18F-FDG PET/CT在子宫颈癌放疗靶区勾画中的价值

目的 探讨18F-FDG PET/CT在子宫颈癌放疗靶区勾画中的价值.方法 收集2015年3月至2016年10月经病理学检查证实为子宫颈鳞癌Ⅲb期患者33例,由3名放疗医师分别基于单纯CT和PET/CT融合图像勾画原发病灶大体肿瘤靶区体积(gross target volume,GTV),比较不同医师所勾画靶区的差异.结果 3名医师在单纯CT和PET/CT融合图像下定义的GTV比较差异均有统计学意义(P＜0.001).不同医师定义GTVCr差异有统计学意义(F=4.28,P＜0.001),但GTVPERT-CT差异无统计学意义(F=0.21,P=0.81).3位医师应用PET/CT图像勾画的肿瘤靶区体积变异减小(7.75 cm3 vs 24.50 cm3).结论 PET/CT融合图像可以提高靶区勾画的准确性.     

基于MRI/CT融合的高级别胶质瘤术前、后放疗靶区勾画的对比研究

目的探讨术后放疗对高级别胶质瘤的临床疗效。方法对40例术后病理检查证实为高级别胶质瘤患者,术后2～4周内行放射治疗,均行MRI/CT定位,随机分为2组实施放疗。一组以术前MRI与术后CT（MRI术前/CT术后）融合为参照勾画靶区;另一组以术后MRI与术后CT（MRI术后/CT术后）融合为参照勾画靶区。随访复发时间和部位,评价两组疗效。结果 MRI术前/CT术后组平均复发时间及生存时间较MRI术后/CT术后组长,有统计学意义,MRI术后/CT术后组边缘复发及野外复发例数明显多于MRI术前/CT术后组。结论以MRI术前/CT术后融合为参照勾画靶区更精准,可明显提高高级别胶质瘤患者的生存率。     

PET/CT用于肿瘤放疗计划靶区勾画的相关问题

PET/CT用于精确放疗靶区勾画时,目前存在诸多不确定因素。主要包括以下几个方面：PET/CT扫描条件和影像融合方式;谁来勾画靶区以及采取的勾画方式;靶区勾画阈值的选择;针对PET和CT靶区范围差异的靶区确立原则。正因为在许多方面尚无法达成统一的共识,所以,各研究机构和治疗中心更应有谨慎和严格的质量控制程序和标准。     

CT与MR图像融合在鼻咽癌放射治疗大体肿瘤靶区勾画中的应用

目的探讨CT与MR图像融合在鼻咽癌放射治疗大体肿瘤靶区(GTV)勾画中的临床应用价值。方法40例鼻咽癌患者均在1周内分别进行CT和MR扫描。全部CT和MR图像传送至荷兰核通公司PLATO放射治疗计划系统,进行图像融合。由4位有经验的放疗科医师对CT靶区和CT与MR融合图像大体肿瘤靶区(GTV)进行勾画及评价分析。结果经t检验,融合图像对GTV的显示明显优于单独CT图像。医师对CT-MR融合靶区勾画一致性较好。结论CT-MR图像融合技术有利于鼻咽癌靶区的确定,从而提高临床医师对鼻咽癌大体肿瘤靶区(GTV)进行勾画的准确率,有利于患者的诊治。     

SPECT/CT三维融合重建技术指导鼻咽癌放疗靶区勾画

目的:常规放疗靶区勾画一般参考MRI和CT图像,对颅底局部小结构骨侵犯的敏感性较低.SPECT/CT三维融合重建技术能准确显示骨局部侵犯.本研究尝试利用SPECT/CT三维融合重建技术指导勾画鼻咽癌放疗靶区,提高鼻咽癌(nasopharyngeal carcinoma,NPC)患者局部控制率.方法:对本院近1年来32例...     

