Data processing system for nuclear medicine images

A software system (MicroSegams) is described which is able to acquire, store, present, and process nuclear medicine images. The most important basic procedures (e.g., image acquisition from a gamma camera, selection of a study from the catalogue, drawing regions of interest, etc.) and complete clinical procedures (e.g., renography, brain perfusion, etc.) can be activated directly from the system menu by mouse. The language sL an (a subset of programming language C containing more than 200 elementary functions) can also be used to write new procedures to be interpreted or compiled. The system is offered as a basic tool for the performance of static, dynamic, gated, or tomographic investigations in clinical practice.     

堆芯摄像中的双视场合成原理及设计

为了实现两个不同方位的目标在同一视场中成像,通过反射镜将摄像机视场分成两个部分,这样光程相等的两目标便能在同一视场中成像。在堆芯摄像中,根据这一原理设计了具体的光学结构,并对光路进行了具体分析,同时对实际使用中的标识符进行了验算,表明该设计是合理的。     

Extraction generator of 223Ra for nuclear medicine

A novel ²²⁷Ac/²²³Ra extraction generator for nuclear medicine was developed. Its operation is based on selective extraction of ²²³Ra with a solution of chlorinated cobalt dicarbollide and polyethylene glycol in a polar diluent from a solution of a mineral acid and a complexing agent. Radium is stripped to any appropriate aqueous solution on adding TBP into the extractant. Trials performed in the manual mode showed that ²²³Ra is efficiently separated from the parent isotopes ²²⁷Ac and ²²⁷Th (decontamination factor of ²²³Ra from ²²⁷Ac and ²²⁷Th >10⁶). It is the most convenient to use the ²²³Ra generator for the radionuclide production in a regional center, because it allows fairly simple production of large batches of ²²³Ra, avoiding problems associated with the need for skilled staff for working with the generator in a medical center and with the radiation-induced degradation of the matrix (ion-exchange resin).     

Hand exposure in nuclear medicine workers

As a result of the gamma radiation emitted by radioactive elements (e.g. 99mTc and 131I) used in nuclear medicine laboratories for diagnostic and therapeutic purposes, nuclear medicine workers are exposed to whole-body doses. These doses arc usually measured by using individual film dosemeters. Lead or lead glass shields used during the handling of radioisotopes minimise the whole-body doses received. Nevertheless, part of the job has to be performed manually, hence the hands are more exposed to radiation. This paper presents the results of measuring the equivalent dose to the hands of workers employed in five selected nuclear medicine laboratories where technetium and iodine radioisotopes are in common use. Sixty workers, including physicians, nurses, radiopharmacists and technicians, were included in the study. Doses were measured at 1 month intervals. The study indicated that, in some instances, the danger of radiation dose to the hand may be significant. Monthly doses exceeded 50 mSv, which may suggest that an annual dose may be higher than 500 mSv.     

Individual monitoring of internal exposure for nuclear medicine workers in Switzerland

Monitoring of internal exposure for nuclear medicine workers requires frequent measurements due to the short physical half-lives of most radionuclides used in this field. The aim of this study was to develop screening measurements performed at the workplace by local staff using standard laboratory instrumentation, to detect whether potential intake has occurred. Such measurements do not enable to determine the committed effective dose, but are adequate to verify that a given threshold is not exceeded. For radioiodine, i.e. (123)I, (124)I, (125)I and (131)I, a calibrated surface contamination monitor is placed in front of the thyroid to detect whether the activity threshold has been exceeded. For radionuclides with very short physical half-lives (≤ 6 h), such as (99m)Tc and those used in positron emission tomography imaging, i.e. (11)C, (15)O, (18)F and (68)Ga, screening procedures consist in performing daily measurements of the ambient dose rate in front of the abdomen. Other gamma emitters used for imaging, i.e. (67)Ga, (111)In and (201)Tl, are measured with a scintillation detector located in front of the thorax. For pure beta emitters, i.e. (90)Y and (169)Er, as well as beta emitters with low-intensity gamma rays, i.e. (153)Sm, (177)Lu, (186)Re and (188)Re, the procedure consists in measuring hand contamination immediately after use. In Switzerland, screening procedures have been adopted by most nuclear medicine services since such measurements enable an acceptable monitoring while taking into account practical and economic considerations.     

Microlens arrays for integral imaging system

When designing a system capable of capturing and displaying 3D moving images in real time by the integral imaging (II) method, one challenge is to eliminate pseudoscopic images. To overcome this problem, we propose a simple system with an array of three convex lenses. First, the lateral magnification of the elemental optics and the expansion of an elemental image is described by geometrical optics, confirming that the elemental optics satisfies the conditions under which pseudoscopic images can be avoided. In using the II method, adjacent elemental images must not overlap, a condition also satisfied by the proposed optical system. Next, an experiment carried out to acquire and display 3D images is described. The real-time system we have constructed comprises an elemental optics array with 54 H x 59 V elements, a CCD camera to capture a group of elemental images created by the lens array, and a liquid crystal panel to display these images. The results of the experiment confirm that the system produces orthoscopic images in real time, and thus is effective for real-time application of the II method.     

