腹部转移性肿瘤CT模拟定位立体定向适形放疗的剂量分布优势

目的 :评价腹腔转移瘤CT模拟定位立体定向适形放疗的剂量分布优势。方法 :选择腹腔转移瘤病人共 38例 ,在CT定位并确定计划靶区 (planningtargetvolume,PTV)后 ,采用三维适形治疗计划系统 (TPS) ,以尽量小的治疗区 (treatedvolume,TV)完全包绕PTV区的原则 ,设计适形野照射计划 ,利用TPS的剂量、体积计算功能评价本组病例适形野立体定向放射治疗的剂量分布特点和优势。结果 :38例患者PTV内平均最大剂量为 ( 115 .30± 5 .2 3) % ,最小剂量为 ( 88.0 0±2 32 ) % ,平均剂量为 ( 99.2 0± 1.2 0 ) % ;PTV区相应水平膀胱、肾脏、脊髓、肝脏等邻近正常重要器官的平均最大剂量分别为 ( 6 5 .4 5± 2 .2 3) %、( 35 .2 2± 1.32 ) %、( 6 0 .32± 1.13) %、( 2 6 .32± 2 .5 7) % ;平均剂量分别为 ( 30 .2 0± 1.6 6 ) %、( 2 6 .12±31 12 ) %、( 2 9.4 2± 1.0 2 ) %、( 15 .32± 2 .0 2 ) % ;(TV PTV) /TV值为 ( 7.2 2± 2 .32 ) %。结论 :采用适形立体定向放射治疗腹腔转移肿瘤 ,TV高度适形PTV ,从而使PTV受到高剂量照射的同时大大减少了邻近正常器官受照剂量     

CT模拟定位在食管癌放射治疗的临床应用

目的　探讨CT模拟定位在食管癌放射治疗的临床应用价值。方法　对 49例食管癌应用CT模拟定位技术进行定位扫描 ,将扫描数据传输至放射治疗计划系统计算机工作站 ,比较以食管腔为中心和以实体肿瘤为中心设置照射野的 90 %等剂量线分布情况。结果　以CT图像所示的非对称性肿瘤占 85 .7% ,以实体肿瘤为中心设置照射野的 90 %等剂量线分布能 10 0 %包全肿瘤病灶。结论　CT扫描能更多显示有治疗意义的征象 ,基于CT模拟定位的放射治疗计划使食管癌放疗照射野的设置更加精确合理     

螺旋CT在食管癌三维适形放射治疗中的应用价值

目的:探讨在三维适形放射治疗临床Ⅲ期食管癌中螺旋CT增强扫描应用价值.材料和方法:对Ⅲ期食管癌86例,螺旋CT增强5mm层厚连续扫描,在STAR2000治疗计划机中建立3D模型,依次勾画GTV,CTV,最后确定计划靶体积(PTV)及受保护器官,根据不同需要确定照射野.治疗后行螺旋CT增强扫描对照.结果:螺旋CT增强扫描确定PTV较常规X线模拟定位准确性高,可准确将瘤体与正常组织区分,提高照射野准确性,减少正常组织受照射范围,降低放疗反应的发生率.其治疗总有效率达95.3%,放射性肺炎发生率8.8%,出血穿孔1.5%,肺间质纤维化13.9%.结论:螺旋CT增强扫描是食管癌行之有效的定位方法,利于3DCRT计划设计,同时也是食管癌3DCRT治疗后随访的有效方法.     

鼻咽癌放射治疗的CT模拟定位技术探讨

目的　探讨鼻咽癌放射治疗最佳治疗定位技术。　方法　用 CT模拟定位、三维治疗计划系统,加速器两个等中心、适形射野设计治疗计划并用于患者的放射治疗。　结果　靶区整体剂量分布为处方剂量的 113%~97%, 野之间衔接处剂量可控制在处方剂量的±5%,临床初步疗效及放射反应观察表明效果良好。　结论　鼻咽癌放射治疗使用 CT模拟定位治疗技术靶区整体剂量分布满意,照射技术简便。     

