2450MHz食管腔内微波辐射器热分布的在体研究

目的研究２４５０ＭＨｚ食管腔内微波辐射器在人体内热分布情况。材料与方法通过５例食管癌病人开胸术中进行食管内辐射器加温并在壁内不同深度测温并与管腔内温度进行对照得出食管壁不同深度的温升情况。结果在腔内温度维持４５℃左右时，辐射器有效加温长度中心深０．５ｃｍ、１ｃｍ处温度约在４１℃和３９℃，从表面往深度去的温降呈指数下降，比理论计算值（０．５ｃｍ３８．０℃，１ｃｍ３７．４℃）要好得多。结论２４５０ＭＨｚ食管腔内辐射器在深部温降呈指数型，０．２５ｃｍ，０．５ｃｍ，１ｃｍ深度温度与表面温度（０ｃｍ）之差分别为２℃、４℃及６℃。     

915MHz微波天线不同插植深度的功率特别吸收率(SAR)变化

在以往的微波组织间插植热疗中,我们发现微波天线的热分布会随着插植深度的不同而有变化。为具体了解这种情况,提高治疗质量我们采用两种常见的915MHz微波插植天线进行了不同插入深度的功率特别吸收率(SAR)测定。1　材料和方法　　两种915MHz微波天线均是利用半硬的同轴电缆制成(micro-COAX,USA):A为偶极天线,即去掉最末3.9cm外导体:B为单极天线,即最末2cm外导体与天线的外导体成0.3cm间隙,并在天线的最末端与内导体焊接。体模配方:蒸馏水75.44%,聚乙烯15.20%,TX-150粉8.45%和食用盐0.91%。SAR仪(CheungLaboratoriesINC.USA)为…     

加温复合放射对小鼠EMT_6肿瘤的影响

采用放射线和微波加温方法处理小鼠EMT_6移植肿瘤,并进行分组研究.用一般组织学技术和电镜技术,以形态学的动态变化观察、分析所得结果.结果显示肿瘤细胞经加温和放射后最显著的变化反映在组织学和形态学变化上.本文初步运用DNA含量的变化来评价治疗效果.     

射频加温装置入射功率和循环水温对升温的影响

目的 了解RF-8深部加温治疗冷却循环水温度及入射功率的变化对加温局部温度的影响，掌握加温的有效范围，寻找临床治疗合适的冷却循环水温度。方法 选择两个相同直径(30cm)的电极对固体等效肌肉琼脂体模进行加温。在设定循环水10℃时，测试不同入射功率两电极中心垂直轴之间各点的温度；以及不同循环水温度时体模水平中心平面及其上下各5cm处平面内的温度分布。结果在体模上下表面中心的连线上，入射功率和升温速率呈现明显的线性关系(r=0．999，P=0．020)；体模与电极接触的两侧表面到大约5cm深处温度变化差别较大，循环水为6℃时电极接触体模表层的温度低于体模基础温度，10℃与16℃时体模表浅部温度逐渐升高。结论 容式射频深部加温治疗机RF-8在深部加温治疗时，入射功率与升温速率呈正比关系；在两个直径30cm电极加温时，进入体模表面约5cm以内温度分布比较均匀；冷却循环水温度影响体模表浅部的温度。     

加温联合羟基喜树碱对人肺腺癌细胞的影响

目的为了提高热疗治疗肿瘤的效果,通过细胞学实验方法观察加温联合羟基喜树碱对人肺腺癌细胞的影响.方法本文采用MTT法,绘制不同温度(37.0℃,41.0℃,42.0℃,43.0℃)下的药物生物活性曲线,各组数据用SPSS统计软件进行相关性分析.结果同一温度下,药物浓度越高,则细胞存活率越低,二者呈显著负相关(P＜0.05);同一药物浓度下,当羟基喜树碱浓度介于0.1～60μg/ml之间时,随着温度的增高,细胞存活率降低,二者呈显著负相关(P＜0.05);药物生物活性曲线特征参数IC5o值与温度呈显著负相关(P＜0.05).结论同一温度下,羟基喜树碱对人肺腺癌细胞系Anip973的杀伤作用呈显著的浓度依赖性,而在一定浓度羟基喜树碱作用下,加温与化疗药物联合作用对人肺腺癌细胞的杀伤作用呈显著的温度依赖性,并且证明羟基喜树碱为无阈值药物.     