Task-specific information for imaging system analysis

Imagery is often used to accomplish some computational task. In such cases there are some aspects of the imagery that are relevant to the task and other aspects that are not. In order to quantify the task-specific quality of such imagery, we introduce the concept of task-specific information (TSI). A formal framework for the computation of TSI is described and is applied to three common tasks: target detection, classification, and localization. We demonstrate the utility of TSI as a metric for evaluating the performance of three imaging systems: ideal geometric, diffraction-limited, and projective. The TSI results obtained from the simulation study quantify the degradation in the task-specific performance with optical blur. We also demonstrate that projective imagers can provide higher TSI than conventional imagers at small signal-to-noise ratios.     

Integrated nuclear data utilisation system for innovative reactors

A five-year research and development project on an integrated nuclear data utilisation system was initiated in 2002, for developing innovative nuclear energy systems such as accelerator-driven systems. The integrated nuclear data utilisation system will be constructed as a modular code system, which consists of two sub-systems: the nuclear data search and plotting sub-system, and the nuclear data processing and utilisation sub-system. The system will be operated with a graphical user interface in order to enable easy utilisation through the Internet by both nuclear design engineers and nuclear data evaluators. This paper presents an overview of the integrated nuclear data utilisation system, describes the development of a prototype system to examine the operability of the user interface and discusses specifications of the two sub-systems.     

新型便携式汽车动态参数检测系统

介绍基于三星ARM9处理器S3C2410和ATMEL公司的AT89C5131单片机的汽车动态参数检测系统,该系统能够完成汽车在运动状态下的各种运动参数的检测。充分利用了S3C2410处理器提供的丰富的功能接口和强大的处理数据的能力以及AT89C5131单片机提供的USB功能接口。使运动参数传感器模块经模数转换器AD7656与单片机AT89C5131相连,然后通过USB接口连接到S3C2410处理器平台,共同构成即插即用型的便携式检测系统,从而给出了一个完整的汽车动态参数检测系统的实现方案。     

Advanced designs for output improvement of triboelectric nanogenerator system

The large-scale popularization of 5G mobile network technology accelerates the arrival of modern intelligent society. In this society, billions of distributed sensors are needed as the sense organ for information collection, posing a grand challenge of high precision sensor and distributed power supply. As an emerging technology, triboelectric nanogenerator (TENG) can effectively harvest varied environmental low frequency mechanical energy and convert it into electricity with the merits of low cost, environmentally friendliness and strong adaptability, showing a great potential as a distributed power source. However, there is still a distance for its commercial use due to the insufficient function modes and output performance of TENG. Therefore, in order to push forward its commercial process, here we systematically review TENG, from the basic characteristics, improving output performance of alternating current (AC) TENG, working modes of direct current (DC) TENG to effective power management. Besides, we suggest some unified and standardized terminologies on energy efficiency to solve some confusing nomenclature. At last, challenges and future research focus in this field are also predicted to provide a significant guideline for the next stage development of TENG for the research community.     

Task-specific monitoring of nuclear medicine technologists' radiation exposure

Many studies have demonstrated that the exposure of nuclear medicine technologists arises primarily from radioactive patients rather than from preparation of radiopharmaceuticals. However, in order to devise strategies to reduce staff exposure, it is necessary to identify the specific tasks within each procedure that result in the highest radiation doses. An ESM Eberline FH41B-10 radiation dosemeter, which records the ambient dose equivalent rate, was used to monitor the radiation exposure of a technologist and to record the dose rate in microSv per hour every 32 s throughout a working day. The technologist recorded the procedures that were being performed so that the procedures that resulted in higher doses could be identified clearly. The measured doses clearly showed that the major contributions to the technologist's dose were the following: (1) transferring incapacitated patients from the imaging table to a hospital trolley; (2) difficult injections without syringe shields; and (3) setting up patients for gated myocardial scans. The average dose to the technologist from transferring patients after a bone scan was 0.54 microSv, 40% of the total dose of 1.3 microSv for the complete bone scan procedure. The average dose received injecting 900 MBq of 99Tcm-HDP using a tungsten syringe shield was 0.57microSv, but the highest dose was 1.6 microSv, in a patient in whom the injection was difficult. A 0.5 mm lead apron was found to reduce the dose when setting up a patient for a gated stress 99Tcm-sestamibi myocardial scan by approximately a factor of 2. The average dose per patient for this task was reduced from 1.1 to 0.6 microSv. It is recommended that staff waiting for assistance with patient transfers stand away from the patient, that tungsten syringe shields be used for all radiopharmaceutical injections and that a 0.5 mm lead apron be worn when attending patients containing high activities of 99Tcm radiopharmaceuticals, such as those having myocardial imaging.     

