矩阵剂量仪半导体探测器性能测试技术研究

针对加速器不适宜在实验室使用且发出的射线会伤害人体等问题,为方便考察仪器性能,采用标准光源模拟加速器照射的方法,对矩阵剂量仪半导体探测器进行性能测试。经过刻度之后,矩阵剂量仪能够完成在加速器照射下的实际测量。实验结果表明:采用标准光源模拟加速器照射矩阵剂量仪,对半导体探测器进行性能测试的技术是可行的。     

放射性治疗水平剂量仪

本文简单的介绍了治病水平电离室型剂量仪的一般要求,其中包括剂量仪的主机（静电计）与电离室的结构,原理同时也介绍了我国相应的规程与国际电工委员会（ＩＥＣ０有关的报告对治疗水平是离室型剂量仪的技术要求,另外对日常中送检用户所提共性问题,（如,剂量仪的正确使用,维护与保养等）的处理进行讨论。     

TQ-2000型多通道剂量仪

本文介绍了最新研制的“TQ-2000型多通道剂量仪”基本原理和技术性能。主要应用包括：患者重要器官在放疗时的剂量测量和剂量监测;全身照射入口剂量和出口剂量及透射率测量;体内中心剂量测量;三维适形调强放疗剂量分布测量和相应的计划系统剂量分布检验;放疗设备和后装机系统稳定性测量;辐射场分析及剂量分布测量等。它与体模配套使用,能进行体内外剂量测量。     

放射性治疗水平剂量仪

本文简单的介绍了治疗水平电离室型剂量仪的一般要求,其中包括剂量仪的主机(静电计)与电离室的结构、原理,同时也介绍了我国相应的检定规程与国际电工委员会(IEC)有关的报告对治疗水平电离室型剂量仪的技术要求.另外对在日常检定中送检用户所提共性问题(如剂量仪的正确使用、维护与保养等)的处理进行讨论.     

胶片剂量仪与半导体探测器在小野剂量数据测量中的比较分析

小照射野的建模数据对于调强放射治疗和立体放射治疗十分重要。在加速器使用6MV光子束条件下,采用胶片与0.01cm³的半导体探头,在IBA Blue Phantom 2水箱与固体水中,测量0.6cm×0.6cm至10.0cm×10.0cm照射野的百分深度剂量(PDD)曲线、profile、点剂量等数据,并计算射野总散射因子Scp。测试结果表明:对于PDD曲线,不同的照射野情况下,半导体探头与胶片在建成区测得数据基本吻合,在水深2～10cm测量结果存在微小偏差,当水深超过10cm以后差距明显(达7%);对于profile曲线,不同照射野下,胶片与半导体探头测量数据无明显差异,但胶片具有更好的空间分辨率,体现在半影区剂量跌落更明显;半导体探头、胶片剂量仪测得的点剂量与计划系统计算相同深度的点剂量比较,差异明显(最大误差分别为-2.7%、12%)。分析得出:不同的测量探头,对小野物理数据测量的准确性可能存在很大差异;胶片剂量仪具有优越的空间分辨率,但是胶片的吸收剂量范围有限,具有能量和方向依赖性。     

DR图像质量与放射剂量的关系和分析

清晰的DR图像对临床医生的诊断起到很好的辅助作用,但太高的辐射剂量对患者的危害是显而易见的,本文结合日常的DR计量检测工作,对DR机的辐射剂量如何影响图像质量进行研讨和分析,希望能对DR机检测工作者和DR放射技师的工作有所帮助。     

DR检查在新生儿肺透明膜病诊断中的应用价值

目的:分析数字化X射线摄影系统(DR)检查在新生儿肺透明膜病(HMD)诊断中的应用价值。方法:选取收治的224例HMD患儿(2018年3月-2019年3月),以胸部X线片检查为金标准,均行CT、DR检查,分析CT、DR检查的诊断价值。结果:DR诊断HMD不同病情程度的准确率95.09%高于CT 85.71%(P<0.05)。结论:DR检查应用于HMD患儿不同病情中,能显著提高诊断准确率,为临床评估病情程度、实施对症治疗提供循证支持。     

X射线诊断剂量仪溯源分析

本文介绍了我国X射线辐射源量传覆盖情况,连续3年对全国范围内多种型号的诊断水平剂量仪的多种性能参数进行了比较、评价.了解到我国医用诊断X光机的计量检定工作同发达国家还有很大差距,应加大医用诊断X光机量值传递的投入力度.     

