前列腺癌大分割精确放疗分次治疗间和分次治疗内位置变动分析

目的 了解前列腺癌精确大分割放疗时分次间和分次内前列腺靶区位移情况。方法 对 2013—2016年间28例接受5 Gy9次放疗的前列腺癌患者,定位前2周B超引导下经直肠穿刺前列腺内植入纯金标记3颗,仰卧位体膜固定充盈膀胱并直肠内插置直肠扩张球囊充气60 ml后CT定位,Pinnacle系统制定放疗计划。23例患者Synergy加速器治疗,每次疗前CBCT校位,扫描图像与计划图像行骨配准记录摆位误差,然后通过前列腺内金标位置配准记录前列腺位移误差,两次之差为分次间位移。5例患者Novalis加速器治疗,通过前列腺内金标配准,疗中ExacTrac系统实时跟踪金标位置变化,观察前列腺分次内位移。结果 23例患者每次疗前均测量位移共计207次,左右、上下、前后位移平均值分别为(0.05±0.10)、(0.20±0.22)、(0.19±0.18) cm;3个方向>0.3 cm位移分别为1、52、49次,>0.5 cm位移分别为1、29、16次。5例患者每次疗时监测测量金标位置移动5次共计225次,左右、上下、前后位移平均值分别为(0.61±0.50)、(0.68±0.69)、(0.70±0.67) mm,各方向>3 mm移动分别为0、1、1次。结论 前列腺癌精确大分割放疗时分次间位移远远大于分次内位移,分次间位移必须校正后才能放疗。分次内靶区位移尽管变化较小,但仍有必要监测分次内靶区位移,以防患者体位变动造成靶区脱靶照射。直肠内球囊插入对前列腺位置具有固定作用。     

Prostate and seminal vesicle displacement following urethrography: a computed tomography-based study]

PURPOSE: It has been suggested that urethrography used for localization of the prostate apex may cause a systematic cranial displacement of the organ. Our objective was to use CT-CT image registration to identify if a clinically relevant systematic shift occurs in the position of the prostate and seminal vesicles following retrograde urethrography. PATIENTS AND METHODS: Patients were scanned twice at the time of simulation. They were imaged supine, bladder empty. Scan resolution was 512x512 with 5 mm cuts. After the first CT sequence, with the patient still on the CT couch, an urethrogram was performed. The patients were then re-scanned. The image sets were registered through the use of external skin fiducials. A single author reviewed x, y and z-axis displacement. Z-axis motion of the prostate was also assessed by having three blinded radiation oncologists mark the cranial limit of the prostate on all 104 image sets. RESULTS: Fifty-two pairs of CT scans were analyzed for post-urethrogram organ displacement. The mean x axis displacement of the prostate was 0.016 mm (P=0.8), the mean y-axis displacement was 1.3 mm anterior (P<0.001). Mean z-axis displacement of the prostate, using the blinded assessments, was a 1.35 mm cranial shift (P<0.0001). Analogous shifts were identified for the seminal vesicles. CONCLUSION: Our results suggest a small cranial and anterior displacement of the prostate and seminal vesicles following retrograde urethrography.     

