脑转移瘤同期加量混合调强放疗与调强放疗的剂量学比较

目的:探讨同时运用三维适形与调强的混合调强放疗（Hybrid-IMRT）与调强放疗（IMRT）用于脑转移瘤同期加量的剂量学差异。方法:选取20例进行头颅放疗的患者，分别设计Hybrid-IMRT计划和IMRT计划。Hybrid-IMRT计划包括全脑行三维适形（两野对穿）3 600 cGy/20 F、脑转移灶行IMRT同期加量至5 000 cGy/20 F；IMRT计划全程运用IMRT给予全脑照射3 600 cGy/20 F、脑转移灶5 000 cGy/20 F。在满足临床要求的前提下，比较两组计划靶区的均匀性指数、适形度指数、平均剂量和机器跳数，危及器官脑干、视神经、晶体、视交叉、眼球的最大剂量和平均剂量。结果:两种计划均能满足临床要求。Hybrid-IMRT计划的PGTV均匀性优于IMRT计划（P<0.001）；Hybrid-IMRT计划的脑干、视交叉、左右晶体的最大剂量与平均剂量，左右眼球的平均剂量以及左右视神经的最大剂量均低于IMRT计划（P<0.05）；Hybrid-IMRT计划的机器跳数比IMRT计划减少了约70%（P<0.001）。结论:两种计划均能满足临床要求，Hybrid-IMRT计划相较IMRT计划靶区剂量更加均匀，治疗时间缩短，也能更好地保护危及器官。     

Improving IMRT dose accuracy via deliverable Monte Carlo optimization for the treatment of head and neck cancer patients

The purpose of this work is to investigate the effect of dose-calculation accuracy on head and neck (H&N) intensity modulated radiation therapy (IMRT) plans by determining the systematic dose-prediction and optimization-convergence errors (DPEs and OCEs), using a superposition/convolution (SC) algorithm. Ten patients with locally advanced H&N squamous cell carcinoma who were treated with simultaneous integrated boost IMRT were selected for this study. The targets consisted of gross target volume (GTV), clinical target volume (CTV), and nodal target volumes (CTV nodes). The critical structures included spinal cord, parotid glands, and brainstem. For all patients, three IMRT plans were created: A: an SC optimized plan (SCopt), B: an SCopt plan recalculated with Monte Carlo [MC(SCopt)], and C: an MC optimized plan (MCopt). For each structure, DPEs and OCEs were estimated as DPE(SC)=D(B)-D(A) and OCE(SC)=D(C)-D(B) where A, B, and C stand for the three different optimized plans as defined above. Deliverable optimization was used for all plans, that is, a leaf-sequencing step was incorporated into the optimization loop at each iteration. The range of DPE(SC) in the GTV D98 varied from -1.9% to -4.9%, while the OCE(SC) ranged from 0.9% to 7.0%. The DPE(SC) in the contralateral parotid D50 reached 8.2%, while the OCE(SC) in the contralateral parotid D50 varied from 0.91% to 6.99%. The DPE(SC) in cord D2 reached -3.0%, while the OCE(SC) reached to -7.0%. The magnitude of the DPE(SC) and OCE(SC) differences demonstrate the importance of using the most accurate available algorithm in the deliverable IMRT optimization process, especially for the estimation of normal structure doses.     

同步加量调强与常规调强放射治疗食管癌的效果比较

目的：探讨同步加量调强与常规调强放射治疗食管癌的效果。方法：回顾分析149例食管癌患者的临床资料,根据治疗方式不同将其分为同步组（n=77）和常规组（n=72）,同步组患者予以同步加量调强放射治疗,常规组患者予以常规调强放射治疗。比较两组患者治疗后临床疗效、血清肿瘤因子鳞状细胞癌抗原（SCC）、糖类抗原125(CA125)、癌胚抗原（CEA）水平、体力状况评分（Karnofsky评分）、生活质量评分（SF-36评分）、不良反应。结果：治疗后,同步组临床总有效率高于常规组（93.51%vs 81.94%, P<0.05）;同步组血清肿瘤因子SCC、CA125、CEA水平均低于常规组（P<0.05）;同步组Karnofsky评分和SF-36评分均高于常规组（P<0.05）;同步组不良反应轻于常规组。结论：同步加量调强与常规调强放射治疗食管癌均有一定临床效果,但相较于常规调强放射治疗,同步加量调强放射治疗对食管癌患者临床效果更为理想,能有效控制血清肿瘤因子高表达,改善预后,且不良反应相对较少。     