不同条件微波辐射对PC12细胞周期、死亡方式和超微结构的影响

目的探讨不同条件微波辐射对PC12细胞的损伤效应,为深入研究微波辐射的损伤机制提供剂量学依据。方法采用平均功率密度(重复频率×脉宽)分别为10 m W/cm2(100 pps$500 ns)、30 m W/cm2(300 pps$500 ns)和30 m W/cm2(1000 pps$150 ns)的微波辐射NGF诱导后的PC12细胞5 min,于辐射后6 h,采用流式细胞术检测细胞周期、凋亡和坏死率,采用激光扫描共聚焦显微镜观察细胞凋亡和坏死率,采用透射电镜观察PC12细胞超微结构的改变。结果10 m W/cm2(100 pps$500 ns)辐射后6 h,G0-G1期PC12细胞数减少(p<0.05),G2-M期细胞数增加(p<0.01);30 m W/cm2(1000 pps$150 ns)辐射后6 h,G0-G1期细胞数增加(p<0.05),G2-M期减少(p<0.01);30 m W/cm2(300 pps$500 ns)辐射后6 h,G0-G1期细胞数增加(p<0.05),S期细胞数减少(p<0.01),细胞凋亡率增加(p<0.01),PC12细胞核膜间隙增宽,染色质浓缩边集,核仁呈蜂窝状;线粒体肿胀、空化。结论 30 m W/cm2(300 pps$500 ns)微波辐射可引起PC12细胞生长抑制,凋亡率增加,结构损伤;30 m W/cm2(300 pps$500 ns)可作为深入研究微波辐射的损伤机制的辐射剂量。     

微波修复时间对CD44V6抗原表达的影响

抗原修复已成为免疫组化技术中不可缺少的方法之一。一般采用温度控制在９２℃～９８℃，微波持续辐射８～１０分钟，对大多数抗原修复可达到最佳效果，但对少数抗原修复效果却不满意。为此我们观察了不同微波修复时间对ＣＤ４４Ｖ６抗原表达的影响，发现微波辐射组织切片...     

加温或／和化疗药对结肠癌细胞系THC—8908多药耐药基因表达的影响

用MTT法检测中药AF-7，丝裂霉素（MMC），5-氟脲嘧啶（5－Fu）在单纯用药及加温与加药共同应用，对人结肠高分化腺癌细胞系THC8908的作用，并用抗多药耐药（MDR）基因表达蛋白P170单抗及免疫组化法，检测该细胞在上述条件下（MDR）基因表达的异同。结果发现：1）加温可增强AF－7、MMC和5－Fu对肿瘤细胞的杀伤作用。2）免疫组化染色揭示，正常培养条件下该细胞MDR为中度表达，经加142．5℃1小时再培养72小时其MDR则不表达。单独用药各组均为中度表达，而加温与加药共同应用组均为低度表达，且MMC组MDR表达的阳性细胞数高于AF－7组。研究证明加温能明显抑制MDR基因表达，从而提高化疗效果。     

加温对乏氧培养中的舌癌细胞株增殖活性影响的实验研究

目的:探讨加温对乏氧培养中的人舌癌Tca8113细胞株增殖活性的影响,为临床上加温治疗口腔癌提供理论基础.方法:根据是否给予加温处理分为A组(未加温组)和B组(加温组);根据乏氧时间A、B组又分别分为0h、3h、6h、12h、24h 5个小组.依此分组,采用MTT法检测加温对乏氧人舌癌Tca8113细胞增殖活性的抑制率.结果:加温可降低乏氧人舌癌Tca8113细胞的增殖活性;且随着乏氧时间的延长,此作用越明显.结论:乏氧可提高肿瘤细胞对加温的敏感性,为加温联合放、化疗治疗口腔癌提供进一步的理论依据.     

