|
|
|
| Long-term Constancy Analysis of CT Numbers for Cone-beam CT Images of a Varian OBI System |
| SHI Fei-yue1,TIAN Shu-chang2,JIN Xun3,QIN Hang2,QIN Wei1 |
1. Radiation Therapy Center, Nanjing First Hospital, Nanjing, Jiangsu 210006, China
2. Department of Medical Equipment, Nanjing First Hospital, Nanjing, Jiangsu 210006, China
3. The Second Clinical Medical College, Nangjing University of Chinese Medicine, Nanjing, Jiangsu 210023, China |
|
|
|
|
Abstract The long-term constancy of CT numbers for cone-beam CT images of Varian on-board imager (OBI) system were evaluated, by analyzing the data of CT numbers for seven materials obtained from long-term quality assurance (QA) tests. QA tests for an OBI system equipped by the Varian Clinac iX linear accelerator were carried out with the Catphan504 phantom monthly. CBCT images were obtained with three scan protocols: high-quality head (HQH), standard-dose head (SDH) and Pelvis for the phantom. The DoseLab software was utilized to analyze the 36 series of CBCT images acquired from Mar. 2017 to Feb. 2018, and the CT numbers (Y) and corresponding difference from standard CT numbers (ΔY) for the seves materials were obtained.The datas were analysised by statistical method , and the mean, standard deviation and range values of Y and the mean of ΔY were obtained after calculation for the seven materials with three scan protocols. The results showed that the constancy of CT numbers of the CBCT images from the Varian OBI system was in good condition in 12 months by and large, the scan protocols of SDH and Pelvis were suitable for QA and metering tests of CBCT image quality, the difference between CT numbers of CBCT images with HQH and the standard CT numbers varied greatly with the increasing of relative electron density of material.
|
|
Received: 14 June 2018
Published: 19 December 2019
|
|
|
|
|
|
［1］刘浩, 白靖平, 李公平, 等. 锥形束CT图象引导放疗的应用性测试［J］.中国医学物理学杂志, 2013, 30(1): 3877-3880.
Liu H, Bai J P, Li G P, et al. Application testing for cone-beam CT image-guided radiation therapy ［J］. Chines Journal of Medical Physics, 2013, 30(1): 3877-3880.
［2］Vestergaard A, Muren L P, Sφndergaard J, et al. Adaptive plan selection vs. re-optimisation in radiotherapy for bladder cancer: A dose accumulation comparison ［J］. Radiotherapy and Oncology, 2013, 109(3): 457-462.
［3］Elstrφm U V, Olsen S R, Muren L P, et al. The impact of CBCT reconstruction and calibration for radiotherapy planning in the head and neck region–a phantom study ［J］. Acta Oncol, 2014, 53(8): 1114-1124.
［4］孟慧鹏, 冯远明, 董化江. 基于锥形束CT图像的肿瘤放疗计划剂量计算可行性分析［J］.辐射研究与辐射工艺学报, 2017, 35(4):29-34.
Meng H P, Feng Y M, Dong H J. Feasibility analysis of dose calculation for tumor radiotherapy planning based on cone-beam computed tomography images ［J］. Journal of Radiation Research and Radiation Processing, 2017, 35(4):29-34.
［5］王雪桃, 柏森, 李光俊, 等.千伏级 CBCT 图像 CT 值校正及在放疗剂量计算中应用［J］.中华放射肿瘤学杂志, 2015, 24(4): 457-461.
Wang X T, Bai S, Li G J, et al. Investigation of CT numbers correction of kilo-voltage cone-beam CT images for accurate dose calclulation ［J］. Chinese Journal of Radiation Oncology, 2015, 24(4): 457-461.
［6］庄永东, 王彬, 朱金汉, 等. 医用直线加速器机载影像系统QC图像定量评估方法研究［J］. 中华放射肿瘤学杂志, 2017, 26(4): 442-447.
Zhuang Y D, Wang B, Zhu J H, et al. A quantitative evaluation of quality control image for on·board imaging system of medical linear accelerator ［J］. Chinese Journal of Radiation Oncology, 2017, 26(4): 442-447.
［7］孙小喆, 孟慧鹏, 毛京群, 等.OBI影像引导放射治疗系统的质量保证(QA)及维护保养［J］.中国医学物理学杂志, 2013, 30(6):4527-4529.
Sun X Z, Meng H P, Mao J Q, et al. OBI image guided radiation therapy system of quality assurance (QA) and maintenance ［J］. Chines Journal of Medical Physics, 2013, 30(6): 4527-4529.
［8］Yoo S, Kim G Y, Hammoud R, et al. A quality assurance program for the on-board imagers ［J］. Med Phys, 2006, 33(11): 4431-4447.
［9］时飞跃, 任军, 吴正参, 等.西门子Sensation Open CT模拟机CT值稳定性分析［J］.中华放射肿瘤学杂志, 2017, 26(12): 1407-1410.
