The effect of the target-organ geometric complexity on the choice of delivery between RapidArc and sliding-window IMRT for nasopharyngeal carcinoma

We attempted to assess the effect of target-organ geometric complexity on the plan quality of sliding-window intensity-modulated radiotherapy (IMRT), double-arc (RA2), and triple-arc (RA3) RapidArc volumetric-modulated arc radiotherapy for nasopharyngeal carcinoma (NPC). Plans for 9-field sliding-window IMRT, RA2, and RA3 were optimized for 36 patients with NPC ranging from T1 to T4 tumors. Initially the patients were divided into 2 groups, with group A representing the most simple early stage (T1 and T2) cases, whereas group B represented the more complex advanced cases (T3 and T4). Evaluation was performed based on target conformity, target dose homogeneity, organ-sparing capability, and delivery efficiency. Based on the plan quality results, a subgroup of advanced cases, group B2, representing the most demanding task was distinguished and reported separately from the rest of the group B cases, B1. Detailed analysis was performed on the anatomic features for each group of cases, so that planners can easily identify the differences between B1 and B2. For the group A cases, RA3 plans were superior to the IMRT plans in terms of organ sparing, whereas target conformity and dose homogeneity were similar. For the group B1 cases, the RA3 plans produced almost equivalent plan quality as the IMRT plans. For the group B2 cases, for most of which large target volumes were adjacent to (5 mm or less) and wrapping around the brain stem, RA2 and RA3 were inferior to the IMRT regarding both target dose homogeneity and conformity. RA2 plans were slightly inferior to IMRT and RA3 plans for most cases. The plan comparison results depend on the target to brain stem distances and the target sizes. The plan quality results together with the anatomic information may allow the evaluation of the 3 treatment options before actual planning.     

Comparison of whole-field simultaneous integrated boost VMAT and IMRT in the treatment of nasopharyngeal cancer

To study the feasibility of using volumetric-modulated arc therapy (VMAT) to deliver whole-field simultaneous integrated boost (WF-SIB) to treat patients with nasopharyngeal cancer (NPC).WF-SIB intensity-modulated radiotherapy (IMRT) plans, one-arc WF-SIB VMAT plans, and two-arc WF-SIB VMAT plans were generated with identical objective functions for 8 patients with NPC of various stages. Isodose distributions and dose-volume histograms were evaluated. Dosimetric and biological quality indices of clinical target volume (CTV) and organs at risk (OARs) were calculated to study the optimization capability of these 3 modalities in the treatment of patients with NPC. The optimization time, delivery time, required monitor units (MUs), and delivery accuracy were also compared to investigate the feasibility of these 3 modalities.There was no significant difference (p = 0.92) in target coverage (TC) between WF-SIB IMRT (99.00 ± 0.79) and two-arc WF-SIB VMAT (97.98 ± 1.29). However, both had higher TC than one-arc VMAT plans (89.92 ± 6.32, p < 0.01). IMRT demonstrated the best protection of the spinal cord, whereas two-arc VMAT showed the minimum D_max to OARs. No other significant differences were observed among these 3 modalities on CTV coverage and OAR sparing. The delivery and MU efficiency of one-arc and two-arc WF-SIB VMAT were greatly improved compared with WF-SIB IMRT. The optimization time of one-arc and two-arc WF-SIB VMAT plans were 5 and 10 times greater than that of WF-SIB IMRT, respectively. The delivery accuracy of WF-SIB VMAT was not affected by the increased freedom.For patients with NPC, one-arc WF-SIB VMAT might not be able to achieve sufficient TC, whereas two-arc WF-SIB VMAT was able to achieve reasonable TC. No significant advantage on OAR protection was demonstrated by VMAT compared with IMRT. WF-SIB VMAT has significantly shorter delivery times, but WF-SIB IMRT may still be the first treatment choice for patients with NPC.     