基于四维CT技术肺内孤立性肿瘤位移模型的建立与验证

目的 基于四维CT (4DCT)测量肺内孤立性肿瘤三维方向的位移,建立肿瘤的位移模型并进行验证。方法 对建模样本中290例肺内孤立性肿瘤行4DCT模拟定位和主动呼吸控制(ABC)下螺旋扫描,并基于4DCT测量不同肺段肿瘤三维方向位移,在ABC图像上构建静止状态下肿瘤体积。用模拟定位机测量患侧膈肌的运动幅度,用肺功能仪测量肺活量及潮气量。采集患者性别、年龄、身高、体重、呼吸频率,肿瘤所在肺叶、肺段等信息。采用多元线性回归对肿瘤三维方向的位移与患者性别、年龄、身高、体重、呼吸频率、肿瘤体积、位置、膈肌运动幅度等因素进行分析,建立肺内孤立性肿瘤三维方向的位移模型。序贯收集17例肺内孤立性肿瘤对位移模型的计算结果进行测试。结果 上叶肺内孤立性肿瘤三维方向的位移模型分别为X_上=-0.267+0.002TV+0.446DM,Y_上=-1.704+0.004TV+0.725DM+2.250SⅡ+1.349SⅢ,Z_上=0.043+0.626DM+0.599SⅡ+0.519SⅢ。中叶及上、下舌段肿瘤三维方向的位移模型分别为X_中=0.539+0.758DM,Y_中=-2.316+2.707DM+0.009TV,Z_中=0.717+1.112DM。下叶肿瘤三维方向的位移模型分别为X_下=-0.425+0.004TV+0.857DM,Y_下=4.691+4.817DM+0.005TV-0.307RR+3.148SⅨ+2.655SⅩ,Z_下=0.177+0.003TV+0.908DM。(DM:膈肌运动幅度,TV:潮气量,RR:呼吸频率,SⅡ:后段,SⅢ:前段,SⅨ:外侧底段,SⅩ:后底段)。位移模型的预测结果与4DCT法实测肿瘤的位移相近(P>0.05)。结论 肺内孤立性肿瘤三维方向位移的主要影响因素为膈肌运动幅度和患者潮气量,同一肺叶不同肺段肿瘤头脚方向的位移差异显著,中叶不同肺段之间肿瘤的位移相近。位移模型法能较好地预测肺内孤立性肿瘤的位移,为个体化靶区构建提供参考。     

Online ultrasound image guidance for radiotherapy of prostate cancer: impact of image acquisition on prostate displacement

AIM: Numerous studies reported the use of ultrasound image-guidance system to assess and correct patient setup during radiotherapy for prostate cancer. We conducted a study to demonstrate and quantify prostate displacement resulting from pressure of the probe on the abdomen during transabdominal ultrasound image acquisition for prostate localization. MATERIAL AND METHODS: Ten healthy volunteers were asked to undergo one imaging procedure. The procedure was performed in a condition that simulates the localization of prostate during online ultrasound guidance. A 3D ultrasound machine was used. The procedure started with the placement of the probe on the abdomen above the pubis symphysis. The probe was tilted in a caudal and posterior direction until the prostate and seminal vesicle were visualized. The probe was then fixed with a rigid arm, which maintained the probe in a static position during image acquisition. The probe was then moved, in a short time, stepwise toward the prostate, acquiring images at each step. The prostate and seminal vesicles were identified and selected in all planes. The first 3D volume was used as reference 1, to which all other scans were matched using a gray value matching algorithm. RESULTS: Prostate motion was quantified as a 3D translation relative to the patient coordinate system. The resulting translations represented the amount of prostate movement as a function of probe displacement. Between 7 and 11 images were obtained per volunteer, with a maximal probe displacement ranging between 3 and 6 cm. Prostate displacement was measured in all volunteers for all the probe steps and in all directions. The largest displacements occurred in the posterior direction in all volunteers. The absolute prostate motion was less than 5 mm in 100% of the volunteers after 1 cm of probe displacement, in 80% after 1.5 cm, in 40% after 2 cm, in 10% after 2.5 cm, and 0% after 3 cm. To achieved a good-quality ultrasound images, the probe requires an average displacement of 1.2 cm, and this results in an average prostate displacement of 3.1 mm. No correlations were observed between prostate motion and prostate-probe distance or bladder size. CONCLUSION: Probe pressure during ultrasound image acquisition causes prostate displacement, which is correlated to the amount of probe displacement from initial contact. The induced uncertainty associated with this process needs to be carefully evaluated to determine a safe margin to be employed during online ultrasound image-guided radiotherapy of the prostate.     

CBCT分析乳腺癌保乳术后瘤床钛夹标记位置变化

目的 分析乳腺癌保乳术后瘤床钛夹标记位置的变化及其影响因素。 方法 回顾分析 2016年间收治的 14例乳腺癌保乳术后放疗患者的锥形束CT影像,分别测量胸壁以及每个钛夹在放疗过程中的误差。将钛夹的位移与钛夹的相对位置、乳腺体积、胸壁切线垂直距离以及乳腺最大厚度等因素进行Pearson相关性分析。 结果 胸壁系统误差和随机误差在左右、头脚、前后方向分别为4.42、3.44、5.13 mm和3.55、3.07、4.54 mm。钛夹相对胸壁有较大的位移,主要集中在左右方向,最大系统误差、随机误差分别为4.39、2.42 mm。钛夹位移与乳腺体积、乳腺的厚度无明显相关(P>0.05)。钛夹头脚方向的相对位置与最下、最外、最前与最后钛夹的位移相关(P<0.05)。最上钛夹的近胸壁组与远胸壁组的位移差异有统计学意义(P=0.02)。 结论 乳腺癌放疗中采用真空垫进行体位固定时存在较大的摆位误差,钛夹在放疗过程中存在较大的位移,不推荐使用同步加量照射技术;缺乏良好的固定可能是钛夹存在较大位移的主要影响因素。     