PET/CT在肿瘤放射治疗计划设计中的应用进展

0 引言 1999年,匹兹堡大学Townsend等[1]首先报道了他们研制的PET/CT:将PET与具有高空间分辨率的螺旋CT安装在同一机架中,一次扫描可获得PET、CT及PET与CT的融合图像,达到取长补短、信息互补的目的,使PET的功能性信息与CT的形态学信息通过工作站准确融合,以更准确地完成定位与定量诊断[2].2000年,PET/CT(positron emission eomography/ computed tomography,PET/CT)在北美放射学年会(RSNA)正式问世,其后众多学者对PET/CT在恶性肿瘤的筛查、诊断及分期做了大量的研究,结论是尽管应用的成本较高,价格昂贵,并且可能会有假阴性的结果出现,但PET/CT仍是用于肿瘤筛查、诊断和分期的一个非常好的工具[3-11].PET图像在辅助分期及转移预期方面的应用,会强烈影响治疗策略的选择[10],甚至有一些患者会因此而避免不必要的开胸手术[11].近些年来,随着科学技术的突飞猛进,该设备的应用数量逐步增加,其应用范围也从最初的临床诊断、检查和(或)研究工作扩展至肿瘤放射治疗的定位及治疗计划设计领域.     

CT/MRI影像融合对肺癌脑转移放射治疗靶区勾画的影响

背景与目的脑转移瘤靶区勾画的准确性一直是放射治疗的关键,CT/MRI融合技术提供了可行的方法 ,本研究旨在探讨CT/MRI图像融合技术在肺癌脑转移靶区勾画中的作用。方法将31例肺癌脑转移患者的增强CT和MRI图像传送至图像处理工作站,分别在CT和CT/MRI融合图像上勾画GTV,比较勾画后的GTV体积,分析最大平均误差及瘤周水肿对靶区勾画的影响。结果 CT/MRI融合图像上勾画的GTV明显小于CT图像上勾画的GTV;瘤周水肿对靶区勾画存在明显影响。结论 CT/MRI图像融合技术可以提高肺癌脑转移靶区勾画的准确性。     

CT/MR融合图像在鼻咽癌三维适形放疗大体肿瘤靶区勾画中的应用

[目的]探讨CT与CT/MR图像融合在鼻咽癌三维适形放疗大体肿瘤靶区(GTV)勾画中的应用价值。[方法]80例初治鼻咽癌患者随机分为研究组(A组)和对照组(B组)。B组(n=40)单纯应用CT扫描定位,由4名放疗医师根据CT图像按ICRU50号报告要求确定GTV。A组(n=40)在同一固定体位下,使用同一扫描条件(FOV、层厚、层间距)分别作CT、MR扫描,同样由4名放疗医师应用CT/MR图像融合技术按ICRU50号报告要求确定GTV。比较两组不同GTV应用于临床治疗后的1、3、5年生存率和野外复发率。[结果]CT/MR融合图像对GTV的显示明显优于单独CT图像。两组1、3、5年总生存率比较差异均无显著性(P>0.05)。研究组3、5年野外复发率较对照组有下降趋势(2.5%vs10%,5%vs15%),但差异无显著性(P>0.05)。[结论]CT与MR图像融合有助于提高鼻咽癌肿瘤靶区勾画的精确性,可以最大限度减少肿瘤靶区的遗漏,并可能降低野外复发率。     

脑胶质瘤靶区勾画的进展

脑胶质瘤是最常见的颅内原发性肿瘤,约占全部脑肿瘤的35％-60％。其治疗以外科手术为主,但由于肿瘤侵袭转移的生物学特性,手术常难以彻底切除。另外对于部分肿瘤诊断明确而不适合外科手术的病人,放射治疗则占有重要地位。精确放射治疗包括三维适形调强放疗是近年来发展的一项崭新的放射治疗技术。与常规放疗相比,     

The Dilemma of Target Delineation with PET/CT in Radiotherapy Planning for Malignant Tumors

Currently there are many unanswered questions concerning contouring a target with PET/CT in radiotherapy planning.Who should contour the PET volume-the radiation oncologist or the nuclear medicine physician?Which factors will contribute to the dual-observer variability between them?What should be taken as the optimal SUV threshold to demarcate a malignant tumor from the normal tissue?When the PET volume does not coincide with the local area CT findings,which portion should be contoured as the target?If a reginal lymph node draining area or a remote region is shown to be PET positive but CT negative,or PET negative but CT positive,how is the target identified and selected?Further studies concerning the relationship between PET/CT and the cancerous tissue are needed.The long-term clinical results showing an increased therapeutic ratio wil finaly verify the applicability of guidelines to contour the target with PET/CT in radiotherapy planning.     

