容积旋转调强计划遮挡技术应用于早期鼻腔NK/T细胞淋巴瘤的剂量学研究

目的:比较3种容积旋转调强计划（VMAT）的剂量学差异,探讨VMAT遮挡技术对早期鼻腔NK/T细胞淋巴瘤的剂量学影响。方法:选取20例早期鼻腔NK/T细胞淋巴瘤患者,分别设计无晶体遮挡（VMAT-OFF）计划、晶体半遮挡（VMAT-E）计划和晶体全遮挡（VMAT-E&E）计划,评估3组计划的计划靶区体积（PTV）和危及器官（OARs）剂量学参数,评估机器跳数（MU）和SCIMOCA通过率（3%/2 mm）。结果:3种计划的靶区剂量分布均能满足临床要求,PTV的D2%、D98%、V95%、均匀性指数、适形度指数均无统计学差异;在MU方面,VMAT-OFF<0.05）;在oars晶体（dmax、dmean）方面,vmat-e&e><0.05）,vmat-e&e>     

RapidArc技术应用于早期鼻腔NK／T细胞淋巴瘤调强放疗的剂量学研究

目的：研究RapidArc技术应用于早期鼻腔NK／T细胞淋巴瘤调强放疗的剂量学特性。方法：选取10例早期鼻腔NK／T细胞淋巴瘤患者,在其CT模拟定位图像勾画靶区及危及器官,分别设计3D-CRT计划和RapidArc计划,以3D—CRT计划为参考。评估RapidArc计划计划靶体积（PTV）及危及器官的剂量学参数。结果：2种治疗计划均能满足处方剂量要求,与3D-CRT计划相比,RapidArc计划PTV的最大剂量（Dmax）减小5．49Gy（t=12．784,P=-0．000）、平均剂量（D/mean）减小1．32Gy（t=8．416,P=0．000）、适形指数cI‰变好（t=12．805,P=0．000）、适形指数C195％变好（t=10．138,P=-0．000）、均匀指数HI变好（产7．817,P=-0．000）;左视神经Dmean增加4．94Gy（t=-2．494,P=-0．034）,右视神经Dmean增加7．79Gy（t=-3．031,P=-0．014）,左眼Dmax减少5．83Gy（t=4．470,P=0．002）,右眼Dmax减少6．43Gy（t=4．756,P=-0．001）,左腮腺Dmax减少7．69Gy（t=3．076,P=0．013）,右腮腺Dmax减少6．93Gy（t=2．478,P=-0．035）。结论：早期鼻腔NK／T细胞淋巴瘤患者采用RapidArc技术可获得优于3D—CRT计划的靶区剂量分布,同时更好的保护了部分危及器官,其疗效还需进一步临床评估。     

鼻腔NK/T细胞淋巴瘤行全脑全脊髓照射的放疗计划设计

目的:探讨多靶区多中心多阶段调强放疗计划设计。方法:选取5例鼻腔NK/T(Natural Killer/T)细胞淋巴瘤且中枢神经系统侵犯的患者;采用头先进,仰卧位,双手置体侧,使用头颈肩热塑体模加胸腹热塑体模固定在一体板上的定位方式;对于不同的单次剂量和照射次数,采取同一计划多中心点的调强放疗设计,且以多阶段设计的方案设计物理计划;计划评估主要观察100%的剂量覆盖的靶区体积,以及靶区最大剂量点与最小剂量点;在计划执行之前,使用三维验证设备进行计划验证,采用3%,3 mm,10%的Gamma分析法。结果:将各阶段计划进行叠加,总计划在没有冷热点的情况下,100%临床处方剂量覆盖了95%的靶区体积,满足临床处方剂量要求;各阶段计划的相对剂量和绝对剂量的γ通过率都大于95%。结论:多靶区多中心多阶段的病例通过调强计划设计可实现靶区衔接处没有冷热点,剂量分布均匀。     

