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infoRAD |
1 From the Departments of Radiology (A.E.F.) and Medical Informatics (M.E.G.), Thomas Jefferson University Hospital, 132 S 10th St, Suite 1072, Main Bldg, Philadelphia, PA 19107 and the Department of Radiology, University of Utah, Salt Lake City (R.H.W.). Received January 24, 2003; revision requested February 19 and received March 20; accepted March 24. Address correspondence to A.E.F. (e-mail: adam.flanders@jefferson.edu).
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Abstract |
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 Top Abstract IntroductionPDA BasicsPDAs in MedicineRadiology and the PDAConclusionsReferences |
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© RSNA, 2003
Index Terms: Computers, diagnostic aid • Computers, educational aid • Images, display • Radiology and radiologists, design of radiological facilities
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Introduction |
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TopAbstractIntroductionPDA BasicsPDAs in MedicineRadiology and the PDAConclusionsReferences |
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This article briefly discusses the short history of the handheld computer and provides a nontechnical description of PDA design and features. Current clinical uses of PDAs in healthcare and radiology are discussed, in addition to proposed solutions for enhancing clinical work flow in radiology by using the handheld computer.
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PDA Basics |
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TopAbstractIntroductionPDA BasicsPDAs in MedicineRadiology and the PDAConclusionsReferences |
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John Scully, former CEO and chairman of Apple Computer (Cupertino, Calif), coined the term personal digital assistant at a keynote address given at a consumer electronics show in 1992. Around this time, one of Apple’s development teams was already hard at work on a pen-based, handheld computer tablet with handwriting recognition called the Newton MessagePad, marketed in 1993 (1).
The "Newton" was a battery-operated computer that used handwriting recognition and offered features similar to those available on a PC, such as word-processing, spreadsheet, and database capabilities. Innovative to its design was the absence of a conventional keyboard and the use of a stylus, a touch screen, an early form of handwriting recognition, and infrared capabilities. The Newton was bulky and expensive; however, it provided proof of concept, and it fostered the development of the Palm Pilot.
Although Apple Computer was able to sell 80,000 Newtons in 1993, the success of the PDA is largely credited to the design and innovation of the Palm Pilot by Palm (Milpitas, Calif) and its popular operating system (Palm OS). Palm released its first model, Palm Pilot 1000, in 1995. This device had a simpler handwriting recognition capability than the Newton. Also, it was much smaller, cheaper, faster, and lighter than the Newton. By 1999, Palm had sold over 5 million units and controlled 70% of the market share in total PDA sales.
It is currently estimated that one of six Americans own one or more PDA devices (2). Sales figures for the worldwide PDA market surpassed 10 million units in 2000. In 2000, the PDA market was worth $2.3 billion; however, as organizations strive to move away from outdated paper and telephony-based processes, the PDA market is expected to show an annual growth rate of 30%. In 2002, U.S. PDA sales declined 12%, equivalent to 5.76 million units sold (3). Global recession has decreased the future growth rate (projected at 20%–30%), with sales expected to exceed 85 million units by 2006 (equivalent to $6.6 billion in sales) (2).
The PDA has evolved substantially from a simple digital "Rolodex" for storing phone numbers and addresses to a fully functional multimedia computer. Today’s PDAs are capable of receiving e-mail, surfing the Internet, recording digital audio or dictation, capturing digital images, and playing compressed audio files. Entire texts with illustrations can be stored on a PDA for leisurely reading or for electronic searches for reference purposes. The display characteristics of PDAs, although of lower quality by conventional CRT (cathode ray tube) standards, are capable of displaying color images with remarkable clarity and with thousands of colors. Digital images can be viewed (and in some instances captured) with today’s color-enabled PDA. A PDA user can perform reasonable word-processing tasks. Even scaled-down versions of presentation software are available for giving PDA-enabled digital presentations.
Common PDA Software Features
Although the number and complexity of features that can be packed into today’s handheld devices increases with each new product release, the majority of PDA users still rely on the most basic features for daily use. These features are commonly referred to as personal information management (PIM) applications that consist of an address book, a date book with alarm clock and digital agenda planner, a memo or document composer, and a reminder or to-do list. This functionality alone replaces a large Rolodex, date planner, file cabinet, and, in some instances, a personal secretary. More advanced software features include Internet access, simple e-mail client software, spreadsheet and database programs, word processing, and digital media (audio, video, and image) players.
