放射治疗设备信息整合探讨

目的分析放疗科设备之间信息的整合。材料与方法通过对DICOM RT（Radiotherapy in DICOM）标准的了解,利用Pinnacle放射治疗计划系统（Treatment Planning System,TPS）、PrecisePLAN放射治疗计划系统和Eclipse放射治疗计划系统对某一选定病人进行轮廓勾画和剂量计算。然后,把轮廓勾画好的病人信息及计算完毕的病人信息分别在这三台TPS之间进行相互传递,并比较传递前后病人信息的差异。结果1）大孔径CT得到的CT图像可以传递给TPS;2）Pinnacle TPS的数据信息可以传递给PrecisePLAN TPS和Eclipse TPS,但是存在轮廓缺陷;3）PrecisePLAN TPS和Eclipse TPs之间不能互相传递数据,也不能把数据信息传递给Pinnacle TPS;4）三台TPS都不能把病人的治疗计划传递给另外的TPS。结论在当前三家国外生产加速器的大公司并存及国内生产加速器的企业落后的情况下,医院设备主管部门应当考虑购买兼容性较好的设备或者购买同一家公司的放射治疗设备。     

蒙特卡罗方法和三维数字人体模型在放疗计划质量保证中的应用

放射治疗的质量保证是保证放射治疗成功的有力方法。对于放疗计划的验证和评估有CT模拟机、仿体等方法,这些方法各有优缺点。文章提出了一种用人体图像数据构造仿真模型的方法,并用蒙特卡罗软件和美国“可视人项目”的数据集计算该模型在接受放射治疗时体内剂量的三维分布。由于采用人体的真实图像数据,以及蒙特卡罗方法计算粒子输运时的准确性,该方法能够得到真实的三维剂量分布。     

功能与分子影像在头颈部肿瘤放射治疗计划和疗效评价中的应用

目前临床普遍采用功能与分子影像检测手段能来评价头颈部肿瘤的放射治疗计划和疗效,可指导个体化治疗从而提高疗效。文章概述了功能与分子影像技术CT,MRI,PET-CT,超声检测技术在头颈部肿瘤放射治疗计划制定和疗效评价中的应用进展。结果显示,不同分子影像检测方法如在检查时机的选择、诊断和鉴别诊断的价值、观察放射治疗后肿瘤的残存和复发、预测放射治疗效果、指导后续治疗等方面均可起到重要作用。采用图像融合技术进行联合应用,如PET-CT和MRI-CT等,可提高检测的准确率。临床医生需在常规影像学手段的基础上,根据头颈部肿瘤患者病情和治疗方法的不同选用正确的功能和分子影像检测手段,更好地指导制定放射治疗计划及综合评价放射治疗后的疗效。     

应用KV-CBCT分析鼻咽癌调强放射治疗的摆位误差

目的:应用KV-CBCT分析鼻咽癌调强放射治疗时的摆位误差,为鼻咽癌调强放射治疗计划设计时CTV外扩PTV边界的大小提供参考。方法:选取30例IMRT的鼻咽癌患者,治疗过程中每周一次应用KV-CBCT采集患者治疗前的CT图像,将所得图像与定位CT图像进行匹配,分别测定X、Y、Z轴三个方向的摆位误差。结果:30例患者共拍摄168次KV-CBCT,获得168组摆位误差结果,群体摆位误差分别为X轴-0.15±1.43 mm,Y轴0.20±1.58 mm,Z轴-0.21±1.65 mm;根据Van Herk公式计算得到各方向的CTV-PTV外放边界值X、Y、Z轴分别为3.1 mm、3.3 mm和3.4 mm。结论:应用KV-CBCT影像系统可实时测量摆位误差并在线进行纠正,减小摆位误差,为CTV-PTV外放边界提供参考。     

调强放射治疗在宫颈癌治疗中的临床研究

目的:探讨中晚期宫颈癌患者应用调强放射治疗(IMRT)技术在提高靶区剂量与减少正常组织受量方面的价值.方法:40例中晚期宫颈癌患者均给予全程IMRT 1.8～2.2 Gy/次,每周4次外照射和1次内照射,外照射的处方剂量为50～55 Gy,中位剂量为53.5 Gy,内照射共给6次,每次5 Gy.同时拟设计该40例患者2野和4野的放疗计划,拟给予相同的处方剂量,比较危险器官(OAR)直肠、小肠、膀胱和骨髓的受照射剂量和体积.结果:40例患者均完成全程的IMRT,放射治疗计划靶区(PTV)的平均剂量为54.5 Gy,90%的等剂量曲线(中位剂量53.5 Gy)可以覆盖99%以上的肉眼靶区(GTV)体积.IMRT与普通2野和4野放疗组比较,小肠、直肠、膀胱和骨髓的受照射剂量和体积均明显减少(P<0.05).急慢性放射反应明显减轻.1,2年生存率比较,差异无统计学意义.结论:IMRT放疗技术可以使患者的放疗靶区获得较为理想的剂量分布,邻近危险器官得到很好的保护,从而减小了急慢性放疗反应,毒副反应可以耐受,但未能提高近期生存率.     

