鼻咽癌容积调强旋转放疗和固定野适形调强放疗的剂量学对比

目的:对比旋转容积调强技术（RapidArc ）和固定野适形调强放疗（intensity modulated radiation therapy ,IMRT）治疗鼻咽癌剂量学方面的差异,探索不同T 分期从何种技术获益最大。方法:选取60例无远处转移鼻咽癌患者,按鼻咽癌2008分期T 1～2期20例,T 3 期20例,T 4 期20例。使用瓦里安公司Eclipse 系统,每例患者分别制定RapidArc 和固定野IMRT 计划,比较两者靶区覆盖、危机器官剂量、跳数和治疗时间的差别。结果:IMRT 和RapidArc 均能满足临床要求,靶区剂量分布差异无统计学意义（P >0.05）,均匀性和适形性相当。按T 分期分层比较,T 4 期患者RapidArc 组PGTV、PTV 1、PTV 2 的靶区剂量较高（P < 0.05）,PGTV 均匀指数较好（P = 0.059）。 RapidArc 组视神经、晶体、颞叶、腮腺V 20、喉、颞颌关节受照剂量均较低（P < 0.05）。 按T 分期分层比较,脑干剂量T 1～2 期、T 3 期两组比较差异无统计学意义（P > 0.05）,T 4 期患者脑干D 1% 、Dmax剂量RapidArc 组较IMRT 组低（P < 0.05）。RapidArc 和IMRT 相比,治疗跳数节省65% ,治疗时间节省63% 。结论:RapidArc 和9 野IMRT 治疗鼻咽癌均可满足临床要求,Rap?idArc 可明显降低正常器官剂量,缩短治疗时间,减少治疗跳数。对局部早、中期（T 1～3 期）患者,两者有相似的靶区剂量分布,但对局部晚期（T 4 期）患者,RapidArc 更具有将高剂量区集中在靶区而减少正常器官受照剂量的优势。      

宫颈癌术后容积旋转调强与三维适形调强放疗技术的剂量学差异

目的:比较宫颈癌术后放疗中旋转调强放射治疗(VMAT)与三维适形调强放疗(IMRT)的剂量学差异。方法:随机选取 20 例宫颈癌术后患者,在Eclipse计划系统中分别对每例患者进行容积旋转调强和7野固定野调强放疗(7IMRT)计划设计,比较两种技术的靶区的适形指数、危及器官的受照剂量、机器跳数和治疗时间的差异。结果:VMAT 技术靶区的平均剂量为52.05 Gy,高于 7IMRT技术的51.46 Gy(P＜0.05),靶区的均匀性指数与适形度优于7IMRT 技术,机器跳数和治疗时间 VMAT 比7IMRT明显减少,差异有统计学意义。小肠、膀胱的V30、V50 、Dmean较7IMRT降低,差异有统计学意义;但直肠和股骨头的保护性上,两种放疗技术差异无统计学意义。结论:VMAT技术较IMRT技术可得到更好的靶区剂量分布,危及器官也能得到更好的保护,治疗时间明显缩短,值得在临床中开展应用。     

局部进展期鼻咽癌快速旋转调强与固定野动态调强放疗的剂量学比较

目的 比较快速旋转调强与固定野动态调强放疗技术在局部进展期鼻咽癌治疗中的剂量学差异.方法 选取10例局部进展期鼻咽癌患者,采用两种治疗技术设计同步推量调强放疗计划.在满足95%计划靶体积达60 Gy情况下,比较两种计划的剂量体积直方图、靶区和危及器官剂量、机器跳数、治疗时间.结果 快速旋转调强与固定野动态调强放疗计划在局部进展期鼻咽癌治疗剂量学上无差异.快速旋转调强计划比固定野动态调强放疗技术的靶区平均剂量略升高,最大、最小剂量无差异,脑干、下颌骨及整个治疗区域正常组织受量降低,腮腺、视神经、晶体等危及器官剂量无差异.快速旋转调强计划比固定野动态调强放疗计划的总机器跳数平均减少了57%(589.5 MU:1381.0 MU),每次治疗时间平均减少了70%(2.33 min:7.82 min).结论 两种放疗技术的治疗计划剂量分布基本一致,均能满足临床治疗需要.快速旋转调强放疗每次治疗时间明显缩短,其总机器跳数的降低减少了正常组织受照剂量.     

