微波热疗组织超声衰减系数的温度相关性研究

研究微波热疗组织超声衰减系数的温度相关性,以期实现肿瘤微波热疗超声无创测温。通过对离体猪肝进行微波加热实验,采集肝组织在不同温度下的超声回波信号,计算不同温度下离体猪肝的超声衰减系数,获得超声衰减系数的温度相关性。实验结果表明超声衰减系数与温度具有较强的相关性（相关系数在0.5以上）,基于超声衰减系数的温度相关性进行温度检测具有较高的温度测量精度（温差范围在0.2～4℃之间）。     

肿瘤患者微波热疗的护理

目的探讨肿瘤患者微波热疗的护理。方法对27例恶性肿瘤患者进行微波热疗护理。结果及时解决了各种并发症的发生,减轻了患者的疾病痛苦,提高了疗效及治疗后的生活质量。结论热疗前的各项准备工作的充分程度、热疗中细心的观察护理及整个过程中的心理指导是保证微波热疗取得成功的关键。     

浅谈使用微波热疗机的基本知识

八十年代末我国有关医院引进了微波热疗机，九十年代以来，国内一些厂家和公司研制出了多种类型的微波热疗机。全国大部分肿瘤医院和一些大型的综合医院，都已装置了微波热疗设备，基本形成了利用微波热能治疗各种疾病的热潮。据作者所看到的一些医院和医务工作者，由于专业的局限性，对微波的特性、微波热疗原理、应用范围，对微波热疗机的操作和作用，还缺乏一定的基本知识。为了提高微波热疗技术，正确有效的使用微波热疗机，在此讲讲有关微波热疗的知识。微波热疗主要是利用微波电磁场能量的热效应原理，通过热疗机的各种天线（辐射器）…     

多元阵肿瘤热疗系统的实时温度测量与控制

介绍了自制的超声肿瘤热疗系统。该系统有九个功率放大器分别给九个超声换能器提供能源。利用九路测温系统实时采集体内九点温度值，依据温度数据的反馈，能及时地对各路功率放大器输出的功率进行调整。以保证热疗达到预期的效果。     

BSD-2000热疗系统构造原理及临床应用

<正>高温治疗肿瘤正日益受到临床重视,它存在与发展的医学依据主要有3点:①肿瘤组织和正常组织对热的耐受力及散热能力有较大差异,即所谓的热敏感性不同.肿瘤组织一般在42℃～43℃便开始坏死(而正常组织在超过45℃时才发生不可逆转变化),且因肿瘤组织内血窦丰富,血循环较差,散热能力差,导致温升高于周边正常组织.②热疗与放疗化疗结合,具有显著的增敏作用,可以减低放疗化疗剂量,减轻放疗化疗带来的副作用.③热疗对人体基本上没有副效应.热疗装置种类较多,按频率分有超声、射频和微波热疗机;按辐射器形式分有电容式、电感式和环形阵列式等.此外,根据辐射器放置部位,还有腔内、体外之分.射频和微波热疗技术较为成熟,在射频热疗机中,以日本产RF-8 电容式和美国产BSD-2000 环形阵列式为代表.本文介绍BSD-2000热疗系统构造原理及临床应用.     

肿瘤热疗中组织热物性参数对热场分布的影响

肿瘤微波热疗温度场模拟是预测热场分布的重要手段。由于人体组织的复杂性,目前模拟结果普遍存在准确度较差的问题。组织热物性参数随加热温度变化而发生变化是导致模拟结果不准确的重要原因之一。本文采用有限元方法进行温度场模拟,通过模拟结果分析组织热物性参数变化对温度分布的影响。     

热疗过程中体温监测器的研制

目的研制一种主要用于热疗过程中的体温监测器,可提供实时体温显示,并根据设置的参考体温值及时发出报警,为安全热疗提供保障。方法采用温度传感器检测体温,通过对信号进行线性处理和放大,经模数转换和单片机AT89C52处理,最终通过液晶对体温进行显示。结果该温监测器能够在误差小于±1%的条件下对热疗过程中的体温进行测量。结论该体温监测器能够实时、连续地对热疗过程中的体温进行准确监测。     

肿瘤患者全身微波热疗的护理

目的探讨并规范肿瘤患者全身微波热疗时的护理方法。方法对89例恶性肿瘤患者进行全身热疗护理,贯穿以人为本的护理理念,加强心理护理,实践优质护理。结果增加了热疗患者的舒适感,及时解决各种并发症的发生,保证了热疗的顺利完成,减轻患者的疾病痛苦,提高了疗效及治疗后的生活质量。结论热疗前的各项准备工作的充分程度、热疗中细心的观察和护理及整个过程中的心理指导是保证全身热疗取得成功的关键。     

微波高频热疗配合局部化疗治疗转移癌

微波高频热疗治疗癌肿是利用物理疗法使组织加热,达到杀灭癌细胞的温度,治疗恶性肿瘤的有效方法之一。由于肿瘤组织散热不良,肿瘤组织温度高于肿瘤邻近正常组织,加上癌细胞对高热敏感,因此高热能杀灭癌细胞而对正常细胞则无损     

用国产WRL-4型微波热疗机合并放疗治疗表浅肿瘤

199例浅表性肿瘤患者,用915MHz微波以两种不同的加温方式(升温式与降温式)热疗并联用放疗,作临床疗效比较研究,结果显示降温式热疗加放疗优于升温式热疗加放疗.疗效提高显著,降温组总有效率优于加温组,提示热疗具有增敏作用.     