Variability of gross tumor volume delineation in head-and-neck cancer using CT and PET/CT fusion

PURPOSE: To assess the need for gross tumor volume (GTV) delineation protocols in head-and-neck cancer (HNC) treatment planning by use of positron emission tomography (PET)/computed tomography (CT) fusion imaging. Assessment will consist of interobserver and intermodality variation analysis. METHODS AND MATERIALS: Sixteen HNC patients were accrued for the study. Four physicians (2 neuroradiologists and 2 radiation oncologists) contoured GTV on 16 patients. Physicians were asked to contour GTV on the basis of the CT alone, and then on PET/CT fusion. Statistical analysis included analysis of variance for interobserver variability and Student's paired sample t test for intermodality and interdisciplinary variability. A Boolean pairwise analysis was included to measure degree of overlap. RESULTS: Near-significant variation occurred across physicians' CT volumes (p = 0.09) and significant variation occurred across physicians' PET/CT volumes (p = 0.0002). The Boolean comparison correlates with statistical findings. One radiation oncologist's PET/CT fusion volumes were significantly larger than his CT volumes (p < 0.01). Conversely, the other radiation oncologist's CT volumes tended to be larger than his fusion volumes (p = 0.06). No significant interdisciplinary variation was seen. Significant disagreement occurred between radiation oncologists. CONCLUSION: Significant differences in GTV delineation were found between multiple observers contouring on PET/CT fusion. The need for delineation protocol has been confirmed.     

Consequences of additional use of PET information for target volume delineation and radiotherapy dose distribution for esophageal cancer

Background and purpose

To determine the consequences of target volume (TV) modifications, based on the additional use of PET information, on radiation planning, assuming PET/CT-imaging represents the true extent of the tumour.

Materials and methods

For 21 patients with esophageal cancer, two separate TV’s were retrospectively defined based on CT (CT-TV) and co-registered PET/CT images (PET/CT-TV). Two 3D-CRT plans (prescribed dose 50.4 Gy) were constructed to cover the corresponding TV’s. Subsequently, these plans were compared for target coverage, normal tissue dose-volume histograms and the corresponding normal tissue complication probability (NTCP) values.

Results

The addition of PET led to the modification of CT-TV with at least 10% in 12 of 21 patients (57%) (reduction in 9, enlargement in 3). PET/CT-TV was inadequately covered by the CT-based treatment plan in 8 patients (36%). Treatment plan modifications resulted in significant changes (p < 0.05) in dose distributions to heart and lungs. Corresponding changes in NTCP values ranged from −3% to +2% for radiation pneumonitis and from −0.2% to +1.2% for cardiac mortality.

Conclusions

This study demonstrated that TV’s based on CT might exclude PET-avid disease. Consequences are under dosing and thereby possibly ineffective treatment. Moreover, the addition of PET in radiation planning might result in clinical important changes in NTCP.     

GTV spatial conformity between different delineation methods by FDG PET/CT and pathology in esophageal cancer

Purpose

To find optimal threshold of length and GTV delineation for esophageal cancer using ¹⁸FDG PET/CT.

Materials and methods

Sixteen patients with esophageal carcinoma underwent surgery. For each patient, six GTVs were defined. GTV_CT was based on CT data alone. GTV_20%, GTV_40%, GTV_2.5 and GTV_40%M were generated by PET/CT, using SUV_bgd + 20%(SUV_max(slice) − SUV_bgd), SUV_bgd + 40%(SUV_max(slice) − SUV_bgd), 2.5 and 40%SUV_max(total) as thresholds. GTV_path was derived from pathology. Lengths of GTVs were recorded as L_CT, L_20%, L_40%, L_2.5,L_40%M and L_path, respectively. The former five GTVs/lengths were compared with GTV_path/L_path by means of a conformity index CI/CI′, which is the square of intersection of two GTVs/lengths divided by their product.