Dosimetric difference amongst 3 techniques: TomoTherapy,sliding-window intensity-modulated radiotherapy (IMRT), and RapidArc radiotherapy in the treatment of late-stage nasopharyngeal carcinoma (NPC)

To investigate the dosimetric difference amongst TomoTherapy, sliding-window intensity-modulated radiotherapy (IMRT), and RapidArc radiotherapy in the treatment of late-stage nasopharyngeal carcinoma (NPC). Ten patients with late-stage (Stage III or IV) NPC treated with TomoTherapy or IMRT were selected for the study. Treatment plans with these 3 techniques were devised according to departmental protocol. Dosimetric parameters for organ at risk and treatment targets were compared between TomoTherapy and IMRT, TomoTherapy and RapidArc, and IMRT and RapidArc. Comparison amongst the techniques was done by statistical tests on the dosimetric parameters, total monitor unit (MU), and expected delivery time. All 3 techniques achieved similar target dose coverage. TomoTherapy achieved significantly lower doses in lens and mandible amongst the techniques. It also achieved significantly better dose conformity to the treatment targets. RapidArc achieved significantly lower dose to the eye and normal tissue, lower total MU, and less delivery time. The dosimetric advantages of the 3 techniques were identified in the treatment of late-stage NPC. This may serve as a guideline for selection of the proper technique for different clinical cases.     

局部进展期鼻咽癌同期调强放化疗Ⅰ期临床观察

目的 前瞻性研究局部进展期鼻咽癌调强放疗联合同期化疗的不良反应,探讨同期调强放化疗的最佳剂量方法。方法 2004年8月至2006年3月,20例Ⅲ～Ⅳa期的鼻咽癌患者在北京大学临床肿瘤学院接受了调强放疗和同期化疗。肿瘤靶体积和临床靶体积的放疗中位剂量分别是70.8和61.5 Gy。同期化疗采用顺铂和氟尿嘧啶方案,化疗药物分为4个剂量水平。MRI和CT用于疗效评价。CTC2.0评分标准用于评价近期治疗相关的不良反应。结果 中位随访时间是16.5个月。随访期间局部区域控制率是100%。2例出现远地转移。放疗结束时影像学评价疗效,完全缓解:20.0%,部分缓解:75.0%,稳定:5.0%。近期治疗相关不良反应随着化疗药物剂量的增加而加重。结论 同期调强放化疗的近期不良反应程度与化疗药物剂量明显相关。选择同期化疗剂量时应将3、4度不良反应分别控制在30%～40%和10%以下。     

鼻咽癌束流调强放疗的腮腺保护剂量学研究

目的探讨不同鼻咽癌束流调强放疗计划对腮腺剂量分布的影响。方法在相同的剂量要求和限制下,比较鼻咽癌常规束流调强放射治疗计划与仅保护一侧腮腺时或腮腺扩大计划靶区（加2或3mm边缘）时的束流调强放射治疗计划。结果仅保护一侧腮腺的调强计划与常规计划比较,PTV70在靶区覆盖情况、均匀指数和适形指数方面均相似。PTV59.4的最小剂量大于常规计划（P〈0.01）,D95也得到提高（P〈0.01）。两个计划需保护的腮腺D50%VOL和Dmean相似。扩大腮腺计划靶区（加2或3mm边缘）的调强计划与常规计划比较：PTV70在靶区覆盖情况、均匀指数和适形指数方面均相似。然而从常规计划到腮腺加2mm边缘的调强计划再到加3mm边缘的调强计划,PTV59.4的Dmin和Dmean有下降的趋势,而脑干和脊髓的受量有增加的趋势。结论调强计划中腮腺保护困难时,可仅做保护一侧腮腺的束流调强放疗计划;估计腮腺可能产生明显的位置变化时,可考虑加大腮腺的计划靶区,以保证治疗过程腮腺始终能得到较好的保护。     