不同强度的低功率微波辐射对雄性小鼠生殖系统的影响

背景与目的:探讨不同强度低功率微波辐射对雄性小鼠生殖系统的影响.材料与方法:48只雄性ICR小鼠,随机分为3个辐射组和1个对照组,每组各12只,辐射组用频率900 MHz,功率密度分别为250、150、50 μW/cm2的连续波,对小鼠每天辐射24 h,连续辐射34.5 d.辐射结束观察小鼠性行为能力的扑捉潜伏期(capture incubation period,CIP)、睾体比、睾丸病理变化、精子相对计数、精子畸形率及血清睾酮等指标的变化.结果:各辐射组与对照组比较,150 μW/cm2组小鼠CIP明显延长(P＜0.05)、睾丸发生轻微病理变化、精子相对计数明显减少(P＜0.05);精子畸形率明显增加(P＜0.05);血清睾酮水平明显降低(P＜0.05);睾体比之间的差异无统计学意义.结论:低功率微波辐射(150 μW/cm2)能引起雄性小鼠睾丸病理改变,性功能(CIP)减退,精子相对计数减少,精子畸形率升高,血清睾酮水平降低,影响雄性小鼠生殖功能.     

A multiple-site perineal applicator (MUPIT) for treatment of prostatic,anorectal, and gynecologic malignancies

Recently, transperineal interstitial-intracavitary applicators have been used to treat locally limited and advanced perineal and gynecologic malignancies. We have developed a single afterloading applicator, referred to as the “MUPIT” (Martinez Universal Perineal Interstitial Template), which with its prototypes has been utilized to treat 78 patients with malignancies of the cervix, vagina, female urethra, perineum, prostate, and anorectal region. The device basically consists of two acrylic cylinders, an acrylic template with a predrilled array of holes that serve as guides for trocars, and a cover plate. Some of the guide holes on the template are angled outward to permit a wide lateral coverage without danger of striking the ischium. The cylinders have an axial hole large enough to pass a central tandem or a suction tube for the drainage of secretions. Thus, the device allows for the interstitial placement of ¹⁹²Ir ribbons as well as the intracavitary placement of either ¹³⁷Cs tubes or ¹⁹²Ir ribbons. In use, the cylinders are placed in the vagina and rectum and then fastened to the template, so that a fixed geometric relationship among the tumor volume, normal structures, and source placement is preserved throughout the course of the implantation. Howlow, closed-end, stainless steel trocars are then inserted through the guide holes that produce optimal coverage of the treatment volume. Appropriate computer programs also have been developed on a minicomputer for the corresponding dose-rate computations. These programs run with sufficient speed that they may be used for both the planning of the source placement beforehand and the computation of the actual dose-rate distribution obtained. The advantages of the system are (1) greater control of the placement of sources relative to the tumor volume and critical structures owing to the fixed geometry provided by the template and cylinders, and (2) improved dose-rate distributions obtained by means of computer-assisted optimization of the source placement and strength during the planning phase.     

Combination of external beam irradiation and multiple-site perineal applicator (MUPIT) for treatment of locally advanced or recurrent prostatic, anorectal, and gynecologic malignancies

We have devised a single after-loading applicator, the Martinez Universal Perineal Interstitial Template (MUPIT), which has been used in combination with external beam irradiation to treat 104 patients with either locally advanced or recurrent malignancies of the cervix, vagina, female urethra, prostate, or anorectal region. Twenty-six patients treated for prostate cancer are excluded because of their short follow-up. Local failure developed in 13 of the 78 remaining patients (16.6%)--major complications developed in 4 patients (5.1%). Follow-up has been 1 year to 7 1/2 years; 60/78 patients have been followed for more than 2 years. All local recurrences and complications occurred before 18 months. The device consists of two acrylic cylinders, an acrylic template with an array of holes that serve as guides for trocars, and a cover plate. In use, the cylinders are placed in the vagina and/or rectum or both and then fastened to the template so that a fixed geometric relationship among the tumor volume, normal structures, and source placement is preserved throughout the course of the implantation. Appropriate computer programs have been developed to calculate the dose from these implants. The advantages of the system are (a) greater control of the placement of sources relative to the tumor volume and critical structures, as a result of the fixed geometry provided by the template and cylinders, and (b) improved dose-rate distributions obtained by means of computerized optimization of the source placement and strength during the planning phase. We conclude that the local control rate (83.4%) with low morbidity (5.1%) achieved with the combination of external beam irradiation and MUPIT applicator in these patients with locally advanced malignancies represents an improvement over previous published results with other applicators.     