CT模拟定位在食管癌放射治疗中的临床应用

目的：探讨CT模拟定位在食管癌放射治疗的临床应用价值。方法：45例食管癌病例行CT模拟定位,全部病例以肿瘤中心为照射野的等中心点,照射野长度为肿瘤上、下缘放大3.5 cm,野宽为肿瘤边缘外放1.0 cm,总剂量为DT 60 Gy～70 Gy,2 Gy/次,5次/周。结果：CT模拟定位可以和X线模拟定位一样完成从定位到做体表标记的全过程。45例病例近期疗效显示完全缓解率达60.00%（27/45）,部分缓解率为40.00%（18/45）。结论：CT模拟定位可以准确提供食管癌病变情况,利用CT模拟定位,可提供更多的原始信息和提高模拟精度。     

非共面布野方式的调强放射治疗泪腺腺样囊性癌

目的 改进调强放射治疗的照射野布野方法,在提高靶区剂量的同时,尽量减少患侧晶体及其他正常组织的受照射剂量,提高患者长期生存质量.方法 5例患有泪腺腺样囊性癌患者（左侧）,所有患者靶区均包括患侧眶左下壁和眶顶壁.布野方式采取以下三种：（1）常规共面均分9野;（2）非常规共面不均分5野;（3）非常规非共面不均分6野（以下分别简称为9野、5野和6野）.比较以上三种布野方式完成计划的剂量体积直方图（dose volume histogram,DVH）、剂量分布图及物理和生物学参数（最大、最小、平均剂量,适形指数（conformity indexes,CI）和等效均匀剂量（equivalent uniform dose,EUD）.结果 6野计划靶体积（planning target volume,PTV）的D98%、V95%分别比9野和5野增大1.3%、0.6%和11.4%、3.5%,D2%比5野小1%,CI及EUD无明显差别.对于危及器官（organ at risk,OAR）,6野除了脑干的Dmin略差于5野以外,其余均优于9野和5野.结论 从PTV和OARs所受剂量比对情况来看,非常规不均分6野明显具有剂量学优势,要优于其他两种方法.     

低熔点铅在Graves眼病放疗中的剂量学优势分析

目的 对低熔点铅(LML)和多叶光栅(MLC)两种照射野成形方法在眼眶放疗中的剂量学差异进行比较,以便使用晶体剂量更低的技术用于临床Graves眼病的治疗.方法 选择适于放疗的单、双侧Graves眼病患者各10例,采用相同的靶区勾画原则,计划靶区(PTV)处方剂量为2000cGy/10次,单侧组布野方法为3野(2个X线平野+1个电子线野),双侧组为4野(2个X线平野+2个电子线野),分别采用LML和MLC形成照射野.比较两种照射野成形方法的靶区适形指数(CI)和剂量体积直方图(DVH);采用免冲洗胶片和剂量分析软件分析两种方法形成半野照射野的有效半影区大小及其对晶体受量的影响.结果 MLC单侧组患侧晶体剂量为582±34cGy,健侧晶体剂量为160±22cGy,CI为0.69;双侧组左右晶体剂量分别为591±47cGy和585±52cGy,CI为0.67.LML单侧组患侧晶体剂量为252±45cGy,健侧晶体剂量为148±19cGy,CI为0.71;双侧组左右晶体剂量分别247±44、256±42cGy,CI为0.68.在X线能量设定为4MV和8MV时,半野照射野Scm×5cm,深度4cm,LML的有效半影区与MLC比较小约3mm.结论 用LML来形成小面积照射野可能更加适形,并可减小照射野半影,显著降低患者患侧晶体的受量.     

三维CT模拟定位在适形放疗的应用

目的：通过对三维CT模拟定位系统在临床的应用，评价其在适形放疗中的作用。方法：用CT机、激光定位系统、“魔十字”、三维计划系统和加速器共同完成对肿瘤病人的CT模拟定位和治疗计划的制定。结果：CT模拟定位可为靶区的确定、复杂多野照射、立体定向放疗提供更多的原始信息和更高的定位精度，治疗等中心与实际靶中心的误差小于2mm。结论：CT模拟定位可用于对大多数肿瘤病人的定位。     