基于多叶准直器日志文件的鼻咽癌调强放疗的累积剂量验证

目的 利用多叶准直器(MLC)日志文件验证鼻咽癌患者动态调强放疗的累积剂量,分析MLC叶片位置偏差与剂量学关系。方法 跟踪记录5例鼻咽癌患者的28个分次动态调强放疗,共计1 400个日志文件。通过Argus软件解析和提取MLC叶片的实际位置信息,并与MLC叶片的计划位置信息比较,计算每个MLC叶片的位置偏差和所有患者的整体平均叶片位置偏差。将MLC文件导入治疗计划系统(TPS)进行剂量重建计算,分别比较和分析每个病例重建计划和原计划的28次累积剂量差异及单次相对剂量差异。结果 单个叶片位置偏差<0.50 mm约占90%,0.50~1.00 mm之间的占4%~11%,1.00~1.50 mm约占8‰,整体平均叶片位置偏差为0.16 mm。与原始计划累积剂量相比,重建计划的叶片位置偏差导致靶区累积相对剂量差异<±0.1%,危及器官的累积相对剂量差异<±0.6%,差异均无统计学意义(P>0.05);而与原始计划的单次剂量相比,重建计划的靶区和脑干、脊髓和右眼晶状体单次剂量差异有统计学意义(z=-2.02~4.61和4.46、-4.51、2.07, P<0.05)。结论 基于动态调强日志文件的分次累积剂量验证,一定程度上减小了单次MLC叶片位置偏差对剂量的影响,验证结果可更加精确地反映患者的实际受照剂量。     

A systematic benchmark method for analysis and comparison of IMRT treatment planning algorithms

Tools and procedures for evaluating and comparing different intensity-modulated radiation therapy (IMRT) systems are presented. IMRT is increasingly in demand and there are numerous systems available commercially. These programs introduce significantly different software to dosimetrists and physicists than conventional planning systems, and the options often seem initially overwhelmingly complex to the user. By creating geometric target volumes and critical normal tissues, the characteristics of the algorithms may be investigated, and the influence of the different parameters explored. Overall optimization strategies of the algorithm may be characterized by treating a square target volume (TV) with 2 perpendicular beams, with and without heterogeneities. A half-donut (hemi-annulus) TV with a “donut hole” (central cylinder) critical normal tissue (CNT) on a CT of a simulated quality assurance phantom is suggested as a good geometry to explore the IMRT algorithm parameters. Using this geometry, the order of varying parameters is suggested. First is to determine the effects of the number of stratifications of optimized intensity fluence on the resulting dose distribution, and selecting a fixed number of stratifications for further studies. To characterize the dose distributions, a dose-homogeneity index (DHI) is defined as the ratio of the dose received by 90% of the volume to the minimum dose received by the “hottest” 10% of the volume. The next step is to explore the effects of priority and penalty on both the TV and the CNT. Then, choosing and fixing these parameters, the effects of varying the number of beams can be looked at. As well as evaluating the dose distributions (and DHI), the number of subfields and the number of monitor units required for different numbers of stratifications and beams can be evaluated.     

Volumetric Modulated Arc Therapy vs. IMRT for the Treatment of Distal Esophageal Cancer

Several studies have demonstrated that volumetric modulated arc therapy (VMAT) has the ability to reduce monitor units and treatment time when compared with intensity-modulated radiation therapy (IMRT). This study aims to demonstrate that VMAT is able to provide adequate organs at risk (OAR) sparing and planning target volume (PTV) coverage for adenocarcinoma of the distal esophagus while reducing monitor units and treatment time. Fourteen patients having been treated previously for esophageal cancer were planned using both VMAT and IMRT techniques. Dosimetric quality was evaluated based on doses to several OARs, as well as coverage of the PTV. Treatment times were assessed by recording the number of monitor units required for dose delivery. Body V₅ was also recorded to evaluate the increased volume of healthy tissue irradiated to low doses. Dosimetric differences in OAR sparing between VMAT and IMRT were comparable. PTV coverage was similar for the 2 techniques but it was found that IMRT was capable of delivering a slightly more homogenous dose distribution. Of the 14 patients, 12 were treated with a single arc and 2 were treated with a double arc. Single-arc plans reduced monitor units by 42% when compared with the IMRT plans. Double-arc plans reduced monitor units by 67% when compared with IMRT. The V₅ for the body was found to be 18% greater for VMAT than for IMRT. VMAT has the capability to decrease treatment times over IMRT while still providing similar OAR sparing and PTV coverage. Although there will be a smaller risk of patient movement during VMAT treatments, this advantage comes at the cost of delivering small doses to a greater volume of the patient.     

