Redesigning the Nuclear Medicine Reading Room

Redesigning the Nuclear Medicine Reading Room Nigist Zemariame, MD,* Nancy Knight, PhD,† and Eliot L. Siegel, MD†,‡ The process of image review and interpretation has become increasingly complex and challenging for today’s nuclear medicine physician from many perspectives, especially with regard to workstation integration and reading room ergonomics. With the recent proliferation of hybrid imaging systems, this complexity has increased rapidly, along with the number of studies performed. At the same time, clinicians throughout the health care enterprise are expecting remote access to nuclear medicine images whereas nuclear medicine physicians require reliable access at the point of care to the electronic medical record and to medical images from radiology and cardiology. The authors discuss the background and challenges related to integration of nuclear medicine into the health care enterprise and provide a series of recommendations for advancing successful integration efforts. Also addressed are unique characteristics of the nuclear medicine environment as well as ergonomic, lighting, and environmental considerations in the design and redesign of the modern reading room. Semin Nucl Med 41:463-471 © 2011 Elsevier Inc. All rights reserved.

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uclear medicine, perhaps more than any other imaging specialty, has been a pioneer in the early adoption of computer technology, especially for the primary interpreting physician. In 1983, Parker et al1 described their all-digital department more than 10 years before the first completely digital radiology department began routine operations.2,3 Parker’s group described the review, manipulation, and interpretation of diagnostic images by using “remote display stations in an interpretation area.” They used a digital dictation system, and indicated that images were maintained on “large storage discs” that could be retrieved for subsequent review of images. In addition, the group described the ways in which images could either be reviewed “elsewhere in the hospital” or transmitted from a remote site to the image interpretation area. These and other early all-digital nuclear medicine departments were not only far ahead of the adoption curve for imaging information systems but, by necessity, were independent systems that almost never interfaced with other imaging equipment outside the nuclear medicine department, nor did they interface with other hospital information systems (HISs) or with fledgling efforts to aggregate and manage

*University of Maryland Medical Center, Baltimore, MD. †University of Maryland School of Medicine, Baltimore, MD. ‡Veterans Affairs Maryland Health Care System, Baltimore, MD. Address reprint requests to: Nancy Knight, PhD, Department of Diagnostic Radiology and Nuclear Medicine, University of Maryland School of Medicine, 22 S. Greene Street, Baltimore, MD 21201. E-mail: nknight@ umm.edu

0001-2998/11/$-see front matter © 2011 Elsevier Inc. All rights reserved. doi:10.1053/j.semnuclmed.2011.06.003

electronic medicine records (EMRs). For many technical, clinical, economic, and even cultural reasons, nuclear medicine has remained relatively independent and isolated from other hospital and imaging information systems, despite the integration of imaging systems in multiple other modalities and with other systems, such as the radiology information system (RIS), the hospital picture archiving and communication system (PACS), and the EMR/HIS. Along with and partially because of this independence, nuclear medicine image storage and information systems have evolved at a relatively slower pace than PACS and similar efforts in other medical imaging specialties. The use of PACS in these other areas has been associated with improved departmental efficiency, especially when implemented in concert with a re-engineering of departmental workflow.4 Advances in network infrastructure and associated image transfer rates, HIS and RIS integration, commercial off-the-shelf workstations with more reliable and brighter monitors, improved image presentation and navigation software, image enhancement, computer-aided diagnosis, and integrated speech recognition have received substantial attention in the research and development communities as candidates for improved radiologist efficiency and productivity. Additional critical factors include image format standardization and improved storage capacity.5 Unfortunately, comparatively little attention has been paid to either integration of nuclear medicine systems with general PACS or to redesign of the nuclear medicine reading room to integrate new technologies, innovations in reporting, or streamlined workflows. Relatively little information has appeared in the 463

464 nuclear medicine literature on the potential of improvements in reading room design to enhance diagnostic performance. This is unfortunate, because although the practice of nuclear medicine has several unique aspects that distinguish it from other imaging modalities, it is our experience that relatively small investments in integration as well as room design and workstation ergonomics can have major effects on productivity, efficacy, and accuracy.