二维半导体面阵列实时剂量验证系统的研制及应用

调强放疗(IMRT)是放疗技术的发展方向。为实现精确放疗的目标和严格的射线质量控制,以及技术安全保证,自主研发的二维半导体面阵列剂量实时验证测量系统,(TQ-2000B剂量分布图检测仪)该系统由445个半导体探测器按面阵列栅格精确排列,主要用于放疗射线质量控制:加速器QAI、MRT的TPS实时验证。通过实测的等剂量图、剂量值与相同条件下TPS计算的结果以及剂量胶片测量的结果进行比较,从而实现对调强放疗TPS实时验证。同时还介绍了它在加速器QA方面部分项目的测试应用。二维半导体面阵列剂量实时验证测量系统的研制成功,填补了国内空白,其主要技术指标和性能达到了国外同类产品的先进水平。     

射频含水仪在计量中的应用

分队计量数据是油田降油油输差,实现产量承包的关键数据,文章介绍了一种由射频含水仪构成的分队计量系统。     

Comparison on characteristics of radiophotoluminescent glass dosemeters and thermoluminescent dosemeters

The radiophotoluminescent glass dosemeter (RPLGD) system is applicable for measurement of radiation dose of X rays and gamma rays by using radiophotoluminescent glass (silver-activated phosphate glass). When the radiophotoluminescent glass is exposed to ionizing radiation, stable luminescent centres are created. During pulsed ultraviolet laser excitation (337.1 nm) in the reader, the centres emit a radiation induced orange fluorescent light (600-700 nm). This phenomenon is called radiophotoluminescence. This study compared the RPLGD system with lithium fluoride (LiF) thermoluminescence dosimetry system and the results of the study revealed that the RPLGD had not only good basic characteristics for reproducibility of readout value, dose linearity, energy dependence and fading, but also infinite repeatable measurements and could be one of the most important radiation dose measurement instruments.     

Review of international standards for dosemeters

International standards for radiation protection dosemeters are published by the International Electrotechnical Commission and the International Organization for Standardization. Several standards exist side by side, although they treat the same measuring task, and specify different requirements, so that dosemeters of different quality result. In this paper, the quality of dosemeters is compared by calculating the uncertainty of dose measurements for dosemeters, which just basely fulfil the respective standard. The results are related to general yardsticks on uncertainty laid down by international organisations. Furthermore, technical differences are standards and addressed and a method to make them conform is presented.     

Application of TL dosemeters for dose distribution measurements at high temperatures in nuclear reactors

Al2O3:Mg,Y ceramic thermoluminescence dosemeters were developed at the Institute of Isotopes for high dose applications at room temperatures. The glow curve of Al2O3:Mg,Y exhibits two peaks--one at 250 degrees C (I) and another peak at approximately 400 degrees C (II). In order to extend the application of these dosemeters to high temperatures, the effect of irradiation temperature was investigated using temperature controlled heating system during high dose irradiation at various temperatures (20-100 degrees C). The new calibration and measuring method has been successfully applied for dose mapping within the hermetic zone of the Paks Nuclear Power Plant even at high temperature parts of blocks.     

Implementing new recommendations for calibrating personal dosemeters

This paper analyses the differences between the calibration procedures for personal dosemeters recommended by ICRU 47 and ISO 4037-3. The tissue equivalence of the PMMA and the ISO water slab phantoms are analysed by means of the Penelope Monte Carlo code for monoenergetic and filtered X ray photon beams and compared with the results of two other independent codes. The influence of the calibration method is also verified experimentally, both on a thermoluminescence and an electronic personal dosemeter. Good consistency between both calibration procedures is shown provided that a correction factor for backscatter differences between the PMMA and the ICRU phantom is introduced. The Monte Carlo simulation is used to determine this correction to a greater accuracy.     

