| 张基永,陆佳扬,洪丹丽,吴丽丽,谢文佳,彭逊.宫颈癌患者锥形束CT影像剂量计算的算法修正[J].中国医学影像技术,2017,33(1):114~118 |
| 宫颈癌患者锥形束CT影像剂量计算的算法修正 |
| A correction algorithm for cone-beam computed tomography dose calculations in patients with cervical cancer |
| 投稿时间：2016-06-28 修订日期：2016-11-16 |
| DOI：10.13929/j.1003-3289.201606160 |
| 中文关键词: 剂量计算 直方图匹配算法 体层摄影术,X线计算机 锥形束CT |
| 英文关键词:Dose calculation Histogram matching algorithm Tomography,X-ray computed Cone beam computed tomography |
| 基金项目:汕头市医疗科技计划项目[汕府科（2015）123号]。 |
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| 摘要点击次数: 1957 |
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| 中文摘要: |
| 目的 利用修正算法对宫颈癌患者锥形束CT（CBCT）影像进行修正，探讨CBCT影像剂量计算的准确性。方法 采用CIRS-062电子密度模体分别在Brilliance CT Big Bore 4D-CT模拟定位机及Truebeam加速器机载CBCT上执行CT扫描，获得计划CT（pCT）和CBCT的CT值-相对电子密度曲线。采用直方图匹配算法对CBCT影像的CT值进行修正，得到修正后的CBCT（mCBCT）。将25例宫颈癌患者的调强放疗计划分别移植到模体和患者的pCT、CBCT和mCBCT上进行剂量计算，比较其绝对剂量和剂量分布的差异。结果 模体等中心处，CBCT计算的绝对剂量与pCT计算的绝对剂量偏差为0.87%±0.24%，mCBCT与pCT的偏差为0.05%±0.03%，差异有统计学意义（t=3.625，P<0.05）。患者治疗等中心处，CBCT计算的绝对剂量与pCT计算的绝对剂量偏差为1.05%±0.32%，mCBCT与pCT的偏差为0.18%±0.09%，差异有统计学意义（t=3.023，P<0.05）。靶区剂量分布的剂量体积图显示，mCBCT的剂量分布和pCT的剂量分布相似，而CBCT的剂量分布和pCT的剂量分布差异较明显。结论 CBCT影像经算法修正后，可用于宫颈癌放疗中的剂量计算，并能提高剂量计算的准确性。 |
| 英文摘要: |
| Objective To investigate the accuracy of dose calculations in cone beam computed tomography (CBCT) for cervical cancer radiotherapy using a correction algorithm. Methods The Hounsfield units (HU) and electron density (HU-density) curves were obtained for both planning CT (pCT) and CBCT using a CIRS-062 calibration phantom. The histogram matching algorithm was used for CBCT images to correct the deviation, and got the corrected CBCT (mCBCT). The intensity-modulated radiation therapy (IMRT) plans of 25 cases of cervical cancer were transferred to the pCT, CBCT and mCBCT data sets, and the dose were calculated. The dose differences and dose distributions were compared between CBCT and mCBCT plans. Results For the phantom, the deviations of absolute point dose for CBCT and mCBCT compared with pCT were 0.87%±0.24% and 0.05%±0.03%, respectively. The significant difference was shown between CBCT and mCBCT (t=3.625, P<0.05). For the patients, the deviations of CBCT and mCBCT compared with pCT were 1.05%±0.32% and 0.18%±0.09%, respectively, there was a significant difference between CBCT and mCBCT (t=3.023, P<0.05). According to the dose-volume histogram of target coverage, mCBCT showed an equal dose distribution compare to pCT. Conclusion The CBCT images are feasible for dose calculation in cervical cancer radiotherapy, and the correction algorithm can be useful for improving the accuracy of dose calculation in radiation therapy. |
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