Background By the early 1990s digital nuclear medicine departments already had years of experience with the problems associated with proprietary vendor file formats that made it difficult to share a common archive and display images with a single workstation. It was this quality assurance challenge that finally spurred the development of a standard file format known as “Interfile.” Interfile was originally developed by Working Group 1 of the European project COST-B26 with a protocol based on a report from the American Association of Physicists in Medicine (AAPM) to facilitate data transfer between different commercial systems.7 It used a “Babel Box” to translate between each proprietary format and Interfile with a floppy disk and also had the capability of acquiring clinical data associated with specific patients. The Interfile format was widely adopted but was limited to a file format, unlike Digital Imaging and Communications in Medicine (DICOM), which specified a communication protocol as well. The American College of Radiology–National Electrical Manufacturers Association (ACR–NEMA) standard for medical images evolved from an initial 1.0 version in 1985 to the DICOM 3.0 standard released in 1992. DICOM provided not only a general file format for diagnostic imaging but also a standard for image communication, storage, and printing. ACR and NEMA formed an ad hoc committee that produced a DICOM Nuclear Medicine Supplement, issued in 1995, which provided detailed information specifying the semantic content of nuclear medicine images. A separate positron emission tomography (PET) Information Object Definition (IOD) was also specified. Honeyman and colleagues8 created an Interfile/ACR– NEMA gateway that facilitated access to images from multiple vendors by using a DICOM-based PACS, effectively creating a bridge between these 2 standards.9 Subsequent authors have suggested tremendous potential advantages of the use of an integrated DICOM-based PACS for nuclear medicine. In 2002, Lassmann and Reiners10 reported that, in their experience, the installation of a RIS connected to a HIS and a PACS “seems mandatory for a nuclear medicine department in order to guarantee a high patient throughput.” They created a “completely DICOM-based PACS,” including a “departmentspecific archive purely based on DICOM” that was integrated with their RIS using what they referred to as a DICOM-based workflow using a DICOM modality worklist. The use of this DICOM standard allows an imaging modality, such as a single-photon emission computed tomography (SPECT) system, to retrieve a list of scheduled patients and associate a patient and study’s demographic information with an imag-

N. Zemariame, N. Knight, and E.L. Siegel ing examination, resulting in increased efficiency, consistency, and accuracy. Despite these advantages, adoption of DICOM by nuclear medicine vendors and interoperability with Interfile has been slow. Somer,11 in an editorial in Nuclear Medicine Communications, observed that “as the original digital imaging modality, nuclear medicine had already developed its own alternatives to standards such as DICOM and has been reluctant to give these up in favor of the limited advantages offered by PACS integration.” In addition to the relatively slow adoption of DICOM by the nuclear medicine community, PACS providers have historically not made nuclear medicine a high priority in comparison with other modalities. Although critically important to practitioners of nuclear medicine, from the vendors’ pointof-view integration of nuclear medicine into PACS has represented a difficult challenge requested by only a small minority of PACS users, coming in line well behind such high-volume modalities as computed tomography (CT), magnetic resonance imaging (MRI), ultrasound, and conventional radiography. As a result, nuclear medicine has typically either not been included as a modality in hospital-wide PACS or, alternatively, has been included in a limited capacity—such as the use of screen captures rather than the richer feature set that would be available with full support for DICOM images in nuclear medicine. In most institutions, this has resulted in the use of PACS only for secondary reviews of nuclear medicine images, with primary reviews on either a nuclear medicine generic workstation or a proprietary single-vendor nuclear medicine workstation. Another standard, Health Level-7 (HL7) is a synergistic communication protocol used to exchange information among medical applications. This standard provides the groundwork for encoding and exchanging the health care information of a patient among different hospital systems. With this standard, patient record, order entry, and financial information can be passed to HIS, RIS, and PACS without human intervention. Unlike DICOM, HL7 does not represent a standard for image file format or for exchange of medical images. The latest HL7 version 3 Clinical Document Architecture provides an extensible mark-up language (ie, XML) standard that specifies the semantics, structure, and encoding of clinical documents and references but does not replace DICOM for medical images.12

Current Challenges to Nuclear Medicine Integration The rapid and widespread adoption of PET/CT during the past decade13 has resulted in a renewed and accelerated interest in and clinical requirement to improve integration or at least interoperability between nuclear medicine and HISs, including PACS. This renewed interest has been the result of several requirements and challenges associated with multimodality image interpretation that have amplified the need and potential advantages of improved integration of nuclear medicine images into the health care enterprise. These in-

