[an error occurred while processing this directive]|[an error occurred while processing this directive]
呼吸运动对4D锥形束CT图像质量影响分析
杨昕,张可,任信信,戴建荣
100021 北京协和医学院 国家癌症中心/中国医学科学院肿瘤医院放疗科
Influence of respiratory motion on image quality of 4D-CBCT
Yang Xin,Zhang Ke,Ren Xinxin,Dai Jianrong
Department of Radiation Oncology,National Cancer Centre/Cancer Hospital,Chinese Academy of Medical Sciences,Peking Union Medical College,Beijing 100021,China
Abstract： Objective To investigate the relationship between the image quality of 4D cone beam CT (4D-CBCT) and the characteristic parameters of respiratory motion. Methods Catphan 500 was fixed on the Mapcheck XY/4D table by a fixation device. The control platform was utilized to simulate the static and 19 motion states. A synergy accelerator was adopted to perform 4D-CBCT scan of the image quality detection module under different motion states. By analyzing the geometric accuracy,spatial resolution,low-contrast visibility,CT value uniformity and motion position accuracy of the images of the 10 phases of the reconstructed images,the relationship among the image quality of 4D-CBCT,motion direction,amplitude and cycle was analyzed. Results 4D-CBCT images could not be properly reconstructed in the static state or only in the left-right (LR) direction. The image quality was significantly worse than that in the SI direction. The contrast-to-noise ratio (CNR) was decreased as the motion cycle was increased. When the cycle was increased from 2 s to 6 s,the CNR was significantly declined from 3.33 to 1.72(P<0.01),whereas respiratory motion exerted no significant effect upon the geometric accuracy,spatial resolution and sagittal position. Conclusions The CNR,horizontal and vertical geometric accuracy and motion position accuracy of 4D-CBCT image quality are significantly affected by respiratory motion,whereas spatial resolution and sagittal geometric accuracy are not significantly influenced by respiratory motion.4D-CBCT requires the intervention of periodical motion in the SI direction. Excessively slow or absence of periodical motion can influence the image quality and even the images cannot be accurately reconstructed.4D-CBCT image reconstruction equally requires the intervention of periodical motion in the SI direction. The image quality is simultaneously affected by the amplitude and cycle of respiratory motion. For 4D-CBCT scan,the respiratory cycle of<6 s and an amplitude of>0.75 cm are recommended.
Yang Xin,Zhang Ke,Ren Xinxin et al. Influence of respiratory motion on image quality of 4D-CBCT [J]. Chinese Journal of Radiation Oncology, 2018, 27(8): 763-768.
[1] Sweeney RA,Seubert B,Stark S,et al. Accuracy and inter-observer variability of 3D versus 4D cone-beam CT based image-guidance in SBRT for lung tumors[J].Radiat Oncol,2012,7(8;7:81).DOI:10.1186/1748-717X-7-81. [2] 王佳浩.NSCLC-SBRT中4D-CBCT图像配准方式研究[J].中华放射肿瘤学杂志,2016,25(1):71-75.DOI:10.3760/cma.j.issn.1004-4221.2016.01.018. Wang JH.Research on 4D-CBCT Image Registration in NSCLC-SBRT[J].Chin J Radiat Oncol,2016,25(1):71-75.DOI:10.3760/cma.j.issn.1004-4221.2016.01.018. [3] Sonke J-J,Zijp L,Vanherk M,et al. Respiratory correlated cone beam CT[J].Med Phys,2005,32(4):1176-1186.DOI:10.1118/1.1869074. [4] 李金凯.利用4D锥形束CT研究肺癌放疗的靶区外放范围[J].东南大学学报(医学版),2015,34(4):609-612.DOI:10.3969/j.issn.1671-6264.2015.04.024. Li JK.Evaluation of the margins of PTV in radiotherapy on lung cancer using 4D-CBCT[J].J Southeast Univ (Med Sci Edi),2015,34(4):609-612.DOI:10.3969/j.issn.1671-6264.2015.04.024. [5] Vergalasova I,Maurer J,Yin FF.Potential underestimation of the internal target volume (ITV) from free-breathing CBCT[J].Med Phys,2011,38:4689-4699.DOI:10.1118/1.3613153. [6] Sonke J,Van Herk M,Belderbos J,et al. An off-line 4D cone beam CT based correction protocol for lung tumor motion[J].Int J Radiat Oncol Biol Phys,2005,63:S389-S390.DOI:10.1016/j.ijrobp.2005.07.666. [7] Lujan AE,Larsen EW,Balter JM,et al. A method for incorporating organ motion due to breathing into 3D dose calculations[J].Med. Phys.,1999,26(5):715-720.DOI:10.1118/1.1609057. [8] George R,Vedam SS,Chung TD,et al. The application of the sinusoidal model to lung cancer patient respiratory motion[J].Med Phys,2005,32(9):2850-2861.DOI:10.1118/1.2001220. [9] Shirato H,Seppenwoolde Y,Kitamura K,et al. Intrafractional tumor motion:lung and liver[J].Semin Radiat Oncol,2004,14:10-18.DOI:10.1053/j.semradonc.2003.10.008. [10] Wolthaus JW,Schneider C,Sonke JJ,et al. Mid-ventilation CT scan construction from four-dimensional respiration-correlated CT scans for radiotherapy planning of lung cancer patients[J].Int J Radiat Oncol Biol Phys,2006,65(5):1560-1571.DOI:10.1016/j.ijrobp.2006.04.031. [11] Li T and Xing L,Optimizing 4D cone-beam CT acquisition protocol for external beam radiotherapy[J].Int J Radiat Oncol Biol Phys.2007,67(4):1211-1219.DOI:10.1016/j.ijrobp.2006.10.024. [12] Li G,Citrin D,Camphausen K,et al. Advances in 4D medical imaging and 4D radiation therapy[J].Technol Cancer Res Treat,2008,7(1):67-81.DOI:10.1177/153303460800700109. [13] Andrew P,Kwang H,Qin YJ,et al. Evaluation of gantry speed on image quality and imaging dose for 4D cone-beam CT acquisition[J].Radiat Oncol,2016,11:98.DOI:10.1186/s13014-016-0677-8. [14] Sheeba T,Kathleen S,Pascal M,et al. Difference in performance between 3D and 4D CBCT for lung imaging:a dose and image quality analysis[J].Radiat Oncol Phys,2016,17:97-106.DOI:10.1120/jacmp.v17i6.6459. [15] Chan M,Leung-Chiang C,Lee V,et al. Target localization of 3D versus 4D cone beam computed tomography in lipiodol-guided stereotatic radiotherapy of hepatocellularcarcinomas[J/OL].PLoS One,2017,12(4):e0174929.DOI:10.1371/journal.pone.0174929.
2018, Vol. 27 