A proposed four-element neutron-photon-beta thermoluminescence dosimeter.

It is common practice for a worker exposed to a mixed field with neutrons to wear both a photon-beta dosimeter and a neutron dosimeter. In this study, a thermoluminescence dosimeter has been designed and is proposed for use in mixed fields. The maximum applicable ranges of the mixed field can have photons with unknown energy from 20 keV to 2 MeV, betas with unknown energy from 147Pm to 90Sr-Y, and neutrons of known energy from thermal to 15 MeV. This proposed dosimeter (a combination of Harshaw beta-gamma thermoluminescence dosimeter and albedo neutron thermoluminescence dosimeter) has an advantage of using a minimum number of thermoluminescence dosimeter elements (therefore, making it less costly) to measure the dose equivalents in a mixed field of neutron, photon, and beta radiation. The basic dosimeter design consists of four thermoluminescence elements of TLD-600 and TLD-700 with different filtrations. Using the high-temperature peak methodology for TLD-600 and a filtration algorithm, the neutron, photon, and beta dose equivalents in a mixed field can be determined. The design, detection principle, and three dosimetric algorithms for three versions of the basic design of the four-element dosimeter are presented and discussed. The work that is required for the proposed dosimeter to be usable when it is made is also presented.     

Sugar as an emergency populace dosimeter for radiation accidents

Ordinary sugar can be used as an emergency dosimeter for any person exposed to a nuclear or radiation accident. The number of free radicals in sugar created by radiation does not decrease at room temperature for two months after irradiation and is not changed by thermal treatment for about 18 h at even 55 degrees C. A 600 mg granulated sugar sample can detect about 0.05 Gy (5 rad) as the minimum detectable absorbed dose using electron spin resonance equipment. If sugar is present at the time of a radiation or nuclear accident, the absorbed dose can be evaluated from the sugar and will be useful for both the medical treatment and health effects of the exposed persons.     

Thermal neutron fluence measurement in a research reactor using thermoluminescence dosimeter TLD-600.

A thermal neutron fluence in the range between 10(11) and 10(13) n cm(-2) in the reactor core of the Tehran research reactor has been measured using TLD-600 thermoluminescence dosimeters. After a thermal treatment of 1 h at 400 degrees C followed by 20 h cooling down to room temperature of pre-exposed dosimeters in the reactor, the accumulated TL light was measured after periods of storage of 24, 48 and 72 h. The influence of the irradiation-induced damage effect on the response of TLDs and their subsequent readings has been minimized in this manner. The induced TL light due to self-activity in the TLD-600 dosimeters, which is dependent on the neutron fluence, caused a conveniently measurable TL glow curve. The induced TL in the dosimeter due to the Q-value for the beta-decay of tritium Ebeta-max = 18.6 keV has been reproduced separately by a beta source to check the proportions of radionuclides in the chip. A short theoretical treatment is also presented.     

Effect of reader and oven annealing on the glow curve structure and fading of a LiF:Mg,Cu,P TL dosimeter.

The effect of pre-irradiation annealing in an oven at 240 degrees C/10 min (oven anneal) and in a TLD reader at 6 degrees C s(-1), 10 s dwell time at a maximum temperature 240 degrees C (reader anneal), on the glow curve structure of a home made sample of LiF:Mg,Cu,P powder has been investigated. It is shown that on oven annealing the glow peak areas of peaks 2 and 3 increase and that of peak 4 decreases, while on reader annealing the area of peak 4 increases and those of peaks 2 and 3 effectively decrease. Values of fading during a post-irradiation storage of 6 months were measured to be 26% and 12% for samples undergoing oven and reader annealing respectively. To reduce the effect of fading several pre-heats at temperatures of 100, 110, 120 and 130 degrees C for 10 min were investigated and 120 degrees C/10 min was chosen as the optimal condition for pre-heat. It is also observed that when imposing pre-heat thermal treatment on this dosimeter or storing the irradiated dosimeter the height of peak 4 effectively increases while the integral of TL signals remains constant.     

Dosimeter for detection of hydrogen fluoride

The passive dosimeter for hydrogen fluoride monitoring consists of a plastic box with 40 holes of 1 mm in diameter in the front side containing a Na2CO3-impregnated filter paper as the collection medium. The sampling rate of this dosimeter is independent of the exposure dose and temperature but depends on the relative humidity. At 20% relative humidity the sampling rate is 1.69 l.h-1, however at 70% the sampling rate is 0.68 l.h-1. The dependence of the sampling rate on the relative humidity phi is expressed by the equation AR = - 0.0198.phi + 2.04.     