Field Displacement During External Radiotherapy In Prostatic Adenocarcinoma Treated With Radioactive 198Au Implants And External Irradiation

The purpose of this work was to study displacement error and internal movements of the prostate during external beam radiotherapy. Verification films in the frontal (n = 194) and lateral (n = 64) portals were investigated in 14 patients treated with radioactive ¹⁹⁸Au implants. Displacement errors of two implants were investigated. In seven patients, filling of the rectum and the bladder with contrast medium or isotonic saline was performed during CT investigation for planning purposes to detect movements of the prostate. Most (95%) of the displacement errors were less than 10 mm in the frontal portal and less than 15 mm in the lateral portals. No correlation to the patient's weight was found. The displacement errors were randomly distributed. The spatial relations between the implants were not altered during the treatments. Small movements of the prostate were observed. To conclude, the positioning system employed at present (laser) can be sufficient for the margins used (2 cm). In lateral portals, however, the system did not have the ability to detect a possible systematic displacement error from simulator to accelerator. The intention is to decrease the margins to 1 cm, which will necessitate a better positioning system.     

Measurement of beam-axis displacement from the isocenter during three-dimensional conformal radiosurgery with a micro-multileaf collimator.

We describe the displacement of the beam-axis from the planning isocenter in clinical situations during three-dimensional conformal radiosurgery using an Acculeaf bi-directional micro-multileaf collimator. The displacements were recorded for 64 ports using a video imaging system and a stereotactic arc. The mean displacement was 0.41+/-0.25 mm.     

Three-dimensional visualization and dosimetry of stranded source migration following prostate seed implant

PurposeComputed tomographic (CT) imaging was used to determine the displacement of stranded seeds between day 0 and day 30 following prostate seed implants. Post-plan dosimetry was used to assess the dosimetric consequence of strand displacement.Methods and MaterialsBetween March 2006 and December 2009, 86 prostate seed implant patients had day 0 and day 30 post-plan CT imaging. Migrated strands were first identified by inspection of day 0 and day 30 scans. The exact distance of displacement was measured using 3-dimensional fusion software. Post-plan dosimetric analysis was performed using CMS software.ResultsOf the 1550 strands placed, 23 strands exhibited substantial movement and these displacements occurred in 21 of the 86 cases. The measured distance of strand movement ranged from 0.31 cm to 3.44 cm, with mean displacement of 2.75 cm. Of the displaced strands, 15 strands moved away from the implant center while 8 strands moved toward the implant center. A comparison of changes in dosimetric parameters between day 0 and day 30 revealed expected increases in D90 related to resolution of prostate edema. When cases of strand displacement were compared with cases without displacement, there were no differences in D90 or V100 at day 0. At day 30, however, statistically significant decreases in D90 (96.8% vs 89.5%; P = .0061) and V100 (85.9% vs 82.2%; P = .046) were noted for cases with strand displacement. When the data were analyzed by looking at the change in dosimetric parameters over time for each individual case (eg, comparing the difference in D90 from day 0 to day 30 per patient) there was a trend toward decrease in D90 with displacement of the strands but this did not achieve statistical significance (P = .09).ConclusionsStranded seeds show unexpected spatial instability in the craniocaudal dimension. Strand displacement may occur in approximately 1.5% of stranded sources placed and about 25% of cases. One may expect mean decreases in D90 and V100 of about 7% and 3%, respectively, among cases exhibiting strand migration in the first month following seed implant. Resolution of prostate edema during the same time period accounts for an approximately 30% increase in D90 and V100.     