影像增强剂对脑瘤螺旋断层放疗剂量计算的影响

目的:研究影像增强剂对脑瘤螺旋断层放疗(HT)计划剂量计算的影响,探讨使用定位CT增强图像替代平扫图像用于靶区勾画和剂量计算的临床可行性。方法:收集30例脑瘤病例,所有病例均在增强图像上勾画靶区和危及器官轮廓,再把靶区和危及器官轮廓复制到平扫图像上。在HT计划系统中分别以增强图像和平扫图像设计两组放疗计划,比较两组靶区和危及器官的CT值、剂量分布和治疗时间。结果:两组图像的CT值在瘤区域(PGTV)处具有统计学差异(P0.05),其他组织CT值比较无统计学差异;计划靶区和危及器官的剂量学、治疗时间等参数的差异比较均无统计学差异(P0.05)。结论:影像增强剂对脑瘤HT计划剂量计算影响极小,脑瘤放疗中可以使用定位CT增强图像替代定位CT平扫图像用于靶区勾画和螺旋断层放疗计划剂量计算。     

巨块型非小细胞肺癌两种三维适形放疗计划方法的剂量学比较分析

目的:对巨块型局部晚期非小细胞肺癌制定三维适形放疗计划时,通过改变档块大小优化计划在不增加正常组织受照剂量的同时提高靶区剂量。材料与方法:应用STAR-2000计划系统,对15例巨块型局部晚期非小细胞肺癌分别制定T1、T2模式三维适形放疗计划,T1模式采用以PTV为主设3～4个照射野,档块外扩0 cm～0.2 cm,根据临床处方要求进行优化评估,T2模式是在T1模式3～4个照射野的基础上,PTV档块左右内收-1 cm～-1.5 cm,上下档块不变(0.2 cm)。另加两个照射野,PTV档块左右内收-1.7 cm～-2.5 cm,上下档块不变(0.2 cm),两照射野权重另加总权重的20%。通过体积直方图(DVH)分别统计比较两种模式下的PTV、CTV、GTV危及器官包括脊髓、双肺V20、V30、和心脏的剂量参数。用SPSS13.0软件对两模式计划单因素分析。结果:两模式下的PTV的D95双肺V20、V30、和心脏的各剂量变异均无统计学意义(P>0.05)靶区CTV、GTV的D95剂量差异均有统计学意义(P<0.05)。结论 :T2与T1模式相比,对靶区PTV档块内收进行剂量优化,靶区PTV边缘总剂量及危及器官(肺、脊髓、心脏)总剂量不变,而靶区CTV、GTV总剂量分别增加12%～20%,剂量的提升以期提高靶区的局部控制率。类似于调强放疗的同步加量。     

肝细胞癌共面和非共面容积旋转调强放疗与螺旋断层放疗的剂量学研究

目的:分析肝细胞癌共面和非共面容积旋转调强放疗(VMAT)与螺旋断层放疗(HT)的剂量学特点,比较三者在正常肝脏组织保护和靶区剂量分布的差异。方法:选取10例肝细胞癌患者,分别设计共面VMAT(C-VMAT)、非共面VMAT(NC-VMAT)和HT计划,通过DVH图评估不同计划的靶区和危及器官剂量学的差异。结果:HT靶区的最大剂量、平均剂量、D2以及均匀性指数(HI)均优于C-VMAT和NC-VMAT(P?0.05),3种计划在最小剂量、D98以及适形度指数(CI)方面无统计学意义。C-VMAT与NC-VMAT相比,两者仅在D98参数上具有统计学意义(P?0.05)。正常肝脏的低剂量区体积参数V5、V10,NC-VMAT具有明显优势,而肝脏高剂量区体积参数V40、V50,HT与C-VMAT和NC-VMAT相比具有一定优势。NC-VMAT的脊髓最大剂量与C-VMAT的相应值之间差异有统计学意义且最低。NC-VMAT的左、右肾Dmean优于C-VMAT计划,差异显著(P?0.05),3组计划的其余正常组织参数之间无明显差异。结论:3组计划均能满足处方剂量要求,HT产生更高的靶区均匀性的同时能够明显降低正常肝脏组织高剂量区的体积,而NC-VMAT计划可以减少患者正常肝脏低剂量区的体积。     

