【摘要】 目的 利用不同匹配区域对锥形束CT（CBCT）与定位CT（FBCT）分别配准，测量出鼻咽癌放射治疗中颈部的变形误差。 方法 分析2007年4月-2008年12月收治鼻咽癌患者23例，调整治疗床前198次CBCT扫描。将鼻咽部扫描CBCT图像匹配区域分为上下两个区域进行对比分析。其中上匹配区域为:上界为蝶窦上缘，下界为颈4下缘，侧界包括下颌骨外轮廓，前界为上颌窦1/2，后界为平棘突后缘；下匹配区域为:上界约颈4下缘，下界约胸2-3下缘，侧界包括椎体外轮廓，前界包括皮肤，后界平棘突后缘。匹配方式选择骨，比较匹配结果差异。 结果 选择上与下匹配区域结果除Y（头脚）方向旋转误差无统计学差异外，余均有统计学差异（Plt;0.05） 。差值在X（左右）、Z（前后）、Y（头脚）方向平移分别为（1.14±2.80）、（0.47±1.41）、（0.58±3.88） mm，旋转误差X、Y、Z方向分别为（0.90±1.98）、（0.80±2.03）、（0.68±1.90）°。 结论 鼻咽癌放射治疗中颈部区域存在一定变形误差，通过CBCT引导发现变形误差并进行正确纠正是必须的，结合临床实际及靶区与危及器官的变化为重新计划提供依据。【Abstract】 Objective To investigate the rotation errors due to neck deformation in nasopharyngeal cancer (NPC) radiotherapy with different match areas to register conebeam CT(CBCT) from image guiding and fanbeam (FBCT) from simulation. Methods A total of 198 pre-correction CBCT data sets from 23 NPC patients from April 2007 to December 2008 were retrospectively analyzed. The matching areas in CBCT images were divided into up and down region of interest (ROI). For the up ROI, the superior, inferior, left and right, anterior, and posterior boundary were set parallel with sphenoid sinus up side, C4 down side, mandible outside, and 1/2 of maxillary air sinus and acanthi. For the down ROI, the lines were set parallel with C4 down side, T2-3 down side, neck outside, skin surface and acanthi respectively in all directions. All registrations were performed automatically by bony anatomy and the results were compared. Results The registration results by the up and the down ROI showed significant difference except Y direction for rotation. The translation error was (1.14±2.80),(0.47±1.41),and (0.58±3.88) mm, respectively; and the rotation error was (0.90±1.98),(0.80±2.03),and (0.68±1.90) ° in X, Y, and Z direction, respectively. 〖WTHZ〗Conclusions〖WTBZ〗There are some significant deformation errors at neck areas in NPC radiotherapy. It is important to find out the deformation and correct it with CBCT image guiding. This kind of error information may provide clues for re-planning in addition to clinical practice and the changes of clinical targets and involved organs.
【摘要】 目的 研究使用Bowtie滤线器（F1）后，保证加速器CBCT患者扫描图像质量前提下，如何合理设置扫描条件，尽量降低辐射剂量。 方法 使用Piranha辐射测量仪测量CBCT在使用F1与未使用F1时射线的半价层。设定不同的扫描模式，使用直径30 cm的有机玻璃模体测量扫描剂量，并使用XVI附带的Catphan503模体测量客观图像质量。在此基础上，研究扫描剂量以及图像质量与扫描条件的关系，提出了适合临床患者的胸部与腹部不同的扫描条件。 结果 使用F1后射束的半价层增加了0.77～0.92 mmAl，扫描剂量明显减少，中心点减少了22%~29%，边缘点减少了41%~45%，皮肤剂量减少显著。图像质量随着扫描剂量的增大而提高。空间分辨力受FOV影响较大，但一般能识别1～2 mm的物体，完全能够满足分辨细小骨结构与标记点的临床要求。图像伪影在使用L20时的大mAs下明显。胸部低剂量的CBCT图像如100 kV，M20，0.5 mAs的扫描条件亦可满足临床要求。腹部则需要使用较大剂量的扫描模式，CBCT图像才达到进行配准的要求。 结论 F1的使用在改善图像质量的前提下降低了扫描剂量，使用新的扫描序列能平衡二者的关系。【Abstract】 Objective To explore the influence of bowtie filtration on absorb dose and half-value layer inaluminum (Al) of cone-beam CT, estimate the image dose under different scan protocol, and establish the relationship between the image quality and the scan protocol after using F1. Methods Piranha was used to measure the HVL. Dose measurements were performed with an 0.6 cc Farmer type ionization chamber with a 30 cm-diam cylindrical shaped water phantoms in 100 and 120 kV with a series of mAs and FOV. CNR, noise and uniformity were measured on the Catphan503 images. Results HVL increased 0.77-0.92 mmAl where XVI generally had more penetrating beams at the similar kV settings. Scanning dose significantly reduced, the center point decreased 22%-29%, the edge with a decrease of 41%-45% which meant a very significant reduction in skin dose. Image quality improved with mAs increase. The spatial resolution mainly changed with FOV. But generally can identify 1-2 mm-diam objects, fully meet the clinical requirements of identify small bone structure and marker. Through this clinical investigation, low-dose CBCT images in chest, such as 100 kV, M20, and 0.5 mAs scanning protocol appeared to be an optimal settings. Abdomen image needed a higher dose to reach the requirements of registration. Conclusion Using F1 under the premise of improving the image quality then reducing the scanning dose and using a new scanning sequence can balance the image quality and scanning dose.