晚期鼻咽癌RapidArc与固定野调强放疗的比较研究

  目的  近年RapidArc的临床应用已引起越来越多的关注, 本研究比较RapidArc与固定野调强放射治疗(IMRT)两种放疗技术在晚期鼻咽癌治疗计划中的差异。  方法  随机选取10例晚期鼻咽癌患者, 采用RapidArc与IMRT两种技术进行计划设计与剂量验证, 比较计划的靶区剂量、危及器官与正常组织剂量、机器跳数、治疗时间与剂量验证结果。  结果  两种计划的剂量分布基本一致, 均能提供足够的靶区剂量。RapidArc的PTVnx最小剂量, PTVnd、PTV60、喉、腮腺的平均剂量低于IMRT, PTV60的HI值高于IMRT, 机器跳数比IMRT减少约58%, 治疗时间减少约70%。以3%/3mm为界, RapidArc验证的γ指数通过率为(98.75±0.50)%, IMRT的通过率为(98.86±0.67)%。  结论  两种放疗技术均能够满足临床治疗需要, 剂量验证结果能够较好的符合计划计算结果。RapidArc比IMRT有着更多的优势, 不仅可以减少机器跳数, 缩短治疗时间, 而且可以减少喉、腮腺的受照剂量。      

鼻咽癌放射治疗IMRT与Arc调强计划的剂量学比较

目的分析鼻咽癌放射治疗IMRT与Rapid Arc调强放疗计划方案,为临床提供参考。方法 10例鼻咽癌CT增强扫描模拟定位后勾画CTV,按统一标准外扩PTV;实施均分9野IMRT计划和单弧、双弧、3弧Arc调强计划;以PTV处方剂量70Gy,分析各治疗计划靶区剂量分布和危及器官受限剂量,进行剂量学对比研究并比较治疗时间的长短。结果 IMRT调强计划适形指数及不均匀指数明显优于单弧,与双弧和3弧没有明显区别;各计划之间危及器官受量均低于参考受限剂量;照射体积(irradiation volume,IV)未见明显区别;机器跳数(monitor unit,MU),Arc调强计划明显低于IMRT调强计划;治疗时间上Arc调强计划更短。结论目前虽IMRT计划更符合鼻咽癌的治疗剂量要求,但Arc计划在缩短治疗时间、降低治疗时的机器跳数上有明显优势。     

简化调强技术在鼻咽癌外照射中应用的剂量学研究

背景与目的：放射治疗是治疗鼻咽癌的首选方法。该文旨在研究简化调强放射治疗(simplified intensity-modulated radiation therapy,sIMRT )与调强放疗(intensity-modulated radiation therapy,IMRT)技术在鼻咽癌(nasopharyngeal carcinoma,NPC)放射治疗中的剂量学差异。方法：对10例NPC患者以相同处方剂量和目标条件分别设计9野IMRT和sIMRT计划,比较两种计划靶区剂量分布和剂量适形指数(conformity index,CI)与均匀性指数(homogeneity index,HI),不同危及器官(organ at risk,OAR)剂量参数、机器总跳数(MU)和总子野数。结果：IMRT和sIMRT的CI、HI分别为0.647、0.057和0.633、0.071(t=2.14,P=0.062;t=-6.21,P=0.000),sIMRT计划的靶区均匀性略差于IMRT,但两种治疗计划均能满足临床剂量学的要求。两种计划中各OAR剂量参数差异无统计学意义(t=-0.51~2.22,P=0.053~0.621) 。sIMRT计划的机器总跳数和总子野数均少于IMRT计划。结论：鼻咽癌sIMRT计划的靶区剂量覆盖与IMRT计划相当,均匀性略差于IMRT;危及器官受照剂量相当,但sIMRT技术可显著减少机器总跳数和总子野数,对患者数量大的治疗中心提高治疗效率具有较高的优势。     