宫颈癌复发放疗中不同照射方式的剂量学研究

目的针对宫颈癌复发病例,比较逆向调强(IMRT)、三维适形(3D-CRT)及超级伽玛刀弧形适形(SGS-CRT)三种照射方式的剂量学特点。方法对15例宫颈癌复发患者进行IMRT、3D-CRT及SGS-CRT计划设计,以包绕计划靶区(PTV)体积95%的等剂量线为处方剂量线,分别给予50Gy的处方剂量,分次方案均为2Gy×25次,根据剂量-体积直方图(DVH)评价三种照射方式中靶区和危及器官的剂量学特点。结果 3D-CRT的95%处方剂量包括靶区体积(99.9%±0.2%)高于IMRT(99.5%±0.5%)及SGS-CRT(99.3%±0.8%,P<0.05);SGS-CRT的靶区剂量梯度(85%±20%)明显高于IMRT(10%±7%)及3D-CRT(8%±5%,P<0.05);IMRT的适形指数(0.9±0.3)优于SGS-CRT(0.8±0.2,P<0.05),且SGS-CRT优于3D-CRT(0.7±0.5,P<0.05)。DVH显示,在10~30Gy之间,SGS-CRT膀胱平均受照体积(27.8%)明显低于IMRT(40.1%)和3D-CRT(57.4%,P<0.05);在5~45Gy之间,直肠平均受照射体积SGS-CRT(25.4%)明显低于IMRT(48.9%)和3D-CRT(73.2%,P<0.05);在小肠剂量分布上,三种照射方式无显著差异。结论在宫颈癌复发放疗中,SGS-CRT具有一定剂量学优势,值得在临床应用中进一步探讨。     

腮腺癌术后高危复发区放疗的不同治疗计划剂量学比较

目的 探讨腮腺癌术后高危复发区用何种照射方法可以更有效的使靶区剂量均匀及更好的保护危及器官.方法 对8例腮腺癌术后患者设计治疗计划,处方剂量为95%计划靶区(PTV)60 Gy/30次.对常规放疗、二维适形放疗(2D-CRT)、三维适形放疗(3D-CRT)和调强放疗(IMRT)等放射治疗技术的腮腺癌术后靶区进行放疗计划设计,分析比较各种治疗计划靶区适形度和在保护危及器官等方面的优劣.结果 在2D-CRT时,以计算点深度取3.5 cm,电子线能量采取12 MeV及X射线/电子射线(X/E)剂量比为1∶2时靶区的适形度和均匀度较好,危及器官的受量较低.与2D-CRT比较,常规放疗照射野能够较好地包括CT断层图像上勾画的靶区.与2D-CRT及3D-CRT相比,IMRT计划有最好的靶区适形度及均匀度,同时对危及器官有较好的保护作用.结论 X射线与电子线混合线束照射时,剂量计算点深度取3.5 cm左右、电子线能量采取12 MeV及X/E剂量比为1∶2时,靶区的适形度和均匀度较好,对正常组织的保护较好,但具体患者最好用计划系统来选择以上指标.常规放疗按解剖标志确定的照射野能够较好地包括三维靶区.IMRT计划的靶区适形度及均匀度最好,并且危及器官受量较低,在腮腺癌术后放射治疗中IMRT技术是值得推广并普及的放射治疗技术.     

Interindividual Variability of Lymph Drainages in Patients with Cervical Cancer

BACKGROUND AND PURPOSE: Lymph node metastases and the number of positive lymph nodes are important prognostic factors for patients with cervical cancer. The most important route is the lateral drainage via the obturator to the internal and external iliac and common iliac area. The risk for common iliac lymph node metastases is increased in patients with positive pelvic or paraaortic lymph nodes. Positive common iliac lymph nodes are associated with a poorer prognosis than positive pelvic lymph nodes excluding common iliac group. For radiation planning in patients with cervical cancer, lymph node regions at high risk for metastases have to be encompassed. Usually, standard fields are used with the upper field border on the fourth/fifth lumbar vertebra. The authors evaluated whether standard fields are sufficient for encompassing the common iliac lymph nodes. PATIENTS AND METHODS: Pretreatment computed tomographic (CT) images of 42 patients with cervical cancer were evaluated to locate the aortic bifurcation and the subsequent common iliac lymph drainage. Anatomy of the lymph drain was correlated with standard radiation portals. RESULTS: In 17/42 patients (40%) the aortic bifurcation lay superior to the upper field border. In an additional nine patients (21%) the bifurcation was located on the level of the upper field border. In 26/42 patients (62%) standard radiation fields encompassed the common iliac lymph nodes insufficiently. CONCLUSION: Common iliac lymph node metastases are found in up to 50% of patients with node-positive cervical cancer. The results of this study demonstrate an unsatisfactory coverage of the common iliac lymph drain by standard fields in most patients. Thus it is necessary to individualize the planning target volume and to include the whole common iliac vessels according to the patient's anatomy on radiation treatment planning CT in order to improve local control.     

