30.Vedantham S, et al. Full Breast digital mammography with anamorphous silicon-based flat panel detector: Physical characteristics of a clinical prototype. Med Phys 2000; 27(3):558–567.

31.Albagli D, et al. Performance of advanced a-Si/CsI-based flat panel X-ray detectors for mammography. In: Yaffe MJ, Antonuk LE, editors. Proceedings of SPIE. Medical Imaging 2003: Physics of Medical Imaging, Vol. 5030, June 2003. p 553–563.

32.Shaw J, Albagil D, Wei C-Y. Enhanced a-Si/CsI-based flat panel X-ray detector for mammography. In: Yaffe MJ, Flynn MJ, editors. Proceeding of SPIE. Medical Imaging 2004: Physics of Medical Imaging. Vol. 5368, May 2004. p 370–378.

33.Tesic MM, Picaro MF, Munier B. Full field digital mammography scanner. Eur J Rad 1997;31:2–17.

34.Boone JM, et al. Grid and slot scan scatter reduction in mammography: Comparison by using Monte Carlo techniques. Radiology 2002;222:519–527.

35.Operator Manual, SenoScan: Full Field Digital Mammography System, Fischer Imaging Corporation, Denver, CO, Dec. 2002.

36.Smith AP. Fundamentals of digital mammography: Physics, technology and practical considerations. Radiol Manager 2003, Sep.–Oct.; 25(5):18–24, 26–31.

37.Mahesh M. AAPM/RSNA physics tutorial for residents, Digital mammography: an overview. Radiographics 2004;24: 1747–1760.

38.The ACR Mammography Quality Control Manual. Preston, VA: ACR, 1999.

39.Pisano ED, Yaffe MJ. Digital mammography. Radiology 2005;234:353–362.

40.Hemminger BM, et al. Evaluation of the effect of display luminance on the feature detection of simulated masses in mammograms. Proc SPIE 1997;3036:12.

41.Pisano ED, et al. Radiologists’ preferences for digital mammographic display. Radiology 2000;216:820–830.

Further Reading

Mahesh M, AAPM/RSNA physics tutorial for residents, Digital mammography: An overview. Radiographics 2004;24:1747– 1760.

Smith AP, Hall PA, Marcello DM. Emerging technologies in breast cancer detection. Radiology Manager 2004, July.–Aug.; 26(4): 16–24.

Shramchencko N, Blin P, Mathey C, Klausz R. Optimized exposure control in digital mammography. In: Yaffe MJ, Flynn MJ, editors. Proceedings of SPIE. Medical Imaging 2004: Physics of Medical Imaging. May 2004; Vol. 5368, p 445–456.

Curry III TS, Dowdey JE, Murry Jr. RC. Christensen’s Physics of Diagnostic Radiology. 4th ed., Philadelphia: Lea & Febiger; 1990. (This is a textbook used in various radiology residency programs across the United States.)

Online References

FDA Home page. [Online]. Available at http://www.fda.gov/cdrh/ mammography/frmamcom2.html.

ACR Home page. [Online]. Available at http://www.acr.org/. ACRIN Home Page. [Online]. Available at http://www.acrin.org. GE Healthcare Home Page. [Online]. Available at http://www.

gehealthcare.com/usen/whc/whcindex.html.

Fischer Imaging Home Page. [Online]. Available at http://www. fischerimaging.com/default/default.asp.

Fujifilm Medical Systems USA Home Page. [Online]. Available at http://www.fujimed.com.

Hologic Home Page. [Online]. Available at http://www.hologic. com/.

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MATERIALS, BIOCOMPATIBILITY OF. See

BIOCOMPATIBILITY OF MATERIALS.

MATERIALS, PHANTOM, IN RADIOLOGY. See

PHANTOM MATERIALS IN RADIOLOGY.

MATERIALS, POLYMERIC. See POLYMERIC MATERIALS.

MATERIALS, POROUS. See POROUS MATERIALS FOR

BIOLOGICAL APPLICATIONS.

MEDICAL EDUCATION, COMPUTERS IN

ARIE HASMAN

Maastricht

The Netherlands

INTRODUCTION

The amount of knowledge is increasing rapidly in many disciplines. Medicine is not an exception. Because of scientific research new knowledge comes available at such a pace, that physicians should read 19 articles a day, every day of the week, to keep up to date. Since that is not possible the results of scientific research often are applied clinically only years later. Computers can support physicians in finding relevant recent information. In the next section, the reasons for using computers in medical education are presented. Then the roles computers can play in medical education are reviewed. Since health professionals increasingly use computer systems for their work, they need to know the benefits and limitations of these systems. The discipline of medical informatics is responsible for developing these systems and therefore is discussed. The next sections discuss the use of Internet and electronic patient records. Also, it is discussed why knowledge of information systems is important for health professionals.