胸中段食管癌三维适形放疗、调强放疗及旋转调强放疗的剂量学研究

 目的　研究胸中段食管癌三维适形放疗（3DCRT）、调强放疗（IMRT）、旋转调强放疗（IMAT）3种放疗计划的剂量差异。方法　选取胸中段食管癌患者15例,以Varian Eclipse 8.6计划系统分别设计3DCRT、IMRT、IMAT 3种放疗计划,其中3DCRT采用5～8个共面射野,IMRT采用7个共面射野,IMAT采用2个弧度。比较3种计划的剂量学差异。结果　IMRT、IMRT的靶区均匀指数（HI）、适形指数（CI）、95 % 计划靶体积（PTV）体积剂量均优于3DCRT,全肺V5、V20、V35、心脏V30受照剂量低于3DCRT（t＝2.531,P＜0.05）,而在全肺V10、V15、V25、V30、全肺平均、心脏平均、脊髓Dmax剂量之间三者的差异均无统计学意义（t＝1.325,P＞0.05）。结论　IMAT与IMRT在胸中段食管癌放疗靶区体积剂量覆盖和危及器官保护方面相似,二者均优于3DCRT。IMAT的机器跳数和照射时间均少于IMRT。     

宫颈癌调强放疗中两种计划方法的比较

目的:研究宫颈癌大野调强放疗(Intensity-modulated radiation therapy IMRT)时分野和限定射野两种方法的差异.方法:选取接受放疗的宫颈癌患者10例进行研究,对每例患者分别使用两种方法设计调强计划,在射野参数和优化条件相同的前提下,比较两种计划模式下体积直方图(DVH)、靶区和危及器官的剂量、子野数、机器跳数.结果:两种计划模式设计的计划均满足临床要求,剂量分布一致,DVH图相似;与分野法相比,限定射野法靶区的剂量均匀性稍好,子野数减少(16.99%)和机器跳数减少(13.44%).结论:与分野法相比较,限定射野的方法更适用于大野宫颈癌的调强计划设计.     

两种不同放疗技术治疗鼻咽癌的疗效及计量学差异比较

目的:分析探讨两种不同放疗技术治疗鼻咽癌的疗效及计量学差异。方法:选取我院于2016年4月至2019年4月期间收治的63例鼻咽癌患者,根据鼻咽癌2008分期,其中T4期鼻咽癌患者有21例,T3期鼻咽癌患者有21例,T1-2期鼻咽癌患者有21例;所有入选患者均根据其具体情况制定固定野IMRT计划和旋转容积调强放疗计划,分别比较各期患者两套计划的计量学参数;分析两套计划的治疗时间和跳数、危及器官剂量、靶区覆盖等差异。结果:两种不同放疗技术均具备较好的靶区剂量分布,其中PTV1和PGTV的适行性和均匀性相当,两者剂量分布差异并没有统计学意义（均P>0.05）。IMRT组的PTV2剂量显著高于RapidArc组,并且前者的均匀性显著优于后者（均P<0.05）,但是RapidArc组的剂量分布也能够满足临床需要。在按照患者T分期进行分层比较时,T3期患者和T1-2期患者的两种不同放疗技术靶区剂量分布相似,并且适形性和均匀性均相当。对于T4期患者而言,RapidArc组的PTV2、PTV1、PGTV靶区剂量均显著高于IMRT组（均P<0.05）;RapidArc组T4期患者的PGVT均匀指数优于IMRT组,两组数据比较差异虽无统计学意义（P=0.059）,但P值接近0.05。RapidArc组治疗时间和治疗跳数分别为（185.92±32.19）s和（651.29±112.20）MUs,分别低于IMRT组的（522.29±73.39）s和（1 891.28±253.39）MUs,两组数据比较差异具有统计学意义（t=13.283,t=22.192,均P<0.05）。结论:对鼻咽癌患者采用9野IMRT和RapidArc治疗均能够达到临床要求,但是后者的治疗时间和治疗跳数更短,可以显著降低正常器官的剂量,在T4期鼻咽癌患者的治疗方面可以将高剂量区集中在靶区,从而大大减少正常器官的受照剂量,值得在临床上加以推广运用。     