不同分割剂量同步推量调强放疗治疗肺癌脑转移瘤的安全性分析

目的:分析不同分割剂量同步推量调强放疗治疗肺癌脑转移瘤的安全性及生存情况。方法:选取肺癌脑转移瘤患者75例,随机分为3组,均实施同步推量调强放疗,其中A组放疗方案为全脑40 Gy/20f（2.0 Gy/f）+瘤区同步推量46 Gy/20f（2.3 Gy/f）,B组方案为全脑40 Gy/20f（2.0 Gy/f）+瘤区同步推量52 Gy/20f（2.6 Gy/f）,C组方案为全脑40 Gy/20f（2.0 Gy/f）+瘤区同步推量58 Gy/20f（2.9 Gy/f）。放疗开始后,对3组患者危及器官（眼球、晶体、视神经、脑干）平均剂量及最大剂量和3组患者放疗相关不良反应进行比较。治疗结束后定期复查颅脑MRI评价疗效,观察3组患者1年生存率。结果:A、B、C组危及器官平均剂量及最大剂量差异不显著（P>0.05）;A、B、C组急性放疗不良反应发生率差异不显著（P>0.05）,晚期神经系统不良反应发生率亦差异不显著（P>0.05）,3级放疗不良反应低于5%,无4级放疗不良反应发生。随访1年,C组生存率高于A、B组（P<0.05）。结论:同步推量调强放疗治疗肺癌脑转移瘤是一种安全有效的方法,随着放疗剂量增加,疗效有增加趋势。     

Impact of MLC leaf position errors on simple and complex IMRT plans for head and neck cancer

The dosimetric impact of random and systematic multi-leaf collimator (MLC) leaf position errors is relatively unknown for head and neck intensity-modulated radiotherapy (IMRT) patients. In this report we studied 17 head and neck IMRT patients, including 12 treated with simple plans (<50 segments) and 5 treated with complex plans (>100 segments). Random errors (-2 to +2 mm) and systematic errors (+/-0.5 mm and +/-1 mm) in MLC leaf positions were introduced into the clinical plans and the resultant dose distributions were analyzed based on defined endpoint doses. The dosimetric effect was insignificant for random MLC leaf position errors up to 2 mm for both simple and complex plans. However, for systematic MLC leaf position errors, we found significant dosimetric differences between the simple and complex IMRT plans. For 1 mm systematic error, the average changes in D(95%) were 4% in simple plans versus 8% in complex plans. The average changes in D(0.1 cc) of the spinal cord and brain stem were 4% in simple plans versus 12% in complex plans. The average changes in parotid glands were 9% in simple plans versus 13% for the complex plans. Overall, simple IMRT plans are less sensitive to leaf position errors than complex IMRT plans.     

电穿孔疗法在头颈癌治疗中的应用

头颈癌严重地威胁着人类生命 ,而传统的化学治疗方法由于受癌细胞对药物吸收率的限制 ,其疗效也受到限制。电穿孔由于能使细胞膜出现暂时微孔 ,从而能大大提高癌细胞对药物的吸收率。在此基础上 ,结合传统的化疗方法形成的电穿孔疗法成为一种新型的头颈癌治疗法。博来梅素由于其自身的优良特性成为电穿孔疗法的首先药物。离体实验和临床研究表明 ,与传统方法相比 ,电穿孔疗法对于治疗头颈癌能取得更好的疗效     

Quackery in head and neck cancer

Most human beings will do almost anything to prolong their existence or to relieve the suffering of disease. Others will do anything to exploit these desires by selling what they claim to be pain killing remedies or life prolongation nostrums. We present three cases of head and neck cancer patients; two used complementary and alternative medicine (CAM) prior to presenting to our service and the third declined conventional treatment to seek CAM instead. We discuss here the diagnosis, the time delay between CAM and commencement of conventional treatment, and the outcome in each case. Our aim is to define Quacks and to heighten public awareness of the potential harm they can cause.     

