宫颈癌术后容积弧形调强与固定野动态调强放疗技术的剂量学比较

目的 比较宫颈癌术后放疗中容积弧形调强放射治疗(VMAT)与固定野动态调强放射治疗(dIMRT)的靶区剂量分布、危及器官受照剂量及治疗时间,为临床治疗选择放疗技术提供依据。方法 选取10例宫颈癌术后患者,在Monaco5.11计划系统中分别对每例患者进行容积弧形调强和7野固定野动态调强放疗计划设计,比较两种技术的靶区和危及器官的剂量分布,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46.86Gy,略高于dIMRT技术的46.68Gy(P＜0.05),直肠的V₁₀,V₂₀和小肠V₃₀受照剂量VMAT比dIMRT技术分别高了0.63%,3.34%和4.14%(P＜0.05),靶区的均匀性、适形度和其他危及器官的受照剂量相比,两者没有统计学意义,机器跳数和治疗时间VMAT比dIMRT计划分别减少13.4%和50.6%(P＜0.05)。结论 VMAT技术与dIMRT技术相比剂量分布相当或略优,机器跳数和治疗时间明显减少,在临床应用上对于宫颈癌术后患者建议使用VMAT技术。     

宫颈癌术后限定骨盆骨髓剂量调强放疗剂量学研究

目的 比较非限定骨髓剂量的调强放疗（intensity modulated radiotherapy,IMRT）和限定骨髓剂量的调强放疗（bone marrow sparing intensity modulated radiotherapy,BMS-IMRT）在宫颈癌术后靶体积剂量覆盖及危及器官保护中的差异,探讨BMS-IMRT治疗计划的临床应用价值。方法 对13例宫颈癌术后患者进行CT模拟定位,在医师工作站勾画临床靶体积（clinical target volum,CTV）,CTV 均匀外扩1 cm 生成计划靶体积（planning target volum,PTV）,勾画小肠、直肠、膀胱、骨髓等危及器官（organ at risk,OAR）。利用Monaco 5.11计划系统设计IMRT和BMS-IMRT两种治疗计划,PTV 95％体积要求达到处方剂量50 Gy,比较靶区各项指标及OAR体积剂量参数。结果 BMS-IMRT计划的靶区剂量均匀性不如IMRT,靶区平均剂量提高0.36%,差异有统计学意义（P<0.05）。BMS-IMRT治疗计划的通过率下降,其中绝对剂量通过率差异有统计学意义［（99.466±0.150）% vs （99.750±0.175）%,t=3.576,P=0.016］。BMS-IMRT治疗计划中骨髓的V₁₀、V₂₀、V₃₀、V₄₀分别比IMRT下降1.99％、10.30％、13.79％、26.46％,差异有统计学意义（P<0.05）。两种治疗计划小肠V₄₅和V₃₀、膀胱V₄₀、直肠V₄₀和V₅₀等差异无统计学意义（P>0.05）。结论 宫颈癌术后BMS-IMRT和IMRT计划剂量差别不明显,BSM-IMRT可降低骨髓剂量受照体积,值得临床推广应用。     