Evaluation of the GMD systems, Inc., thermally-desorbable diffusional dosimeter for monitoring methyl chloride

The GMD Systems, Inc., thermally-desorbable diffusional dosimeter using Anasorb GM solid sorbent was evaluated for monitoring methyl chloride (CH3Cl) in the workplace. The effects of CH3Cl concentration; dosimeter exposure time; relative humidity, temperature, and face velocity during exposure; excursion exposure behavior; and storage temperature and duration after collection were investigated. Only extremely low face velocities (0.020 m/sec) and storage periods of over 8 days at room temperature or of around 30 days at reduced (refrigerator or freezer) temperatures caused sample degradation. Side-by-side measurements of CH3Cl using the diffusional monitor and a validated charcoal tube method under field conditions yielded statistically indistinguishable results. This diffusional monitor used in combination with Anasorb GM solid sorbent is a satisfactory means of determining CH3Cl exposures in the workplace.     

Quantification of the temperature equilibrium time of the cavity in parallel-plate-type ionization chambers by thermal analysis

Temperature corrections are necessary to account for the varying mass of air in the cavity volume of a vented ionization chamber. The temporal response resulting from temperature changes in a cylindrical and/or Farmer-type ionization chamber, which is the standard dosimeter, has been thoroughly discussed by some researchers. The purpose of this study was to characterise and analyse the dependence of the cavity air temperature of the parallel-plate-type ionization chamber on changes in the ambient temperature. Ionization chambers NACP-02 (IBA Dosimetry, GmbH) and Advanced Markus TN34045 (PTW, Freiburg) were modelled using thermal analysis software to present the temperature equilibrium time and the entire ionization chamber temperature distribution. The temporal response of each ionization chamber was measured for comparing the calculation results of the thermal analysis. The ionization chamber cavities of NACP-02 and TN34045 reached complete equilibrium in 670 and 750 s, respectively. Heat transfer occurred faster at the centre of the front wall of TN34045 than at the outside of the centre except for the edges. Further, the non-uniformity of temperature in the cavity was in the range of 24.2–24.8°C for NACP-02 and 23.7–24.4°C for TN34045 at 200 s after the ionization chamber was installed in the water phantom. The previous proposal to wait for about 15 mins after submerging the chamber in a water phantom before the measurement is demonstrated to be appropriate for parallel-plate-type ionization chambers.     

眼晶体、指环剂量计的部分剂量学性能实验测试研究

目的 比较国产与进口眼晶体、指环剂量计的部分性能测试结果,掌握眼晶体、指环剂量计的部分剂量学性能指标.方法 依据IEC 62387-2012和GBZ 128-2019中性能要求,分别使用国产和进口热释光探测器开展了眼晶体剂量计和指环剂量计在光子响应下的性能对比实验;测试进口眼晶体和指环剂量计在相同照射条件下照射2次的剂...     

Neutron dosimetry in the containment of a pressurized water reactor using a neutron-sensitive beta/gamma dosimetry system

In this study the Panasonic UD-802 dosimeter was evaluated as a potential neutron dosimeter for use in the containment of a pressurized water reactor by comparing the results from the UD-802 with remmeter readings. The Panasonic UD-802 dosimeter is used routinely as a beta and gamma dosimeter but due to the natural Li and B in the thermoluminescent materials, it is also sensitive to neutrons. Since a dosimeter's response to neutrons is energy-dependent, proper calibration of the UD-802 in the environment for which it is to be used was an important consideration of the study. To calibrate the system, UD-802 dosimeters were mounted on polyethylene phantoms and irradiated to reference doses at selected locations in containment. The reference doses were determined based on remmeter dose-rate measurements and stay times. The thermoluminescent response of the dosimeters and the reference measurements were used to obtain a response ratio at each location. The average response ratio (unit of dosimeter response per millirem) was 3.7 and all response ratios were within +/-30% of this mean value. Specific characteristics of the UD-802 were also investigated, that is, the effects that dosimeter distance from the phantom and a person's movement through containment have on response. The dosimeter distance from the phantom was found to have a minimal effect on response, but the system was found to be dependent upon the angle of the phantom relative to the reactor core, necessitating a correction in the calibration factor. The overall conclusion of this study was that the Panasonic UD-802 dosimeter can be used for neutron dosimetry in containment of a pressurized water reactor.     

An integrating thermoluminescent Rn daughter personal dosimeter

An integrating Rn daughter dosimeter using conventional Dy-doped CaSO4 thermoluminescent (TL) material has been developed for use as a personal monitor. The dosimeter was found to have a linear response over the range 0.5 WL-h to 25 WL-h and to be insensitive to the state of equilibrium of the Rn daughters. The use of the dosimeter to monitor both 222Rn and 220Rn daughters is described. The limiting sensitivity of the dosimeter, at a sampling rate of 1 L min-1, was determined to be 0.1 WL-h for 222Rn daughters and 0.5 WL-h for 220Rn daughters. The application of the thermoluminescent dosimeter (TLD) to occupational monitoring of 222Rn and 220Rn daughters is discussed.