图像引导放射治疗老年非小细胞肺癌30例

目的:分析图像引导放射治疗(IGRT)对老年非小细胞肺癌患者的临床疗效.方法:30例老年非小细胞肺癌患者,全部采用医科达图像引导放射治疗系统,GTV:60Gy,参考剂量线为95%～98%,分割方式3～4Gy/次.结果:肿瘤完全缓解率为33%(10/30),部分缓解率为50%(15/30),总有效率为83%(25/30).1、2、3年生存率为85%、70%、67%.结论:图像引导放射治疗(IGRT)对老年非小细胞肺癌有较好的局部控制率,是治疗老年非小细胞肺癌患者的有效方法之一.     

常规模拟定位和CT模拟定位的比较

目的:对比食管癌放射治疗中CT模拟定位和常规模拟定位的优劣。方法:对60例食管中、下段癌患者,同时行CT扫描和常规模拟定位;用三维计划系统制定治疗方案,比较分析这两种定位方法所描述靶区肿瘤的最大直径和等剂量分布情况。结果:两种定位方法肿瘤最大直径对比差别前后、右后、和左后分别为:2.0±0.5、4.3±1.2、1.4±0.35、4.0±1.1、1.5±0.4、3.6±1.2;等剂量曲线分布为60例和31例,差异有统计学意义。结论:CT模拟定位较常规模拟定位能更充分显示肿瘤外侵范围并反映其非对称性生长。     

鼻咽癌的放射治疗技术探究

目的:通过比较鼻咽癌放射治疗的不同技术方法,了解其优势及不同点,以期找到更有效并切合实际的技术方法,提高鼻咽癌的放疗技术水平。方法:常规外照射技术;等中心整体挡铅技术;三维适形放射治疗技术。结果:三种技术方法各具优缺点,结论:三维适形放射治疗技术最具优势,但设备和技术要求高;常规外照射技术经济实用,技术稳定性较差;等中心整体挡铅技术质量稳定。     

陀螺旋转式伽玛刀分次治疗颅内转移瘤的临床疗效观察

目的:评价大分割伽玛射线立体定向放射治疗对颅内转移瘤的临床疗效.方法:采用陀螺旋转式伽玛射线立体定向放射设备治疗颅内转移瘤患者91例.单纯伽玛射线立体定向放射治疗采取大分割分次方式,处方剂量3.2-5Gy,每周5次,计划靶区边缘(45％或65％等剂量线处)总剂量全程为35-50Gy.结果:近期有效率(CR+PR)颅内移瘤少于3个组为93.06％ (67/72),大于3个组为73.69％ (14/19);局部剂量与肿瘤复发的关系,照射剂量50GY者复发率为11.86％(7/59),照射剂量为40GY者复发率为31.25％(10/32);生存率陀螺刀治疗的中位生存期为11.9个月.6、12、24个月生存率分别为:76.92％ (70/91)、60.44％(55/91)、29.67％(27/91).结论:大分割伽玛射线立体定向放射治疗脑部和体部恶性肿瘤近期疗效满意.     

放射治疗联合血管内皮抑制素对大鼠移植性肝癌的治疗作用

目的:探讨放射治疗联合血管内皮抑制素对大鼠移植性肝癌的治疗作用。方法:SD大鼠随机分为5组:假手术组,模型组,血管内皮抑素组,放疗组,联合组,血管内皮抑素组和联合组每日尾静脉注射浓度为10%重组人血管内皮抑素0.1 ml(20μg),共12天,联合组在第5天～10天时给予放射治疗,1次/2天。各组动物于移植术后12d处死,分离肿瘤组织备用。结果:血管内皮抑素组、放疗组、联合组均能显著抑制肿瘤生长,抑制VEGF表达,其中联合组抑制效果更为明显。结论:放射治疗联合血管内皮抑制素有明显肿瘤抑制作用,其机制可能与下调VEGF的表达有关。     

Antitumor efficacy of combined gene and radiotherapy in animals

Antitumor efficacy of the combined suicide gene therapy and radiotherapy was studied on the model of CT26 murine colon adenocarcinoma. CMV-FCU1-IRES-mGM-CSF-pGL3 construct with PEG-PEI-TAT (FCU1–mGM/5-FC) block copolymer as a vector was used for intratumoral administration. Tumors were irradiated with a single 5 Gy dose. The efficacy was evaluated according to the grade of tumor growth inhibition (T/C) and lifespan of the animals. Pronounced antitumor activity of the combined use of FCU1–mGM/5-FC system with radiotherapy on the background of prolonged lifespan and the synergism of the applied methods was revealed.     

