6 MV和10 MVX线宫颈癌经典适形照射治疗计划比较分析

目的 研究不同身高、体质量宫颈癌术后患者不同能量6 MV和10 MVX线经典适形四野照射治疗计划的剂量分布,指导临床照射能量的选择.方法 选取21例患者,按体质指数(BMI)分为肥胖组和非肥胖组并进行6 MV和10 MV X线箱式照射治疗的计划设计,统计分析治疗计划相关的剂量学参数.结果 采用10 MV X线的治疗计划:①2组均能降低计划靶区(PTV)的最大剂量(Dmax)、最小剂量(Dmax)、提高适形指数(CI)和不均匀性指数(HI);不能降低平均剂量(Dmax);非肥胖组中位剂量(D50)有变化;肥胖组患者更能有效地降低Dmax和提高HI.②能降低靶区周围危及器官(OAR)的剂量.③更能有效地减少患者中低受量体积.④更能有效地减少机器跳数(MU).结论 对于肥胖宫颈癌患者,采用10 MV X线治疗计划具有优势.     

Analysis of various beamlet sizes for IMRT with 6 MV photons

Application of intensity modulated radiation therapy (IMRT) using multileaf collimation often requires the use of small beamlets to optimize the delivered radiation distribution. Small-beam dose distribution measurements were compared to dose distributions calculated using a commercial treatment planning system that models its data acquired using measurements from relatively large fields. We wanted to evaluate only the penumbra, percent depth-dose (PDD) and output model, so we avoided dose distribution features caused by rounded leaf ends and interleaf leakage by making measurements using the secondary collimators. We used a validated radiochromic film dosimetry system to measure high-resolution dose distributions of 6 MV photon beams. A commercial treatment planning system using the finite size pencil beam (FSPB) dose calculation algorithm was commissioned using measured central axis outputs from 4.0x4.0 to 40.0x40.0 cm2 beams and radiographic-film profile measurements of a 4.0x4.0 cm2 beam at twice the depth of maximum dose (dmax). Calculated dose distributions for square fields of 0.5x0.5 cm2, and 1.0x1.0 cm2, to 6.0x6.0 cm2, in 1.0x1.0 cm2, increments were compared against radiochromic film measurements taken with the film oriented parallel to the beam central axis in a water equivalent phantom. The PDD of the smaller field sizes exhibited behavior typical of small fields, namely a decrease in dmax with decreasing field size. The FSPB accurately modeled the depth-dose and central axis output for depths deeper than the nominal dmax of 1.5 cm plus 0.5 cm. The dose distribution in the build-up and penumbra regions was not accurately modeled for depths less than 2 cm, especially for the fields of 2.0x2.0 cm2 and smaller. Using the gamma function with 2 mm and 2% criteria, the dose model was shown to accurately predict the penumbra. While for single small beams the compared dose distributions passed the gamma function criteria, the clinical appropriateness of these criteria is not clear for a composite IMRT plan. Further investigation of the cumulative impact of the observed dose discrepancies is warranted. We speculate that the observed differences in the penumbra regions arise from some energy dependent artifact in the radiographic-film profiles used for commissioning. In the future, radiochromic film based commissioning might provide a more accurate data set for dose modeling.     

虚拟仿真手术与常规手术对肾结石治疗效果的比较

目的 重建肾脏的三维立体模型,模拟经皮肾镜碎石术在虚拟仿真手术和常规手术的效果.为临床教学和科研提供方法,为年轻医生快速缩短手术学习时间.方法 随机选取2017年12月～2019年2月北京房山区良乡医院就诊的30例肾结石患者作为试验组,对照组是同期在该院进行体检的正常人30例.两组采集肾脏CT扫描数据,利用Mimics...     

Comparison between conventional and QBC methods for diagnosis of malaria

Stained blood film examination is a widely used technique for the diagnosis of malaria. Comparison of this technique was made with the QBC method, which is based on fluorescent staining of the blood cells and parasites. Of the 1435 blood samples studied, 57 (3.97%) samples were positive for malarial parasites by QBC method, while only 44 (3.07%) samples were positive by the blood film examination. Plasmodium vivax was detected in 27 (47.37%), P. falciparum in 26 (45.61%) and mixed infection of P. vivax and P. falciparum in 4 (7.02%) cases. Samples with low levels of parasitaemia (QBC grades 1+ and 2+) were often found to be negative by blood film examination. QBC method was easy to perform, had a higher sensitivity and could be interpreted rapidly, as compared to the Leishman stained blood film examination.     