Data stored on the handheld device are regularly synchronized (synced) with a corresponding application on the user’s desktop PC. This synchronization ensures that the desktop PC always holds a duplicate copy of all the PDA’s data. In the event that the PDA is misplaced or damaged, all the data can be reconstructed from the desktop PC data set. Changes made to data on the handheld device or the desktop computer are reconciled via the synchronization process such that data on either device are up to date.
When the PDA is used effectively, the busy professional can maintain an up-to-date agenda on a PDA linked to the office desktop PC. By regularly synchronizing the handheld device with the desktop computer, the user is constantly kept appraised of changes in meetings and appointments. Pertinent content related to upcoming meetings such as contact information, maps, images, reports, and documents (including digital presentations) can also be downloaded at the same time. This synchronization process is performed at the desktop PC either locally through an infrared connection or remotely via the Internet or a wireless connection. With the addition of wireless access capabilities, stored data can be continually updated, obviating a physical connection to another computer.
PDA Hardware Features
The functionality of today’s PDA is strikingly similar to that of the desktop PC. However, to achieve a handheld size, significant design compromises were made to create a lightweight form. The most radical part of this design is the incorporation of the display and keyboard into the device. In principle, the goal of the PDA designers was to reduce the size of the components of a typical desktop PC and find substitutes for the fragile, heavy, energy-hungry, or bulky components.
Similar to the PC, the core of the PDA is built around a microprocessor. Although the current conventional desktop microprocessor is rated at over 1 GHz, the typical PDA processor operates at lower, energy-conservative speeds of 60–200 MHz. New Pocket PC 2002 devices (Microsoft, Redmond, Wash) include a new 400-MHz processor from Intel (Albuquerque, NM).
Instead of a television screen, the output or display is made of an energy-efficient, flat-panel display similar to those used on notebook computers. Improvements in display design with thin film transistor (TFT) technology now permit a backlit color display ranging from 160 x 160-pixel to 480 x 320-pixel resolution and 16-bit color (thousands of colors). More than 90% of PDAs will have a color display by mid-2004 (3). In most instances, the display doubles as an input device by using touch-screen technology, thus eliminating the need for a conventional keyboard. This capability is particularly true for the new generation of "tablet" computers.
Rather than storing data or programs in a bulky, fragile, and energy-hungry disk drive, PDAs are designed to store all essential data in lightweight, inexpensive, energy-efficient memory chips. Typical PDAs come with 8–64 Mbytes of nonvolatile random access memory (RAM) installed with options for installation of additional memory in a variety of media. The combination of these technologies allows for a sturdy, energy-efficient, portable handheld computer that is usable for a long period of time without recharging the internal battery.
In summary, regardless of the manufacturer, all handheld computers have several physical features in common: (a) they are small, lightweight, and battery operated; (b) they have a liquid crystal display and touch screen (color or black and white); (c) input is done with a handheld pen or stylus on a miniature, touch-sensitive keyboard or writing area for handwriting recognition; and (d) they have an access port and software that allows data to be written to and read from a desktop PC.
Handheld Operating Systems
The core software that "wakes up" the computer and knows how to interact with its various hardware components is the system software or operating system (OS). The two primary OSs for PDAs are Palm OS and Pocket PC (formerly known as Microsoft Windows CE), and at least one manufacturer offers a unit featuring the Linux OS (Sharp Zaurus; Sharp Electronics, Manwah, NJ). Each PDA manufacturer designs its hardware to function with one OS. Although Microsoft dominates the PC industry, this is not necessarily true for the growing PDA market. The industry leader in unit sales of hardware and software is Palm, with its Palm and the Palm OS (3). Other manufacturers, including Handspring (Mountain View, Calif) and Sony (New York, NY), produce their own innovative devices and license the Palm OS for use on their own products. Palm OS currently is the leading PDA OS, but it is seeing increasing competition from Microsoft Windows CE/Pocket PC. The Pocket PC has become a formidable competitor and is gaining market share, resulting in a decrease in that of the Palm OS (from 71% in 2000 to 58% in 2001) (4). In 2002, 55% of units sold worldwide used Palm OS, compared with 25% for Pocket PC (3). To the end user who requires only basic PDA functionality, there is little difference between the two OSs and their bundled applications. However, Microsoft currently leads the way for multimedia intensive applications and Internet and wireless needs.