旋转调强与固定野调强治疗肝癌的剂量学比较

目的 比较旋转调强(RapidArc)与固定野调强放疗(IMRT)在肝癌治疗计划中的剂量学差异。方法 选择10例肝癌患者的CT数据,分别设计IMRT计划与单弧(RA1)和双弧(RA2)计划,比较设计计划的靶区剂量分布、危及器官受量、正常组织受量、机器跳数以及治疗时间。结果 RA1和RA2计划靶区剂量的最大值都低于IMRT(Z=-2.090、-2.666,P＜0.05),计划90%的处方剂量的适形指数低于IMRT(Z=-2.805、-2.809,P＜0.05);危及器官胃与小肠的V40也比IMRT计划低。但IMRT左肾平均剂量低于RapidArc计划组(Z=-1.988、-2.191,P＜0.05);正常组织的V₅、V₁₀和V₁₅IMRT计划低于RapidArc计划组,V20、V25和V30IMRT计划高于RapidArc计划组。RapidArc计划机器跳数是IMRT计划的40%和46%,治疗时间是IMRT计划30%和40%。结论 两种技术设计的计划剂量分布均能满足临床要求,并且剂量分布基本一致。RapidArc计划的适形指数优于IMRT,危及器官剂量也比IMRT计划略有降低,正常组织的低剂量区RapidArc计划组与IMRT相比有先高后低的趋势,并且机器跳数少,治疗时间短。     

Radiation therapy of synchronous bilateral breast carcinoma (SBBC) using multiple techniques

The purpose of this study was to establish intensity-modulated radiation therapy (IMRT) and volumetric-modulated arc therapy (VMAT) treatment plans for synchronous bilateral breast cancer (SBBC) and to compare those plans with the previous treatment plans using 3D conformal radiation therapy (3DCRT). The differences among the treatments were also statistically compared regarding dosimetry distribution and treatment efficiency. The research was conducted with 10 SBBC patients. The study established IMRT (12 fields with a single isocenter) and VMAT (2 partial arcs with a single isocenter) treatment plans for SBBC patients and then compared those plans with 3DCRT (8 fields with multiple isocenters). The plans were evaluated based on a dose-volume histogram analysis. For planning target volumes (PTVs), the mean doses and the values of V_95%, V_105%, conformity index, and homogeneity index were reported. For the organs at risk, the analysis included the mean dose, maximum dose, and V_XGy, depending on the organs (lungs, heart, and liver). To objectively evaluate the efficiency of the treatment plans, each plan's beam times, treatment times (including set-up time), and monitor units were compared. Tukey test and one-way analysis of variance were used to compare the PTV and organs at risk values of the 3 techniques. Additionally, the independent-samples t-test was used to compare the 2 techniques (IMRT and VMAT) based on the values of Rt. PTV and Lt. PTV (p?<?0.05). For PTV dose distribution, IMRT showed increases of approximately 1.2% in D_mean and of approximately 5.7% in V_95% dose distribution compared with 3DCRT. In comparison to VMAT, 3DCRT showed about 3.0% higher dose distribution in D_mean and V_95%. IMRT was the best in terms of conformity index and homogeneity index (p?<?0.05), whereas 3DCRT and VMAT did not significantly differ from each other. In terms of dose distribution on lungs, heart, and liver, the percentage of volume at high doses such as V_30Gy and V_40Gy was approximately 70% lower for IMRT and approximately 40% lower for VMAT than for 3DCRT. For distribution volumes of low doses such as V_5% and V_10%, that for 3DCRT was approximately 60% smaller than for IMRT and approximately 70% smaller than for VMAT. Comparison between IMRT and VMAT showed that the IMRT was superior in all distribution factors. VMAT showed better treatment efficiency than 3DCRT or IMRT. Among the SBBC radiotherapy treatment plans, IMRT was superior to 3DCRT and VMAT in terms of PTV dose distribution, whereas VMAT showed the most outstanding treatment efficiency.     