Results

Mean L_CT, L_20%, L_40%, L_2.5, L_40%M and L_path were 6.30 ± 2.69, 5.55 ± 2.48, 6.80 ± 2.92, 6.65 ± 2.66, 4.88 ± 1.99 and 5.90 ± 2.38 cm. Mean , , , and were 0.68 ± 0.16, 0.84 ± 0.17, 0.76 ± 0.14, 0.78 ± 0.15 and 0.80 ± 0.11. and was significantly superior to (P < 0.05). Mean GTV_CT, GTV_20%, GTV_40%, GTV_2.5, GTV_40%M and GTV_path were 29.16 ± 18.56, 18.75 ± 12.37, 12.52 ± 8.08, 22.69 ± 14.84, 9.18 ± 5.96 and 28.16 ± 17.02 cm³. Mean CIs increased significantly from CI_40%&path(0.27 ± 0.09) and CI_40%M&path(0.28 ± 0.08) < CI_20%&path(0.52 ± 0.16) and CI_2.5&path(0.52 ± 0.20) < CI_CT&path(0.77 ± 0.17).

Conclusions

The SUV_bgd + 20%(SUV_max(slice) − SUV_bgd) method optimally estimated gross tumor length, but only reached an unsatisfactory CI for GTV. Due to possible motion factor enveloped in PET images and lack of histopathologic transverse reference, the information from both PET and CT should be referred to complementarily when delineating GTV.     

Correlation of PET standard uptake value and CT window-level thresholds for target delineation in CT-based radiation treatment planning

PURPOSE: To develop standardized correlates of [18F]fluoro-2-deoxy-d-glucose positron emission tomography (FDG-PET) standard uptake value (SUV) to computed tomography (CT)-based window and levels. METHODS AND MATERIALS: Nineteen patients with non-small-cell lung cancer who underwent imaging with positron emission tomography (PET) and CT were selected. A method of standardizing SUV within CT planning software was developed. A scale factor, determined by a sensitivity calibration of the PET scanner, converts voxel counts to activity per gram in tissue, allowing SUVs to be correlated to CT window and levels. A method of limiting interobserver variations was devised to enhance "edges" of regions of interest based on SUV thresholds. The difference in gross tumor volumes (GTVs) based on CT, PET SUV >or= 2.5, and regions of 40% maximum SUV were analyzed. RESULTS: The mean SUV was 9.3. Mean GTV volumes were 253 cc for CT, 221 cc for SUV >or= 2.5, and 97 cc for SUV40%Max. Average volume difference was -259% between >or=2.5 SUV and CT and -162% between SUV40%Max and CT. Percent difference between GTV >or= 2.5 SUV and SUV40%Max remained constant beyond SUV > 7. For SUVs 4-6, best correlation among SUV thresholds occurred at volumes near 90 cc. Mean percent change from GTVs contoured according to CT (GTV CT) was -260% for GTV2.5 and -162% for GTV40%Max. Using the SUV40%Max threshold resulted in a significant alteration of volume in 98% of patients, while the SUV2.5 threshold resulted in an alteration of volume in 58% of patients. CONCLUSIONS: Our method of correlating SUV to W/L thresholds permits accurate displaying of SUV in coregistered PET/CT studies. The optimal SUV thresholds to contour GTV depend on maximum tumor SUV and volume. Best correlation occurs with SUVs >6 and small volumes <100 cc. At SUVs >7, differences between the SUV threshold filters remain constant. Because of variability in volumes obtained by using SUV40%Max, we recommend using SUV >or= 2.5 for radiotherapy planning in non-small-cell lung cancer.     