直肠癌术后固定剂量率容积调强放射治疗的初步研究

目的 初步探讨固定剂量率容积调强在直肠癌术后盆腔放射治疗中的可行性。方法 选取10例直肠癌放疗患者,利用RayStation计划系统为每例患者制定可变剂量率容积调强(VDR-VMAT)、固定剂量率容积调强(CDR-VMAT)和5野静态调强(5F-sIMRT)计划。运用剂量体积直方图评估三种计划的靶区、危及器官和正常组织剂量学参数,评估机器总跳数(MU)和计划执行时间。结果 靶区剂量方面,三种计划的靶区D2%、D_mean、D98%、HI和CI在总体上均有差异(P＜0.001)。CDR-VMAT与VDR-VMAT相比较,D2%、D_mean、D98%、HI、CI差异均无统计学意义;CDR-VMAT与5F-sIMRT相比较,D2%减小1.55 Gy(P=0.005)、D_mean减小0.99 Gy(P=0.005)、D98%增大0.60 Gy(P=0.03)、HI值减小(P=0.008)、CI值增大(P=0.008)。危及器官方面,三种计划的膀胱D_mean、V₄₅、V₄₀,小肠D_mean、D_max、V₄₅,左右股骨头D_mean在总体上均有差异(P＜0.05);小肠V₄₀、V₃₅,左右股骨头V₄₅、V₄₀在总体上均无差异(P＞0.05)。CDR-VMAT与VDR-VMAT相比较,膀胱、小肠、左右股骨头的各剂量学参数差异无统计学意义;CDR-VMAT与5F-sIMRT相比较,膀胱D_mean减小3.05 Gy(P=0.005)、V₄₀减小0.88%(P=0.042),小肠D_mean减小1.75 Gy(P=0.002)、D_max减小1.70 Gy(P＜0.001),左、右股骨头D_mean减小(P=0.008,0.042)。正常组织低剂量受照体积方面,三种计划的正常组织受照低剂量体积除V₁₀(P=0.497)之外,V₅、V₁₅、V₂₀、V₂₅和V₃₀在总体上均有差异(P＜0.001)。CDR-VMAT与VDR-VMAT相比,V₅、V₁₀、V₁₅、V₂₀、V₂₅和V₃₀差异无统计学意义;与5F-sIMRT相比,CDR-VMAT的V₅减小1.18%(P=0.005)、V₁₅减小0.61%(P=0.022)、V₃₀减小0.80%(P=0.022),V₁₀、V₂₀和V₂₅差异无统计学意义。CDR-VMAT计划的MU为(668.51±45.92),比VDR-VMAT(574.13±50.20)增加16.44%,比5F-sIMRT(537.19±37.34)增加24.45%;CDR-VMAT计划执行时间(3.34±0.22)min是VDR-VMAT(1.76±0.04)min的近两倍,比5F-sIMRT(4~6)min稍短。结论 CDR-VMAT可形成与VDR-VMAT一样高质量的计划,较5F-sIMRT有更优的靶区覆盖率、危及器官保护和正常组织低剂量受照体积。但CDR-VMAT计划的MU比VDR-VMAT和5F-sIMRT增多;执行时间比VDR-VMAT长,比5F-sIMRT稍短。CDR-VMAT初始成本较低,有望为不具备可变剂量率的直线加速器提供额外的旋转放疗的选择。     

两种算法在宫颈癌术后调强放疗中的剂量学比较研究

目的: 比较蒙特卡罗算法与筒串卷积算法在宫颈癌术后调强放射治疗中的剂量学差异。方法: 随机选择25例宫颈癌术后行调强放疗患者,对同一治疗计划分别用两种算法进行剂量计算,通过剂量体积直方图的剂量体积参数比较两者靶区和危及器官的剂量学差异。结果: 靶区D₉₈、D₂、D₅₀、HI蒙特卡罗算法结果低于筒串卷积算法（P﹤0.05）;CI结果高于筒串卷积法（P﹤0.05）。膀胱V₃₀、V₄₀,直肠V₄₀、D₅₀,股骨头、盆骨V₃₀、V₄₀、D₅₀,脊髓D₂、D₅₀蒙特卡罗算法结果低于筒串卷积算法;靶区CI、结肠V₃₀、V₄₀、D₅₀ 蒙特卡罗算法结果高于筒串卷积算法,以上结果差异均具有统计学意义（P﹤0.05）。结论: 宫颈癌术后调强放射治疗,优先选择蒙特卡罗算法进行计划设计,同时应适当充盈膀胱,减少小肠、结肠卷入射野的体积;如果只能选用筒串卷积算法,应适当增大最小子野面积,减少子野数量。     