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PDAs in Medicine |
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TopAbstractIntroductionPDA BasicsPDAs in MedicineRadiology and the PDAConclusionsReferences |
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In the clinical setting, computers have proved helpful as tools by which healthcare providers can reduce paperwork, minimize duplication, maintain privacy, and improve efficiency; however, in most hospitals, the computers are not always located at the most convenient locations. Hospital desktop computers routinely provide access to patient laboratory data and historical information. They also provide methods to record new information (historical and clinical) and a paperless mechanism to order tests, medications, and therapies. The most practical and cost-effective method to use a computer in the medical workplace is to provide convenient access at the point where the care is delivered. This concept, known as "point-of-service" or "point-of-care" delivery is where the handheld computer will likely establish itself as a clinical tool in the hospital setting. Although the small screen size (and font size) of a PDA and the absence of a traditional keyboard are too cumbersome or impractical for entry of longer documents, the PDA may realize most of its use in the review of clinical data and work-flow management (5). With the entry of the tablet PC into the marketplace, some of the obstacles regarding work space size may be overcome.
The PDA has the potential to be used as an alternative in most hospital functions that traditionally use paper as a recording medium. These could include recording patient history, physical findings, and vital signs, as well as placing orders for medications. In addition, the PDA can be used to track or assimilate a patient’s laboratory data without ever locating a paper chart. A portable device with wireless access to the hospital information system (HIS) can be used at the bedside to record limited clinical information; access current laboratory data; and look up appropriate reference data such as correct drug dosages, alternatives, and interactions or differential diagnoses and clinical algorithms. Pilot programs of mobile computers established in various hospitals in Europe have shown distinct advantages to an accessible EMR; however, lack of convenient access points, network inefficiencies, and display limitations were shown to be problematic in making these systems successful (6).
A principal role of PDAs in medicine is improved access to reference material including entire textbooks. The power of this type of portable electronic access is illustrated by one of the more popular electronic drug references, Epocrates (www.epocrates.com; ePocrates, San Mateo, Calif). This software is an abridged searchable drug database and formulary that fits in a handheld computer. This program replaces the bulky Physicians Desk Reference (PDR) and is easier to transport. All relevant medications, including dosages and interactions, are fully accessible to the user on a PDA, and the software self-updates with each synchronization.
Other PDA functionality that will prove valuable with physicians is order entry. In most facili-ties, patient orders are handwritten to a paper chart or selected on a desktop PC. Acknowledgment and status of the current orders are not readily available. With the appropriate technology infrastructure in place, the status of all outstanding orders can be checked and new orders placed directly on a PDA. This direct electronic link to services and information improves efficiency by eliminating middleware (eg, ward clerks) and reduces errors and omissions.
Although the display of textual information and low-resolution graphics is easily accomplished with current PDA technology, it remains to be determined whether there is sufficient demand by physicians for handheld display of high-resolution imaging studies. Small screen size, low inherent display resolution (typically ranging from 160 x 160 pixels to 320 x 320 pixels), pixel depth, data transfer rates, and memory requirements currently pose some limitations for display of radiologic images on a PDA (7,8). A radiologic image differs drastically in quality when shown on a low-resolution, gray-scale display (Fig 1a) compared with a display with better characteristics (Fig 1b). These technical limitations likely will be overcome in the next several years with the release of devices with VGA display characteristics and larger screen, tablet devices. Methods have been devised to convert standard DICOM (Digital Imaging and Communications in Medicine) data to a "manageable" format that can be accommodated by the limited display functionality of most handheld devices (Fig 2). In the schema illustrated in Figure 2, a DICOM image is stripped of the header data and appropriate window and level settings are extracted for conversion to an 8-bit depth image suitable for PDA or Web display. Display of full 12-bit DICOM data is not practical on most current handheld devices because of hardware limitations. A practical method for on-demand wireless image access is not commercially available; however, new wireless networking technologies purport to overcome many of these limitations (8).
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Although PDA medical technology is far from mature, the inherent value of accessibility to relevant clinical information without being tethered to a medical office or hospital nursing station is just being realized. A number of institutions are currently testing the impact of wireless order entry and electronic medical charts on physician work flow, efficiency, and error rates.