【摘要】 目的 研究千伏级锥形束CT（kV-cone beam CT，kV-CBCT）影像用于鼻咽癌调强放射治疗计划剂量计算的可行性和精确度。 方法 2010年7-9月7例鼻咽癌患者 ，获取每例患者的第1天放射治疗时的kV-CBCT影像。用CIRS062密度模体和患者自身特定区域亨氏单位值（hounsfield unit，HU）映射的两种方法重新刻度亨氏单位值-相对电子密度（HU-RED）表，分别进行剂量计算，并与在传统扇形束CT（FBCT）影像上的原放射治疗计划结果进行对比，包括辐射剂量分布、靶区和危及器官的剂量体积直方图（DVH）。 结果 kV-CBCT影像的治疗计划和原治疗计划在剂量分布和DVH上有较好的一致性。在剂量分布的比较上采用了γ分析（2%/2 mm标准的通过率），用基于模体的HU-RED表得到的治疗计划与原治疗计划对比，在经过等中心冠状面、矢状面和横断面的通过率分别为92.7%±3.5%、95.1%±3.1%和95.7%±3.4%，用基于患者的HU-RED表得到治疗计划与原治疗计划对比的通过率分别为94.8%±2.7%、96.6%±2.9%和97.4%±2.7%。DVH的统计数据表明，两种方法得到的kV-CBCT治疗计划和原治疗计划相比较，靶区和危及器官剂量偏差大多数在2%以内。有1例因在横断面发生了明显的旋转误差，导致在横断面的通过率很低，DVH统计数据较原计划偏差较大。 结论 kV-CBCT影像可以用来做辐射剂量计算，基于患者自身影像生成的HU-RED表的治疗计划较原治疗计划有更高的符合度。【Abstract】 Objective To evaluate the feasibility and accuracy of dose calculation based on cone beam CT (CBCT) data sets for intensity modulated radiation therapy (IMRT) planning of nasopharyngeal cancer (NPC). Methods Seven NPC patients were selected. The kV-CBCT images for each patient were acquired on the first treatment day. Two correction strategies were used to generate the cone beam HU value vs relative electron density calibration tables which named CIRS062 phantom based HU-RED tables and patient specific HU-RED tables respectively for dose calculation. The dose distributions and dose volume histograms (DVHs) of the target and organs at risk (OAR) based on kV-CBCT images were compared to the plans based on the fan-beam CT (FBCT). Results The DVH and dose distribution comparison between plans based on the FBCT and those on the CBCT showed good agreements. The γ analysis with a criterion of 2 mm/2% was used for the comparison of dose distribution at the coronal plane, sagital plane and cross plane through the isocenter point. The passing rate from phantom based HU-RED tables were (92.7±3.5) %, (95.1±3.1) %, and (95.7±3.4)%, respectively. The passing rates from the patient specific HU-RED tables were (94.8±2.7) %, (96.6±2.9) %, and (97.4±2.7) %, respectively. The dose difference between plans based on CBCT and those based on FBCT was within 2% at most patients by analyzing DVH based parameters. Only one patient who had significant rotation setup error resulted in the low passing rate and disagreement in DVH. Conclusion The CBCT images can be used to do dose calculation in IMRT planning of NPC. The differences between plans based on HU-RED tables generated by specific patient and the original plans are less than those between plans based on CIRS062 phantom based HU-RED tables and the original plans.