VMAT和dIMRT技术在鼻腔肿瘤放疗中的剂量学比较

目的：比较VMAT和dIMRT在鼻腔肿瘤放疗计划中的剂量学差异。方法：利用瓦里安Eclipse10.0计划系统对8例鼻腔肿瘤患者,分别设计单弧、非共面双弧VMAT计划和非共面5野dIMRT计划,在计划满足临床要求的前提下,利用剂量体积直方图（DVH）统计比较靶区的相关剂量学参数、敏感器官（OARs）的剂量体积参数以及机器总跳数（MY）、总治疗时间（T）。结果：本研究中三种计划的靶区剂量学参数,只有CTV的D2、Dmean有统计学差异（P〈0．05）,其余均无统计学差异（P〉0．05）;危及器官中,全脑的Dmean、脑干的D2、Dmean、左眼的Dmean、右视神经的D2、视交叉的Dmean、左腮腺的D2、Dmean、右腮腺的Dmean均有统计学差异（P〈0．05）,其余均无统计学差异（P〉0．05）;机器总跳数（MU）、总治疗时间（T）均有统计学差异（P〈0．001）。结论：三种治疗计划均能满足临床要求,危及器官的受量各有优缺点,VMAT计划能够明显减少机器总跳数和总治疗时间。综合考虑,笔者认为单弧VMAT计划应该是鼻腔肿瘤放疗的首选。     

基于图像变形配准的肺癌自适应放疗剂量学研究

目的:应用图像配准技术实现肺癌自适应放疗中剂量的累加,并评价放疗计划中靶区、正常组织和危及器官相应的剂量学改变。方法:选取9例接受自适应调强放射治疗的肺癌患者,这些患者在经过20次分次治疗后,重新采集CT图像,运用变形图像配准技术将2次CT图像进行剂量累加,得到累加剂量以及相关计量学参数,然后比较自适应放疗及常规的调强放射的剂量学差异。结果:经自适应放疗,大体肿瘤体积(GTV)体积相对于放疗前平均缩小53.2%,靶区肿瘤受照剂量相对于常规调强放疗计划平均提高0.41 Gy;肺组织V_(20)、V_(30)分别平均降低2.17%、3.32%;心脏V_(30)平均降低1.14%,V_(40)降低2.98%;脊髓最大受照剂量降低1.21 Gy。结论:肺癌放疗过程中,自适应放疗相对于常规调强放疗能提高靶区受照剂量,有效减少周围正常组织剂量,降低放疗副作用的发生。     

三维适型放疗与调强放疗在胸中段食管癌根治性放疗中的 剂量学比较

目的 比较胸中段食管癌三维适型放疗与调强放疗对靶区和危及器官的剂量学影响,探讨两种放射治疗方法在胸中段食管癌根治性放疗中重要器官受保护的优劣,寻找食管癌放射治疗的理想计划模式。方法 15例经病理证实胸中段食管鳞癌患者,经体位固定、CT模拟定位扫描成像传输到治疗计划系统、勾画肿瘤体积、临床靶区体积和危及器官。15例病例均做三维适型和调强计划,60 Gy/30次,评估/优化后应用剂量体积直方图比较两种计划对靶区及危及器官的剂量学影响。结果 在相同靶区、相同剂量模式下,对胸中段食管癌患者的放射治疗中,调强放疗对靶区剂量的分布及对危及器官的保护均优于三维适形放疗。结论 胸中段食管鳞癌,长度4~18 cm放射治疗,三维适型/调强放疗对危及器官剂量学的影响有明显差异。同部位的肿瘤受到相同剂量照射情况下,调强放疗对危及器官的影响较三维适型放疗小,靶区剂量分布均匀度好。     