6MV与15MVX线在肺癌调强放疗中的剂量学比较

目的：分析、比较用于治疗非小细胞肺癌（NSCLC）的6MV和15MVX线调强放疗（IMRT）计划。方法：随机选择10例NSCLC患者，采用6MV和15MVX射线对每例NSCLC进行IMRT的计划设计，并用ADAC Pinnacle3计划系统提供的卷积／迭加（convolution／superposition）算法对两种能量条件下相同布野方案的IMRT计划进行剂量计算，比较靶区及危及器官的剂量分布、DVH等指标。结果：6MV与15MV放疗计划的等剂量线和DVH相近，6MV计划的靶区剂量均匀性优于15MV计划．而15MV计划高剂量覆盖靶区的程度略优于6MV计划，食管、心脏、脊髓等危及器官的受量基本相同。结论：对于NSCLC，剂量计算应采用能够精确修正组织不均匀性影响的卷积／迭加等算法，调强放疗时应首选6MV X射线。     

Effective atomic numbers of biological materials in the energy region 1 to 50 MeV for photons, electrons, and He ions

A study of effective atomic numbers for biological materials such as bone, muscle, spleen, liver, mucin, and water has been carried out in the energy region 1 to 50 MeV for photons, electrons, and He ions. It is noticed that the effective atomic number for photons and electrons increases with energy, and remains, more or less the same, for He ions.     

Comparison between a novel and conventional artificial pancreas for perioperative glycemic control using a closed-loop system

This clinical study aimed to compare a novel and conventional artificial pancreas (AP) used in surgical patients for perioperative glycemic control, with respect to usability, blood glucose measurements, and glycemic control characteristics. From July in 2010 to March in 2015, 177 patients underwent perioperative glycemic control using a novel AP. Among them, 166 patients were eligible for inclusion in this study. Intensive insulin therapy (IIT) targeting a blood glucose range of 80–110 mg/dL was implemented in 82 patients (49 %), and the remaining 84 patients (51 %) received a less-intensive regime of insulin therapy. Data were collected prospectively and were reviewed or analyzed retrospectively. A comparison study of 324 patients undergoing IIT for glycemic control using a novel (n = 82) or conventional AP (n = 242) was conducted retrospectively. All patients had no hypoglycemia. The comparison study revealed no significant differences in perioperative mean blood glucose level, achievement rates for target blood glucose range, and variability in blood glucose level achieved with IIT between the novel AP and conventional AP groups. The usability, performance with respect to blood glucose measurement, and glycemic control characteristics of IIT were comparable between novel and conventional AP systems. However, the novel AP was easier to manipulate than the conventional AP due to its smaller size, lower weight, and shorter time for preparation. In the near future, this novel AP system might be accepted worldwide as a safe and useful device for use in perioperative glycemic control.     

Comparison between conventional systems and a newer system of combined cultures for isolation of influenza viruses

Summary The sensitivity of conventional systems was compared with the sensitivity of the newer system of combined cultures for the isolation of influenza viruses. Both systems were comparable. It was found, that certain isolates were obtained only by conventional systems, and conversly, others by combined cultures only. These results showed that the joint usage of both the conventional and newer systems resulted in a significantly higher isolation rate.     

经肌间隙与传统入路行腰椎融合固定术的对比研究

目的　比较肌间隙与传统入路对腰椎内固定术中腰背肌损伤及术后病人短期恢复情况的影响。 方法　采用随机对照临床试验设计,将病人分为肌间隙入路组（A组）和传统入路组（B组）。按照随机数字表进行随机分组。测量基线肌酸激酶（CK）、谷草转氨酶（AST）、VAS和ODI评分。记录手术时间、术中出血量,术后第1和第3天的CK、AST,术后48 h内引流量、术后3 d经B超测定的伤口积液量,术后5 d、3个月的VAS和ODI评分。 结果　共纳入57例病人,其中A组27例,B组30例。两组的年龄、基线CK、AST、VAS和ODI评分无显著差异（P>0.05）。两组的手术时间、术中出血量无显著差异。术后48小时融合侧的引流量无显著差异,但融合对侧有显著差异（P<0.05）。术后第1天的CK、AST有显著差异（P<0.05）,而第3天无显著差异。术后第5天和3个月的VAS和ODI评分有显著差异（P<0.05）。 结论　经肌间隙入路能减轻手术对多裂肌的损伤,有利于病人术后恢复。     