电子射野影像装置机械运动的位置误差研究

目的 研究不同类型电子射野影像装置(EPID)机械运动的相对位置偏差,为基于EPID进行调强放疗剂量验证提供位置误差的修正依据。
方法 对3种不同类型EPID (瓦里安aS1000、aS500和医科达iViewGT)采用5 cm×5 cm射野进行照射。通过自编软件系统对EPID采集的射野图像进行分析,并确定射野中心点在EPID上投影。对臂架0°~360°射野中心点在EPID上投影位置进行分析,并与臂架0°时位置比较以确定相对位置偏移。
结果 在瓦里安aS1000、aS500、医科达iViewGT的EPID最大相对偏移左右方向上分别为(－0.23±0.17)、(2.94±0.17)、(0.35±0.09) mm,上下方向上分别为(－4.16±0.20)、(－4.15±0.25)、(－1.66±0.11) mm。对上下方向上的相对位移采用四次方经验函数可较好地进行拟合。
结论 不同类型EPID在不同角度下相对位置误差不同,且在上下方向上明显较左右方向大,应用EPID进行调强验证时必需考虑对在不同臂架角度下相对位置误差进行修正。     

Irradiation of true pelvis for bladder and prostatic carcinoma in supine, prone or Trendelenburg position

Small bowel transit was performed in 50 patients with bladder or prostatic carcinoma. The patients were all examined in supine and prone positions; some were also studied in 25 degrees Trendelenburg position and 25 degrees inclined procubitus to investigate the effect of the various positions on the displacement of the small bowel loops out of the true pelvis. The prone position proved to be superior to the supine position in 78% of patients. A mean displacement of 0.9 cm was obtained. Greatest shifts generally were found in the Trendelenburg position and inclined procubitus, with a mean displacement of 1.9 and 2.0 cm, respectively. The patients' height, weight, maximal abdominal circumference and Quetelet's index were analyzed with regard to the shifts of bowel loops under the various conditions. Only weight and Quetelet's index were correlated with the shifts in the Trendelenburg and inclined procubitus positions. The shifts were generally larger in case of heavier patients. We conclude that pelvic irradiation should preferably be done in the Trendelenburg or inclined procubitus position, especially in case of obesity.     

驻留点权重标准差与施源器位置不确定性对宫颈癌患者剂量影响分析

目的 研究三维后装中驻留点权重标准差与施源器位置不确定性对宫颈癌患者受量影响。方法 选取已完成治疗的根治性宫颈癌患者20例,均使用Fletcher施源器(Nucletron#189.730),基于原CT图像和结构信息,重新设定一组新计划,记录原计划和新计划中驻留点权重并计算驻留点权重标准差(DWSD),按照DWSD大小患者2个计划被分成高低两组,即LDWSD组(0.141~0.299)和HDWSD组(0.211~0.337),利用Oncentra^® Brachy V4.3计划系统模拟Fletcher施源器中宫腔施源器,阴道施源器发生±1 mm位移时的剂量分布。统计CTV的D₁₀₀、D₉₀和V₁₅₀,、膀胱、直肠、小肠的D_0.1cc、D_1cc和D_2cc,分析DWSD与施源器位置不确定性对三维后装剂量的影响。结果DWSD越大,由施源器位置不确定性产生的剂量偏差就越大。当宫腔施源器、阴道施源器发生1 mm位移时,CTV的HDWSD组D₁₀₀、D₉₀、V₁₅₀比LDWSD组分别高3.0%、23.8%、4.8%和0.5%、1.2%、5.2%,膀胱、直肠、小肠HDWSD组D_0.1cc、D_1cc、D_2cc都高于LDWSD组,其中小肠最明显,分别高44.0%、22.8%、16.8%和10.3%、14.4%、12.4%。结论 宫颈癌三维后装计划的评估应考虑驻留点权重因素,可以减小由施源器位置不确定导致的剂量偏差。     

Intra-fraction Motion during Extreme Hypofractionated Radiotherapy of the Prostate using Pre- and Post-treatment Imaging