乳腺癌术后放疗H-IMRT技术与H-VMAT技术剂量学比较

目的 比较基于IMRT的混合调强计划(H-IMRT)与基于VMAT的混合容积调强计划(H-VMAT)在左侧乳腺癌根治术后(胸壁+锁骨上+內乳区)放射治疗计划的剂量学参数,为复杂的乳腺癌术后放疗计划设计提供一定的参考。方法 选取我院2018年1月—2020年12月,20例左侧乳腺癌根治术后患者。所有患者胸壁、锁骨上淋巴结、内乳淋巴结均需要接受放射治疗,每个患者分别设计制作H-IMRT与H-VMAT两种放疗计划。CRT射野对胸廓方向进行2cm的多叶准直器(MLC)外放。靶区处方剂量50Gy,通过剂量计算比较靶区和危及器官的剂量参数。结果 H-IMRT计划靶区均匀性指数为(0.13±0.06),适形指数为(1.33±0.08)。H-VMAT计划靶区均匀性指数为(0.12±0.04),适形指数为(1.24±0.07)。H-VMAT计划中靶区均匀性指数和适形指数均高于H-IMRT计划(P＜0.05)。H-IMRT计划患肺V₅(48.99±2.91)%、V₂₀(24.5±1.1)%,H-VMAT计划患肺V₅(45.87±3.53)%、V₂₀(20.6±1.6)%,H-VMAT计划患肺V₅和V₂₀剂量均低于H-IMRT计划(P＜0.05)。H-IMRT计划心脏V₃₀(10.44±3.62)%、V₄₀(6.59±3.53)%,H-VMAT计划心脏V₃₀(5.87±1.53)%、V₄₀(4.9±2.8)%,H-VMAT计划心脏V₃₀和V₄₀均低于H-IMRT计划(P＜0.05)。H-IMRT计划心脏D_mean(7.43±1.78)Gy,H-VMAT计划心脏D_mean(9.7±0.7)Gy,H-VMAT计划略高于H-IMRT计划(P＜0.05)。结论 对于带有內乳淋巴结的乳腺癌术后放疗靶区,H-VMAT对比H-IMRT靶区适形度更好,危及器官受照剂量更低。     

宫颈癌术后盆腔容积调强弧形治疗与固定野调强放疗计划的剂量学研究

目的 研究宫颈癌术后患者应用固定野调强放疗(FF-IMRT)和容积调强弧形治疗(VIMAT)计划剂量学差异。方法 选择 13例宫颈癌术后调强放疗患者CT模拟定位并勾画靶区及危及器官,对同一CT图像设计FF-IMRT计划和VIMAT计划,评估计划靶体积(PTV)及危及器官的剂量学参数。两种计划参数比较用配对t检验。结果 与FF-IMRT计划相比,VIMAT计划PTV的95%覆盖度增加(t=9.84,P=0.000)、110%覆盖度降低(t=－3.72,P=0.003)、最大剂量(D_max)降低(t=－3.51,P=0.005)、适形指数变差(t=5.93,P=0.000),但PTV105%覆盖度、平均剂量(D_mean)、不均匀指数均相似(t=－0.02、－0.60、1.13,P=0.842、0.560、0.283);膀胱 V₃₀降低约10%(t=－4.99,P=0.000)、D_mean降低1.4 Gy (t=－3.65,P=0.004)、D_max降低1.5 Gy (t=－18.03,P=0.000),直肠 V₄₀降低约10%(t=－2.99,P=0.012),D_mean降低0.6 Gy (t=－2.98,P=0.013)、D_max降低0.8 Gy (t=－4.05,P=0.002),小肠 V₄₀降低最多(10%)(t=－4.74,P=0.001)、D_max降低0.8 Gy (t=－9.45,P=0.000),骨髓 V₅₀降低最多(16%)(t=－4.04,P=0.002)、D_mean降低1.9 Gy (t=－16.21,P=0.000),左、右股骨头 D₅和马尾神经 D_max分别降低1.6、2.7 Gy和1.5 Gy (t=－2.89、－6.22、－4.80,P=0.015、0.000、0.001);机器跳数减少57%(t=－40.54,P=0.000)。结论 宫颈癌患者采用VIMAT技术可获得等同于或优FF-IMRT计划的剂量分布,机器数量明显降低,但其疗效还需进一步临床评估。     

宫颈癌图像引导下调强放疗中危及器官变化对靶区的影响

目的 探讨晚期宫颈癌患者调强放疗中危及器官体积及位置变化对靶区的影响。方法 选取行图像引导下调强放疗宫颈癌患者16例，分别于放疗剂量达9 Gy/5f、18 Gy/10f、27 Gy/15f、36 Gy/20f及48.6 Gy/27f时用锥束CT（CBCT）扫描，采集CBCT图像，与原始治疗计划CT图像配准，分别在CT和CBCT图像中勾画大体肿瘤靶区及危及器官，比较危及器官体积、体积变化率及DICE相似度指数（dice's similarity coefficient，DSC） 。结果 放疗0~27分次膀胱、直肠、乙状结肠与小肠体积范围分别为88.48~195.49 cm³、40.41~42.93 cm³、792.85~907.86 cm³、38.49~49.05 cm³。膀胱0~27 分次体积变化差异有统计学意义（P=0.002），其余器官体积变化差异无统计学意义（P>0.05）。膀胱、直肠、乙状结肠及小肠0~27分次体积变化率和DSC差异均无统计学意义（P＞0.05）。膀胱、直肠体积变化率与宫颈靶区、宫体的DSC均呈负相关（P<0.05）。结论 宫颈癌调强放疗中膀胱、直肠等体积与位置变化较大，其变化可能影响宫颈靶区、子宫体的空间位置。     