三维适形与调强放疗技术在胸上段食管癌放疗中的剂量学比较

目的:比较调强放疗技术(IMRT)和三维适形放疗技术(3DCRT)治疗胸上段食管癌的剂量学差异。方法:选择34例胸上段食管癌患者,对每例患者分别进行调强适形放疗和三维适形放疗,利用剂量体积直方图来比较两种计划中靶区及器官的剂量学差异。结果:IMRT在靶区适合度和靶区剂量均匀性方面均优于3DCRT,IMRT减少了脊髓最大所受剂量,差异均有统计学意义(P<0.05);双肺受照剂量V5 IMRT高于3DCRT(P<0.05),但是V20差异无统计学意义(P>0.05)。结论:对胸上段食管癌IMRT有更好的剂量适形性,优于3DCRT放疗。     

T2期鼻咽癌旋转调强与固定野动态调强计划的剂量学比较研究

目的：比较旋转调强（ intensity-modulated arc radiotherapy,IMAT）与固定野动态调强（ dynamic intensity-modulated radiation therapy,dIMRT）在T2期鼻咽癌放射治疗计划中的剂量学差异。方法：随机选取10例已经接受固定野动态调强放射治疗的T2期鼻咽癌病例,将这10例放疗计划改为旋转调强方式,重新进行计划优化,比较两种计划的等剂量分布、靶区和危机器官的剂量参数、机器跳数以及治疗时间等。结果：两种计划的靶区剂量分布D98、D95以及D2等参数均无统计学差异（P〉0．05）,IMAT计划的脑干Dmax和D1cc、脊髓Dmax、右腮腺Dmean、右颞颌关节Dmax以及左中耳Dmean和Dmax均明显小于dIMRT计划的受量（P〈0．05）;同时IMAT计划的左右晶体Dmax、左右视神经Dmax和视交叉Dmax均明显大于dIMRT计划的受量（P〈0．05）。 IMAT计划正常组织受照剂量为5Gy的总体积明显大于dIMRT计划（P〈0．05）,而受照剂量在20Gy和30Gy的总体积明显小于dIMRT计划（P〈0．05）。 IMAT比dIMRT计划的单次照射总机器跳数平均减少了47．0%,单次照射时间平均减少48．2%。结论：对于T2期鼻咽癌,两种计划的剂量分布均满足临床要求,在靶区剂量分布没有统计学差异的情况下,IMAT技术能显著降低机器跳数,大大缩短治疗时间。     

宫颈癌调强放射治疗进展

中晚期宫颈癌的主要治疗方式是放射治疗.调强放疗技术具有很大优势,其计划设计个体化,靶区剂量分布安全合理.与常规放疗相比,调强技术提高了疗效,减少了并发症.因此调强放疗将成为宫颈癌治疗的主要方式.     

