Long-term evaluation and cross-checking of two geometric calibrations of kV and MV imaging systems for Linacs.
Long-term evaluation and cross-checking of two geometric calibrations of kV and MV imaging systems for Linacs.
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DOI：
10.1120/jacmp.v16i4.5140
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发表时间：
2015-07-08
影响因子：
2.1
通讯作者：
Mao W
中科院分区：
文献类型：
--
作者：
Chiu TD;Yan Y;Foster R;Mao W
用两套geoomertirc校准系统（Varian IsoCal几何校准系统和自主开发的gQA系统）监测了两台瓦里安TrueBeam直线机的千伏和中伏成像系统的几何或机械精度。对两种系统的结果进行了交叉检查，并对直线的长期几何稳定性进行了评估。两种几何校准方法被用于评估千伏和中伏成像系统及其在两个TrueBeam直线机上的一致性，周期约为一年。这两个系统分析kV或MV投影图像的特殊设计的幻影检索几何参数的成像系统。然后根据不同角度多次投影的结果计算出等中心——激光等中心和kV成像仪和EPID的旋转中心。将两个系统的长期校准结果进行比较以进行交叉检查。两个系统在两个TrueBeam直线上进行了24次并排校准。两种标定系统的等心偏差均小于1mm。大差异主要发生在垂直方向（AP方向），平均差异为0.45 mm。其他方向等心的平均差值为0.09 mm。除了长期校准监测之外，对于准确性测试，通过故意错置QA幻影（在AP， SI和横向方向上距离设置等心5毫米）来执行特殊测试，以测试两个系统在已知偏差下的责任性能。误差在0.5 mm以内。IsoCal和gQA两种几何校准系统都能够检测出直线电机kV和MV成像系统的几何偏差。长期评估还表明，在一年的研究期间，两种直线的几何参数和几何精度的偏差都很小，并且非常一致。PACS编号：87.56
Geometric or mechanical accuracy of kV and MV imaging systems of two Varian TrueBeam linacs have been monitored by two geomertirc calibration systems, Varian IsoCal geometric calibration system and home‐developed gQA system. Results of both systems are cross‐checked and the long‐term geometric stabilities of linacs are evaluated. Two geometric calibration methodologies have been used to assess kV and MV imaging systems and their coincidence periodically on two TrueBeam linacs for about one year. Both systems analyze kV or MV projection images of special designed phantoms to retrieve geometric parameters of the imaging systems. The isocenters — laser isocenter and centers of rotations of kV imager and EPID — are then calculated, based on results of multiple projections from different angles. Long‐term calibration results from both systems are compared for cross‐checking. There are 24 sessions of side‐by‐side calibrations performed by both systems on two TrueBeam linacs. All the disagreements of isocenters between two calibrations systems are less than 1 mm with SD. Most of the large disagreements occurred in vertical direction (AP direction), with an averaged disagreement of 0.45 mm. The average disagreements of isocenters are 0.09 mm in other directions. Additional to long‐term calibration monitoring, for the accuracy test, special tests were performed by misaligning QA phantoms on purpose (5 mm away from setup isocenter in AP, SI, and lateral directions) to test the liability performance of both systems with the known deviations. The errors are within 0.5 mm. Both geometric calibration systems, IsoCal and gQA, are capable of detecting geometric deviations of kV and MV imaging systems of linacs. The long‐term evaluation also shows that the deviations of geometric parameters and the geometric accuracies of both linacs are small and very consistent during the one‐year study period. PACS number: 87.56.Fc
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影响因子：
3.5
作者：
Noo, F;Clackdoyle, R;Roney, TJ
通讯作者：
Roney, TJ
DOI：
10.1016/j.ijrobp.2007.06.086
发表时间：
2008-01-01
影响因子：
7
作者：
Bissonnette, Jean-Pierre;Moseley, Doug;Jaffray, David A.
通讯作者：
Jaffray, David A.
DOI：
10.1016/j.ijrobp.2005.09.018
发表时间：
2006-02-01
影响因子：
7
作者：
McBain, CA;Henry, AM;Price, P
通讯作者：
Price, P
影响因子：
3.8
作者：
Mao, Weihua;Lee, Louis;Xing, Lei
通讯作者：
Xing, Lei
影响因子：
3.8
作者：
Ford, J. Chetley;Zheng, Dandan;Williamson, Jeffrey F.
通讯作者：
Williamson, Jeffrey F.