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Radiology and the PDA |
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TopAbstractIntroductionPDA BasicsPDAs in MedicineRadiology and the PDAConclusionsReferences |
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Portable computers offer a reasonable alternative to paper for displaying textual data; however, the capacity to render a diagnostic quality radiologic image on a small screen is both technically unfeasible and largely impractical to the radiologist who expects a full-fidelity rendering on a large display (5,8). Moreover, the bandwidth limitations of current wireless networking infrastructure does not allow for efficient transfer of full imaging data to a handheld device. Nevertheless, some centers continue to experiment with transmission of lower quality single images. Even when the technical challenges have been surpassed, the question will remain regarding under what clinical circumstance a radiologist would choose a PDA to assess an imaging study over alternative methods. Portable display of low-resolution images may remain popular only with referring clinicians who have fewer alternatives for reviewing radiologic studies.
New technologies are widely adopted by users when they replace an older, less efficient method. The capability to access any medical record with a handheld device is compelling enough to convince a clinician to adopt the newer, more efficient technology. For the radiologist, however, use of a wireless handheld device to access imaging data is not as persuasive because it does not replace or supplement current technologies that are becoming commonplace in many radiology departments. These technologies include the higher resolution and speed of a clinical PACS workstation to handle tasks such as image review and interpretation, management of radiology work flow (via the RIS), speech recognition, and image processing. Current PDA technology does not support diagnostic quality images; however, selective images of "consultative quality" are easily displayed on today’s devices (Figs 1, 4) (5). Nevertheless, radiologists have found many other ways to leverage handheld technologies to complement their clinical practices.
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Future Applications
Work-flow monitoring and maintenance may be the most compelling future application of PDAs in radiology (5). Networking and connectivity of imaging centers have fostered much of the growth of radiology practices in the past decade. As radiology practices continue to merge and therefore expand, not only is there an impetus to tightly integrate work flow with resources but also to have this information readily available. A wireless handheld device that monitors the clinical schedule and modality work list has potential value to the "mobile" radiologist. Erberich et al (16) demonstrated active wireless transmission of a modality work list from a RIS/PACS to a handheld device, with subsequent initiation of a DICOM query and retrieve transaction by the handheld unit to a PACS archive. In addition, they showed that PACS work flow could be remotely monitored on a handheld device. Other investigators demonstrated a prototype clinical protocol simulator that featured bidirectional DICOM image and text transmissions (17). Using this proposed system, a technologist queries the radiologist by sending a preliminary protocol and a selected image via a wireless PDA. The radiologist revises the protocol on his or her handheld device and transmits the new protocol back to the scanning console (Fig 11) (17). Notification via PDA of pending radiology reports awaiting signature is another method of augmenting work flow. Reports can be reviewed, corrected, and approved remotely. From the PDA, a radiologist can instruct the RIS to print, fax, or transmit the results to a PDA or text pager of a referring clinician.
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As handheld technology and networking performance evolve, wireless display and review of full-fidelity imaging studies will be possible. Investigators from Japan recently demonstrated the feasibility of transmitting an entire CT or MR imaging study as streaming video to a conventional PDA by using the third-generation wireless protocol. The third-generation protocol is currently available only in Japan and is capable of 225-Kbytes/sec transmission speeds. CT or MR imaging studies are encoded into Windows media file formats on a Web server, which are then available for download by using the third-generation protocol (8,11).
Despite the tremendous interest in applying portable computing to medicine and the rapid proliferation of resources readily available on the Internet, the implementation of this technology to mainstream medicine remains in its infancy. Market penetration of PDAs and medical applications are largely untapped. Moreover, acceptance of this technology is variable among physicians, many of whom were trained before the growth of the computer age; however, this level of technology is accepted and often expected with the current residents in training. For many physicians, paper and film are more portable, more readable, and more durable than any PDA in existence. There are still many significant issues that must be resolved before the PDA will become a universal standard for data access and entry in the healthcare environment. These issues include bandwidth and security requirements for wireless networks; choosing which form is most acceptable for specific tasks (eg, use of a tablet instead of a PDA for specific applications); preventing theft, loss, or damage to the PDA and unauthorized access to data on the PDA; and display requirements for text and images (eg, larger font sizes are preferred by older physicians) (20). Despite these technical challenges, medical centers, vendors, and healthcare providers will continue to find solutions as they incorporate this technology into clinical practice.
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Conclusions |
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TopAbstractIntroductionPDA BasicsPDAs in MedicineRadiology and the PDAConclusionsReferences |
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Footnotes |
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References |
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TopAbstractIntroductionPDA BasicsPDAs in MedicineRadiology and the PDAConclusionsReferences |
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C.-S. Yam Projecting PowerPoint Presentations with a PDA Am. J. Roentgenol., April 1, 2005; 184(4): 1356 - 1359. [Abstract] [Full Text] [PDF]
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