目的 通过非小细胞肺癌（NSCLC）图像引导放射治疗（IGRT）过程中，每次治疗前获取的锥形束CT图像，动态观察肿瘤体积的变化。 方法 2009年2月－2010年8月18例周围型NSCLC患者接受IGRT。每次治疗前进行千伏级锥形束CT（KV-CBCT）图像的采集。每周在KV-CBCT图像上勾画肿瘤靶区并计算靶区体积，经统计后分析肿瘤治疗过程中体积的变化。 结果 治疗开始时平均体积为28.5 cm3（2.5～109.1 cm3），治疗结束时平均体积为17.1 cm3 （1.4～73.4 cm3）。平均退缩率为35.9%（3.9%～68.9%），平均每天的退缩率为1.5% （0.1%～5.4%）。治疗结束时，0例病灶完全消退，1例部分消退，10例微小消退，7例稳定。 结论 治疗过程中，NSCLC肿瘤的退缩可以通过KV-CBCT进行观察。当病灶为周围型时，能对肿瘤体积的变化进行客观有效的评价。放射治疗过程中肿瘤的体积改变具有很大的异质性，肿瘤在治疗过程中体积均有一定的退缩，但治疗结束时大多数病灶仅为微小消退或稳定。
目的 分析比较锥形束CT(CBCT)与MOSAIQ两系统用于测量胸部放射治疗(放疗)摆位误差情况。 方法 2011年2月－9月,随机选择21例用热塑模固定的胸部调强治疗患者，进行同次摆位的CBCT图像采集和电子射野影像(EPID)正侧位图像采集。将CBCT图像与定位CT图像进行匹配，图像经iViewGT系统传输至MOSAIQ系统图像处理模块中与计划生成的数字重建图像(DRR)正侧位片进行匹配，分别记录两套系统图像匹配结果在X(左右)方向、Y(头脚)方向、Z(前后)方向的平移误差及CBCT的旋转误差值，计算其均值、标准差，进行统计学处理。 结果 本研究共获取图像106组，每组内包含一次CBCT图像和EPID图像。CBCT和MOSAIQ系统下EPID匹配结果平移误差在X、Y、Z方向分别为(−0.103 ± 0.240)cm、(−0.086 ± 0.342)cm、(0.017 ± 0184)cm和(0.005 ± 0.214)cm、(−0.004 ± 0.0.315)cm、(−0.113 ± 0.239)cm；旋转误差在X、Y、Z方向分别为(0.792 ± 1.173)°、(−0.130 ± 1.407)°、(0.793 ± 0.960)°，其中≤3°的概率分别为98.2%、97.2%、99.1%，最大绝对值分别为5°、3.4°、3.3°。两套系统在X、Y、Z三个方向的平移误差经配对样本检验，在Y方向P＞0.05，在X和Z方向上P值均＜0.05， 两系统的测量差值有直线负相关关系。 结论 CBCT和EPID在测量胸部放疗靶区中心的平移误差中差异有统计学意义，因此建议在做胸部放疗时有CBCT的情况下应优先使用。
We applied Demons and accelerated Demons elastic registration algorithm in radiotherapy cone beam CT (CBCT) images, We provided software support for real-time understanding of organ changes during radiotherapy. We wrote a 3D CBCT image elastic registration program using Matlab software, and we tested and verified the images of two patients with cervical cancer 3D CBCT images for elastic registration, based on the classic Demons algorithm, minimum mean square error (MSE) decreased 59.7%, correlation coefficient (CC) increased 11.0%. While for the accelerated demons algorithm, MSE decreased 40.1%, CC increased 7.2%. The experimental verification with two methods of demons algorithm obtained the desired results, but the small difference appeared to be lack of precision, and the total registration time was a little long. All these problems need to be further improved for accuracy and reducing of time.