宫颈癌术后正向调强放射治疗计划的设计

[目的]探讨宫颈癌术后正向调强放射治疗计划的设计方法。[方法]15例宫颈癌术后患者,给予50.4Gy的处方剂量,分28次完成。依据靶区形状与大小并考虑危及器官耐受量的同时,使用多叶准直器（MLC）预设照射野方向和形状,通过一系列的射野优化与射束调整,获得符合临床要求的正向调强计划。[结果]15例宫颈癌术后患者的正向调强放疗计划,其适形度CI为0.6-0.8,平均0.71,平均照射野数18个,跳数444。而四野计划的CI只有0.54,正向调强计划提高了靶区适形度CI,且大大降低了危及器官直肠、膀胱、股骨头、小肠在高剂量区45Gy、50Gy等剂量水平的相对受照体积。45Gy时,直肠、膀胱、股骨头、小肠的受照体积分别降低55%、44%、47%、26%;50Gy时则分别为86%、63%、70%、43%。[结论]宫颈癌正向调强放疗计划优于四野适形计划,可操作性强,掌握一定的方法和技巧后,通过合理布野,可得到符合临床要求的放疗计划。     

前列腺癌多目标优化VMAT计划剂量学研究

目的 探讨多目标优化在前列腺癌VMAT计划中的应用。方法 随机抽取已接受治疗的14例前列腺癌患者VMAT计划资料。这些计划基于单目标优化,保持优化条件不变,改用多目标优化。配对t检验两种计划剂量学参数差异。结果 两种计划均满足临床要求,与单目标计划相比,多目标计划PTV 95%、100%处方剂量覆盖度增加(P=0.000、0.000),105%处方剂量覆盖度降低(P=0.000),D_max降低0.35 Gy (P=0.063);直肠V₂₀、V₃₀、V₄₀、V₅₀和D_mean分别降低24.7%、36.8%、31.1%、20.5%和6.8 Gy (P=0.000、0.000、0.000、0.001、0.000),D₂cc增加1.4 Gy (P=0.000);膀胱V₁₀、V₂₀、V₃₀、V₄₀、V₅₀和D_mean分别降低5.7%、18.5%、20.9%、12.5%、5.4%和3.5 Gy (P=0.006、0.000、0.000、0.000、0.002、0.000);小肠V₁₀、V₂₀、V₃₀和D_mean多目标计划有优势。结论 多目标计划在满足靶区剂量情况下可以进一步降低OAR剂量,但结果还需进一步研究和评估。     

造影剂对食管癌调强放疗剂量分布的影响

目的:比较有无造影剂对食管癌放疗靶区及危及器官剂量分布的影响。方法:选择食管癌患者12例,分别采集平扫和增强的CT断层图像传入计划系统。在增强CT图像上勾画靶区、危及器官和设计优化调强放疗计划。采用两种比较方案:①将勾画轮廓及计划复制到CT平扫上重新计算与原计划进行比较;②将勾画轮廓及优化条件复制到CT平扫上重新优化计算后与原计划进行比较。结果:Body、PTV、肺、心脏的电子密度在有造影剂时较高。方案①靶区在D_2%、D_50%、D_95%、D_98%、Body_95%、CI和HI有造影剂的情况下的计划小于平扫。两者之间的机器跳数（MU）没有统计学差异。危及器官肺V₅、V₂₀、D_mean;心脏V₄₀及D_mean;脊髓最大剂量在有造影剂的情况下较少。方案②两者在靶区D_2%、D_50%、D_95%、D_98%、Body_95%、CI、HI;肺V₅、V₂₀、D_mean;心脏V40及D_mean;脊髓最大剂量之间无统计学差异。在MU方面,无造影剂时较少。结论:静脉注射造影剂对食管癌调强放疗剂量分布的影响很小,临床上可以接受这样的误差,但在平扫上优化治疗计划可以得到更精确的剂量。     

Endorectal balloon reduces anorectal doses in post-prostatectomy intensity-modulated radiotherapy

Background and purpose

To investigate the effect of an endorectal balloon (ERB) on anal wall (Awall) and rectal wall (Rwall) doses in high-dose post-prostatectomy intensity-modulated radiotherapy (IMRT).