Successful treatment of advanced murine renal cell cancer by bicompartmental adoptive chemoimmunotherapy

The most challenging aspect of cancer treatment remains the management of invasive and metastatic tumor growth. Recent progress in the development and use of biologic response modifiers for immunomodulation has raised the possibility that the immune system can be used as an additional antitumor treatment modality in conjunction with surgery, chemotherapy, and/or radiotherapy for the treatment of established tumors and their metastases. As a model for adoptive chemoimmunotherapy (ACIT) of renal cancer we have used a murine renal cancer (Renca) of spontaneous origin that mimics the tumor progression characteristically observed for human renal cell carcinoma. In the present study, we demonstrate that broadly cytotoxic lymphocytes, generated by in vitro culture with human recombinant interleukin 2, and used in conjunction with the chemotherapeutic drug doxorubicin hydrochloride, are effective in treating invasive and metastatic renal cell cancer. Administration of ACIT i.v. or i.p., alone, or after nephrectomy of the tumor-bearing kidney, did not cure mice with stage II (locoregional invasive tumor) or stage III (lymph node metastases) disease. In contrast, nephrectomy followed by simultaneous bicompartmental i.v. and i.p. ACIT administration cured 80% of mice with either stage II or stage III Renca. These data demonstrate that simultaneous bicompartmental ACIT affords dramatically improved cure rates for advanced and metastatic Renca. This effect most likely results from efficient control of both locoregional and metastatic tumor growth.     

Cannabinoid receptors in atherosclerosis

PURPOSE OF REVIEW: Recent findings suggesting that cannabinoid receptors are potential targets for the treatment of atherosclerosis are reviewed. RECENT FINDINGS: Cannabinoids, such as Delta9-tetrahydrocannabinol, the major psychoactive compound of marijuana, their synthetic analogs and endogenous cannabinoid ligands, produce their biological effects by interacting with specific receptors. In the apolipoprotein E knockout mouse model of atherosclerosis, Delta9-tetrahydrocannabinol was shown to inhibit disease progression through pleiotropic effects on inflammatory cells. Blocking of cannabinoid receptor CB2, the main cannabinoid receptor expressed on immune cells, abolished the observed effects. The development of novel cannabinoid receptor ligands that selectively target CB2 receptors or pharmacological modulation of the endocannabinoid system might offer novel therapeutic strategies in the treatment of atherosclerosis. Several reports demonstrating an implication of the endocannabinoid system in different inflammatory conditions support this hypothesis. SUMMARY: The immunomodulatory capacity of cannabinoids is now well established and suggests a broad therapeutic potential of cannabinoids for a variety of conditions, including atherosclerosis. New strategies based on nonpsychotropic cannabinoid receptor ligands or compounds modulating endocannabinoid synthesis or stability might solve the problem of the unwanted side effects associated with cannabinoid administration.     

Effects of kinins, kallikrein and its inhibitor on certain indices of cell-mediated immunity and humoral immunity in rabbits

The experiments were carried out on 54 rabbits in 9 groups of 6 animals each: group I -- controls, groups II, III, IV -- bradykinin i.v., groups V, VI, VII -- Depot-Kallikrein i.m. every other day for 3 weeks, groups VIII and IX -- Traskolan (trasylol) i.v. four times at intervals of 1 or 12 hours. The determined indices of cell-mediated and humoral immunity included: phagocytic activity of the reticuloendothelial system and peripheral blood leucocytes and their leukergic adhesiveness, haemagglutinin and haemolysin levels, serum complement titre, and the number of cells forming rosettes (RFC) or plaques (PFC) in the blood and spleen. These indices were determined 15 minutes, 3 and 24 hours after bradykinin administration, after 1, 2 and 3 weeks of kallikrein administration, and 1 or 12 hours after the last dose of Traskolan. Most determined indices showed always some fall. Only the phagocytic activity of the reticuloendothelial system was moderately increased in all groups, and in the bradykinin group leucocyte phagocytosis was increased slightly while their leukergic reaction was increased very strongly.     