Effect of angular response properties of personal dosemeters on the estimation of effective dose using two dosemeters

Even though the two-dosemeter approach successfully solved the underestimation problem of the single-dosemeter approach for posterior incident radiations, this approach significantly overestimates effective dose for the lateral and overhead beam directions when isotropic-responding dosemeters are used for measurement. This kind of overestimation can be reduced by using anisotropic-responding dosemeters whose responses decrease as the incident angle increases, i.e. from 0 degree (normal incidence) to 90 degrees (lateral incidence). To quantify the reduction of overestimation by using anisotropic-responding dosemeters, this study applied the two-dosemeter approach to several types of anisotropic-responding dosemeters--both ideal and commercial--and then compared the results with those of isotropic-responding dosemeters. This study also derived a set of angular response factors (ARF) which can be used to develop a personal dosemeter with ideal angular response properties for use in the two-dosemeter approach.     

Dose measurement for medical staff with glass dosemeters and thermoluminescence dosemeters during 125I brachytherapy for prostate cancer

Photoluminescence glass dosemeters (PLDs) and thermoluminescence dosemeters (TLDs) are commonly used as a personal monitoring dosemeter. PLDs and TLDs were used for surface dose monitoring of medical staff involved in (125)I brachytherapy for prostate cancer because these dosemeters have a wide dose-response linearity and high sensitivity for low photon energy. Surface doses measured with PLDs agreed with those with TLDs within ～20 % except for a few cases. Surface doses at a surgeon's left hand and arm were higher than those at the other measuring points. A surgeon received a maximum dose of 650 μGy at the back of left hand. Surface doses to an assistant were <100 μGy. Surface doses to a nurse, a radiologist, an anaesthesiologist and a radiological technologist were <10 μGy. The occupational exposure to a surgeon could be reduced by the adjustment of fluoroscopic parameters and the use of lead gloves.     

Comparison test of electronic dosemeters

To assist with a planned purchase of electronic dosemeters by the Swiss Federal Office for Civil Protection, the calibration laboratory of the Paul Scherrer Institute performed tests on 11 types of electronic dosemeters manufactured by 10 European and American companies. The technical specifications for the World Trade Organisation (WTO) tendering procedure were largely in accord with the specifications of the international standard IEC 61526. First tests were performed with samples from each type of dosemeter. The reproducibility of a dose of 0.1 mSv generated with 137Cs radiation at a dose rate of 2.1 mSv.h-1 was found adequate for all tested dosemeter types. The response for environmental levels of radiation showed a large variation, indicating insufficient background correction of some dosmeters. A very high dose rate of 10 Sv.h-1 provoked faulty dose readings for more than half of the tested dosemeters. Dosemeter response for low-energy photon radiation was satisfactory for two of the tested dosemeter types. Four dosemeter types were selected for extended technical tests. Three samples of each of these dosemeter types were purchased. For drop and temperature tests the specifications of the WTO tendering procedure outranged the specifications of the IEC standard. Whereas even at a temperature of -25 degrees C the tested dosemeters functioned normally, drops from a height of 2 m onto a wooden surface rendered the samples of two dosemeter types inoperative.     

New concept of IEC standards for radiation protection dosemeters

The International Electrotechnical Commission (IEC) develops new standards for radiation protection dosemeters which follow a new concept. They are much more flexible in detail, but still ensure the same measurement quality. They are, for example, no longer specific for the detector type, but rather specific for the measurement task, e.g. for individual monitoring with active direct-reading instruments. Another example is that they are flexible with respect to the ranges of influence quantities. The conceptual changes are described in this paper, together with the advantages this new concept provides for manufacturers, users and legislators.     

Performance and approval procedures for active personal dosemeters

Active personal dosemeters (APDs) are well accepted as useful and reliable instruments for individual dosimetry measurements. The increasing concern about studying the behaviour of APDs in pulsed fields is illustrated through revision of the results of the most representative studies on the performance of APDs in the last 5 y. The deficiencies of APDs in pulsed fields are discussed together with proposals to overcome them. Although there are no legal constraints or technical limitations for recognising APDs for legal dosimetry in facilities with continuous radiation fields, APDs continue to be mainly used as operational dosemeters. The approval procedures applicable to APDs, especially the approach undertaken by Germany, are presented. Finally, some trends in the developments and use of APDs are summarised.     

Calibration of neutron albedo dosemeters

It is shown that by calibrating neutron albedo dosemeters under the proper conditions, two complicating effects will essentially cancel out, allowing accurate calibrations with no need for explicit corrections. The 'proper conditions' are: a large room (> or = 8 m on a side). use of a D2O moderated 252Cf source, and a source-to-phantom calibration distance of approximately 70 cm.