Materials and methods

For 20 patients, referred for salvage IMRT after prostatectomy for prostate cancer, two planning CT-scans were performed: one with and one without an air-filled ERB. A planning target volume (PTV) was defined, using international guidelines. Furthermore, the Awall and Rwall were delineated. In both the scans, IMRT plans were generated with a prescribed dose of 70 Gy. The mean dose (D_mean), maximum dose, minimum dose, and volumes exposed to doses ranging from ?20 to ?70 Gy (V₂₀-V₇₀) to the Awall and Rwall were calculated. Finally, inner Rwall surface areas exposed to doses ranging from ?20 to ?70 Gy (A₂₀-A₇₀) were calculated. Dose-parameters were compared between plans with and without ERB.

Results

All Awall parameters, except V₇₀, were significantly reduced by the ERB with an overall D_mean reduction of 6 Gy. Absolute reductions in dose-volume parameters varied from 5% to 11%. Significantly reduced Rwall V₃₀, V₄₀, and A₄₀ were observed with ERB, irrespective of the target volume size.

Conclusion

ERB application significantly reduces Awall and to a lesser degree Rwall doses in high-dose post-prostatectomy IMRT.     

基于11C-MET PET-CT与MRI对脑胶质瘤精确放疗GTV勾画的比较研究

目的 探讨¹¹C-MET PET-CT和MRI图像对脑胶质瘤GTV确定的差异。方法 选取6例经病理证实为胶质瘤患者的术前MRI及¹¹C-MET PET-CT图像,分别由我科5位医师在两种图像资料上勾画GTV,比较两者差异。结果 在MRI¹¹C-MET PET-CT上勾画的GTV体积相似(P=0.917),GTV变异系数也相似(P=0.600)。勾画的GTV重合度最大为73.0%、最小为51.8%。方差分析显示不同勾画者之间在两种图像资料上勾画的GTV相似(P=0.709),但PET-CT组GTV最大差值为27.66 cm³,而MRI组的为40.37 cm³。结论 MRI与PET-CT显示的肿瘤边界存在差异,不同勾画者勾画的GTV相似,PET-CT组的GTV最大差值较MRI组的小,¹¹C-MET PET-CT显示GTV较为直观。     

调强放疗条件下鼻咽癌原发肿瘤体积对预后的影响

目的 探讨调强放疗条件下鼻咽癌原发肿瘤体积(PTV)对患者预后的影响。方法 330例接受调强放疗的鼻咽癌初治患者入组本研究。所有患者治疗前均行CT增强扫描,扫描图像资料输人三维治疗计划系统进行肿瘤轮廓勾画和PTV计算。在国际抗癌联盟2002年T分期框架内借助受试者工作特征曲线,将所有患者按PTV大小分为V₁(<10 cm³)、V₂(10~ 25 cm³)、V₃(>25~50 cm³)、V₄(>50 cm³)组。用 Kaplan Meier 法计算生存率并 Logrank 检验, Cox 回归模型分析原发肿瘤体积与患者预后的关系。结果 随访率100%。330例 鼻咽癌患者所测平均PTV为(34.2±27.1) cm³(0.4~153.7 cm³)。V₁、V₂、V₃、V₄组 3年总生存率分别为88.6%、90.0%、91.2%、74.2%(χ²=12.83, P=0.005)。PTV>50 cm³ (V₄组)和≤50 cm³(V₁+V₂+V₃) 者 3年无远处转移生存率和无瘤生存率及总生存率均明显下降 [77.4%∶89.9%(χ²=7.24, P=0.007)和64.5%∶85.1%(χ²=13.95, P=0.000) 及74.2%∶90.3% (χ²=11.76, P=0.001)]。多因素分析证实PTV同N分期一样,是影响患者生存的预后因素(χ²=0.00, P=2.580)。结论 鼻咽癌PTV可能是影响患者生存的一个重要的预后因素。     

Improving bladder cancer treatment with radiotherapy using separate intensity modulated radiotherapy plans for boost and elective fields

