Abstract：Objective To study the methods of matching kilovolt CBCT image with planning CT scan. Methods A total of 121 CBCT scans were matched with planning CT scan using a manual and four automatic match methods by four observers in the offline. In the manual match, the live contour was used as a surrogate for image registration. Four automatic match methods, including routine soft-tissue match, routine bone match, automatic liver match and vertebral body match, were performed using image registration sofeware. First, the stability of the sofeware was tested. Then, the reproducibility of the same automatic match method was evaluated by comparing different observers’ match results. After the manual match by four observers, the mean of the match results was used as a standard to compare with others. The differerces was test by McNemar method. Results In the uniform match factors, automatic match result would not change. The reproducibility of routine soft-tissue and bone match are best, automatic vertebral body match is better than automatic liver match. Howerver, the automatic liver match result is the most similar to manual match, the percentages of match result have an absolute error no more than 3 mm in left-right, superior-inferior and anterior-posterior directions are 84.3%, 77.7% and 92.6%. Conclusions Automatic liver match can be used in image-guided radiotherapy for liver cancer, however, it should be performed by experienced oncologist and technologist together in each fraction, after that, the matching result should be adjusted carefully according to live contour.
Wang Jianting,Liu Ming,Zhai Fushan et al. Comparing different image registration methods in kilovolt cone-beam computed tomography image-guided radiotherapy for liver cancer[J]. Chinese Journal of Radiation Oncology, 2015, 24(4): 444-448.
[1] Siewerdsen JH, Jaffray DA. Cone-beam computed tomography with a flat-panel imager:magnitude and effects of x-ray scatter[J]. Med Phys,2001,28(2):220-231. DOI:10.1002/jmr. 606. [2] Graham SA, Moseley DJ, Siewerdsen JH, et al. Compensators for dose and scatter management in cone-beam computed tomography[J]. Med Phys,2007,34(7):2691-2703. [3] Brock KK. Imaging and image-guided radiation therapy in liver cancer[J].Semin Radiat Oncol,2011,21(4):247-255.DOI:10.1016/j.semradonc.2011.05.001. [4] Dawson LA, Eccles C, Bissonnette JP, et al. Accuracy of daily image guidance for hypofractionated liver radiotherapy with active breathing control[J]. Int J Radiat Oncol Biol Phys,2005,62(4):1247-1252.DOI:10.1016/j.ijrobp.2005.03.072. [5] Hawkins MA, Brock KK, Eccles C, et al. Assessment of residual error in liver position using kV cone-beam computed tomography for liver cancer high-precision radition therapy[J]. Int J Radiat Oncol Biol Phys,2006,66(2):610-619.DOI:10.1016/j.ijrobp.2006.03.026. [6] 陈林,刘莉莉,冯丽娜,等.肝癌碘油标记图像对锥形束CT图像配准方法及靶区外放的影响[J].中华放射肿瘤学杂志,2012,21(1):60-62.DOI:10.3760/cma.j.issn.1004-4221.2012.01.017. [7] Park JC, Park SH, Liu ZW,et al. Liver motion during cone beam computed tomography guided stereotactic body radiation therapy[J]. Med Phys,2012,39(10):6431-6442.DOI:10.1118/1.4754658. [8] Wunderink W, Mendez Romero A, Seppenwoolde Y, et al. Potentials and limitations of guiding liver stereotactic body radiation therapy set-up on liver-implanted fiducial markers[J]. Int J Radiat Oncol Biol Phys,2010,77(5):1573-1583.DOI:10.1016/j.ijrobp.2009.10.040. [9] Seppenwoolde Y, Wunderink W, Wunderink-van Veen WR, et al. Treatment precision of image-guided liver SBRT using implanted fiducial markers depends on marker-tumour distance[J]. Phys Med Biol,2011,56(17):5445-5468.DOI:10.1088/0031-9155/56/17/001. [10] Case RB, Moseley DJ, Snoke JJ,et al. Interfraction and intrafraction changes in amplitude of breathing motion in stereotactic liver radiotherapy[J]. Int J Radiat Oncol Biol Phys,2010,77(3):918-925.DOI:10.1016/j.ijrobp.2009.09.008.
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