THE REASONS FOR USING COMPUTERS

IN MEDICAL EDUCATION

The goal of academic medical education is to educate students to become physicians. During the study knowledge, skills and attitudes have to be mastered. Students are taught academic skills like critical reading, they are acquainted with the principles of research methods, and they should know the scientific background of the basic disciplines (like anatomy, molecular cell biology and genetics, endocrinology and metabolism, immunology and inflammation, growth, differentiation and aging) as far as they are related to the study of abnormalities and to diagnosis and therapy. Because of the explosive growth of biomedical knowledge, it is not possible anymore to teach all the currently available knowledge. This does not have to be a problem since part of the knowledge presented to medical students during their formal education may be more or less obsolete by the time they are in their main professional practice. Moreover, it is difficult to teach medicine for the coming era, since most of the future’s

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technology is probably nonexistent today. Students therefore must be taught how to become life-long learners. Computers can support this process.

Computers play an increasing role in the practice of medicine too. No doctor—whether a general practitioner or a specialist in advanced or social care—will be able to escape the confrontation with some form of information processing. The work of health professionals is dominated by information collection, storage, retrieval, and reasoning. Health professionals both use individual patient data and general medical or nursing knowledge. The amount of medical and nursing knowledge increases so quickly that health professionals cannot stay fully up to date. Tools are therefore needed to acquire relevant knowledge at the time it is needed.

Computer systems are installed in many hospital departments and physician offices. Hospital information systems support, for example, financial, administrative, and management functions. Clinical departmental systems are used to collect, store, process, retrieve, and communicate patient information. Clinical support systems are used in function laboratories [for electroencephalogram (EEG), electrocardiogram (ECG), electromyogram (EMG), and spirometry analysis], for imaging [magnetic resonance imaging (MRI), computerized tomography (CT), nuclear medicine, ultrasound], and in clinical laboratories (analysis of electrolytes, etc.). The results of clinical support systems are increasingly stored in so-called electronic patient records, together with the medical history, results of physical examination, and progress notes. Electronic patient records gradually replace the paper patient record. Apart from the fact that electronic paper records are better readable they also support functions (like decision support) paper records cannot provide. Students must learn the benefits and limitations of these kinds of systems.

Decision support systems are used to support clinicians during the diagnostic or therapeutic process and for preventive purposes to prevent either errors of omission (when, eg, the physician does not order a mammography when indicated) or commission (when, eg, the physician prescribes the wrong drug).

Clinical patient data are increasingly stored in the above mentioned electronic patient records (EPRs), from which they can be later retrieved by physicians or nurses who are in need of the data. Also, information systems can retrieve relevant data from the electronic patient record when a suitable interface between system and EPR is available. When a standard vocabulary is used for representing data values in the EPR, decision support systems can interpret these data and remind, alert, or critique the physician or provide access to relevant knowledge, based on patient data available in the EPR. Health professionals should have insight in and knowledge of the principles, concepts, and methods underlying electronic patient records.

Also, patients become active players in the field and increasingly demand access to the EPR.

Patient management increasingly has become the combined task of a group of healthcare workers. Therefore the memory-aid role of the patient record more and more changes into a communication role. Paper records have

several limitations in this respect. In addition, since the appearance of the report ‘‘To err is human’’ of the IOM (1) it is apparent that due to miscommunication (among which are problems with reading handwritten information, with incomplete information, etc.) medical errors are made that even may lead to the death of patients. Electronic patient records and order entry systems can reduce the number of errors because they are not only more readable, but because they can also be interfaced with decision support systems when standardized terminology is used.

Decision support can be passive in the sense that the decision support system contains information that has to be searched by the physician. In this case, the healthcare professional takes the initiative to search for information, for example, via PubMed or the Cochrane Library. Decision support can also be active. In this case, the decision support system volunteers advice based on information it can retrieve from the EPR. Decision support systems can either proactively suggest the next step in a diagnostic or treatment process or reactively remind the healthcare professional that a (preventive) procedure was not performed or a step in the protocol was not carried out.

ROLES FOR COMPUTERS IN MEDICAL EDUCATION

What roles can computers play in medical education? In the first place, information systems can be used to manage the learning process. Students can get access to the curriculum via so-called learning environments (e.g., Blackboard or WebCT), can get overviews of their marks, can access computer aided instruction programs, can access PowerPoint presentations of their teachers, and so on. Computers provide access to the internet so that they can search for content knowledge.