Role of acoustic cavitation in the delivery and monitoring of cancer treatment by high-intensity focused ultrasound (HIFU)

Acoustic cavitation has been shown to play a key role in a wide array of novel therapeutic ultrasound applications. This paper presents a brief discussion of the physics of thermally relevant acoustic cavitation in the context of high-intensity focussed ultrasound (HIFU). Models for how different types of cavitation activity can serve to accelerate tissue heating are presented, and results suggest that the bulk of the enhanced heating effect can be attributed to the absorption of broadband acoustic emissions generated by inertial cavitation. Such emissions can be readily monitored using a passive cavitation detection (PCD) scheme and could provide a means for real-time treatment monitoring. It is also shown that the appearance of hyperechoic regions (or bright-ups) on B-mode ultrasound images constitutes neither a necessary nor a sufficient condition for inertial cavitation activity to have occurred during HIFU exposure. Once instigated at relatively large HIFU excitation amplitudes, bubble activity tends to grow unstable and to migrate toward the source transducer, causing potentially undesirable pre-focal damage. Potential means of controlling inertial cavitation activity using pulsed excitation so as to confine it to the focal region are presented, with the intention of harnessing cavitation-enhanced heating for optimal HIFU treatment delivery. The role of temperature elevation in mitigating bubble-enhanced heating effects is also discussed, along with other bubble-field effects such as multiple scattering and shielding.     

Compliance to the prescribed overall treatment time (OTT) of curative radiotherapy in normal clinical practice and impact on treatment duration of counteracting short interruptions by treating patients on Saturdays

Background and purpose  To evaluate the compliance of the prescribed OTT in a normal clinical practice and to establish the incidence, duration and causes of unplanned interruptions of radiation therapy. To quantify the impact of an institutional policy to maintain the OTT counteracting some short interruptions by treating patients on Saturday morning. Material and methods  The treatment charts of all new patients treated with curative intent in a period of one year were reviewed retrospectively. All treatments started on Monday or Tuesday and split-course was not used. The difference between the actual realized and the planned OTT was calculated as a measure of compliance. Recalculations of OTT were made to quantify the impact of compensating short gaps by treating patients on Saturday. The cause of interruption was also recorded and classified. Results  The charts of 478 consecutive patients treated with curative intent were reviewed. The overall incidence of unplanned interruptions was 76.6%. Public holidays and machine maintenance caused most of interruptions, and machine breakdown caused 13%. 17.9% of the interruptions were greater than 5 days and 5.6% greater than 10 days. Only 23.4% of patients finished their radiotherapy in the planned OTT (12.6% if no compensation on Saturday). 48.9% of head and neck cancer patients finished their treatment in the planned OTT (19.5% if no compensation on Saturday). The time in excess ranged up to 44 days, and the average time in excess was 3.3 days for the entire group (4.2 days if no compensation on Saturday). For head and neck cancer patients, the time in excess was 1.9 days (3.9 days if no compensation on Saturday). Conclusions  This study has documented that the incidence and duration of unplanned interruptions of standard treatment schedules is a major problem in normal clinical practice. Most interruptions are short and due mainly to public holidays and machine maintenance and for these reasons they can be planned. In spite of the extra costs, counteracting some short interruptions by treating patients on Saturday is a good way to maintain the OTT without loss of local control.     