Possibilities of combined surgical treatment of lung tumours and heart diseases

The purpose of the study was a retrospective evaluation of the outcome of surgical therapy of lung cancer in patients where there was concomitant cardiac disease and who underwent a cardiac operation either because of ischemic heart disease or because of valvular disease. These patients were operated on at various time intervals (two to ten months) after their cardiac operation. Some patients had their lung cancer surgery after the cardiac operation because of the high risk of possible cardiac postoperative complications; in one patient the lung operation preceded the cardiac one.     

In vivo dosimetry: intercomparison between p-type based and n-type based diodes for the 16-25 MV energy range

This paper compares two different types of diodes designed to cover the energy range from 16 to 25 MV, one n-type (diode-A) and the other p-type (diode-B). A 18 MV x-ray beam has been used for all tests. Signal stability postirradiation, intrinsic precision and linearity of response with dose, front-back symmetry, and dose decrease under the diode were studied. Also, the water equivalent thickness of the build up caps was determined. Both types of diodes were calibrated to give entrance dose. Entrance correction factors for field size, tray, source skin distance, angle, and wedge were determined. Finally, the effect of dose rate, temperature and accumulated dose on the diode's response were studied. Only diode-A had full build-up for 18 MV x rays and standard irradiation conditions. Field size correction factor was about 2%-4% for field sizes bigger than 20 x 20 cm2 for both diodes. Tray correction factor was negligible for diode-A while diode-B would overestimate the dose by a 2% for a 40 x 40 cm2 field size if the correction factor was not applied. Wedge correction factors are only relevant for the 60 degrees wedge, being the correction factor for diode-A significantly higher than for diode-B. Diode-A showed less temperature dependence than diode-B. Sensitivity dependence on dose per pulse was a 1.5% higher for diode-A than for diode-B and therefore a higher SSD dependence was found for diode-A. The loss of sensitivity with accumulated radiation dose was only about 0.3% for diode-A, after 300 Gy, while it amounted to 8% for diode-B. Weighing the different correction factors for both types of diodes no conclusions about which type is better can be driven. From these results it can be also seen that the dependence of the diode response on dose rate in a pulsed beam does not seem to be associated with the fact of being n-type or p-type but could be related to the doping level of the diodes.     

质子和其他放射治疗肿瘤的比较

质子加速器是目前世界上最先进的放射治疗设备。本文对质子和目前各国常用的常规射线(兆伏特级的光子和电子),在肿瘤的放射治疗方面进行了比较。并复习了世界各国用质子治疗肿瘤的经验,介绍质子治疗肿瘤的优点、发展历史以及发展前景。质子束进入人体组织时,其大量的能量集中在接近射程终点,称为Bragg峰。放射治疗医生可以通过调节质子加速器能量的方式,使高能量区集中在病人体内一定的区域;在此高量区的后方,放射剂量骤降为零。因此,医生可以使放射线的高剂量区集中在靶区(肿瘤区),避免周围正常组织部受到照射。而用常规射线照射时,周围正常组织仍受到较高量的照射。用目前先进的三维适形放射治疗和调强放射治疗技术,只需用少数的照射野,即可达到非常满意的放射剂量分布。到2004年2月,世界上已有11个国家正在开展质子治疗工作;已用质子治疗病人35838例。所治疗的肿瘤有眼葡萄膜黑色素瘤、中枢神经系统肿瘤、颅底肿瘤、前列腺癌、非小细胞肺癌、胃肠道肿瘤、鼻咽癌、乳腺癌和官颈癌等,均取得较好的效果。目前已引起世界各国放射治疗学界的重视。     

Hysteresis heating for the treatment of tumours

A method is described whereby, utilising a biocompatible magnetic glass-ceramic material, effective hysteresis heating in living tissue was accomplished. Initial experiments on mice showed that a significant heating effect can be obtained in the ceramic-impregnated regions. An analysis is also given for the projected safe operating field-frequency regime of the hysteresis therapy.     