Dose Escalation in Large Anterior Skull-Base Tumors by Means of IMRT

PURPOSE: To evaluate the feasibility and tolerance of dose escalation with stereotactic intensity-modulated radiotherapy (sIMRT) for skull-base tumors. PATIENTS AND METHODS: Between 01/2003 and 12/2004, twelve patients were treated. Nine were exclusively treated at the Novalis site with one planning target volume (PTV) field boost, three were administered boost IMRT treatment (two with each one PTV-shrinking field, one with single PTV) after conventional three-dimensional conformal radiotherapy. This resulted in 23 PTVs with a median volume of 93.63 cm3 (range, 88.58-125.88 cm3). Dose calculation was done by the pencil-beam algorithm. Median total doses of 66.6, 77.4, and 63.9 Gy were prescribed for sIMRT alone, sIMRT after 3-D conformal irradiation of the nasopharynx and cervical lymph nodes with 59.4 Gy, and for reirradiation, respectively. RESULTS: 95% isodose PTV coverage was reached in 86.5% (range, 80-93%). Homogeneity (Dmax/Dref) was 1.11, 1.09, and 1.08. Median total doses to 50% of chiasm, right and left optic nerve were 16.21, 16.82 and 10.23 Gy. 11/12 patients are locally controlled with a median follow-up of 11 months (range, 3-23 months), one has died of pulmonary embolism after cerebrospinal dissemination of retinal adenocarcinoma. CONCLUSION: SIMRT enables dose escalation to tumors located close to critical organs. Inverse planning for micro-multileaf collimator stereotactic irradiation is practicable in the daily routine irradiation program. SIMRT needs special verification and still, the following parameters have to be standardized: IMRT dose specification, dose maxima, length of radiation delivery time.     

Evaluation of the process of lumbo-aortic metastasis in carcinoma of the cervix uteri

Paraaortic lymph nodes involvement in patients with cervical carcinoma, even in less advanced stages, found in 100 cases examined, besides the data reported in literature, has driven the authors to locate, through the examination of lymphangiograms, the routes by which paraaortic metastases can occur. Authors pointed out different ways of invasion, besides the more common subsequent involvement going from pelvic to paraaortic nodes or from posterior channels that can lead to paraaortic spread without lesions in common iliac nodes. In detail lymphatic pathways have been opacified connecting distant nodal chains and finally external routes from external iliac lymph nodes directly to paraaortic chain.     

Inverse Treatment Planning and Stereotactic Intensity-Modulated Radiation Therapy (IMRT) of the Tumor and Lymph Node Levels for Nasopharyngeal Carcinomas Description of Treatment Technique, Plan Comparison, and Case Study

PURPOSE: Inverse treatment planning and intensity-modulated radiation therapy (IMRT) promise advantages in the treatment of tumors of the head and neck region. Currently published studies use IMRT only in the treatment of the primary tumor. In these studies, the lymph nodes of the neck were treated using conventional techniques. The feasibility of an IMRT technique which allows treatment of the complete target volume, including the primary tumor and lymph nodes, without a beam split is described. PATIENT AND METHOD: For inverse treatment planning, the KonRad planning system was used. The primary as well as the secondary PTV (bilateral lymph node levels) were treated with one intensity-modulated primary plan. To increase the dose in the primary PTV and suspicious lymph nodes, an intensity-modulated boost plan was performed. The "step and shoot" IMRT technique was used. A plan comparison between the described IMRT approach and an IMRT approach using a split-beam technique was performed focusing on the treatment time. A patient with a carcinoma of the nasopharynx was treated with curative intent by a combined radiochemotherapy. RESULTS: The median total dose to the primary PTV was 70 Gy, to suspicious lymph nodes > or = 66.0 Gy, and to the secondary PTV 52 Gy. The defined maximum doses to the organs at risk were not exceeded, and the median dose to the protected parotid gland amounted to 21 Gy. Comparison of the treatment time between both IMRT approaches revealed only a slightly shorter treatment time (1-3 min) for the split-beam IMRT technique without considering the remaining conventional treatment parts of the split-beam IMRT technique. The patient achieved a complete response, and 18 months after treatment no signs of recurrent disease are visible. CONCLUSIONS: IMRT allows the treatment of the target volumes with high doses combined with an excellent sparing of the organs at risk. The IMRT approach presented here makes the treatment of the whole target volume with a single-beam arrangement feasible and does not increase the treatment time compared to a split-beam IMRT technique. Treatment time was comparable to a conventional three-field technique combined with electrons. This IMRT technique can prevent over- or underdosage at field matchlines in the head and neck region and, moreover, is able to spare parotid glands and therefore better avoid xerostomia compared to conventional techniques.     

