Real-Time Patient Radiation Dose Monitoring System Used in a Large University Hospital

Radiation dose monitoring in medical imaging examination areas is mandatory for the reduction of patient radiation exposure. Recently, dose monitoring techniques that use digital imaging and communications in medicine (DICOM) dose structured reports (SR) have been introduced. The present paper discusses the setup of a radiation dose monitoring system based on DICOM data from university hospitals in Korea. This system utilizes the radiation dose data-archiving method of standard DICOM dose SR combined with a DICOM modality performed procedure step (MPPS). The analysis of dose data based on a method utilizing DICOM tag information is proposed herein. This method supports the display of dose data from non-dosimeter-attached X-ray equipment. This system tracks data from 62 pieces of equipment to analyze digital radiographic, mammographic, mobile radiographic, CT, PET-CT, angiographic, and fluorographic modalities.     

Design of a DICOM image-based program for estimating patient exposure dose in computed tomography.

During the past decade, there has been a notable worldwide increase in the number of computed tomographic (CT) examinations. Since the radiation exposure to the patient during CT examinations is relatively high, it is important to optimize the dose so that it is set as low as possible but remains consistent with the required diagnostic image quality. Therefore we have developed a Digital Imaging and Communications in Medicine (DICOM) image-based program that calculates organ dose and effective dose values corresponding to tube current modulation. The values for primary radiation were derived from manufacturer specifications with international recommendations and from reference values (ICRP publication 60). Based on these values, organ doses can be computed by the program for arbitrary scan protocols in conventional and in spiral CT. In contrast to similar programs for CT dose assessment, our developed program can perform automatic extraction of the scan protocols from the DICOM tag. Users can easily reproduce and recalculate values by loading DICOM data without the requirement for time-consuming work. Additionally, further extensions are planned to our developed software.     

Automatic Monitoring of Localized Skin Dose with Fluoroscopic and Interventional Procedures

This software tool locates and computes the intensity of radiation skin dose resulting from fluoroscopically guided interventional procedures. It is comprised of multiple modules. Using standardized body specific geometric values, a software module defines a set of male and female patients arbitarily positioned on a fluoroscopy table. Simulated X-ray angiographic (XA) equipment includes XRII and digital detectors with or without bi-plane configurations and left and right facing tables. Skin dose estimates are localized by computing the exposure to each 0.01 × 0.01 m² on the surface of a patient irradiated by the X-ray beam. Digital Imaging and Communications in Medicine (DICOM) Structured Report Dose data sent to a modular dosimetry database automatically extracts the 11 XA tags necessary for peak skin dose computation. Skin dose calculation software uses these tags (gantry angles, air kerma at the patient entrance reference point, etc.) and applies appropriate corrections of exposure and beam location based on each irradiation event (fluoroscopy and acquistions). A physicist screen records the initial validation of the accuracy, patient and equipment geometry, DICOM compliance, exposure output calibration, backscatter factor, and table and pad attenuation once per system. A technologist screen specifies patient positioning, patient height and weight, and physician user. Peak skin dose is computed and localized; additionally, fluoroscopy duration and kerma area product values are electronically recorded and sent to the XA database. This approach fully addresses current limitations in meeting accreditation criteria, eliminates the need for paper logs at a XA console, and provides a method where automated ALARA montoring is possible including email and pager alerts.     

Development and Evaluation of a Low-Cost and High-Capacity DICOM Image Data Storage System for Research