Computer-aided instruction can be used to teach students certain subjects. For example, computers are used to simulate regulatory mechanisms occurring in the human body. With a simulation program, students can treat ‘‘patients’’ without risking their patient lives. The simulation is often based on models that present (patho)physiologic processes in the form of mathematical equations. When the models become increasingly accurate they can even be used in patient care. Also, patient management problems can be simulated. In this case, usually no mathematics is involved, but the patient’s signs and symptoms as they develop as a function of time are expressed as text.

There are simulation tools that allow users to evaluate, plan, or redesign hospital departments, or parts of other healthcare systems. Physicians will be confronted with the results of simulations. The model that is used in the simulation has to be checked for validity. Some tools present the modeled processes visually so that physicians or nurses can easily determine the correctness of the model. An example is the modeling of a phlebography service. On the screen, the cubicles and other rooms are displayed and the movements of patients, physicians, and nurses can be followed. In this way, the users can judge whether the model represents the situation of a phlebography service in an adequate way.

Note that computers should not be considered as surrogate teachers controlling students’ learning. Computers should enrich the learning environment by expanding the student’s control over their self-learning and by providing a better learning environment as a supplement to traditional methods of learning. The effectiveness of CAI has always been a subject of controversy. Studies have claimed both that CAI is superior and that CAI is inferior to traditional methods. The majority of the publications, however, support the notion that CAI is as effective as traditional educational methods (2).

Although decision making is the pre-eminent function of a physician, hardly anywhere is the student confronted with a systematic exposition of procedures of good decision making. The use of computers can facilitate the teaching of these procedures. Computer support offers new possibilities to teach problem solving techniques and analytical methods that are presently learned by the student through practice and the observation of mentors.

MEDICAL INFORMATICS

Education concerning the advantages and limitations of the use of computers for supporting the work of health professionals is the responsibility of medical informatics departments. Medical informatics can also be instrumental in developing computer-aided instruction programmes and simulation packages. Medical informatics is the discipline that deals with the systematic processing of data, information, and knowledge in the domains of medicine and healthcare. The objects of study are the computational and informational aspects of processes and structures in medicine and healthcare (3). Medical informatics is a very broad discipline covering subjects like applied technology (bioinformatics, pattern recognition, algorithms, human interfaces, etc.) and services and products (quality management, knowledge-based systems, electronic patient records, operations–resource management, etc.). Also human and organizational factors (managing change, legal issues, needs assessment, etc.) should be taken into account.

Informatics can be either a systems-oriented discipline in which computer systems, operating systems and programming languages are the object of study or a methodsoriented discipline in which the methods are studied that can be used to create algorithms that solve problems in some application domain. In the case of the methodsoriented approach, a problem is studied and formalized solutions are determined. Medical informatics is an example of this approach: it studies the processing of data, information, and knowledge in medicine and healthcare. Medical informatics focuses on the computational and informational aspects of (patho)physiological processes occurring in the patient, cognitive processes going on in the brain of physicians, and organizational processes that control healthcare systems.

The resulting knowledge can be used to design information systems that can support healthcare professionals. It is clear that healthcare professionals need to have some medical informatics knowledge in order to optimally use

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information systems. Medical informatics education should therefore be part of the medical curriculum.

Various groups of professionals with quite different backgrounds can be identified who carry out medical informatics tasks ranging from the use of IT to developing information systems. Users of information systems naturally need less medical informatics knowledge than health informatics experts who develop health information systems or support other healthcare workers in designing terminology servers, coding systems, and so on.

There exists a wide range of job opportunities in the field of medical informatics. These jobs require various medical informatics capabilities. In addition to medical informatics, students (and graduate students) with other backgrounds may prefer a job in the field of medical informatics. In order to obtain the relevant capabilities these students have to learn additional subjects depending on their previous education and the type of specialization they want to achieve. These students can be graduates from healthcare related programs or from informatics–computer science programs. Graduates from healthcare related programs possess the relevant medical knowledge, but need to increase their medical informatics knowledge. Graduates with an informatics or computer science background must learn how the healthcare system is organized and how healthcare professionals are working in order to develop systems that are appreciated by healthcare professionals. Medical informatics is therefore taught in different ways (4) depending on the type of students and the type and extent of specialization that they want to achieve.

USE OF THE INTERNET

Much knowledge can be found on the internet. Browsers allow health professionals and patients to access sites containing (references to) medical knowledge. PubMed is an example. It contains references to the medical literature. The web contains a lot of information of which the quality is not always guaranteed. Especially in the medical arena, this is a big disadvantage. The internet has become one of the most widely used communication media. With the availability of Web server software, anyone can set up a Web site and publish any kind of data that is then accessible to all. The problem is therefore no longer finding information, but assessing the credibility of the publisher as well as the relevance and accuracy of a document retrieved from the net. The Health On the Net Code of Conduct (HONcode) has been issued in response to concerns regarding the quality of medical and health information (5). The HONcode sets a universally recognized standard for responsible self-regulation. It defines a set of voluntary rules to make sure that a reader always knows the source and the purpose of the information they are reading. These rules stipulate, for example, that any medical or health advice provided and hosted on a site will only be given by medically trained and qualified professionals unless a clear statement is made that a piece of advice is offered from a nonmedically qualified individual or organization. Another guideline states that support for the Web site should be clearly identified, including the identities of

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commercial and noncommercial organizations that have contributed funding, services or material for the site. Students searching for information should be introduced to these guidelines.