AimsTo determine intra-fraction displacement of the prostate during extreme hypofractionated radiotherapy using pre- and post-treatment orthogonal images with three implanted gold seed fiducial markers.Materials and methodsIn total, 265 image pairs were obtained from 53 patients who underwent extreme hypofractionated radiotherapy to a dose of 35 Gy in five fractions on standard linear accelerators. Position verification was obtained with orthogonal X-rays before and after treatment and were used to determine intra-fraction prostate displacement.ResultsThe mean intra-fraction prostate displacements were ?0.03 ± 0.61 mm (one standard deviation), 0.21 ± 1.50 mm and ?0.86 ± 1.73 mm in the left–right, superior–inferior and anterior–posterior directions, respectively. The mean intra-fraction displacement during the first two fractions was moderately correlated with the displacement in the remaining three fractions, with correlation coefficients of 0.63 (95% confidence interval 0.43–0.77) and 0.47 (95% confidence interval 0.22–0.65) in the superior–inferior and anterior–posterior directions, respectively. There was no significant correlation in the left–right direction with a coefficient of –0.04 (95% confidence interval ?0.31–0.23).ConclusionsThe mean intra-fraction prostate displacement during a course of extreme hypofractionated radiotherapy is small. A strategy using the first two fractions to predict future displacements >5 mm warrants further validation.     

基于MRI动态图像观察吞咽时器官动度对头颈部肿瘤调强放疗靶区影响

目的 利用MRI技术连续采集头颈部肿瘤患者吞咽时图像,观察并测量软腭、舌、喉的运动规律及最大活动度。方法 随机选取2018年7月-10月在中国医学科学院肿瘤医院接受调强放疗的原发头颈部恶性肿瘤20例患者,其中男17例、女3例,中位年龄58.5岁(28~78岁)。20例患者中鼻咽癌7例,口腔癌3例,口咽癌5例,下咽癌3例,鼻腔鼻旁窦2例。根据AJCC第八版分期Ⅰ-Ⅱ期患者2例,Ⅲ期8例,Ⅳ期10例。结果 吞咽时软腭向上移动移动距离为(1.06±0.31) cm且服从正态分布,向后移动距离为(0.83±0.24) cm且近似正态分布。舌体向后移动距离为(0.77±0.22) cm,且服从正态分布。含压舌板行图像采集患者舌上移位移为0,无压舌板患者舌体中位上移距离为1.23 cm (0.59~1.41 cm)。喉向上移动距离为(1.14±0.22) cm且服从正态分布,向前移动的中位距离为0.4 cm (0.27~0.90 cm)。结论 吞咽运动有可能发生于头颈部肿瘤患者放疗过程中,并引起大体肿瘤体积(GTV)及周围正常组织移动;因此在制定放疗计划时应注意GTV至PGTV的个体化外放距离,以保证肿瘤处方剂量。     

C-RAD Catalyst HD系统在乳腺癌保乳术后调强放疗中实时监测运动位移的剂量学研究

目的:分析光学体表监测系统C-RAD Catalyst HD在放疗中实时监测乳腺癌患者的体表运动位移，给出使用C-RAD Catalyst HD系统应当设定的建议运动阈值。方法:以C-RAD Catalyst HD系统实时监测乳腺癌患者体表运动位移数据为参考，分析其平移方向上的运动位移区间占比，模拟患者运动规律将不同位移等中心代入患者的QA计划中读取剂量学参数。结果:在Y（头脚）与Z（前后）的正方向上位移的计划，计划靶区的D2%、HI呈线性递增趋势，计划靶区的D98%、V95%、CI及危及器官的剂量学参数呈线性递减趋势，且危及器官的剂量学参数均在临床可接受范围之内；在负方向上位移的计划，计划靶区剂量变化趋势和危及器官的剂量学参数均呈线性递增趋势。计划靶区不符合临床处方剂量要求的参数:正方向上位移超过3 mm时计划靶区的V95%；正方向上位移超过5 mm时计划靶区的D2%；负方向上位移超过4 mm时计划靶区的D2%、V95%。超出剂量参考限值的危及器官剂量学参数:负方向上位移超过3 mm时患侧肺的Dmean、V5 Gy和左侧乳腺癌患者心脏的V40 Gy;超过4 mm时健侧乳腺的Dmean、左侧乳腺癌患者心脏（Dmean、V5 Gy、V30 Gy），右侧乳腺癌患者（心脏的Dmean、肝脏的V5 Gy）;超过5 mm时患侧肺的V20 Gy。结论:使用C-RAD Catalyst HD系统监控乳腺癌保乳术后放疗患者在治疗过程中的运动位移时，建议设定3 mm的运动阈值控制加速器束流。     

Geometric and dosimetric variations of ICRU bladder and rectum reference points in vaginal cuff brachytherapy using ovoids