Thin-slice CT data, useful for clinical diagnosis and research, is now widely available but is typically discarded in many institutions, after a short period of time due to data storage capacity limitations. We designed and built a low-cost high-capacity Digital Imaging and COmmunication in Medicine (DICOM) storage system able to store thin-slice image data for years, using off-the-shelf consumer hardware components, such as a Macintosh computer, a Windows PC, and network-attached storage units. “Ordinary” hierarchical file systems, instead of a centralized data management system such as relational database, were adopted to manage patient DICOM files by arranging them in directories enabling quick and easy access to the DICOM files of each study by following the directory trees with Windows Explorer via study date and patient ID. Software used for this system was open-source OsiriX and additional programs we developed ourselves, both of which were freely available via the Internet. The initial cost of this system was about $3,600 with an incremental storage cost of about $900 per 1 terabyte (TB). This system has been running since 7th Feb 2008 with the data stored increasing at the rate of about 1.3 TB per month. Total data stored was 21.3 TB on 23rd June 2009. The maintenance workload was found to be about 30 to 60 min once every 2 weeks. In conclusion, this newly developed DICOM storage system is useful for research due to its cost-effectiveness, enormous capacity, high scalability, sufficient reliability, and easy data access.Key words: Data storage, archive, computed tomography, PACS, thin-slice CT     

医学图像DICOM格式转换软件的设计与实现

PACS（图像存档与通讯系统）应遵循DICOM（医学数字图像通讯）标准。目前国内存在大量不符合DICOM标准的影像设备,为了使这些设备也应用于PACS,我们使用面向对象方法设计和实现了一个具有良好扩充性的格式转换工具包,可进行DICOM格式与各种通用图像格式之间的转换,并具有视频输入与格式转换工具包,可进行DICOM格式与各种通用图像格式之间的转换,并具有视频输入与扫描仪输入的接口。该工具包提供一组DICOM API,可供Windows平台的各种编程环境使用。     

Development of Diagnostic Reference Levels Using a Real-Time Radiation Dose Monitoring System at a Cardiovascular Center in Korea

Digital cardiovascular angiography accounts for a major portion of the radiation dose among the examinations performed at cardiovascular centres. However, dose-related information is neither monitored nor recorded systemically. This report concerns the construction of a radiation dose monitoring system based on digital imaging and communications in medicine (DICOM) data and its use at the cardiovascular centre of the University Hospitals in Korea. The dose information was analysed according to DICOM standards for a series of procedures, and the formulation of diagnostic reference levels (DRLs) at our cardiovascular centre represents the first of its kind in Korea. We determined a dose area product (DAP) DRL for coronary angiography of 75.6 Gy cm² and a fluoroscopic time DRL of 318.0 s. The DAP DRL for percutaneous transluminal coronary intervention was 213.3 Gy cm², and the DRL for fluoroscopic time was 1207.5 s.     

The department of veterans affairs integration of imaging into the healthcare enterprise using the VistA hospital information system and Digital Imaging and Communications in Medicine

The United States Department of Veterans Affairs is integrating imaging into the healthcare enterprise by using the Digital Imaging and Communication in Medicine (DICOM) standard protocols. Image management is directly integrated into the VistA Hospital Information System (HIS) software and clinical database. Radiology images are acquired with DICOM and are stored directly in the HIS database. Images can be displayed on low-cost clinician’s workstations throughout the medical center. High-resolution diagnostic quality multimonitor VistA workstations with specialized viewing software can be used for reading radiology images. Two approaches are used to acquire and handle images within the radiology department. Some sites have a commercial Picture Archiving and Communications System (PACS) interfaced to the VistA HIS, whereas other sites use the direct image acquisition and integrated diagnostic display capabilities of VistA itself. A small set of DICOM services has been implemented by VistA to allow patient and study text data to be transmitted to image producing modalities and the commercial PACS, and to enable images and study data to be transferred back. DICOM has been the cornerstone in the ability to integrate imaging functionality into the healthcare enterprise. Because of its openness, it allows the integration of system components from commercial and noncommercial sources to work together to provide functional cost-effective solutions.     