The impact of central lung distance,maximal heart distance,and radiation technique on the volumetric dose of the lung and heart for intact breast radiation

PURPOSE: To investigate the impact of radiographic parameter and radiation technique on the volumetric dose of lung and heart for intact breast radiation. METHODS AND MATERIALS: Forty patients with both two-dimensional (2D) and computed tomographic (CT) simulations were enrolled in the study. Central lung distance (CLD), maximal heart distance (MHD), and maximal heart length (MHL) were measured under virtual simulation. Four plans were compared for each patient. Plan A used a traditional 2D tangential setup. Plan B used clinical target volume (CTV) based three-dimensional (3D) planning. Both plans C and D used a combination of a medial breast field with shallow tangents. Plan D is a further modification of plan C. RESULTS: Under the traditional tangential setup, the mean ipsilateral lung dose and volume at 20, 30, and 40 Gy correlated linearly with CLD (R = 0.85 approximately 0.91). The mean ipsilateral lung dose (Gy) approximated 4 times the CLD value (cm), whereas the percentage volume (%) of ipsilateral lung at 20, 30, and 40 Gy was about 10 times the CLD (cm). The mean heart dose and percentage volume at 20, 30, and 40 Gy correlated with MHD (R = 0.76 approximately 0.80) and MHL (R = 0.65 approximately 0.75). The mean heart dose (Gy) approximated 3 times the MHD value (cm), and the percentage volume (%) of the heart at 10, 20, 30, and 40 Gy was about 6 times MHD (cm). Radiation technique impacted lung and heart dose. The 3D tangential plan (plan B) failed to reduce the volumetric dose of lung and heart from that of the 2D plan (plan A). The medial breast techniques (plans C and D) significantly decreased the volume of lung and heart receiving high doses (30 and 40 Gy). Plan D further decreased the 20 Gy volumes. By use of the medial breast technique, the lung and heart dose were not impacted by original CLD and MHD/MHL. Therefore, the improvement from the tangential technique was more remarkable for patients with CLD >or= 3.0 cm (p < 0.001). CONCLUSIONS: The CLD and MHD impact the volumetric dose of lung and heart. The application of 3D planning for tangential breast irradiation does not decrease heart and lung dose. Adding a medial breast port significantly decreases percentage volume (PV) of lung and heart receiving high doses, especially when the CLD is excessive.     

THE IMPACT OF RADIOTHERAPY COURSE LENGTH ON THE TREATMENT RESULTS OF NASOPH9

ＴＨＥＩＭＰＡＣＴＯＦＲＡＤＩＯＴＨＥＲＡＰＹＣＯＵＲＳＥＬＥＮＧＴＨＯＮＴＨＥＴＲＥＡＴＭＥＮＴＲＥＳＵＬＴＳＯＦＮＡＳＯＰＨＡＲＹＮＧＥＡＬＣＡＲＣＩＮＯＭＡ（ＮＰＣ）ＣｈｅｎＸｉａｎｚｈａｏ陈显钊；ＴａｎｇＱｉｘｉｎ唐启信（Ｄｅｐａｒｔｍｅｎｔ...     

The impact of the perception of treatment choice on satisfaction with treatment, experienced chemotherapy burden and current quality of life

Previous research has shown that involving patients in the decision-making process may improve their quality of life (QoL). Our purposes were to assess: (1) whether early-stage breast cancer patients perceived that they had treatment choice with regard to adjuvant chemotherapy, (2) what reasons patients provide for their perception of having had no choice of treatment and (3) whether the perception of treatment choice is related to satisfaction with the assigned treatment, experienced chemotherapy burden and current QoL. A total of 448 patients, treated between 1998 and 2003, filled in the questionnaire (response rate: 62%). Patients who indicated that they had not perceived a choice regarding chemotherapy could tick off one or more reasons out of 10 reasons, or provide their own reason(s). Quality of life was measured on a Visual Analogue Scale, by means of the EuroQol, and by means of the Hospital Anxiety and Depression Scale. Of the 405 patients who had answered the question on treatment choice, 316 patients (78%) had perceived no choice. The most frequently indicated reason for lack of choice was: "I follow the doctor's advice." We found no differences in the levels of satisfaction with assigned treatment and in how much of a burden they found chemotherapy between patients who perceived a choice of treatment and those who did not. In general, the perception of choice seemed to have no impact on QoL. However, we found an interaction effect, which indicated that the impact of perception of treatment choice on QoL was dependent upon whether the patient had been treated with chemotherapy or not. Within the group of patients who had not been treated with chemotherapy, the perception of having had a choice was related to lower current QoL. In cases when the decision to be treated or not has potential consequences for the chance of survival, patients' QoL may not be improved by the perception of having had a choice of treatment.