鼻腔鼻咽部淋巴瘤:319例会诊病例分析

目的探讨鼻腔鼻咽部淋巴瘤的临床特点、病理分型及类型构成。方法回顾性分析首都医科大学附属北京友谊医院病理科319例鼻腔鼻咽部淋巴瘤会诊病例的临床资料、病理组织学特征及免疫表型,按WHO(2008)分类标准进行病理诊断及分类,并对统计结果进行对比分析。结果 319例会诊病例中,3例(0.9%)诊断为霍奇金淋巴瘤混合细胞型,考虑肿瘤累及鼻咽,建议全身检查;316例均为非霍奇金淋巴瘤(99.1%),包含非霍奇金T和NK细胞起源淋巴瘤177例(56.0%)、B细胞起源淋巴瘤139例(44.0%)。发病率位于前两位的是NK/T细胞淋巴瘤鼻型160例(50.6%)、弥漫大B细胞淋巴瘤64例(20.3%)。NK/T细胞淋巴瘤发病率高于弥漫大B细胞淋巴瘤。≥60岁的患者106例(33.2%)诊断均为非霍奇金淋巴瘤,其中弥漫大B细胞淋巴瘤40例(37.7%)、NK/T细胞淋巴瘤36例(34.0%),弥漫大B细胞淋巴瘤与NK/T细胞淋巴瘤发病率无统计学意义。60岁的非霍奇金淋巴瘤患者210例(66.5%),其中NK/T细胞淋巴瘤124例(59.0%)、弥漫大B细胞淋巴瘤24例(11.4%),发病率差异有显著性。结论 316例鼻腔鼻咽部非霍奇金淋巴瘤中以NK/T细胞淋巴瘤最为多见,第二位是弥漫大B细胞淋巴瘤;≥60岁老人鼻腔鼻咽部淋巴瘤患者弥漫大B细胞淋巴瘤、NK/T细胞淋巴瘤最为多见,两者之间发病率差异无显著性。     

20例胸中段食管癌根治性放射治疗IMRT与TOMO剂量学比较

目的:对比固定野静态调强放射治疗（IMRT）与螺旋断层放射治疗（TOMO）两种方案治疗胸中段食管癌的剂量学特点,指导临床治疗方案选择。 方法:采用IMRT与TOMO两种技术,处方剂量计划靶区（PTV）:DT 54 Gy/30 F,肿瘤靶区（PGTV）:DT 66 Gy/30 F,主要比较两种方案的靶区剂量学差异。 结果:TOMO组的PTV最大剂量（D2）、中位剂量（D50）以及均匀性指数均低于IMRT组,最小剂量（D98）、适形度指数明显高于IMRT组,以上差异均有统计学意义（P<0.05）;两者的PGTV除D98的差异无明显统计学意义外,其余各指标均与PTV保持一致,有统计学意义（P<0.05）。 结论:胸中段食管癌根治性放射治疗TOMO计划靶区剂量分布及适形度明显优于IMRT计划,危及器官各评级指标显示前者亦优于后者。     

Nodal T/NK-cell lymphoma of nasal type: a clinicopathological study of six cases

Aims:  To investigate the clinicopathological features of six unusual cases of nodal CD56+ and Epstein–Barr virus (EBV)+ T/natural killer (NK)-cell lymphoma, a putative nodal counterpart of nasal NK/T-cell lymphoma (nodal T/NK-cell lymphoma of nasal type) in comparison with nasal NK/T-cell lymphoma with secondary lymph node involvement ( n  = 24) and peripheral T-cell lymphoma (PTCL) of cytotoxic molecule (CTM)+ and EBV+ type ( n  = 21).
Methods and results:  All cases of nodal T/NK-cell lymphoma of nasal type exhibited diffuse infiltration of pleomorphic medium-sized to large tumour cells, reminiscent of those in CTM+ EBV+ PTCL. The tumour cells had a typical phenotype of nasal NK/T-cell lymphoma: CD2+, CD3ε+, CD4−, CD5−, CD56+, T-cell intracellular antigen-1+, granzyme B+, perforin+ and EBV+. However, four of six cases demonstrated clonal T-cell receptor γ-gene rearrangement on polymerase chain reaction analysis, unlike nasal NK/T-cell lymphoma. Comparison of clinical parameters and overall survival among the three groups demonstrated only minor differences.
Conclusions:  Nodal T/NK-cell lymphoma may occupy the grey zone between extranodal nasal-type NK/T-cell lymphoma and nodal CTM+ PTCL in a spectrum of NK to T-cell lymphomas that are EBV+. The close relationship between NK/T-cell lymphomas and cytotoxic T-cell lymphomas was also substantiated.     