CT-MR图像融合技术对勾画鼻咽癌靶体积影响

目的 探讨CT、MR及CT与MR图像融合技术对鼻咽癌靶区勾画的准确性、可行性.方法 共搜集36例鼻咽癌患者资料入组.所有患者治疗前均先在体表不同部位用铅点标记后行CT模拟定位扫描,行MR扫描前同一个位置也同样标记.将图像传输至Tomcon工作站用软件进行图像融合,并用LandMark方法 进行配准,经我科放疗医师及放射科医师对配准进行评价和靶区勾画.对CT、MR及CT-MR图像数据分别进行比较.将试验对象按是否有斜坡破坏分两组并分别比较.按病变程度分层分析分为早期(T_1+T_2期)和进展期(T_3+T_4期)并分别比较.结果 GTV_(CT)、GTV_(MR)GTV_(CT-MR)平均值分别为27.60、30.99、31.71 cm~3(F=7.48,P=0.001),其中GTV_(CT)与GTV_(MR)(q=2.54,P=0.016)、GTV_(CT)与GTV_(CT-MR)(q=3.10,P=0.004)不同,GTV_(MR)与GTV_(CT-MR)相似(q=1.31,P=0.199).有斜坡破坏的GTV_(CT)、GTV_(MR)、GTV_(CT-MR)平均值分别为35.65、42.70、44.22 cm~3(F=14.13,P=0.000),无斜坡破坏的分别为20.79、20.46、21.18 cm~3(F=0.18,P=0.832).早期组GTV_(CT)和GTV_(CT-MR)相似(t=-0.66,P=0.514),进展期组的不同(t=-2.17,P=0.036).结论 CT与MR图像融合有助于提高临床靶区勾画的精确性,特别对斜坡侵犯的诊断及勾画上具有优势,在局部晚期患者具有明显优势,为临床医师提供了更多的理论依据.     

CT与MR多序列融合指导胶质瘤靶区勾画

目的:探讨CT与MR图像融合在脑胶质瘤术后放疗靶区勾画中的应用价值。方法:收集首诊为脑胶质瘤的30例患者进行术后IMRT,基于颅内外标记法的图像配准融合算法进行CT-MR图像融合,并分别根据CT图像及融合图像由资深放疗医师勾画靶区及危及器官,分组进行t检验比较其体积差异。计算CT及CT-MR图像上相应标记点的距离,并计算其体积重合度及中心位置距离。结果:采用颅内外标记法进行图像融合有着较高融合精度,融合误差均小于2 mm。Ⅲ-Ⅳ级胶质瘤组GTVCT比GTVMR+CT显著性减少,分别为GTVCT:（72.23±36.74） cm3,GTVMR+CT:（104.23±32.64） cm3（P=0.043<0.05）;CTVCT比CTVMR+CT也显著性降低,分别为CTVCT:（244.24±65.37） cm3,CTVMR+CT:（346.39±51.54） cm3 （P=0.047<0.05）。CT图像与融合图像的CTV中心位置变化最大,为（7.87±11.54） mm,其次为GTV、脑干,视交叉中心位置变化最小。结论:CT-MR图像融合有助于减少靶区勾画差异性,特别是对有水肿区存在及术后肿瘤残存者价值更大。     

PET/CT在甲状腺癌中的应用

目的:探讨正电子发射型计算机断层成像(PET/CT)在甲状腺癌原发灶、转移灶的诊断,复发检测中的应用价值。方法:回顾性分析应用PET/CT检查的40例甲状腺癌患者的临床资料,将其显像结果与病理,部分与Bus、CT比较。结果:PET/CT显像结果与病理结果符合率极高,对原发灶的诊断灵敏度100%,特异度87.5%,对转移灶的诊断灵敏度92.1%,特异度92.0%,优于CT和彩超。结论:PET/CT对甲状腺癌原发灶、转移灶的诊断,临床分期,甲状腺癌术后观测疗效、监测复发具有明显的优势。     

质子磁共振波谱在脑胶质瘤中的临床应用

质子磁共振波谱(HMRS)是研究人体器官、组织代谢、生化改变及化合物定量分析的惟一无创方法,对脑胶质瘤的诊断、分级、鉴别诊断、放射治疗靶区勾画及预后评价具有重要作用.