Redesigning the nuclear medicine reading room clude the need to decrease the number of workstations required to perform image interpretation; take advantage of modality worklist; compare current and previous studies; support both CT and PET at a single workstation, including advanced navigation, image fusion, and multiplanar display; make previous reports from multiple modalities as well as information from the EMR available for review; compare current CT and PET images with previous CT studies and studies from other imaging modalities; and satisfy the expectation that PET/CT images will be accessible in the same way as other imaging modalities throughout the health care enterprise. In addition to these more general issues regarding integration of nuclear medicine and PACS, specific issues relate to integration of PET and CT when attempting to interpret images at a single workstation. Williams et al14 documented the importance of having radiographic correlation and the need to have complete access to nonnuclear medicine images, rather than using these merely for correlation of PET studies with CT. This group found that when a PACS workstation was available in the nuclear medicine department, it was accessed for correlative images in 62% of nuclear examinations and that nuclear medicine physicians believed these images aided in study interpretation in 74% of accessed cases. The authors concluded that the ready availability of other medical images increased the efficiency of a nuclear medicine department by “allowing timely and conclusive interpretations to be made.”14 Wallis15 listed 5 major hurdles to PACS and nuclear medicine/PET integration. The first was the loss of what are referred to as “private elements” that are vendor specific and are stored in “special” DICOM fields often arbitrarily selected by individual vendors. Because most PACS do not provide support for these fields during storage and retrieval, the information required for reprocessing or review is lost. The second hurdle was the lack of support by PACS providers for the PET IOD portion, even when vendors support the more general nuclear medicine IOD. Third was the related inability to perform quantitative measurements, such as standardized uptake value (SUV) calculation. The fourth issue was a lack of understanding and support by PACS vendors for the nuclear medicine IOD, resulting in an inability to display nuclear medicine images properly on PACS (despite current use of the nuclear medicine IOD by a subset of nuclear medicine vendors). The fifth and related issue was that even when both nuclear medicine and PACS vendors exchange image information properly, PACS vendors who have workstations optimized for conventional radiographs, CT, and MRI studies have a very limited understanding of the requirements for display, review, and analysis of nuclear medicine images. This has made it impractical for nuclear medicine departments to replace their nuclear medicine modality specialty workstations.15 A further level of complexity arises because of differences in implementation of image processing and quantitative measurement by different vendors. Although basic information is stored in the DICOM image, vendors use different strategies for homogeneity correction, SUV calculation, and display of multislice image sets. We have seen this

465 manifest at our institution as significant differences in SUV value calculation when using different workstations. Somer11 also pointed out that “companies that supply and maintain large PACS systems are reluctant to allow the installation of third-party applications, citing security, integrity, and maintenance response conflicts.” He indicated that the nuclear medicine industry response to this has been development and adoption of nuclear medicine mini-PACS, which are typically supplied by vendors who are smaller and who specialize in the preservation of proprietary legacy data and applications and support of DICOM. This has, for the most part, resulted in a situation in which a single nuclear medicine workstation is typically used for multiple nuclear medicine imaging systems in a department, often from multiple vendors, supported by a standalone archival system. These systems unfortunately have only rudimentary support for image arrangement (hanging) protocols, including those that facilitate comparison with prior examinations. These systems also typically do not have support for image fusion and multimodality display, leading to the use of at least 3 (and often more) different types of workstations in the department. These usually include a nuclear medicine subspecialty workstation; a generic PACS workstation for review of general radiographs, CT studies, MRI, and other imaging modalities; and a PET/CT workstation that most often is provided by the vendor of the PET/CT scanner. Many departments also have an advanced visualization workstation for multiplanar and 3D image visualization, and this may or may not support image fusion and image navigation. These separate workstations are most often associated with separate databases and image archives, a situation that contributes to the “tower of Babel” phenomenon that the AAPM was attempting to address using Interfile in the early 1990s. The nuclear medicine modality solution typically does not interface well with a general PACS and provides only limited storage for images in the long term, nor does it provide support for image fusion, nonnuclear medicine modalities, or comparison of current and prior studies. PACS workstations have typically provided only very rudimentary support for nuclear medicine functionality beyond basic multiframe display of multiple gated acquisitions and usually provide no support for image fusion. General radiology PACS typically do not support the software required to analyze cardiac, renal, gastric emptying, or quantitative lung studies, nor are they usually able to display multiple simultaneous cines, use different color schemes, or quantitate regions of interest. Multiple serial scans often cannot be presented simultaneously for comparison, and the ability to add and subtract frames, copy frames from one study to another, rotate and mirror frames, and offset sets of frames (for example, when comparing stress and rest myocardial perfusion slices) are not features of standard radiology PACS. Additional missing features include the display of fused PET/CT images with color, the viewing of transaxial, coronal, sagittal, and maximum intensity projection images to triangulate an area of interest, and the ability to obtain SUVs to quantify metabolic uptake. PACS workstations are also unable to fuse separately acquired images.16