DICOM医学图像采集的方法与实践

医学图像采集是PACS的重要环节,也是PACS实用化的关键。本文比较了几种常见的图像采集方法,重点介绍了通过DICOM接口的图像采集,在详细阐明了DICOM网络的概念和DICOM消息交换的规范之后,介绍了我们编写的DICOM医学图像采集软件,本软件是在Windows平台上利用SocketAPI编写而成,提供了DICOM标准定义的验证、存储、查询和检索等服务,测试结果表明,本软件能够顺利地与成像设备连接并采集图像。     

DICOM for Clinical Research: PACS-Integrated Electronic Data Capture in Multi-Center Trials

Providing surrogate endpoints in clinical trials, medical imaging has become increasingly important in human-centered research. Nowadays, electronic data capture systems (EDCS) are used but binary image data is integrated insufficiently. There exists no structured way, neither to manage digital imaging and communications in medicine (DICOM) data in EDCS nor to interconnect EDCS with picture archiving and communication systems (PACS). Manual detours in the trial workflow yield errors, delays, and costs. In this paper, requirements for a DICOM-based system interconnection of EDCS and research PACS are analysed. Several workflow architectures are compared. Optimized for multi-center trials, we propose an entirely web-based solution integrating EDCS, PACS, and DICOM viewer, which has been implemented using the open source projects OpenClinica, DCM4CHEE, and Weasis, respectively. The EDCS forms the primary access point. EDCS to PACS interchange is integrated seamlessly on the data and the context levels. DICOM data is viewed directly from the electronic case report form (eCRF), while PACS-based management is hidden from the user. Data privacy is ensured by automatic de-identification and re-labelling with study identifiers. Our concept is evaluated on a variety of 13 DICOM modalities and transfer syntaxes. We have implemented the system in an ongoing investigator-initiated trial (IIT), where five centers have recruited 24 patients so far, performing decentralized computed tomography (CT) screening. Using our system, the chief radiologist is reading DICOM data directly from the eCRF. Errors and workflow processing time are reduced. Furthermore, an imaging database is built that may support future research.     

Treatment planning for a small animal using Monte Carlo simulation

The development of a small animal model for radiotherapy research requires a complete setup of customized imaging equipment, irradiators, and planning software that matches the sizes of the subjects. The purpose of this study is to develop and demonstrate the use of a flexible in-house research environment for treatment planning on small animals. The software package, called DOSCTP, provides a user-friendly platform for DICOM computed tomography-based Monte Carlo dose calculation using the EGSnrcMP-based DOSXYZnrc code. Validation of the treatment planning was performed by comparing the dose distributions for simple photon beam geometries calculated through the Pinnacle3 treatment planning system and measurements. A treatment plan for a mouse based on a CT image set by a 360-deg photon arc is demonstrated. It is shown that it is possible to create 3D conformal treatment plans for small animals with consideration of inhomogeneities using small photon beam field sizes in the diameter range of 0.5-5 cm, with conformal dose covering the target volume while sparing the surrounding critical tissue. It is also found that Monte Carlo simulation is suitable to carry out treatment planning dose calculation for small animal anatomy with voxel size about one order of magnitude smaller than that of the human.     

An Algorithm for Intelligent Sorting of CT-Related Dose Parameters

Imaging centers nationwide are seeking innovative means to record and monitor computed tomography (CT)-related radiation dose in light of multiple instances of patient overexposure to medical radiation. As a solution, we have developed RADIANCE, an automated pipeline for extraction, archival, and reporting of CT-related dose parameters. Estimation of whole-body effective dose from CT dose length product (DLP)—an indirect estimate of radiation dose—requires anatomy-specific conversion factors that cannot be applied to total DLP, but instead necessitate individual anatomy-based DLPs. A challenge exists because the total DLP reported on a dose sheet often includes multiple separate examinations (e.g., chest CT followed by abdominopelvic CT). Furthermore, the individual reported series DLPs may not be clearly or consistently labeled. For example, “arterial” could refer to the arterial phase of the triple liver CT or the arterial phase of a CT angiogram. To address this problem, we have designed an intelligent algorithm to parse dose sheets for multi-series CT examinations and correctly separate the total DLP into its anatomic components. The algorithm uses information from the departmental PACS to determine how many distinct CT examinations were concurrently performed. Then, it matches the number of distinct accession numbers to the series that were acquired and anatomically matches individual series DLPs to their appropriate CT examinations. This algorithm allows for more accurate dose analytics, but there remain instances where automatic sorting is not feasible. To ultimately improve radiology patient care, we must standardize series names and exam names to unequivocally sort exams by anatomy and correctly estimate whole-body effective dose.     