Intensity-modulated radiotherapy for head-and-neck rhabdomyosarcoma

PURPOSE: To determine the preliminary results of intensity-modulated radiotherapy (IMRT) for head-and-neck rhabdomyosarcoma. METHODS AND MATERIALS: Twenty-eight patients underwent IMRT as a part of multimodality therapy. Twenty-one tumors were parameningeal, three were orbital, and four were in other sites. The median age was 8 years (range, 1-29 years). Most (89%) had Group III disease. Intracranial extension was present in 71% of parameningeal tumors. A 1.5-cm margin was used, and the median dose was 50.4 Gy (range, 30-55.8 Gy). RESULTS: The actuarial 3-year survival rate for patients with parameningeal tumors was 65%. The 3-year actuarial freedom from failure rate was 95% locally, 90% in regional nodes, 88% in the central nervous system, and 80% at distant sites. No failures occurred among patients with orbit tumors; a single central nervous system failure occurred in 1 patient with a lip/cheek tumor. Disease-free survival was significantly worse for patients with alveolar histologic features (p = 0.01). Acute radiation toxicity was similar to that reported by the Intergroup Rhabdomyosarcoma Study Group. Late radiation toxicity was recorded and was mild. CONCLUSION: IMRT with image fusion results in outstanding local control despite the use of a reduced margin. However, survival among patients with alveolar histologic findings or intracranial extension remains unacceptably low.     

Intensity-modulated radiation therapy for the treatment of nonanaplastic thyroid cancer

PURPOSE: Intensity-modulated radiation therapy (IMRT) enables highly conformal treatment for thyroid cancer (TC). In this study, we review outcomes/toxicity in a series of TC patients treated with IMRT. METHODS AND MATERIALS: Between July 2001 and January 2004, 20 nonanaplastic TC patients underwent IMRT. Mean age was 55. There were 3 T2 and 17 T4 patients. Sixteen patients had N1 disease. Seven patients had metastases before RT. Fifteen underwent surgery before RT. Radioactive iodine (RAI) and chemotherapy were used in 70% and 40%, respectively. Median total RT dose was 63 Gy. RESULTS: With two local failures, 2-year local progression-free rate was 85%. There were six deaths, with a 2-year overall survival rate of 60%. For patients with M0 disease, the 2-year distant metastases-free rate was 46%. The worst acute mucositis and pharyngitis was Grade 3 (n = 7 and 3, respectively). Two patients had Grade 3 acute skin toxicity and 2 had Grade 3 acute laryngeal toxicity. No significant radiation-related late effects were reported. CONCLUSIONS: IMRT for TC is feasible and effective in appropriately selected cases. Acute toxicity is manageable with proactive clinical care. Ideal planning target volume doses have yet to be determined. Additional patients and long-term follow-up are needed to confirm these preliminary findings and to clarify late toxicities.     

Intensity-modulated radiation therapy in childhood ependymoma

PURPOSE: To determine the patterns of failure after intensity-modulated radiation therapy (IMRT) for localized intracranial ependymoma. METHODS AND MATERIALS: From 1994 to 2005, 22 children with pathologically proven, localized, intracranial ependymoma were treated with adjuvant IMRT. Of the patients, 12 (55%) had an infratentorial tumor and 14 (64%) had anaplastic histology. Five patients had a subtotal resection (STR), as evidenced by postoperative magnetic resonance imaging. The clinical target volume encompassed the tumor bed and any residual disease plus margin (median dose 54 Gy). Median follow-up for surviving patients was 39.8 months. RESULTS: The 3-year overall survival rate was 87% +/- 9%. The 3-year local control rate was 68% +/- 12%. There were six local recurrences, all in the high-dose region of the treatment field. Median time to recurrence was 21.7 months. Of the 5 STR patients, 4 experienced recurrence and 3 died. Patients with a gross total resection had significantly better local control (p = 0.024) and overall survival (p = 0.008) than those with an STR. At last follow-up, no patient had developed visual loss, brain necrosis, myelitis, or a second malignancy. CONCLUSIONS: Treatment with IMRT provides local control and survival rates comparable with those in historic publications using larger treatment volumes. All failures were within the high-dose region, suggesting that IMRT does not diminish local control. The degree of surgical resection was shown to be significant for local control and survival.     

Intensity-modulated radiation therapy (IMRT) for meningioma

To assess the safety and efficacy of intensity-modulated radiation therapy (IMRT) in the treatment of intracranial meningioma.