466 PET/CT workstations typically provide limited or no support for other nuclear medicine modalities, especially from other vendors systems, and no substantial storage capacity. Third-party nuclear medicine and advanced visualization workstations have attempted to incorporate more of these features than vendor specific proprietary systems; however, there is still a need for broader functionality. In addition to the lack of integration with other medical imaging networks, displays, and archival devices, nuclear medicine imaging systems and information systems have lagged behind their general radiology counterparts with regard to integration with HISs and EMRs.17-20 This has resulted in manual reregistration in the nuclear medicine department and re-entry of patient demographic information at nuclear medicine imaging modalities without the use of the DICOM modality worklist function.

Integrating the Healthcare Enterprise (IHE) and Nuclear Medicine Despite the use of DICOM and HL7 for medical images and associated metadata in the 1990s, “plug-and-play” interoperability was elusive, and third-party vendors were usually required to create interfaces between the HIS/RIS/PACS and nuclear medicine imaging and information systems. These protocols were not sufficiently specific for successful integration among hospital systems built from different vendors, because interpretation of these standards varies somewhat from vendor to vendor. To overcome this dilemma, the IHE was established in 1999 by the Radiological Society of North America (RSNA) and the Healthcare Information and Management Systems Society as a collaborative project to create profiles that specified in detail how standards, such as HL7 and DICOM, could be used to exchange information in a variety of scenarios. In 2000, the Society of Nuclear Medicine (SNM) created its Computer and Instrumentation Council Advisory Task Force on File Interchange and Network Communication in Nuclear Medicine. On the basis of the findings of this task force, the SNM DICOM Working Group was formed, with a goal to work with vendors to improve DICOM connectivity and interoperability. File repositories were created to facilitate exchange of DICOM images between vendors, and many cross-vendor incompatibilities were identified and fixed during preparation for demonstrations at the 2001 and 2002 SNM annual meetings.15

IHE Nuclear Medicine Profile The IHE Nuclear Medicine profile was originally based on the SNM procedure guideline for telenuclear medicine, which described requirements for “minimum functionality” for telenuclear medicine workstations21 and incorporated the American Heart Association standard for viewing myocardial perfusion studies.22 Wallis15 described the 2 major goals of the IHE nuclear medicine profile. The first goal was to identify the unique aspects of nuclear medicine images, including the

N. Zemariame, N. Knight, and E.L. Siegel need for scheduling software to take into account that nuclear studies (such as a gallium scan) may span several days. The second goal sought to address the fact that nuclear medicine DICOM images may not be organized in simple series, as is true with MRI or CT images, but instead may have multiple camera views or even isotope windows interwoven, requiring an index to sort out these “frames” for display and analysis. The second goal, then, was to create a set of image display profiles for practical image display. These profiles should address the need to: manipulate upper and lower display settings separately rather than the window/level settings used in CT, with additional histogram equalization capability; display multiple cine “movies” simultaneously, such as for a radionuclide ventriculogram or cardiac perfusion study; be able to review multiple series simultaneously and to refer to examples of templates to perform these; and perform multiplanar reconstruction, which is only recently being routinely implemented on PACS workstations. The IHE nuclear medicine profile also specifies features unique to cardiology, such as suggested cardiac fields to indicate the physiological state of the patient, radiopharmaceutical (stress, rest, redistribution, etc.) DICOM fields that specify orientation plane (eg, short axis) relative to the heart rather than to the patient as a whole, and presentation state of grayscale or color images, including the ability to apply specified color look-up tables using a PACS workstation. An IHE profile for image fusion was added soon after the adoption of the IHE nuclear medicine profile. It allows a system, such as a PET/CT, PET/SPECT, or PET/MR scanner to communicate registered image data for additional processing, display, and archival and specifies in detail how 2 datasets are related. It allows the creation of a reproducible “presentation state” (which refers to the way in which the images are displayed, including grayscale or color, how images are made transparent/blended, and other display parameters) in which images are to be fused. This can result in the display at a generic nuclear medicine workstation or PACS of images in the same way these would be displayed on the vendor’s PET/CT or other fused modality workstation.