Multi-institutional evaluation of end-to-end protocol for IMRT/VMAT treatment chains utilizing conventional linacs

We conducted a multi-institutional assessment of a recently developed end-to-end monthly quality assurance (QA) protocol for external beam radiation therapy treatment chains. This protocol validates the entire treatment chain against a baseline to detect the presence of complex errors not easily found in standard component-based QA methods. Participating physicists from 3 institutions ran the end-to-end protocol on treatment chains that include Imaging and Radiation Oncology Core (IROC)-credentialed linacs. Results were analyzed in the form of American Association of Physicists in Medicine (AAPM) Task Group (TG)-119 so that they may be referenced by future test participants. Optically stimulated luminescent dosimeter (OSLD), EBT3 radiochromic film, and A1SL ion chamber readings were accumulated across 10 test runs. Confidence limits were calculated to determine where 95% of measurements should fall. From calculated confidence limits, 95% of measurements should be within 5% error for OSLDs, 4% error for ionization chambers, and 4% error for (96% relative gamma pass rate) radiochromic film at 3% agreement/3?mm distance to agreement. Data were separated by institution, model of linac, and treatment protocol (intensity-modulated radiation therapy [IMRT] vs volumetric modulated arc therapy [VMAT]). A total of 97% of OSLDs, 98% of ion chambers, and 93% of films were within the confidence limits; measurements were found outside these limits by a maximum of 4%, < 1%, and < 1%, respectively. Data were consistent despite institutional differences in OSLD reading equipment and radiochromic film calibration techniques. Results from this test may be used by clinics for data comparison. Areas of improvement were identified in the end-to-end protocol that can be implemented in an updated version. The consistency of our data demonstrates the reproducibility and ease-of-use of such tests and suggests a potential role for their use in broad end-to-end QA initiatives.     

青少年鼻咽癌治疗现状

鼻咽癌(NPC)是一种起源于鼻咽部上皮细胞的恶性肿瘤,是青少年人群头颈部最常见的恶性肿瘤之一。青少年鼻咽癌的治疗通常参照成人治疗指南,但是青少年鼻咽癌有其自身的临床特点。对于处于发育阶段的青少年患者来说,治疗的晚期不良反应也不可忽视。寻找适合青少年的治疗方案具有重要意义。本文对青少年鼻咽癌的流行病学、临床特点、治疗现状...     

Comparison of Prostate IMRT and VMAT Biologically Optimised Treatment Plans

Recently, a new radiotherapy delivery technique has become clinically available—volumetric modulated arc therapy (VMAT). VMAT is the delivery of IMRT while the gantry is in motion using dynamic leaf motion. The perceived benefit of VMAT over IMRT is a reduction in delivery time. In this study, VMAT was compared directly with IMRT for a series of prostate cases. For 10 patients, a biologically optimized seven-field IMRT plan was compared with a biologically optimized VMAT plan using the same planning objectives. The Pinnacle RTPS was used. The resultant target and organ-at-risk dose-volume histograms (DVHs) were compared. The normal tissue complication probability (NTCP) for the IMRT and VMAT plans was calculated for 3 model parameter sets. The delivery efficiency and time for the IMRT and VMAT plans was compared. The VMAT plans resulted in a statistically significant reduction in the rectal V25Gy parameter of 8.2% on average over the IMRT plans. For one of the NTCP parameter sets, the VMAT plans had a statistically significant lower rectal NTCP. These reductions in rectal dose were achieved using 18.6% fewer monitor units and a delivery time reduction of up to 69%. VMAT plans resulted in reductions in rectal doses for all 10 patients in the study. This was achieved with significant reductions in delivery time and monitor units. Given the target coverage was equivalent, the VMAT plans were superior.     

不同淋巴结转移状况的鼻咽癌调强放疗中腮腺和肿瘤靶区体积退缩与受照剂量的相关性

目的 探讨鼻咽癌调强放疗中,不同淋巴结转移状况的腮腺和肿瘤靶区体积退缩与受照剂量的相关性,以便确定再次计划最佳时间。方法 选择30例接受调强放疗的鼻咽癌患者,根据颈部淋巴结直径大小将患者分为3组,分别是淋巴结阴性组(A组),淋巴结≤3 cm阳性组(B组),淋巴结>3 cm阳性组(C组)。初始定位CT命名为CT₀,每位患者在同一体位下每周重新扫描一次CT,即患者第5、10、15、20、25和32次治疗前行日常验证扫描图像获得CT₁、CT₂、CT₃、CT₄、CT₅、CT₆。结果 CT₀显示3组腮腺初始体积大小差异无统计学意义(P>0.05)。与A组相比,B组在CT₄以后腮腺体积开始缩小,差异有统计学意义(t=2.12~2.46,P<0.05);C组CT₂以后体积差异具有统计学意义(t=2.19~3.25,P<0.05)。各组内分次体积与初始体积CT₀相比,A组、B组在CT₃以后体积开始缩小,差异有统计学意义(t=2.16~4.11,P<0.05);C组在CT₂以后就有差异(t=2.37~5.20,P<0.05);C组CT₄与CT₂比较,差异也具有统计学意义(t=2.16、3.34,P<0.05)。结论 出于保护腮腺的考虑,淋巴结较大的患者有必要提前修改计划,建议在第10次放疗重新计划,可能在第20次放疗需要再次计划;淋巴结阴性或者很小的患者建议在第15次修改计划。     