Searching can be carried out by entering keywords. These keywords can be connected by Boolean operators like AND, OR, and NOT. A user can for example enter: Diuretics and Hypertension to search for documents that discuss the use of diuretics in hypertension. The NLM (National Library of Medicine) uses the Medical Subject Headings (MeSH) vocabulary for indexing most of their databases. Students should be taught how to efficiently search in bibliographic databases using, for example, the MeSH vocabularies.

We speak of e-learning when content is accessible via Web browsers. Some characteristics of e-learning follow: Internet is the distribution channel. Access to the content is possible 24 h/7 days a week. It is learner-centered. The student determines the learning environment, the speed of learning, the subjects to consider, the learning method. A mix of learning methods can be used (blended learning): for example, virtual classroom, simulations, cooperation, communities, and ‘‘live’’ learning.

Virtual learning environments aim to support learning and teaching activities across the internet. Blackboard and WebCT are examples of such environments. These environments offer many possibilities. New or modified educational modules can be announced or teachers can give feedback regarding the way a module is progressing. Also general information about a module can be provided. Staff information can be presented with photo, email address, and so on. Assignments can be posted, and so on. The virtual classroom allows students to communicate online, whereas discussion boards allow asynchronous communication. Also, links to other websites can be provided. The internet is a source of information for patients. They can retrieve diagnostic and therapeutic information from the internet. Increasingly, patients present this information to their care providers. Health professionals must know how to cope with this new situation and must be able to assess the quality of the information.

KNOWLEDGE OF INFORMATION SYSTEMS

Information systems are increasingly used in healthcare. They not only support administrative and financial, but also clinical and logistic processes. Since healthcare workers have to use information systems they should know the possibilities, but also the limitations, of information systems. Since in information systems, for example, data can be easily retrieved, the quality of entered data determines the quality of the results: garbage in, garbage out. In addition, they should have the skills to work with information systems. Information systems relevant for healthcare professionals include hospital information systems, departmental systems, electronic patient record systems, order entry and result reporting systems, and so on. But healthcare workers should also be proficient in the use of productivity tools like word processing systems, bibliographic search systems, and so on.

Logistics is becoming more important these days. Hospitals have to work not only effectively, but also more efficiently, thereby taking the preferences of patients into account. Planning systems can reduce the time that ambulatory patients have to spend in the hospital for undergoing tests, but also the length of stay of hospitalized patients can be reduced by planning both the patients and the needed capacity (6).

It is important for healthcare workers to know what support they can expect from information systems and to know which conditions have to be satisfied in order that information systems can really be of help. Optimal use of information systems therefore does not only depend on acquired skills, but also on the insight in and knowledge of the principles, concepts, and methods behind information systems. This is true for all types of healthcare professionals. When hospitals or physicians consider the purchase of information systems they must be able to specify their requirements so that they will not be confronted with systems that do not perform as expected.

ELECTRONIC PATIENT RECORDS

Physicians store information about their patients in patient records. The patient record frequently is a paper record in which the physician writes his notes. Paper records have several advantages because they are easy to use, easy to carry, and so on. But there are also limitations: they may be difficult to read and are totally passive: the physician records the information with little support (e.g., headings in a form) and therefore the recordings are often incomplete. Not only are the data incomplete, they also contain errors, for example, due to transcription or because the patient gave erroneous information. The readers of patient records can interpret the data in the patient record incorrectly. The fact that data are recorded in chronological order makes the retrieval of facts sometimes difficult: such data are not recorded on standard positions in the record. A study showed that because of the constrained organization of paper records, physicians could not find 10% of the data, although these data were present in the paper record (7). The patient data are usually stored in more than one type of record, because each department uses its own records, each with a different lay-out. Paper records are not always available at the time they are needed. Paper records are passive: they will not warn the physician if he overlooks some results. If the results of a lab request are unexpectedly not yet available, the paper record will not indicate that. Despite these drawbacks physicians are usually very positive about the use of the paper record, because they do not recognize their shortcomings.

Electronic patient records have some advantages over paper records. The legibility of electronic patient records is per definition good. Data can be presented according to different views (time-, source-, and problem-oriented), making the data easier to access. Electronic patient records, when interfaced with decision support systems, can provide reminders when a physician forgets something.