Airborne ultrasonic imaging system for parallelepipedic objectlocalization

An ultrasonic image device was designed for use in robotic applications where parallelepipedic objects need to be manipulated. It is based on ranging measurement by an array of ten identical airborne ultrasonic transducers with an operating frequency of 200 kHz and a detection cone angle of approximately 7 degrees. An electronic scanning associated with a mechanical displacement of the array covers an area of 0.4×0.4 m in less than 0.5 seconds (100 measurement points). The system was tested in an automatic packaging line. It allowed a real-time localization of cubic objects as small as 2 cm and the determination of an emplacement in which a new object can be put by a robot arm     

一种用于数字成像的自动对焦系统

提出一种用于数字成像的自动对焦系统,它以CMOS为图像传感器,用DSP进行数据处理并控制驱动电路调整镜头的位置,达到准确自动对焦的目的。系统采用对焦深度法实现自动对焦,通过改变镜头的位置获得一系列模糊程度不等的图像,计算每幅图像的清晰度评价值构成对焦评价曲线;采用梯度函数作为评价标准来评价图像的清晰度;采用窗口选择技术控制对焦感兴趣范围,减少了数据处理量;对实验样机的测试表明,系统有较好的自动对焦性能,并解决了百叶窗问题,对透过玻璃窗户的目标仍然能正确对焦。     

Capacitive system for three-dimensional imaging of fluidized-beddensity

The U.S. Department of Energy's Morgantown Energy Technology Center has been developing a capacitance imaging system (CIS) to support its fluidized-bed research programs. A second-generation system for capacitively imaging a cold, laboratory-scale, 15.24-cm diameter fluidized bed is described. The CIS acquires interelectrode, bed-crossing displacement current data to provide 193-pixel density values at four 2.54-cm vertically spaced levels and presents a three-dimensional density display at a rate of 30 maps per second in real time. The CIS also stores displacement current data at a rate of 60 density maps per level per second for post-run analysis. Different means of data processing are described that produce one method for real-time display and two methods for post-run analysis of data. The results of calibration and fluidization tests are presented, together with the errors associated with each of the methods for the known pixel densities in the calibration tests. Improvement in the calibration procedure to reduce these errors is proposed. Test results indicate the CIS would be a useful tool for research and monitoring operations in two-phase systems     

Advanced nuclear power plant regulation using risk-informed and performance-based methods

This paper proposes and discusses implications of a largely probabilistic regulatory framework using best-estimate, goal-driven, risk-informed, and performance-based methods. This framework relies on continuous probabilistic assessment of performance of a set of time-dependent, safety-critical systems, structures, components, and procedures that assure attainment of a broad set of overarching technology-neutral protective, mitigative, and preventive goals under all phases of plant operations. In this framework acceptable levels of performance are set through formal apportionment so that they are commensurate with the overarching goals. Regulatory acceptance would be the based on the confidence level with which the plant conforms to these goals and performance objectives. The proposed framework uses the traditional defense-in-depth design and operation regulatory philosophy when uncertainty in conforming to specific goals and objectives is high. Finally, the paper discusses the steps needed to develop a corresponding technology-neutral regulatory approach from the proposed framework.     

Radioisotope generators of short-lived α-emitting radionuclides promising for use in nuclear medicine

α-Emitting radionuclides open unique possibilities for nuclear medicine owing to short range of α-particles and high linear energy transfer values. The use of radioactive generators is the simplest and the most efficient method for production of short-lived α-emitting radionuclides. The designs of radioisotope generators and generator systems used for repeated production of short-lived α-emitting radionuclides ²²⁵Ac, ²¹³Bi, ²¹¹Pb/²¹¹Bi, ²¹²Pb/²¹²Bi, ²²³Ra, and ²²⁴Ra, promising for targeted radiotherapy, are described in detail. Particular attention is paid to the methods for production and purification of short-lived α-emitting radionuclides and for their isolation in the form suitable for use in medicobiological studies. Other procedures for producing alternative α-emitting radionuclides (²¹¹At, ²²⁷Th, ²³⁰U, ²⁵³Es, ²⁵⁵Fm, ¹⁴⁹Tb) and possibilities of their use are also considered. The objectives and prospects of radiochemical studies in the field of production and isolation of α-emitting radionuclides meeting the requirements of nuclear medicine are discussed.     

Hand exposure to ionising radiation of nuclear medicine workers

The specific nature of work in nuclear medicine departments involves the use of isotopes and handling procedures, which contribute to the considerable value of an equivalent dose received, in particular, by the fingertips. Standard nuclear medicine department uses ring dosemeters placed usually at the base of the middle finger. The main aim of the study was to find out whether a relationship exists between the doses recorded by thermoluminescent detectors placed at various locations on the radiopharmacists' hands and the doses recorded by the ring detectors, and to determine the character of that relationship. The correction factor represents a correction value to be used to calculate the doses which might be received by locations on the hand from the dose recorded by the ring dosemeter. The dose recorded by the ring dosemeter is on the average five times lower than that received by the fingertips of thumb, index and middle fingers.