Evaluation of intrafraction patient movement for CNS and head & neck IMRT

Intrafraction patient motion is much more likely in intensity-modulated radiation therapy (IMRT) than in conventional radiotherapy primarily due to longer beam delivery times in IMRT treatment. In this study, we evaluated the uncertainty of intrafraction patient displacement in CNS and head and neck IMRT patients. Immobilization is performed in three steps: (1) the patient is immobilized with thermoplastic facemask, (2) the patient displacement is monitored using a commercial stereotactic infrared IR camera (ExacTrac, BrainLab) during treatment, and (3) repositioning is carried out as needed. The displacement data were recorded during beam-on time for the entire treatment duration for 5 patients using the camera system. We used the concept of cumulative time versus patient position uncertainty, referred to as an uncertainty time histogram (UTH), to analyze the data. UTH is a plot of the accumulated time during which a patient stays within the corresponding movement uncertainty. The University of Florida immobilization procedure showed an effective immobilization capability for CNS and head and neck IMRT patients by keeping the patient displacement less than 1.5 mm for 95% of treatment time (1.43 mm for 1, and 1.02 mm for 1, and less than 1.0 mm for 3 patients). The maximum displacement was 2.0 mm.     

Anergy testing in patients with head and neck cancer

Patients with head and neck cancer were found to be deficient in were not clear [correction] Possible explanations include a change in T-lymphocyte numbers, particularly the helper/suppressor T-cell ratio, with the cause of this change still unknown. Tumor immunosuppressing factors and cancer-induced immunosuppression are proposed to be such causes. The deficiency of T cells resulted in an impaired cell-mediated immune response (CMIR), which lowered the host resistance, such facilitating the tumor to spread. As the CMIR can be evaluated by delayed hypersensitivity skin testing (= anergy screen), the objective of this study was to compare the CMIR function of patients with head and neck cancer to a non-cancer control group using this anergy screen. The study group consisted of 20 patients (17 males, 3 females, age range 10-76 years) with head and neck cancer, which were anti-HIV negative and had not received any therapy yet. The control group consisted of another 20 persons (17 males, 3 females, age range 21-72 years) without any cancer and who were also anti-HIV negative. Exclusion criteria were (1) eczema or skin disease in the area to be tested, (2) having received oral prednisolone within the last week and (3) an anti-HIV positive immune status. The antigens used in this study consisted of PPD (5 IU), tetanus toxoid (TT) (0.8 LF/ml and 1.6 LF/ml, Candida albicans (20 PNU/ ml and 200 PNU/ml), mumps-measles-rubella (MMR) vaccine (1:10 v/v and 1:5 v/v). The test was done by intradermal injection of 0.1 ml of each antigen. The anergy screen was considered positive when the test resulted in an erythema or induration larger than 5 mm at 72 hours after the injection. Complete anergy was diagnosed when there was no skin reaction at all, partial anergy when only 1 antigen tested positive and no anergy when there were positive skin reactions to two or more antigens. In the study group, 9 (45%) patients were diagnosed with complete anergy, 11 (55%) with partial anergy and none with no anergy, while in the control group, none were complete anergic, 3 (15%) were partially anergic and 17 (85%) had no anergy. There was a statistically significant difference (p < 0.01) between these two groups. In conclusion, patients with head and neck cancer seemed to have an impaired CMIR, with at least the partial anergy being statistical significantly different compared to the non-cancer group.     

A comparison of techniques for simulating set-up error and uncertainty in head and neck IMRT

We have compared four computational methods for quantifying the effect of set-up error and uncertainty on delivered doses to targets and organs at risk in the intensity modulated radiation therapy treatment of head and neck cancer. These four methods were direct simulation, simple convolution, plus two modified convolution approaches. Discrepancies of up to 20% in the equivalent uniform dose (EUD) between direct simulation and simple convolution were estimated for the relatively superficial parotid gland at a systematic set-up error of 6 mm standard deviation and a random uncertainty of 2 mm standard deviation. Truncated convolution agreed with direct simulation to within 6% for all situations studied. However, of the four methods, only direct simulation can quantify the range of outcomes (EUD) associated with a finite number of courses and fractions. Our results are particularly relevant to the design of dose escalation studies in head and neck cancer.