Image formats: five years after the AAPM standard for digital image interchange

The publication of AAPM Report No. 10 was the first attempt to standardize image formats in the medical imaging community. Since then, three other groups have formed (CART--the Scandinavian collaboration for Computer Assisted Radiation Therapy treatment planning; ACR-NEMA, a collaboration whose purpose is to formulate a standard digital interface to medical imaging equipment; and COST B2 Nuclear Medicine Project a European collaboration whose purpose is to define a format for digital image exchange in Nuclear Medicine). The AAPM format uses key-value pairs in plain text to keep track of all information associated with a particular image. The radiation oncology community in the U.S. has been defining key-value pairs for use with CT, nuclear medicine and magnetic resonance (MR) images. The COST B2 Nuclear Medicine Project has also adopted this format and together with the Australian/New Zealand Society of Nuclear Medicine Technical Standards Sub-Committee which has also adopted this format, has defined an initial set of key-value pairs for Nuclear Medicine images. Additionally, both ACR-NEMA and CART have been defining fields for use with the same types of images. The CART collaboration has introduced a database which is available electronically, but is maintained by a group of individuals. ACR-NEMA operates through committee meetings. The COST B2 Nuclear Medicine Project operates through electronic (and postal where necessary) mail. To insure a consistent set of field names in such a rapidly developing arena requires the use of a server rather than a committee. Via a server a person would inquire if a particular field had been defined. If so, the defined name would be returned.(ABSTRACT TRUNCATED AT 250 WORDS)     

An open architecture for medical imaging systems

Integration of medical imaging is the goal of many standards. Interfile and Digital Imaging and Communications in Medicine (DICOM) standards have made great strides in this area. The impact of DICOM is greater owing to its wider acceptance. However, the lack of conformance testing makes interoperability difficult, often requiring expensive consulting teams in a mixed-vendor environment. DICOM is difficult to learn and deploy because it does not use modern software paradigms. Many hardware and software advances in computer architectures and communications could greatly enhance diagnostic imaging if they could be quickly incorporated into medical imaging standards. These problems led to consideration of a solution able to take advantage of state-of-the-art technology and to allow diverse implementations while ensuring the accurate interchange of information between health care providers. It is an object-oriented system information model, with the common object request broker architecture (CORBA) as the vehicle to ensure interoperability between different implementations of the model. This report presents the model.     

Implementation of the ACR Dose Index Registry at a Large Academic Institution: Early Experience

A rising conciousness within both the medical community and in the public has been created by the current levels of radiation exposure from increased use of computed tomography. The concern has prompted the need for more data collection and analysis of hospital and imaging center exam doses. This has spurred the American College of Radiology (ACR) to develop the Dose Index Registry (DIR), which will allow participating insitutions to compare the radiation dose from their CT exams to aggregate national CT dose data based on exam type and body part. We outline the steps involved in the process of enrolling in the DIR, the technical requirements, the challenges we encountered, and our solutions to those challenges. A sample of the quaterly report released by the ACR is presented and discussed. Enrolling in the ACR dose registry is a team effort with participation from IT, a site physicist, and a site radiologist. Participation in this registry is a great starting point to initiate a QA process for monitoring CT dose if none has been established at an institution. The ACR has developed an excellent platform for gathering, analyzing, and reporting CT dose data. Even so, each insititutions will have its own unique issues in joining the project.     

