity-modulated radiation therapy and volumetric-modulated arc therapy plans.J Med Phys 2018;43:119-128


How to cite this URL:
Woon WA, Ravindran PB, Ekayanake P, Lim YY. Validation of delivery consistency for intensity-modulated radiation therapy and volumetric-modulated arc therapy plans. J Med Phys [serial online] 2018 [cited 2020 May 27 ];43:119-128
Available from: http://www.jmp.org.in/article.asp?issn=0971-6203;year=2018;volume=43;issue=2;spage=119;epage=128;aulast=Woon;type=0