PURPOSE: To investigate the interfractional geometric and dose variations of rectal reference point (R) and bladder reference point (BL) doses in patients receiving vaginal cuff irradiation using high-dose-rate brachytherapy with 2 ovoids and the change in calculated radiobiologic-equivalent dose of R and BL. METHODS: ICRU-38 R and BL reference doses were calculated. The variation in positions of ovoids, R, and BL were determined. Whether the magnitude of displacement shows a time trend and has an effect on calculated R and BL doses was evaluated. The relation between the ovoid diameter and both the magnitude of displacement and changes in R and BL doses was studied. Changes in radiobiologic-equivalent dose of rectum and bladder were determined. RESULTS: The average magnitude of displacements was 3.2 and 12.1 mm, showed no time trend, and no tendency to displacement in a certain direction. Mean changes in BL and R doses were 64-75 cGy and 47-58 cGy, respectively. There was a relation between neither ovoid size and displacement nor R and BL dose change. Dose and geometric variation showed no correlation (p > 0.05). The differences in radiobiologic-equivalent dose of R and B were not significant. CONCLUSION: Although there were significant differences in R and B position and doses among the fractions, the magnitudes of dose changes were relatively small, and total calculated radiobiologic-equivalent doses of R and B did not change significantly. According to the results of this study, the benefit of treatment planning is limited to supporting treatment planning in each fraction.     

基于4DCT的食管癌靶区运动的初步研究

目的 探讨4DCT下的平静呼吸状态食管癌靶区运动特征。方法 20例食管癌患者在平静呼吸状态下采用4DCT采集食管肿瘤运动信息,勾画GTV,测量并记录每个GTV等中心点坐标、体积,并计算中心点在不同呼吸时相的移动距离及体积变化情况。结果 同段食管癌靶区中心在头脚方向位移(0.521±0.319) cm,较左右方向的(0.169±0.083) cm、前后方向的(0.167±0.095) cm均大(P均<0.05)(颈段P=0.009;胸上段P=0.016;胸中段P=0.000)。不同段食管癌靶区中心在同一方向最大位移不同(左右P=0.023;前后P=0.212;头脚P=0.007)。各呼吸时相中食管癌运动规律并不完全一致,以T0时相为基准时相,食管癌GTV等中心点在T50时相时各三维方向上的位移最大。呼气末与吸气末食管靶区体积无变化(P=0.313)。结论 同段食管癌靶区在不同方向运动幅度不同,不同段病灶同一方向的运动幅度也不同,行精确放疗时应综合考虑。对于颈段及胸中上段食管癌,依据吸气末和呼气末融合图像获得ITV可行。颈段及胸中上段食管靶区在呼吸周期中形变不明显。     

Evaluation of intrafraction prostate motion tracking using the Clarity Autoscan system for safety margin validation

BackgroundThe purpose of the study was to monitor intrafraction prostate motion in real-time using transperineal 4D ultrasound (TPUS) and analyze trajectories to validate clinical safety margins.Methods401 trajectories of US monitoring sessions were retrospectively evaluated for 14 patients treated for prostate cancer. The Elekta Clarity Autoscan system was used for intrafraction monitoring along the 3 directions: superior-inferior (SI), left-right (LR) and anterior-posterior (AP).ResultsThe intrafraction monitoring resulted in a mean prostate displacement of (-0.06 ± 0.49) mm, (-0.09 ± 0.61) mm and (-0.01 ± 0.78) mm in the SI, LR and AP directions, respectively. Even though large deviations up to 8 mm were detected, the frequency of occurrence was less than 0.1%. The prostate moved within ±2 mm in 99%, 98.1%, and 96.6% of the treatment time in the SI, LR and AP directions, respectively. During 100 s of monitoring, the median displacement increased from 0.2 mm to 0.8 mm and the maximum displacements increased from 5.2 mm to 7.8 mm. The majority of displacement values (99%) were within the clinical safety margins which ensures a good target coverage.ConclusionsThe largest variation of intrafraction prostate displacement was observed along the AP direction. Throughout most of the treatment time, the prostate moved within a few millimeters. The extent of prostate displacement increased for longer monitoring times. During most of the tracking time, the prostate position was within the clinically safety margins.     