The aim of this study is to investigate to what extent IMRT can decrease the dose to the organs at risk in bladder cancer treatment compared with conformal treatment while making separate treatment plans for the elective field and the boost. Special attention is paid to sparing small intestines. Twenty patients who were treated with the field-in-field technique (FiF) were re-planned with intensity modulated radiotherapy (IMRT) using five and seven beams, respectively. Separate treatment plans were made for the elective field (including the pelvic lymph nodes) and the boost, which enables position correction for bone and tumour separately. The prescribed dose was 40 Gy to the elective field and 55 or 60 Gy to the planning target volume (PTV). For bladder and rectum, V_45Gy and V_55Gy were compared, and for small intestines, V_25Gy and V_40Gy. The dose distribution with IMRT conformed better to the shape of the target. There was no significant difference between the techniques in dose to the healthy bladder. The median V_40Gy of the small intestines decreased from 114 to 66 cc (P = 0.001) with five beam IMRT, and to 55 cc (P = 0.001) with seven beam IMRT compared with FiF. V_45Gy for rectum decreased from 34.2% to 17.5% (P = 0.004) for both five and seven beam plans, while V_55Gy for rectum remained the same. With IMRT, a statistically significant dose decrease to the small intestines can be achieved while covering both tumour and elective PTV adequately.     

Use of benchmark dose-volume histograms for selection of the optimal technique between three-dimensional conformal radiation therapy and intensity-modulated radiation therapy in prostate cancer

PURPOSE: The aim of this study was to develop and validate our own benchmark dose-volume histograms (DVHs) of bladder and rectum for both conventional three-dimensional conformal radiation therapy (3D-CRT) and intensity-modulated radiation therapy (IMRT), and to evaluate quantitatively the benefits of using IMRT vs. 3D-CRT in treating localized prostate cancer. METHODS AND MATERIALS: During the implementation of IMRT for prostate cancer, our policy was to plan each patient with both 3D-CRT and IMRT. This study included 31 patients with T1b to T2c localized prostate cancer, for whom we completed double-planning using both 3D-CRT and IMRT techniques. The target volumes included prostate, either with or without proximal seminal vesicles. Bladder and rectum DVH data were summarized to obtain an average DVH for each technique and then compared using two-tailed paired t test analysis. RESULTS: For 3D-CRT our bladder doses were as follows: mean 28.8 Gy, v60 16.4%, v70 10.9%; rectal doses were: mean 39.3 Gy, v60 21.8%, v70 13.6%. IMRT plans resulted in similar mean dose values: bladder 26.4 Gy, rectum 34.9 Gy, but lower values of v70 for the bladder (7.8%) and rectum (9.3%). These benchmark DVHs have resulted in a critical evaluation of our 3D-CRT techniques over time. CONCLUSION: Our institution has developed benchmark DVHs for bladder and rectum based on our clinical experience with 3D-CRT and IMRT. We use these standards as well as differences in individual cases to make decisions on whether patients may benefit from IMRT treatment rather than 3D-CRT.     

Carbon-11 acetate PET/CT based dose escalated IMRT in prostate cancer

Purpose

To demonstrate the theoretical feasibility of [¹¹C]acetate PET/CT in delineating the malignant intraprostatic lesions (IPL’s) in prostate cancer and to use the data in external beam radiotherapy to boost the biologically defined target volume (BTV).

Methods and materials

Twelve men with intracapsular prostate carcinoma were imaged with [¹¹C]acetate PET/CT and the data were used to delineate the BTV. Six dynamic IMRT plans were generated to each patient: a standard IMRT (sIMRT) plan with a 77.9 Gy dose to PTV (prostate gland with a 6-mm margin) and a simultaneous integrated boost IMRT (SIB_IMRT) plan to deliver 77.9 Gy, 81 Gy, 84 Gy, 87 Gy and 90 Gy to the BTV and 72 Gy to the rest of PTV. To study the theoretical dose escalation based on the delineation of BTV, tumor control probabilities (TCPs) and normal tissue complication probabilities (NTCPs) of bladder and rectum were calculated and compared between the treatment plans.

Results

[¹¹C]Acetate was used to delineate the IPL’s of all 12 patients. With every patient the TCP was increased with SIB_IMRT without increasing the NTCP of the bladder or rectum. The probability of uncomplicated control (PUC) was increased on average by 28% with the SIB_IMRT treatment plans. The highest PUC was achieved with an average dose of 82.1 Gy to the BTV.

Conclusions

Our study indicates that [¹¹C]acetate can be used to define the IPL’s and in combination with SIB_IMRT the defined areas can theoretically be treated to ultra high doses without increasing the treatment toxicity. These results motivate the formal validation of [¹¹C]acetate PET for biological dose planning in prostate cancer.     

非小细胞肺癌 3~5个脑转移瘤优选调强放疗的可行性研究

目的 探讨调强放疗(IMRT)技术治疗非小细胞肺癌 3~5个脑转移瘤的优势。