Shi F Y, Ren J, Wu Z C, et al. Study on constancy of CT numbers of SIEMENS Sensation Open CT-simulator ［J］. Chinese Journal of Radiation Oncology, 2017, 26(12): 1407-1410.
［10］柏正璐, 时飞跃, 蒋红兵. 使用DoseLab检测CT图像均匀性的程序改进［J］.中国数字医学, 2017, 12(12): 57-60.
Bai Z L, Shi F Y, Jiang H B. Program improvement in DoseLab for testing CT image uniformity ［J］. Chinese Digital Medicine, 2017, 12(12): 57-60.
［11］Mutic S, Palta J R, Butker E K, et al. Quality assurance for computed-tomography simulators and the computed-tomography-simulation process: Report of the AAPM Radiation Therapy Committee Task Group No. 66 ［J］. Med Phys, 2003, 30 (10): 2762-2792.
［12］邓小武, 黄邵敏, 祁振宇. CT模拟机的质量控制和质量保证检验［J］.中国肿瘤, 2004, 13(9): 546-550.
Deng X W, Huang S M, Qi Z Y. Quality control and quality assuring requirements of CT-simulator ［J］. China Cancer, 2004, 13(9): 546-550.
［13］管秋, 李楠, 杨波, 等. CBCT图像质量质控体系建立及结果分析［J］.中华放射肿瘤学杂志, 2014, 23(2): 161-164.
Guan Q, Li N, Yang B, et al. Cone beam CT quality assure procedure and the analysis of results ［J］. Chin J Radiat Oncol, 2014, 23(2): 161-164.
［14］陈进琥, 尹勇, 刘同海, 等.机载锥形束CT的质量控制［J］.中国肿瘤, 2010, 19(8): 500-502.
Chen J H, Yin Y, Liu T H, et al. The quality control of mounted cone-beam computed tomography ［J］. China Cancer, 2010, 19(8): 500-502.
［15］周永强, 金献测, 易金玲, 等.锥形束CT的验收与QA探讨［J］.中国医学物理学杂志, 2013, 30(1): 3854-3858.
Zhou Y Q, Jin X C, Yi J L, et al. Commissioning and QA Experience with CBCT ［J］. Chines Journal of Medical Physics, 2013, 30(1): 3854-3858.
［16］肖虹, 高林峰, 姚杰, 等.锥形束X射线CT的应用现状及其质量控制检测方法［J］.中国医疗设备, 2014, 29(5): 66-70.
Xiao H, Gao L F, Yao J, et al. Application of cone beam computed tomography and its qualitycontrol method ［J］. China Medical Devices , 2014, 29(5): 66-70.
［17］汪隽琦, 徐志勇, 胡伟刚, 等. 千伏级锥形束CT图像质量和稳定性及三维影像体积重建精度研究［J］. 中华放射肿瘤学杂志, 2012, 21(2): 176-180.
Wang J Q, Xu Z Y, Hu W G, et al. Quantitative analysis of image quality,stability and volume precision in kilovoltage cone beam CT ［J］. Chinese Journal of Radiation Oncology, 2012, 21(2): 176-180.
［18］巩汉顺, 徐伟, 徐寿平, 等. 不同扫描条件下CBCT影像质量及其HU值长期稳定性分析［J］. 中国医疗器械杂志, 2016, 40(2): 86-89.
Gong H S, Xu W, Xu S P, et al. Evaluation of cone beam CT image quality and analysis of its long-term stability on HU values under different conditions ［J］. Chinese Jonurnal of Medical Instrumention, 2016, 40(2): 86-89.
［19］王甜甜, 余晓锷.CT系统空间分辨率测量技术的改进［J］. 计量学报, 2012, 33(3): 187-192.
Wang T T, Yu X E. An improved methord of the measurement of spatial resolution in CT system ［J］. Acta Metrologica Sinica, 2012, 33(3): 187-192.
［20］廖振宇, 吴金杰, 屈国普, 等. CT电离室校准条件的建立与模拟［J］. 计量学报, 2016, 37(6): 663-666.
Liao Z Y, Wu J J, Qu G P, et al. Establishment simulation of calibration conditions for CT chamber ［J］. Acta Metrologica Sinica, 2016, 37(6): 663-666.
［21］王义旭, 施玉书, 高思田, 等. 工业CT探测尺寸误差的校准及误差分析［J］. 计量学报, 2014, 35(3): 216-220.
Wang Y X, Shi Y S, Gao S T, et al. Calibration and analysis for probing size error of industrial CT ［J］. Acta Metrologica Sinica, 2014, 35(3): 216-220.
［22］郭思明,刘莹,吴金杰, 等. 乳腺X射线基准装置半值层的测量［J］.计量学报, 2018, 39(3): 410-413.
Guo S M, Liu Y, Wu J J, et al. Half Value Layer Measurement of Mammography X-ray Standard［J］. Acta Metrologica Sinica, 2018, 39(3): 410-413. |
|
|
|
2020, Vol. 41 