Comparison between Bactec Nr. 660 and a conventional 12-tube blood culture system

The detection power of the automated blood culture system Bactec NR 660, based on infrared detection of carbon dioxide in an agitated aerobic medium and a non-agitated anaerobic medium, was compared with that of our conventional 12-tube blood culture system. Of 1685 paired blood cultures, 258 (15.3%) were positive in one or both systems. Clinically relevant isolates were found in 11.5%. The dominating species were Escherichia coli(41%), followed by Staphylococcus aureus(14%) and Klebsiella spp.(8%). The Bactec system detected 178 (10.6%) and the 12-tube system 157 (9.3%) clinically relevant microorganisms after seven days' incubation. Significantly more clinically relevant isolates were detected by the Bactec system alone as compared with the conventional system alone (40 versus 19, p less than 0.01). The detection time was significantly shorter in the Bactec system for all isolates and for E. coli and S. aureus separately (p less than 0.01). 1.8% of the isolates in the Bactec system and 2.1% in the 12-tube system were considered clinically non-relevant contaminants.     

Comparison of Photodynamic Therapy versus conventional antifungal therapy for the treatment of denture stomatitis: a randomized clinical trial

In this randomized clinical trial, the clinical and mycological efficacy of Photodynamic Therapy (PDT) was compared with that of topical antifungal therapy for the treatment of denture stomatitis (DS) and the prevalence of Candida species was identified. Patients were randomly assigned to one of two groups (n = 20 each); in the nystatin (NYT) group patients received topical treatment with nystatin (100 000 IU) four times daily for 15 days and in the PDT group the denture and palate of patients were sprayed with 500 mg/L of Photogem®, and after 30 min of incubation, were illuminated by light emitting-diode light at 455 nm (37.5 and 122 J/cm², respectively) three times a week for 15 days. Mycological cultures taken from dentures and palates and standard photographs of the palates were taken at baseline (day 0), at the end of the treatment (day 15) and at the follow-up time intervals (days 30, 60 and 90). Colonies were quantified (CFU/mL) and identified by biochemical tests. Data were analysed by Fisher's exact test, analysis of variance and Tukey tests and κ test (α = 0.05). Both treatments significantly reduced the CFU/mL at the end of the treatments and on day 30 of the follow-up period (p <0.05). The NYT and PDT groups showed clinical success rates of 53% and 45%, respectively. Candida albicans was the most prevalent species identified. PDT was as effective as topical nystatin in the treatment of DS.     

Comparison between highly cross-linked and conventional polyethylene in total knee arthroplasty

The use of highly cross-linked polyethylene in total knee prostheses is still controversial. The aim of the present study was to compare radiographic and clinical results of using conventional and highly cross-linked polyethylene in cruciate retaining total knee prostheses of completely the same design. Two hundred and two consecutive total knee arthroplasties (NexGen CR, Zimmer) were performed using the same procedure. The first consecutive 113 knees had conventional polyethylene insert and following consecutive 89 knees had highly cross-linked polyethylene insert (Prolong, Zimmer). Differences in the age, gender, and diagnosis between two groups were not statistically significant. Preoperative range of motion (ROM) of the knee, and Knee Society Score (KSS) was better in highly cross-linked polyethylene group. Clinical and radiographic results were evaluated at two years after operation. The difference of ROM and KSS between groups was not statistically significant. There was no revision surgery. No knee exhibited osteolysis, aseptic loosening, or polyethylene failure. There was no early catastrophic clinical failure due to use of the new material.     

Computer algebra for x-ray spectral reconstruction between 6 and 25 MV

A previously presented algorithm for the reconstruction of bremsstrahlung spectra from transmission data has been implemented into MATHEMATICA. Spectra vectorial algebra has been used to solve the matrix system A * F = T. The new implementation has been tested by reconstructing photon spectra from transmission data acquired in narrow beam conditions, for nominal energies of 6, 15, and 25 MV. The results were in excellent agreement with the original calculations. Our implementation has the advantage to be based on a well-tested mathematical kernel. Furthermore it offers a comfortable user interface.