Intensity-modulated radiation therapy reduces the dose to normal tissue in T2N0M0 squamous cell carcinoma of the glottic larynx

The purpose of this paper was to compare intensity-modulated radiation therapy (IMRT) and conventional planning for T2N0M0 squamous cell carcinoma (SQCC) of the glottic larynx. Three patients with T2N0M0 SQCC are presented who were treated with IMRT. Conventional plans were also generated for comparison purposes. Isodose distributions and dose-volume histograms (DVHs) were generated for all the plans to evaluate the fitness of the plan as well as the differential benefit of IMRT vs. conventional treatment. The isodose distributions that were obtained by the IMRT plan are much more conformal to the planning target volume (PTV) and clearly show that less healthy tissue is subjected to a high-dose level, thus reducing toxicity. IMRT offers better comformality without compromising the PTV coverage and delivers less dose to normal tissues as compared to conventional radiation therapy in T2N0M0 SQCC of the glottic larynx. With an increase in conformality, it is expected to have an increase in the therapeutic ratio.     

Intensity-modulated radiation therapy reduces the dose to normal tissue in T2N0M0 squamous cell carcinoma of the glottic larynx

The purpose of this paper was to compare intensity-modulated radiation therapy (IMRT) and conventional planning for T2N0M0 squamous cell carcinoma (SQCC) of the glottic larynx. Three patients with T2N0M0 SQCC are presented who were treated with IMRT. Conventional plans were also generated for comparison purposes. Isodose distributions and dose-volume histograms (DVHs) were generated for all the plans to evaluate the fitness of the plan as well as the differential benefit of IMRT vs. conventional treatment. The isodose distributions that were obtained by the IMRT plan are much more conformal to the planning target volume (PTV) and clearly show that less healthy tissue is subjected to a high-dose level, thus reducing toxicity. IMRT offers better comformality without compromising the PTV coverage and delivers less dose to normal tissues as compared to conventional radiation therapy in T2N0M0 SQCC of the glottic larynx. With an increase in conformality, it is expected to have an increase in the therapeutic ratio.     

鼻咽癌颈转移淋巴结的多普勒血流信号特征

目的研究鼻咽癌颈转移淋巴结的彩色多普勒血流信号特征.材料与方法鼻咽癌伴颈淋巴结转移患者52例共134枚颈转移淋巴结,在接受治疗前行彩色多普勒血流检查,分析其血流信号特征和血供强度与淋巴结大小、部位的关系.结果鼻咽癌颈转移淋巴结的动脉血管多分布在淋巴结的周边,血流阻抗(RI)高;淋巴结血流强度的分布因淋巴结部位、大小的变化而不同,大淋巴结较小淋巴结血供丰富;中、下颈淋巴结较上颈淋巴结血供丰富.结论鼻咽癌颈转移淋巴结以周边型高阻血流信号为主.血供强度与淋巴结大小、部位有关.     

Comparison of laparoscopic sonography with surgical pathology in the evaluation of pelvic lymph nodes in women with cervical cancer.