Forty patients with intracranial meningioma (excluding optic nerve sheath meningiomas) were treated using IMRT with the NOMOS Peacock system between 1994 and 1999. Twenty-five patients received IMRT after surgery either as adjuvant therapy for incomplete resection or for recurrence, and 15 patients received definitive IMRT after presumptive diagnosis based on imaging. Thirty-two patients had skull base lesions, and 8 had nonskull base lesions. The prescribed dose ranged from 40 to 56 Gy (median 50.4 Gy) at 1.71 to 2 Gy per fraction, and the volume of the primary target ranged from 1.55 to 324.57 cc (median 20.22 cc). The mean dose to the target ranged from 44 to 60 Gy (median 53 Gy). Follow-up ranged from 6 to 71 months (median 30 months). Acute and chronic toxicity were assessed using Radiation Therapy Oncology Group (RTOG) morbidity criteria and tumor response was assessed by patient report, examination, and imaging. Overall survival, progression-free survival, and local control were calculated using the Kaplan-Meier method.

Cumulative 5-year local control, progression-free survival, and overall survival were 93%, 88%, and 89%, respectively. Two patients progressed after IMRT, one locally and one distantly. Each was treated with IMRT after multiple recurrences of benign meningioma over many years. Both were found to have malignant meningioma at the time of relapse after IMRT, and it is likely their tumors had already undergone malignant change by the time IMRT was given. Defined normal structures generally received a significantly lower dose than the target. The most common acute central nervous system (CNS) toxicity was mild headache, usually relieved with steroids. One patient experienced RTOG Grade 3 acute CNS toxicity, and 2 experienced Grade 3 or higher late CNS toxicity, with one possible treatment-related death. No toxicity was observed with mean doses to the optic nerve/chiasm up to 47 Gy and maximum doses up to 55 Gy.

IMRT is a promising new technology that is safe and efficacious in the primary and adjuvant treatment of intracranial meningiomas. A history of local aggression may indicate malignant degeneration and predict a poorer outcome. Toxicity data are encouraging, but the potential for serious side effects exists, as demonstrated by one possible treatment-related death. Larger cohort and longer follow-up are needed to better define efficacy and late toxicity of IMRT.     

Intensity-modulated radiotherapy for resected mesothelioma: the Duke experience

PURPOSE: To assess the safety and efficacy of intensity-modulated radiotherapy (IMRT) after extrapleural pneumonectomy for malignant pleural mesothelioma. METHODS AND MATERIALS: Thirteen patients underwent IMRT after extrapleural pneumonectomy between July 2005 and February 2007 at Duke University Medical Center. The clinical target volume was defined as the entire ipsilateral hemithorax, chest wall incisions, including drain sites, and involved nodal stations. The dose prescribed to the planning target volume was 40-55 Gy (median, 45). Toxicity was graded using the modified Common Toxicity Criteria, and the lung dosimetric parameters from the subgroups with and without pneumonitis were compared. Local control and survival were assessed. RESULTS: The median follow-up after IMRT was 9.5 months. Of the 13 patients, 3 (23%) developed Grade 2 or greater acute pulmonary toxicity (during or within 30 days of IMRT). The median dosimetric parameters for those with and without symptomatic pneumonitis were a mean lung dose (MLD) of 7.9 vs. 7.5 Gy (p = 0.40), percentage of lung volume receiving 20 Gy (V(20)) of 0.2% vs. 2.3% (p = 0.51), and percentage of lung volume receiving 5 Gy (V(20)) of 92% vs. 66% (p = 0.36). One patient died of fatal pulmonary toxicity. This patient received a greater MLD (11.4 vs. 7.6 Gy) and had a greater V(20) (6.9% vs. 1.9%), and V(5) (92% vs. 66%) compared with the median of those without fatal pulmonary toxicity. Local and/or distant failure occurred in 6 patients (46%), and 6 patients (46%) were alive without evidence of recurrence at last follow-up. CONCLUSIONS: With limited follow-up, 45-Gy IMRT provides reasonable local control for mesothelioma after extrapleural pneumonectomy. However, treatment-related pulmonary toxicity remains a significant concern. Care should be taken to minimize the dose to the remaining lung to achieve an acceptable therapeutic ratio.