963例成熟T和自然杀伤细胞/T细胞淋巴瘤的临床病理特征分析

目的 观察广东地区不同类型成熟T和自然杀伤(NK)细胞/T细胞淋巴瘤及其亚型的临床病理特点.方法 按WHO(2008版)标准重新评估广东地区2002-2006年1137例成熟T和NK/T细胞淋巴瘤患者.由多名血液病理医师复查,补做必要的免疫组织化学染色及原位杂交.结果 963例确诊为成熟T和NK/T细胞淋巴瘤,占同期所有淋巴瘤20.1%(963/4801),发生于结内319例(33.1%),结外644例(66.9%);非特殊型外周T细胞淋巴瘤293例(30.4%);结外鼻型NK/T细胞淋巴瘤281例(29.2%);间变性大细胞淋巴瘤(ALCL)198例(20.6%);血管免疫母细胞性T细胞淋巴瘤(AILT)46例(4.8%).男女比为1.99:1,发病中位年龄为44岁.非特殊型外周T细胞淋巴瘤好发于55～64岁;结外鼻型NK/T细胞淋巴瘤好发于25～54岁;间变性淋巴瘤激酶(ALK)阳性ALCL多见于年轻人而阴性多见于中老年人;AIIJT好发于65～74岁.结论 广东地区成熟T和 NK/T细胞淋巴瘤多见于结外,好发于男性,总体发病与年龄增长无明显关系,但具体类型有不同的年龄侧重群;常见的类型依次为非特殊型外周T细胞淋巴瘤、结外鼻型NK/T细胞淋巴瘤及ALCL;EB病毒感染与NK/T细胞淋巴瘤关系密切.     

结外鼻型NK/T细胞淋巴瘤中EB病毒潜伏膜蛋白1基因30 bp碱基缺失的检测意义及其与预后的关系

目的 比较结外鼻型NK／T细胞淋巴瘤和鼻咽部慢性炎症和扁桃体炎中EB病毒潜伏膜蛋白（LMP）1基因30bp碱基缺失的检出率,初步探讨结外鼻型NK／T细胞淋巴瘤中LMP1缺失型的检出意义及其与预后的关系。方法 通过聚合酶链反应（PCR）检测55例结外鼻型NK／T细胞淋巴瘤和19例鼻咽部慢性炎症和扁桃体炎中EB病毒LMP1基因30bp的缺失情况,结合随访资料进行分析。结果 结外鼻型NK／T细胞淋巴瘤中LMP1野生型和野生为主型9例,LMP1缺失型和缺失为主型46例;鼻咽部慢性炎症和扁桃体炎中LMP1缺失型和缺失为主型16例。LMP1缺失型和缺失为主型的检出率在NK／T细胞淋巴瘤与鼻咽部慢性炎症和扁桃体炎病例间差异无统计学意义（P〉0．05）。结外鼻型NK／T细胞淋巴瘤中LMP1野生型和野生为主型病例比缺失型和缺失为主型病例预后好。结论 不能简单地将LMP1缺失型作为结外鼻型NK／T细胞淋巴瘤的致病因素,但也不能完全否定其促进该淋巴瘤演进的作用。     