To investigate the impact of respiratory movement to determine the target volume on cone beam CT (CBCT) for lung tumor,we used CIRS dynamic thorax phantom (Model-CIRS008) to simulate the sinusoidal motion of lung tumor. With a constant amplitude, the ratio of the time of near-end-expiratory and near-end- inspiratory (E/I) changed when it was scanned with CBCT. We analyzed the contrast changes of target by extracting the CT value of each pixel on the center line of the target movement direction. The targets were contoured with region growing method and compared with the motion volume generated by the tumor trajectory method. The result showed that the contrast of near-end-expiratory increased and the contrast of near-end-inspiratory decreased with increasing E/I. The contoured volume generated by region growing method decreased with increasing E/I. When E/I=4, the amplitude A=1 cm, diameter of 1 cm and 3 cm target volumes were reduced by 48.2% and 22.7%.The study showed that CBCT was not suitable to be used to accurately determine the range of lung tumor movement. The internal target volume (ITV) may be underestimated in CBCT images.
In the design of oral cone beam CT, cooperation between synergic control of X-ray source, real-time acquisition of flat detector and motion of mechanical structure affects the CT image quality. Based on the full analysis of the flat detector's timing signal characteristics, this research was carried out with microprocessor controller (MCU), complex programmable logic device (CPLD), and light couplings to design and realize synchronous exposure control system. To evaluate whether the design of the synchronous exposure control system in this project could reach the required imaging accuracy, we employed the projected images in the system to analyze its stability, linear consistency, signal to noise ratio and precede the FDK construction.
Objective To investigate the safety and feasibility of transcatheter arterial chemoembolization (TACE) assisted by transradial approach and cone beam computed tomography (CBCT) three-dimensional vascular reconstruction in the treatment of primary liver cancer. Methods The clinical data of 124 patients with primary liver cancer who underwent precision TACE via radial artery in our hospital from May 2018 to December 2019 were retrospectively collected. Results Among the 124 patients, 118 patients were successfully punctured through the left radial artery and completed the TACE operation. The operation time was (109.57±31.32) min, and the median of postoperative hospitalization was 3 d. One patient changed to the right radial artery to complete TACE due to chronic renal failure and left brachial artery and vein puncture and catheterization before operation. The operation time was 119 minutes, and the patient was discharged after 5 days of hospitalization. After successful puncture of the left radial artery in one patient, the forearm artery was twisted into a loop and the guide wire catheter failed to pass, and the right femoral artery was used to complete TACE. The operation time was 123 minutes, and the patient was discharged after 4 days of improvement. The radial artery puncture was unsuccessful in four patients, and the right femoral artery approach was used to complete the operation; the operation time was (111.66±32.77) min, and the median of postoperative hospitalization was 3 d. One of the patients successfully completed up to 5 consecutive TACE via the radial artery. All patients underwent precision TACE with superselective cannulation assisted by CBCT three-dimensional vascular reconstruction. No vascular injury andocclusion, urinary retention, subcutaneous hemorrhage, and other complications occurred in all patients. Conclusions Trans-radial arterial precision TACE is safe and effective, which can be repeated many times and has few complications and high patient comfort. It can be used as one of the routine approaches of TACE.
ObjectiveTo explore the clinical application of the comprehensive guidance technologies, such as cone beam computed tomography (CBCT), virtual bronchoscopic navigation (VBN), and superimposed high-frequency jet ventilator for respiratory control in the biopsy of peripheral pulmonary nodules (PPNs). MethodsThe clinical information of 3 patients with PPNs diagnosed by CBCT combined with VBN and superimposed high frequency superposition jet ventilator in Shanghai Changhai Hospital were retrospectively analyzed. Results Clinical data of 3 patients were collected. The average diameter of PPNs was (25.3±0.3) mm with various locations in left and right lung. The first nodule was located in the apex of the left upper lung, and the biopsy was benign without malignant cells. The lesion was not enlarged during the 5-year follow-up. The second one was located in the left lingual lung, and the postoperative pathology was confirmed as mucosa-associated lymphoma. The third one was located in the anterior segment of the right upper lung. After the failure of endobronchial procedure, percutaneous PPNs biopsy under CBCT combined with VBN was performed, and the pathological diagnosis was confirmed as primary lung adenocarcinoma. Postoperative pneumothorax complication occurred in the third patient with right lung compression rate approximately 20%. ConclusionsThe application of CBCT, combined with VBN and the superimposed high frequency jet ventilator for respiratory control can potentially improve the accuracy and safety in the diagnosis of PPNs. Multi-center clinical trials are needed to verify its further clinical application.