部分乳腺外照射不同呼吸状态银夹构成几何体中心位移比较

目的 探讨自主呼吸控制(ABC)部分乳腺外照射(EB-PBI)不同呼吸状态选定银夹位移对术腔中全部银夹所构成几何体中心位移的影响。方法 对本院行保乳术后ABC辅助EB-PBI的 27例患者行适度深吸气呼吸控制(mDIBH)、深呼气呼吸控制(DEBH)、自由呼吸(FB)状态CT模拟定位扫描,并分别获得图像各2套。基于每套CT图像勾画术腔中全部银夹并形成以银夹为顶点的不规则几何体。图像间在自动配准基础上基于选定银夹手动配准,获得自动加手动配准时几何体中心三维方向上位移。用Kruskal-Wallis H及Kolmogorov-Smirnov Z 检验位移差异。结果 mDIBH与mDIBH、FB与FB、DEBH与DEBH状态间几何体中心三维方向位移相似(H=0.00~1.76,P=0.184~0.954),而mDIBH与DEBH状态间则不同(Z=11.31~23.00,P=0.000~0.001)。mDIBH与mDIBH和mDIBH与DEBH间、FB与FB和mDIBH与DEBH间、DEBH与DEBH和mDIBH与DEBH间,4个选定银夹配准所对应的几何体中心位移在前后、头脚方向差异均不同(Z=4.76~25.54,P=0.000~0.029)。结论 ABC辅助EB-PBI放疗分次内同一呼吸状态间银夹构成几何体各方向位移均相似,而两种极端呼吸状态间前后方向及头脚方向位移均不同。     

四维CT测量平静呼吸下原发胸段食管肿瘤运动的初步研究

目的 采用四维CT(4DCT)探讨平静呼吸状态下原发食管肿瘤的运动特征.方法 16例原发食管癌患者在平静呼吸体位下采用4DCT采集原发灶运动信息,并在每个患者10套图像上勾画大体肿瘤体积(GTV1～GTV10),测量并记录每个中心点坐标,计算每个中心点在不同呼吸时相的移动距离,分析胸部各段食管肿瘤运动特征.结果 呼气相和吸气相双肺、食管癌原发灶体积分别为2993.50 cm3和3362.12 cm3(t=12.36,P=0.000)、35.00 cm3和34.84 cm3(t=-0.61,P=O.546).食管癌靶区中心在左右、前后、头脚方向总移动峰值分别为0.65、0.55、2.03 mm(F=41.14,P=0.000),胸上段的分别为0.50、0.48、1.23 mm(F=5.45,P=0.017),胸中段的为0.68、0.62、1.97 mm (F=27.74,P=0.000),胸下段的为0.72、0.38、3.05 mm(F=15.61,P=0.000).结论 胸段食管肿瘤左右、前后方向运动幅度较小,头脚方向运动幅度较大,不同段病灶运动也有所不同.

Abstract：

Objective To investigate the motion characteristics of primary thoracic esophageal carcinoma with four-dimensional computed tomography(4DCT).Methods Sixteen patients with primary thoracic esophageal carcinoma received respiratory gated 4DCT imaging,mapping the GTV1-GTV10 on every patient's each subsequent CT image of 10 images in the full-respiratory phase,and measuring the displacement of each centre of GTV.These displacements and directions were analyzed on different segments of esophagus.Results The mean total lung volume and GTV volume was 2993.5 cm3,35.00 cm3 and 3362.12 cm3,34.84 cm'respectively on end-expiration and end-inspiration phases(t=12.36,P=0.000and t=-0.61,P=0.546).The total mean peak to peak displacement of GTV were 0.65 mm,0.55 mm,and 2.03 nnn in x,y-and z-axis direction,respectively(F=41.14,P=0.000).The motion in x-axis,y-axis and z-axis were 0.50 mm,0.48mm,1.23 mm in the upper segment(F=5.45,P=0.017),0.68 mm,0.62 mm,1.97 mm in the middle segment(F=27.74,P=0.000),0.72 mm,0.38 mm,3.05 mm in the lower segment,respectively(F=15.61,P=0.000).Conclusions The displacement of tumor in z axis is more notable than x-,y-axis in thoracic esophageal carcinoma.The displacement of tumor x-,y-and z-axis is different in different segment of thoracic esophageal carcinoma.