凋亡刺激蛋白抑制因子表达对鼻咽癌预后预测的研究

目的 探讨凋亡刺激蛋白抑制因子（iASPP）的表达水平与鼻咽癌预后的关系。方法 随访2012年1月至12月广西医科大学第一附属医院放疗科治疗的初诊鼻咽癌患者130例。临床分期依据2009 AJCC/UICC分期标准。所有患者均接受调强放射治疗,Ⅲ~Ⅳ_B期患者行铂类为基础的同步放化疗。采用免疫组织化学法检测iASPP在130例鼻咽癌组织中的表达情况,比较iASPP表达与临床病理因素的关系,并分析其表达对鼻咽癌患者疗效和生存的影响。结果 130例患者中iASPP阳性表达者86例（66.2%）,阴性表达者44例（33.8%）。不同N分期和临床分期患者的iASPP阳性表达率比较,差异有统计学意义（χ²=7.565、4.947,P<0.05）。治疗后3个月,iASPP阳性表达者与阴性表达者的近期疗效差异无统计学意义（P>0.05）。单因素分析显示,iASPP阳性表达者3年无远处转移生存（DMFS）和无进展生存（PFS）均低于iASPP阴性表达者（82.6% vs. 95.4%,χ²=4.335,P=0.037和74.4% vs. 93.1%,χ²=6.640,P=0.01）。N_2~3患者3年DMFS、PFS和总生存（OS）均低于N_0~1患者（χ²=8.058、9.554、6.987,P<0.01）。多因素分析显示,iASPP表达水平及N分期是影响PFS的独立预后因素（χ²=4.336、5.228,P<0.05）。结论 鼻咽癌患者iASPP阳性表达水平升高是影响预后的不利因素。     

局部晚期鼻咽癌调强放疗中解剖结构改变及剂量分布变化研究

目的 探讨局部晚期鼻咽癌患者在调强放疗（IMRT）期间的解剖结构体积改变及剂量分布变化。方法 选取18例局部晚期鼻咽癌患者,利用每周锥形束CT （CBCT）分析患者的解剖结构体积变化,并在放疗20次后再次进行IMRT计划设计,探讨二程IMRT计划的剂量学。结果 GTV_nx每周平均缩小3.15%,共缩小22.03%;GTV_nd每周平均缩小5.67%,共缩小39.68%;左右腮腺每周分别缩小4.93%和5.26%,总共缩小29.60%和31.56%。GTV_nd和腮腺在放疗前4周有较大退缩,放疗4周后体积改变趋于平缓。与初始Plan 1相比,Plan 2中PGTV_nd的D₉₅下降2.20%（t=2.382,P<0.05）,而PGTV_nx、PTV₁和PTV₂的D₉₅没有显著变化;左腮腺D_mean、D₅₀和V₃₀分别增加7.34%、12.68%和10.90%,与放疗前比较差异均有统计学意义（t=-3.376、-3.738、-3.679,P<0.05）;右腮腺D_mean、D₅₀和V₃₀分别增加6.13%、11.17%和9.72%,与放疗前比较差异均有统计学意义（t=-2.550、-2.446、-2.673,P<0.05）;喉的D_mean平均增加8.69%,与放疗前比较差异均有统计学意义（t=-3.099,P<0.05）。相比较于Plan 2,综合计划Plan （1+2）中PGTV_nd的D₉₅增加1.37%,差异有统计学意义（t=-3.555,P<0.05）,左腮腺D_mean、D₅₀和V₃₀分别平均降低了2.90%、2.73%和4.62%,差异有统计学意义（t=3.089、2.718、2.705,P<0.05）;右腮腺D_mean、D₅₀和V₃₀分别降低3.49%、3.44%和3.80%,与放疗前比较,差异均有统计学意义（t=2.781、2.958、4.275,P<0.05）;喉的D_mean平均降低3.29%（t=2.747,P<0.05）。结论 局部晚期鼻咽癌患者在IMRT期间靶区和腮腺体积均会显著缩小;放疗中期有必要设计二程放疗计划,以此来提高靶区剂量并一定程度上降低靶区周围危及器官的剂量。     