Evaluation of dosimetric margins in prostate IMRT treatment plans

This work introduces a new concept--the dosimetric margin distribution (DMD)--and uses it to explain the sensitivity of a group of prostate IMRT treatment plans to patient setup errors. Prior work simulated the effect of setup errors on 27 prostate IMRT treatment plans and found the plans could tolerate larger setup errors than predicted by the van Herk margin formula. The conjectured reason for this disagreement was a breakdown in van Herk's assumption that the planned dose distribution conforms perfectly to target structures. To resolve the disagreement, this work employed the same 27 plans to evaluate the actual margin distributions that exist between: (i) the clinical target volume (CTV) and planning target volume (PTV) and (ii) the CTV and PTV minimum dose isodose surface. These distributions were evaluated for both prostate and nodal targets. Distribution (ii) is the DMD. The dosimetric margin in a given direction determines the probability that the CTV will be underdosed due to setup errors in that direction. Averaging over 4 pi sr gives the overall probability of CTV coverage. Minimum doses for prostate and nodal PTVs were obtained from dose volume histograms. Corresponding isodose surfaces were created and converted to regions of interest (ROIs). CTV, PTV, and isodose ROIs were saved as mesh files and then imported into a computational geometry application which calculated distances between meshes (i.e., margins) in 614 discrete directions covering 4 pi sr in 10 deg increments. Measured prostate CTV-to-PTV margins were close to the nominal value of 0.5 cm specified in the treatment planning protocol. However, depending on direction, prostate dosimetric margins ranged from 0.5 to 3 cm, reflecting the imperfect conformance of the planned dose distribution to the prostate PTV. For the nodal CTV, the nominal CTV-to-PTV margin employed in treatment planning was again 0.5 cm. However, due to the planning protocol, the nodal PTV follows the surface of the nodal CTV in several places, ensuring that there is no room for rigid body motion of the nodal CTV inside the nodal PTV. Measured nodal CTV-to-PTV margins were therefore zero, while nodal dosimetric margins ranged from 0.2 to 2.8 cm. Prostate and nodal target coverage were found to be well correlated with the measured DMDs, thereby resolving the apparent disagreement with our prior results. The principal conclusion is that target coverage in the presence of setup errors should be evaluated using the DMD, rather than the CTV-to-PTV margin distribution. The DMD is a useful planning metric, which generalizes the ICRU conformity index. DMDs could vary with number of beams, beam arrangements, TPS, and treatment site.     

Expression of cyclin-dependent kinase 6 (cdk6) and frequent loss of CD44 in nasal-nasopharyngeal NK/T-cell lymphomas: comparison with CD56-negative peripheral T-cell lymphomas

Lymphomas involving the nasal and nasopharyngeal region mainly include CD56-positive natural killer (NK)/T-cell lymphomas, CD56-negative peripheral T-cell lymphomas (PTL), and B-cell lymphomas. Among these, the CD56-positive lymphoma, presumably of an NK/T-cell nature, is frequently seen in Asian, Mexican, and South American patients. NK cells are proposed to be closer developmentally to T cells than to other lymphoid cells, because bipotential common progenitor cells of NK/T-cell lineage have been isolated. In this study, we collected 47 cases of nasal lymphoma and investigated the phenotypic difference between NK/T-cell lymphoma and PTL by examining the pattern of the developmentally differentially expressed molecules cdk6 (cyclin-dependent kinase 6), CD44, CD117, and by examining the rearrangement of the T-cell receptor gene (TcR-GR). cdk6, an essential regulator of the cell cycle in G1 progression, was over-expressed in a subset of cortical thymocytes, but absent in mature thymocytes. In contrast, CD44, a glycosylated adhesion molecule, was absent in cortical thymocytes, but present in mature thymocytes and peripheral activated T cells. We found both over-expression of nuclear cdk6 (n-cdk6) and frequent absence of CD44 in nasal CD56-positive NK/T-cell lymphomas, in contrast to most nasal CD56-negative PTL, which were CD44-immunoreactive with weak or no expression of n-cdk6. Almost all tested cases of NK/T-cell lymphoma displayed a germ-line configuration of TcR, without evidence of gene rearrangement. Thus, there seems to be a useful distinction between the classical NK/T type of nasal lymphoma (CD56+/n-cdk6+/CD44-/TcR-GR-) and PTL (CD56-/n-cdk6-/CD44+/TcR-GR+) involving the nasal region. The presence of Epstein-Barr virus does not seem to be a good marker for distinguishing between NK/T lymphoma and PTL involving the nasal region.     

