AbstractObjective To compare the differences between planning dose and actual dose of targets and organs at risk (OAR) for head and neck cancer patients with helical tomotherapy (HT). Methds 12 head and neck patients with HT were enrolled in this study. Prior to each treatment fraction, an MVCT scan was performed. The MVCT images of the first fraction of each week since the second week treatment were chosen, and dose distributions were recalculated on the MVCT images in Planned Adaptive application of HT, which were the actual dose of each fraction. Each single dose distribution and the corresponding CT image were sent to commercial software (MIM5.5), and deformable image registration was performed to the CT images, and the sum of actual dose was acquired. Dose distribution of targets and OAR of initial treatment plan (Plan-1) and the actual dose distribution (Plan-2) were compared. Results There were no significant differences between Plan-1 and plan-2 for D2, D50 of GTV (P=0.07,0.07) and D2 of PTV (P=0.08). D95, D98 and D100 of GTV in Plan-2 were lower than in Plan-1, with 2.1%, 2.7% and 5.6%(P=0.02,0.02,0.02), respectively. D50, D95, D98 and D100 of PTV in Plan-2 were lower than in Plan-1, with 0.8%, 1.9%, 3.9% and 13.5%(P=0.01,0.00,0.00,0.01), respectively. Dose of spinal cord was higher in Plan-2 than in Plan-1, increasing by an Dmax of 1.2%(P=0.04). Conclusions In radiotherapy for head and neck cancer actual dose of targets was lower than initial plan dose. Max dose of the spinal cord, however, was higher than in initial plan. For patients who have a significant anatomic change, in order to achieve the best therapeutic effect, modification of targets and treatment plan at the appropriate time is essential.
Corresponding Authors:
Wang Yadi, Email:wangyadi@hotmail.com
Cite this article:
Zhang Yongqian,Zhang Fuli,Wang Yadi et al. Dosimetric evaluation for head and neck cancer patients treated with helical TomoTherapy[J]. Chinese Journal of Radiation Oncology, 2014, 23(6): 519-522.
Zhang Yongqian,Zhang Fuli,Wang Yadi et al. Dosimetric evaluation for head and neck cancer patients treated with helical TomoTherapy[J]. Chinese Journal of Radiation Oncology, 2014, 23(6): 519-522.
[1] Shah AP, Langen KM, Ruchala KJ, et al. Patient dose from megavoltage computed tomography imaging[J]. Int J Radiat Oncol Biol Phys,2008,70:1579-1587. [2] Pukala J, Meeks SL, Bova FJ, et al. The effect of temporal hu variations on the uncertainty of dose recalculations performed on mvct images[J]. Phys Med Biol,2011,56:7829-7841. [3] Guckenberger M, Richter A, Wilbert J, et al. Adaptive radiotherapy for locally advanced non-small-cell lung cancer does not underdose the microscopic disease and has the potential to increase tumor control[J]. Int J Radiat Oncol Biol Phys,2011,81:275-282. [4] 侯勇,王鹏程,尹勇,等.医学图像形变配准在图像引导放射治疗中的应用[J].中国医学物理学杂志,2011,28:2882-2886. [5] La Macchia M, Fellin F, Amichetti M, et al. Systematic evaluation of three different commercial software solutions for automatic segmentation for adaptive therapy in head-and-neck, prostate and pleural cancer[J/OL]. Radiat Oncol,2012,7:160[2014-08-20]. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3493511/. [6] 侯勇,尹勇.肺癌锥形束CT与计划CT形变配准自动勾画危及器官可行性研究[J].中华放射肿瘤学杂志,2012,21:460-463. [7] Bhide SA, Davies M, Burke K, et al. Weekly volume and dosimetric changes during chemoradiotherapy with intensity-modulated radiation therapy for head and neck cancer:a prospective observational study[J]. Int J Radiat Oncol Biol Phys,2010,76:1360-1368. [8] Hansen EK, Bucci MK, Quivey JM, et al. Repeat ct imaging and replanning during the course of imrt for head-and-neck cancer[J]. Int J Radiat Oncol Biol Phys,2006,64:355-362. [9] 张希梅,李明辉,曹建忠,等.鼻咽癌调强放疗中靶区剂量变化规律研究[J].中华放射肿瘤学杂志,2010,19:197-200. [10] Capelle L, Mackenzie M, Field C, et al. Adaptive radiotherapy using helical tomotherapy for head and neck cancer in definitive and postoperative settings:initial results[J]. Clin Oncol (R Coll Radiol),2012,24:208-215. [11] Han C, Chen YJ, Liu A, et al. Actual dose variation of parotid glands and spinal cord for nasopharyngeal cancer patients during radiotherapy[J]. Int J Radiat Oncol Biol Phys,2008,70:1256-1262. [12] Wang X, Lu J, Xiong X, et al. Anatomic and dosimetric changes during the treatment course of intensity-modulated radiotherapy for locally advanced nasopharyngeal carcinoma[J]. Med Dosim,2010,35:151-157. [13] Duma MN, Kampfer S, Schuster T, et al. Do we need daily image-guided radiotherapy by megavoltage computed tomography in head and neck helical tomotherapy? The actual delivered dose to the spinal cord[J]. Int J Radiat Oncol Biol Phys,2012,84:283-288.
2014, Vol. 23 