OBJECTIVE: This study compared laparoscopic sonography with surgical pathology in the evaluation of pelvic lymph nodes in women with cervical cancer. SUBJECTS AND METHODS: Intraoperative laparoscopic sonography of pelvic lymph nodes was performed in 31 women with biopsy-proven cervical cancer. A lymph node that was rounded (longitudinal-transverse axis ratio of <2) or showed absence of central hilum was defined as positive for metastasis. For comparison, lymph nodes from each hemipelvis were grouped anatomically into paraaortic, common, internal, and external iliac chains during evaluation on laparoscopic sonography and on surgical pathologic examination. RESULTS: Pelvic dissection in 31 women yielded 630 lymph nodes. There were 54 metastatic nodes in 12 women. Laparoscopic sonography revealed 32 (59%) of all pathologically metastatic lymph nodes. Sensitivity on laparoscopic sonography when comparing groups by hemipelves was 93.3% and by anatomic lymph node chains was 76.2%. Metastatic nodes were most commonly located in the common iliac region and were characteristically rounded, hypoechoic, showed absence of central hilum, and occasionally showed central necrosis. Nine (28%) of 32 metastatic lymph nodes revealed by laparoscopic sonography measured 1 cm or less. Six benign nodes in four patients were also visualized with laparoscopic sonography. CONCLUSION: Laparoscopic sonography achieved a sensitivity exceeding 90% in the detection of metastatic lymph nodes in the hemipelves of women with cervical cancer. Laparoscopic sonography is a feasible and promising technique for the evaluation of pelvic lymph nodes in women with cervical cancer and merits further evaluation.     

Retrospective audit of inter-fraction motion for pelvic node radiotherapy in prostate cancer patients

IntroductionPelvic lymph nodes move independently to the prostate. When delivering radiotherapy to prostate and pelvic lymph nodes, daily inter- and intra-fraction anatomical changes need to be accounted for. Planning target volume (PTV) margins, grown from the pelvic lymph node clinical target volume need to be determined, to account for this variation in position.MethodsTwenty patients who had daily online image guided radiotherapy to prostate and pelvic lymph nodes between April and December 2018 were selected. Ten pre-treatment verification images using cone beam CT from each patient were registered to pelvic bone anatomy, prostate soft tissue or fiducial markers and pelvic lymph node soft tissue to assess the accuracy of treatment delivery. Population systematic and random errors and PTV margins were calculated.ResultsPTV margins of 0.4 cm, 0.4 cm and 0.7 cm left–right (LR), superior–inferior (SI) and anterior–posterior (AP) respectively were derived for the pelvic lymph nodes when registering to prostate. PTV margins of 0.3 cm, 0.2 cm and 0.4 cm LR, SI and AP respectively were derived for the pelvic lymph nodes when registering to bone. There was a posterior systematic shift of the prostate during the treatment course.ConclusionThere is differential motion of pelvic lymph nodes to prostate and in the era of prostate and pelvic radiotherapy for patients with node positive prostate cancer; there is increasing importance in the accuracy of dose delivery to the involved lymph node. Hence, this group of patients may benefit from personalised radiotherapy PTV margins, especially if the involved pelvic lymph node is within the anterior part of the clinical target volume.Implications for practiceOptimisation of dose delivery to the pelvic lymph nodes when prioritising the prostate in prostate and pelvic lymph node image guided radiotherapy.     

Will weight loss cause significant dosimetric changes of target volumes and organs at risk in nasopharyngeal carcinoma treated with intensity-modulated radiation therapy?

This study aimed to quantify dosimetric effects of weight loss for nasopharyngeal carcinoma (NPC) treated with intensity-modulated radiation therapy (IMRT). Overall, 25 patients with NPC treated with IMRT were enrolled. We simulated weight loss during IMRT on the computer. Weight loss model was based on the planning computed tomography (CT) images. The original external contour of head and neck was labeled plan 0, and its volume was regarded as pretreatment normal weight. We shrank the external contour with different margins (2, 3, and 5 mm) and generated new external contours of head and neck. The volumes of reconstructed external contours were regarded as weight during radiotherapy. After recontouring outlines, the initial treatment plan was mapped to the redefined CT scans with the same beam configurations, yielding new plans. The computer model represented a theoretical proportional weight loss of 3.4% to 13.7% during the course of IMRT. The dose delivered to the planning target volume (PTV) of primary gross tumor volume and clinical target volume significantly increased by 1.9% to 2.9% and 1.8% to 2.9% because of weight loss, respectively. The dose to the PTV of gross tumor volume of lymph nodes fluctuated from −2.0% to 1.0%. The dose to the brain stem and the spinal cord was increased (p < 0.001), whereas the dose to the parotid gland was decreased (p < 0.001). Weight loss may lead to significant dosimetric change during IMRT. Repeated scanning and replanning for patients with NPC with an obvious weight loss may be necessary.