Clinical Validation of Elements Multiple Brain Mets SRS by Brainlab

A SYSTEMATIC ANALYSIS OF 2 MONOISOCENTRIC TECHNIQUES FOR THE TREATMENT OF MULTIPLE BRAIN METASTASES

Technology in Cancer Research and Treatment (1 – 6), 2016. DOI: 10.1177/1533034616666998
Ganesh Narayanasamy, PhD1,2, Sotirios Stathakis, PhD1, Alonso N. Gutierrez, PhD1, Evangelos Pappas, PhD3, Richard Crownover, MD, PhD1, John R. Floyd II, MD4, and Niko Papanikolaou, PhD1.

1 Department of Radiation Oncology, University of Texas Health Science Center at San Antonio, TX
2 Department of Radiation Oncology, University of Arkansas for Medical Sciences, Little Rock, AR
3 Technological Educational Institute of Athens, Greece
4 Department of Neurosurgery, University of Texas Health Science Center at San Antonio, TX

Technology in Cancer Research & Treatment
Received: January 14, 2016; Revised: May 16, 2016; Accepted: July 28, 2016.

ABSTRACT

Background: In this treatment planning study, we compare the plan quality and delivery parameters for the treatment of multiple brain metastases using 2 monoisocentric techniques: the Multiple Metastases Element from Brainlab and the RapidArc volumetric modulated arc therapy from Varian Medical Systems.

Methods: Eight patients who were treated in our institution for multiple metastases (3-7 lesions) were replanned with Multiple Metastases Element using noncoplanar dynamic conformal arcs. The same patients were replanned with the RapidArc technique in Eclipse using 4 noncoplanar arcs. Both techniques were designed using a single isocenter. Plan quality metrics (conformity index, homogeneity index, gradient index, and R50%), monitor unit, and the planning time were recorded. Comparison of the Multiple Metastases Element and RapidArc plans was performed using Shapiro-Wilk test, paired Student t test, and Wilcoxon signed rank test.

Results: A paired Wilcoxon signed rank test between Multiple Metastases Element and RapidArc showed comparable plan quality metrics and dose to brain. Mean+ standard deviation values of conformity index were 1.8+0.7 and 1.7+0.6, homogeneity index were 1.3+0.1 and 1.3+0.1, gradient index were 5.0+1.8 and 5.1+1.9, and R50% were 4.9+1.8 and 5.0+1.9 for Multiple Metastases Element and RapidArc plans, respectively. Mean brain dose was 2.3 and 2.7 Gy for Multiple Metastases Element and RapidArc plans, respectively. The mean value of monitor units in Multiple Metastases Element plan was 7286 + 1065, which is significantly lower than the RapidArc monitor units of 9966 +1533 (P < .05).

Conclusion: For the planning of multiple brain lesions to be treated with stereotactic radiosurgery, Multiple Metastases Element planning software produced equivalent conformity, homogeneity, dose falloff, and brain V12 Gy but required significantly lower monitor units, when compared to RapidArc plans.