Long-term infusions of p-boronophenylalanine for boron neutron capture therapy: evaluation using rat brain tumor and spinal cord models

Rat 9L gliosarcoma cells infiltrating the normal brain have been shown previously to accumulate only approximately 30% as much boron as the intact tumor after administration of the boronated amino acid p-boronophenylalanine (BPA). Long-term i.v. infusions of BPA were shown previously to increase the boron content of these infiltrating tumor cells significantly. Experiments to determine whether this improved BPA distribution into infiltrating tumor cells after a long-term i.v. infusion improves tumor control after BNCT in this brain tumor model and whether it has any deleterious effects in the response of the rat spinal cord to BNCT are the subjects of the present report. BPA was administered in a fructose solution at a dose of 650 mg BPA/kg by single i.p. injection or by i.v. infusion for 2 h or 6 h, at 330 mg BPA/kg h(-1). At 1 h after the end of either the 2-h or the 6-h infusion, the CNS:blood (10)B partition ratio was 0.9:1. At 3 h after the single i.p. injection, the ratio was 0.6:1. After spinal cord irradiations, the ED(50) for myeloparesis was 14.7 +/- 0.4 Gy after i.p. administration of BPA and 12.9 +/- 0.3 Gy in rats irradiated after a 6-h i.v. infusion of BPA; these values were significantly different (P < 0.001). After irradiation with 100 kVp X rays, the ED(50) was 18.6 +/- 0.1 Gy. The boron compound biological effectiveness (CBE) factors calculated for the boron neutron capture dose component were 1.2 +/- 0.1 for the i.p. BPA administration protocol and 1.5 +/- 0.1 after irradiation using the 6-h i.v. BPA infusion protocol (P < 0.05). In the rat 9L gliosarcoma brain tumor model, the blood boron concentrations at 1 h after the end of the 2-h infusion (330 mg BPA/kg h(-1); n = 15) or after the 6-h infusion (190 mg BPA/kg h(-1); n = 13) were 18.9 +/- 2.2 microg 10B/g and 20.7 +/- 1.8 microg 10B/g, respectively. The irradiation times were adjusted individually, based on the preirradiation blood sample, to deliver a predicted 50% tumor control dose of 8.2 Gy ( approximately 30 photon-equivalent Gy) to all tumors. In the present study, the long-term survival was approximately 50% and was not significantly different between the 2-h and the 6-h infusion groups. The mode of BPA administration and the time between administration and irradiation influence the 10B partition ratio between the CNS and the blood, which in turn influences the measured CBE factor. These findings underline the need for clinical biodistribution studies to be carried out to establish 10B partition ratios as a key component in the evaluation of modified administration protocols involving BPA.     

The development of patient information leaflets. Care of the mouth after radiotherapy

Objectives: Describe the methodology used to produce a patient leaflet on care of the mouth after radiotherapy. Design: Prospective study to design a patient information leaflet. Setting and Subjects : Patients undergoing radiotherapy for oral cancer. Intervention: After a review of the relevant literature, a patient questionnaire was produced. This was then completed by patients undergoing radiotherapy treatment and gave an indication of the problems being encountered. Healthcare professionals were surveyed for their views. A leaflet was then produced according to published guidelines. It was taken back to another group of patients and a further version produced after input from a health promotion group. Results: A leaflet was produced after wide consultation and survey. Conclusion: Considerable effort must to be put into the production of patient information leaflet. It must be discussed with patients in the target group if it is to be sensitive, understood and find acceptance among its users     

Anti-cancer activities of tea epigallocatechin-3-gallate in breast cancer patients under radiotherapy

The purpose of this study was to test the hypothesis that administration of epigallocatechin-3-gallate (EGCG), a polyphenol present in abundance in widely consumed tea, inhibits cell proliferation, invasion, and angiogenesis in breast cancer patients. EGCG in 400 mg capsules was orally administered three times daily to breast cancer patients undergoing treatment with radiotherapy. Parameters related to cell proliferation, invasion, and angiogenesis were analyzed while blood samples were collected at different time points to determine efficacy of the EGCG treatment. Compared to patients who received radiotherapy alone, those given radiotherapy plus EGCG for an extended time period (two to eight weeks) showed significantly lower serum levels of vascular endothelial growth factor (VEGF), hepatocyte growth factor (HGF), and reduced activation of metalloproteinase-9 and metalloproteinase-2 (MMP9/MMP2). Addition of sera obtained from patients treated with combination of radiotherapy and EGCG feeding for 2-8 weeks to in vitro cultures of highly-metastatic human MDA-MB-231 breast cancer cells resulted in the following significant changes: (1) suppression of cell proliferation and invasion; (2) arrest of cell cycles at the G0/G1 phase; (3) reduction of activation of MMP9/MMP2, expressions of Bcl-2/Bax, c-Met receptor, NF-κB, and the phosphorylation of Akt. MDA-MB-231 cells exposed to 5-10 μM EGCG also showed significant augmentation of the apoptosis inducing effects of γ-radiation, concomitant with reduced NF-κB protein level and AKT phosphorylation. These results provide hitherto unreported evidence that EGCG potentiated efficacy of radiotherapy in breast cancer patients, and raise the possibility that this tea polyphenol has potential to be a therapeutic adjuvant against human metastatic breast cancer.     