We Built This House; It’s Time to Move in: Leveraging Existing DICOM Structure to More Completely Utilize Readily Available Detailed Contrast Administration Information

The Digital Imaging and Communications in Medicine (DICOM) standard is the universal format for interoperability in medical imaging. In addition to imaging data, DICOM has evolved to support a wide range of imaging metadata including contrast administration data that is readily available from many modern contrast injectors. Contrast agent, route of administration, start and stop time, volume, flow rate, and duration can be recorded using DICOM attributes [1]. While this information is sparsely and inconsistently recorded in routine clinical practice, it could potentially be of significant diagnostic value. This work will describe parameters recorded by automatic contrast injectors, summarize the DICOM mechanisms available for tracking contrast injection data, and discuss the role of such data in clinical radiology.     

由DICOM医学图像文件获得设备无关位图的方法

目的:根据临床调查.DICOM3.0医学图像文件格式的解析及解决其显示问题是医学图像处理的基础,对医学影像技术的研究有重要意义.方法:首先针对DICOM3.0标准,系统分析了DICOM医学图像文件格式,主要阐述了文件信息头和数据元素的格式,提出了在Windows平台下利用线性调窗实现DICOM图像的DIB位图显示.结果:利用线性调窗成功实现了CT、MR图像的显示,同时针对默认状态下显示效果欠佳,采用手动调窗改善显示效果.结论:实验证明,该方法能较好地实现DICOM医学图像的显示,满足一定的临床需求,同时也为后续工作奠定基础.     

基于DICOM标准的医学图像数据库

DICOM标准是医疗影像设备信息交换的基础 ,本文依据DICOM的信息模型 ,在关系数据库的平台上 ,设计了基于DICOM标准的图像数据库。经过实验检验 ,本方案具有库结构简单 ,构造方便 ,存储效率高 ,系统扩充余地大 ,数据转换的开销小等优点。本数据库可应用在PACS、远程医疗等系统中。     

Cybersecurity in PACS and Medical Imaging: an Overview

This article provides an overview on the literature published on the topic of cybersecurity for PACS (Picture Archiving and Communications Systems) and medical imaging. From a practical perspective, PACS specific security measures must be implemented together with the measures applicable to the IT infrastructure as a whole, in order to prevent incidents such as PACS systems exposed to access from the Internet. Therefore, the article first offers an overview of the physical, technical and organizational mitigation measures that are proposed in literature on cybersecurity in healthcare information technology in general, followed by an overview on publications discussing specific cybersecurity topics that apply to PACS and medical imaging and present the “building blocks” for a secure PACS environment available in the literature. These include image de-identification, transport security, the selective encryption of the DICOM (Digital Imaging and Communications in Medicine) header, encrypted DICOM files, digital signatures and watermarking techniques. The article concludes with a discussion of gaps in the body of published literature and a summary.     

Anatomy of an Extensible Open Source PACS

The conception and deployment of cost effective Picture Archiving and Communication Systems (PACS) is a concern for small to medium medical imaging facilities, research environments, and developing countries’ healthcare institutions. Financial constraints and the specificity of these scenarios contribute to a low adoption rate of PACS in those environments. Furthermore, with the advent of ubiquitous computing and new initiatives to improve healthcare information technologies and data sharing, such as IHE and XDS-i, a PACS must adapt quickly to changes. This paper describes Dicoogle, a software framework that enables developers and researchers to quickly prototype and deploy new functionality taking advantage of the embedded Digital Imaging and Communications in Medicine (DICOM) services. This full-fledged implementation of a PACS archive is very amenable to extension due to its plugin-based architecture and out-of-the-box functionality, which enables the exploration of large DICOM datasets and associated metadata. These characteristics make the proposed solution very interesting for prototyping, experimentation, and bridging functionality with deployed applications. Besides being an advanced mechanism for data discovery and retrieval based on DICOM object indexing, it enables the detection of inconsistencies in an institution’s data and processes. Several use cases have benefited from this approach such as radiation dosage monitoring, Content-Based Image Retrieval (CBIR), and the use of the framework as support for classes targeting software engineering for clinical contexts.