常规QA设备对脊柱转移瘤SRS/SBRT计划的验证及存在问题探讨

目的:对比aSi-1200 EPID与Octavius 1500电离室矩阵在6 MV非均整脊柱转移瘤计划验证中的应用,探讨可能存在的问题。方法:23例计划在全局归一方式下以不同标准和阈值行2D γ通过率（GPR）评估,将治疗计划系统（TPS）中患者数据导入Verisoft软件重建剂量。引入不同类型和量值的误差:MLC的透射率（TF）和剂量叶片间隙（DLG）、治疗等中心和MU误差,使用GPR方法量化Octavius 1500识别这些误差的灵敏度,并通过评估靶区和危及器官（OARs）剂量学指标变化研究TF和DLG误差的临床意义。结果:与Octavius 1500矩阵相比,EPID方式在同一标准不同阈值下GPR均值更大数据离散程度更小,重建与计算的剂量体积直方图分析表明临床靶区和计划靶区Dmin、Dmax和Dmean的百分剂量偏差（DD%）较大,其中临床靶区最大DD%值为50.00%、11.31%和-8.71%,计划靶区最大DD%值为-25.86%、9.31%和-8.22%。治疗等中心和+3%、+5%的MU误差都被检测到,所有标准均未检测到TF误差,+0.3 mm的DLG误差只被2%/3 mm的标准检测到。TF值增大0.023 6％模型误差和DLG增加0.3 mm模型误差均导致靶区和OARs的剂量增加,其中OARs剂量增加较明显,尤其健侧肺的V20分别增加9.80%和8.85%,脊髓D0.1 cc均增加5.35%。结论:使用GPR方法识别引入误差的MLC模型可靠性不够,提示鉴别TPS问题的根源需要更有效的独立质量保证方法以确保通过TPS计算得出的陡峭剂量梯度的可信度。剂量验证系统软件算法的独立验证研究是有必要的,以确定算法局限性导致的重建剂量不确定性范围。     

Nasal natural killer/T-cell lymphoma and its association with type "i"/XhoI loss strain Epstein-Barr virus in Chile

BACKGROUND: Nasal T/natural killer (NK)-cell lymphoma is an aggressive type of non-Hodking's lymphoma associated with Epstein-Barr virus (EBV) and striking geographical variations worldwide. AIM: To characterise nasal NK/T-cell lymphoma associated with genotypes of EBV in Chile, a Latin American country, where multiple strains of EBV, including two new recombinant strains, in healthy individuals were recently found. METHODS: Cases with diagnosis of primary nasal lymphoma were selected for histological and immunohistochemical analysis (CD3, CD3e, CD4, CD8, CD79a, CD56, CD57 and TIA-1) and in-situ hybridisation, serology and genotyping analysis for EBV. RESULTS: Out of 22 cases, 9 (41%) cases fulfilled the World Health Organization criteria for nasal NK/T-cell lymphoma; of these 7 (78%) cases were positive for EBV. Genotyping analysis revealed 6 cases of type 1 EBV and wildtype F at the BamHI-F region, 4 cases type "i" EBV at the BamHI-W1/I1 region; XhoI wild type was found in 2 and XhoI loss in 4 cases, respectively. Cosegregation analysis of the BamHI-W1/I1 region and XhoI restriction site showed the new recombinant strain type "i"/XhoI loss in 3 cases and type "i"/XhoI wild-type strain in 1 case. Most patients were treated with combined anthracycline-containing regimens. Half of the cases attained complete remission. CONCLUSION: Although nasal NK/T-cell lymphomas from Chile share similar clinicopathological features, high association with EBV and unfavourable prognosis with those described elsewhere, genotype analysis shows that the new recombinant type "i"/XhoI loss strain might contribute to explain the intermediate incidence of nasal NK/T-cell lymphomas in Latin America.