Reduce fluctuations in capacity to improve the accessibility of radiotherapy treatment cost-effectively

This paper is motivated by a case study to reduce the throughput times for radiotherapy treatment. The goal is to find a cost-effective way to meet future throughput targets. A combination of queuing theory and computer simulation was used. First, computer simulation to detect the bottleneck(s) in a multi-step radiotherapy process. Despite, the investment in an additional linear accelerator, the main bottleneck turned out to be the outpatient department (OPD). Next, based on queuing theory, waiting times were improved by reducing the fluctuations in the OPD capacity. Computer simulation was used again to quantify the effect on the total throughput time of a radiotherapy patient. The results showed a reduction in both access times as well as waiting times prior to the consecutive steps: the preparation phase and actual treatment. The paper concludes with practical suggestions on how to reduce the fluctuations in capacity, and seems of interest for other radiotherapy departments or other multi-step situations in a hospital.     

Development and characterization of a synthetic promoter for selective expression in proliferating endothelial cells

BACKGROUND: Systemic administration of non-viral gene therapy provides better access to tumors than local administration. Development of a promoter that restricts expression of cytotoxic proteins to the tumor vasculature will increase the safety of the system by minimizing expression in the non-dividing endothelial cells of the vasculature of non-target tissues. METHODS: Cell cycle promoters were tested for selective expression in dividing cells vs. non-dividing cells in vitro and promoter strength was compared to the cytomegalovirus (CMV) promoter. Successful promoter candidates were tested in vivo using two proliferating endothelium mouse models. Ovarectomized mice were injected with estradiol prior to lipoplex administration and expression levels were measured in the lungs and uterus 4 days after administration. The second model was a subcutaneous tumor model and expression levels were measured in the lungs and tumors. For both animal models, expression levels from the proliferating endothelium promoter were compared to that obtained from a CMV promoter. RESULTS: The results showed that the Cdc6 promoter yielded higher expression in proliferating vs. non-proliferating cells. Secondly, promoter strength could be selectively increased in endothelial cells by the addition of a multimerized endothelin enhancer (ET) to the Cdc6 promoter. Thirdly, comparison of expression levels in the lungs vs. uterus in the ovarectomized mouse model and lungs vs. tumor in the mouse tumor model showed expression was much higher in the uterus and the tumor than in the lungs for the ET/Cdc6 promoter, and expression levels were comparable to that of the CMV promoter in the hypervascularized tissues. CONCLUSIONS: These results demonstrate that the combination of the endothelin enhancer with the Cdc6 promoter yields selective expression in proliferating endothelium and can be used to express cytotoxic proteins to treat vascularized tumors.     

Kinetics of cortisol metabolism and excretion. A hypothetic model based on the cumulative urinary radioactivity in eight multiple pituitary deficient patients.

A new model is proposed to study the kinetics of [3H]cortisol metabolism by using urinary data only. The model consists of 5 pools, in which changes of the fractions of dose are given by a system of 5 ordinary differential equations. After i.v. administration of [3H]cortisol to 8 multiple pituitary deficient (MPD) patients (group I) the urines from each patient were collected in 9-15 portions during the following 3 days. From the urinary data the rate constants of cortisol metabolism were calculated. A published set of urinary data from patients with a normal cortisol metabolism (group II) was used for comparison. The overall half-life of the label in the circulation was 30 min for both groups; the half-life of the label excretion by both groups was 6 h and the time of maximal activity in the main metabolizing pool was 1.8 h in group I and 1.5 h in group II. The 20% of normal cortisol production rate (CPR) in the 8 MPD patients amounted to 7.2 +/- 1.9 mumol/(m2*d). Therefore, the low CPR but normal rate constants, i.e. a normal metabolic clearance rate of cortisol, in the MPD patients suggest a sensitive adjustment of the cortisol response in the target organs.