Dosimetric comparison between cone/Iris-based and InCise MLC-based CyberKnife plans for single and multiple brain metastases.
We performed an evaluation of the CyberKnife InCise MLC by comparing plan qualities for single and multiple brain lesions generated using the first version of InCise MLC, fixed cone, and Iris collimators. We also investigated differences in delivery efficiency among the three collimators. Twenty-four patients with single or multiple brain mets treated previously in our clinic on a CyberKnife M6 using cone/Iris collimators were selected for this study. Treatment plans were generated for all lesions using the InCise MLC. Number of monitor units, delivery time, target coverage, conformity index, and dose falloff were compared between MLC- and clinical cone/Iris-based plans. Statistical analysis was performed using the non-parametric Wilcoxon-Mann-Whitney signed-rank test. The planning accuracy of the MLC-based plans was validated using chamber and film measurements. The InCise MLC-based plans achieved mean dose and target coverage comparable to the cone/Iris-based plans. Although the conformity indices of the MLC-based plans were slightly higher than those of the cone/Iris-based plans, beam delivery time for the MLC-based plans was shorter by 30% ~ 40%. For smaller targets or cases with OARs located close to or abutting target volumes, MLC-based plans provided inferior dose conformity compared to cone/Iris-based plans. The QA results of MLC-based plans were within 5% absolute dose difference with over 90% gamma passing rate using 2%/2 mm gamma criteria. The first version of InCise MLC could be a useful delivery modality, especially for clinical situations for which delivery time is a limiting factor or for multitarget cases.
The University of Pittsburgh Cancer Institute. jangs@upmc.edu.
Si Young
SY
Jang
Ron
R
Lalonde
Cihat
C
Ozhasoglu
Steven
S
Burton
Dwight
D
Heron
M Saiful
MS
Huq
D001932:Brain Neoplasms / Q000556:secondary / Q000601:surgery*; D006801:Humans; D007498:Iris / Q000528:radiation effects*; D019047:Phantoms, Imaging; D011785:Quality Assurance, Health Care / Q000592:standards*; D016634:Radiosurgery / Q000379:methods*; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods*; D050397:Radiotherapy, Intensity-Modulated / Q000379:methods*
Int J Radiat Oncol Biol Phys. 2009 Dec 1;75(5):1596-604
19733447
Strahlenther Onkol. 2014 Jun;190(6):521-32
24715242
Int J Radiat Oncol Biol Phys. 2008;71(1 Suppl):S126-30
18406910
Med Phys. 2008 Jun;35(6):2294-9
18649461
Int J Radiat Oncol Biol Phys. 2002 Jun 1;53(2):453-63
12023150
J Neurooncol. 2010 Jan;96(1):45-68
19960227
Int J Radiat Oncol Biol Phys. 2008 Nov 15;72(4):996-1001
18455326
N Engl J Med. 2010 Mar 25;362(12):1119-27
20335588
Int J Radiat Oncol Biol Phys. 2011 Nov 1;81(3):863-70
21377286
Med Phys. 1998 Oct;25(10):1773-829
9800687
Rep Pract Oncol Radiother. 2013 Aug 17;18(6):383-6
24416583
Med Phys. 2008 May;35(5):2094-103
18561685
Med Phys. 2004 Oct;31(10):2899-911
15543799
J Radiat Res. 2015 Jan;56(1):151-8
25344929
Med Phys. 1998 Oct;25(10):1919-27
9800699
Int J Radiat Oncol Biol Phys. 1993 Dec 1;27(5):1231-9
8262852
Strahlenther Onkol. 2015 Jun;191(6):470-6
25416146
Med Phys. 2011 Jun;38(6):2914-36
21815366
Int J Radiat Oncol Biol Phys. 2010 Mar 1;76(3):935-42
20044214
Phys Med. 2015 Jul;31(5):476-83
26003217
J Appl Clin Med Phys. 2005 Spring;6(2):74-86
15940214
J Appl Clin Med Phys. 2015 Sep 08;16(5):284–295
26699309
Int J Radiat Oncol Biol Phys. 2010 Nov 1;78(3):955-63
20171796
Pract Radiat Oncol. 2012 Jul-Sep;2(3):210-25
25925626
Med Phys. 2010 Aug;37(8):4078-101
20879569
Surg Neurol Int. 2013 May 02;4(Suppl 4):S185-91
23717789
Am J Clin Oncol. 2013 Jun;36(3):310-5
23681017