A comparative study of identical VMAT plans with and without jaw tracking technique.
The unwanted radiation transmission through the multileaf collimators could be reduced by the jaw tracking technique which is commercially available on Varian TrueBeam accelerators. On the basis of identical plans, this study aims to investigate the dosimetric impact of jaw tracking on the volumetric-modulated arc therapy (VMAT) plans. Using Eclipse treatment planning system (TPS), 40 jaw-tracking VMAT plans with various tumor volumes and shapes were optimized. Fixed jaw plans were created by editing the jaw coordinates of the jaw-tracking plans while other parameters were identical. The deliverability of this artificial modification was verified using COMPASS system via three-dimentional gamma analysis between the measurement-based reconstruction and the TPS-calculated dose distribution. Dosimetric parameters of dose-volume histogram (DVH) were compared to assess the improvement of dose sparing for organs at risk (OARs) in jaw-tracking plans. COMPASS measurements demonstrated that over 96.9% of structure volumes achieved gamma values less than 1.00 at criteria of 3 mm/3%. The reduction magnitudes of maximum and mean dose to various OARs ranged between 0.06% ~ 6.76% (0.04 ~ 7.29 Gy) and 0.09% ~ 7.81% (0.02 ~ 2.78 Gy), respectively, using jaw tracking, agreeing with the disparities of radiological characteristics between MLC and jaws. Jaw tracking does not change the delivery efficiency and total monitor units. The dosimetric comparison of VMAT plans with and without jaw tracking confirms the physics hypotheses that reduced transmission through tracking jaws will reduce doses to OARs without sacrificing the target dose coverage because it is meant to be covered by radiation beams going through the opening.
Peking University Cancer Hospital & Institute. 13552661030@139.com.
Hao
H
Wu
Fan
F
Jiang
Haizhen
H
Yue
Qiaoqiao
Q
Hu
Jian
J
Zhang
Zhuolun
Z
Liu
Jian
J
Gong
Sha
S
Li
Jianhao
J
Geng
Yibao
Y
Zhang
D000008:Abdominal Neoplasms / Q000473:pathology / Q000532:radiotherapy*; D006258:Head and Neck Neoplasms / Q000473:pathology / Q000532:radiotherapy*; D006801:Humans; D021621:Imaging, Three-Dimensional; D007568:Jaw / Q000502:physiology / Q000528:radiation effects*; D007574:Jaw Relation Record / Q000295:instrumentation / Q000379:methods*; D058958:Organs at Risk / Q000528:radiation effects; D010347:Patient Care Planning; D010386:Pelvic Neoplasms / Q000473:pathology / Q000532:radiotherapy*; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods*; D050397:Radiotherapy, Intensity-Modulated / Q000379:methods*; D013899:Thoracic Neoplasms / Q000473:pathology / Q000532:radiotherapy*
Pract Radiat Oncol. 2015 May-Jun;5(3):e155-62
25413433
Med Phys. 2011 Oct;38(10):5338-44
21992352
Med Dosim. 2014 Winter;39(4):325-9
25087082
Int J Radiat Oncol Biol Phys. 2001 Mar 1;49(3):685-98
11172950
Med Phys. 2008 Jan;35(1):310-7
18293586
J Appl Clin Med Phys. 2014 Mar 06;15(2):4625
24710450
Med Phys. 2007 Sep;34(9):3674-87
17926971
Med Dosim. 2005 Winter;30(4):205-12
16275562
J Med Phys. 2008 Jul;33(3):114-8
19893701
J Appl Clin Med Phys. 2012 Mar 08;13(2):3707
22402386
Med Phys. 2011 Nov;38(11):5844-56
22047348
Pediatr Radiol. 2006 Sep;36 Suppl 2:121-5
16862418
Int J Radiat Oncol Biol Phys. 1993 Jan 15;25(2):171-9
8420866
Semin Radiat Oncol. 1999 Jan;9(1):48-59
10196398
Int J Radiat Oncol Biol Phys. 2011 Dec 1;81(5):1458-64
20950947
Med Phys. 2013 Oct;40(10):101706
24089896
Radiat Oncol. 2015 Jan 27;10:28
25623899
J Appl Clin Med Phys. 2005 Spring;6(2):74-86
15940214
Med Phys. 1994 Jul;21(7):1031-41
7968833