介入动脉化疗加放射治疗鼻咽癌的近期疗效

目的 探讨经颈动脉灌注化疗药物治疗加放疗对鼻咽癌的疗效.方法 22例患者经临床(包括鼻咽镜检)、影像学(CT、MR)和病理学检查确诊为鼻咽癌,经颈外动脉介入化疗后加放射治疗.化疗药物为阿霉素(ADM)或吡柔比星、5-氟尿嘧啶(5-FU)和顺铂(DDP)或卡铂(CBP).同时随机选择同期单纯放疗的25例作为对照,比较其疗效.结果 介入组总有效率为100.0%,其中CR为90.9%(20/22),对照组总有效率为100.0%,其中CR为68.0%(17/25),两组分别比较差异有统计学意义(P＜0.05).结论 介入动脉化疗后加放射治疗能显著提高鼻咽癌治疗的疗效.     

TPF方案诱导化疗不同给药方式联合调强放疗治疗局部晚期鼻咽癌的中期疗效及预后分析

目的 探讨时间调节化疗联合调强放疗与常规化疗联合调强放疗对局部晚期初治鼻咽癌患者疗效、不良反应和免疫功能的影响。方法 采用随机数表分组法进行前瞻性研究,将本科收治的局部晚期初治鼻咽癌患者66例分为2组,即时辰组36例和常规组30例。两组均采用多西他赛+顺铂+氟尿嘧啶方案诱导化疗2周期,时辰组采用电子化疗全自动注药泵静脉输入给药,常规组采用常规静脉输液,两组均采用同步顺铂联合调强放射治疗。根据Kaplan-Meier法计算生存率和CTC3.0标准评价远期不良反应。结果 时辰组和常规组3年的总生存率（OS）分别为86.1%和93.3%,3年的无进展生存（PFS）分别为83.3%和93.3%,3年的无复发生存（RFS）分别为88.5%和93.3%,3年的无远处转移生存（DMFS）分别为94.1%和100%,差异均无统计学意义（P>0.05）。时辰组口干及听力下降较常规组有降低趋势。时辰组CD3+、CD3+CD4+、CD3+CD4+CD8+、CD4+/CD8+较常规组有升高趋势。结论 时间调节化疗联合调强放疗与常规化疗联合调强放疗相比,两组中期疗效相当,但前者有降低不良反应,改善患者生活质量,改善患者免疫功能趋势。     

三种调强放疗技术对鼻咽癌患者下颈部亚临床靶区剂量分布的影响

目的 比较3种不同调强放疗技术对鼻咽癌患者下颈部和锁骨上区亚临床靶区剂量分布均匀性和正常组织受量。方法 3种照射方法分别为颈部切线野技术,机架角度分别为180°、150°、120°、90°、270°、240°、210°的7野调强技术,机架角度分别为180°、150°、120°、90°、0°、270°、240°、210°的8野调强技术。利用剂量分布和剂量体积直方图比较3种不同照射技术的剂量均匀性以及正常组织受量,高剂量区域用受照剂量>60 Gy体积占全体积(V₆₀)百分比比较,执行效率用子野数目和总机器跳数比较。结果 3种调强治疗技术的处方剂量均能包括计划靶区(PTV₂),但剂量分布存在差别,V₆₀分别为65%、10%和3%。3种技术中脊髓最大受量分别为42.0、48.9和45.1 Gy,气管平均剂量分别32.92、52.17和36.56 Gy。结论 颈部切线野技术方法简单,但下颈部和锁骨上区剂量分布非常不均匀。7野调强技术靶区剂量分布有所改善,但在气管和喉所在区域以及靶区外产生剂量重叠区,脊髓受量也较高。8野调强技术靶区和正常组织剂量分布都明显改善。