Potential Solutions in Integration of Nuclear Medicine into PACS On the basis of our experience and that of others who have reported in the literature and served on the committees that have released the various protocols designed to improve integration of nuclear medicine into the mainstream workflow of imaging within the enterprise, several potential solutions should be considered along the continuum of planning, purchase, workflow design, and implementation. These include but are not limited to: 1. Purchase nuclear medicine imaging equipment that supports DICOM and, more specifically, the DICOM nuclear medicine IOD.

Redesigning the nuclear medicine reading room 2. Specify that any nuclear medicine imaging systems must support the IHE nuclear medicine profile and (even if the system is not a hybrid scanner) the IHE image fusion profile as well. Ask for conformance statements from the vendor for both DICOM support and the IHE profile. Vendors participate in connection testing (known as Connectathons) with other systems, such as HISs and RISs, and should have and be willing to share documentation of which areas resulted in success. Additional information is available from the RSNA. 3. Determine how well the existing nuclear medicine department interfaces with the hospital/clinic PACS. Can the PACS display a variety of nuclear medicine images in a clinically and diagnostically useful format (which is ideal), or does the PACS launch a separate third-party nuclear medicine–specific viewer? If the latter, then does the third-party system allow storage of images in the PACS so the nuclear medicine images can be archived along with other medical images? Can the PACS store these without losing the vendor-specific information in the DICOM headers? At the very least, network and workstation access to radiology and cardiology images should be facilitated in addition to nuclear medicine studies.14 4. Access to the HIS/EMR, including previous nuclear medicine, radiology, and cardiology reports, is critical. 5. Workstations used for display of nuclear medicine images, whether vendor proprietary, nuclear medicine generic, or PACS, should be able to display a current and previous examination, should provide support for multiple monitors, and should include “hanging protocols” to allow customization of image display for specific users and types of studies. Moise and Atkins23 documented the importance of these hanging protocols and the potential they offer to reduce interpretation time by 10%-20%. 6. In general, it is prudent to avoid having patient identification incorporated as part of pixel data associated with an image. Instead, patient identification information should be an image overlay so the user can toggle patient and other information on and off and so that images can be exported in a de-identified fashion to a teaching file or for conference or research purposes. 7. The nuclear medicine and PACS systems should provide support for the IHE Teaching File and Clinical Trial Export profile, which allows one to specify studies or series of images for export to a teaching file, conference file, research archive, or edge server. Although several excellent vendor systems are available to accomplish this, RSNA offers free and open source software available as part of the Medical Imaging Resource Center.

Nuclear Medicine Interpretation Room Design In addition to the importance of interoperability and access to other medical imaging systems (such as PACS) and to patient medical records (including prior reports, progress

467 notes, pathology reports, etc.), the nuclear medicine physician should work in a reading environment that minimizes distractions and promotes good health and optimal efficiency, efficacy, and safety. Almost no reports in the peerreviewed literature have described the importance of an ergonomically optimized nuclear medicine reading room. During the past 18 years, since the transition of radiology from film to digital, many presentations and articles have described experiences with radiology reading room design and provided practical recommendations for improvement.3,24-28 Although these have addressed many important issues, they have not addressed some of the unique challenges associated with nuclear medicine. A few of the features that differentiate nuclear medicine department reading from their radiology counterparts include: 1. Nuclear medicine physicians more frequently are asked to talk to and perform examinations on their patients and to check examinations in progress in the imageacquisition areas. Thus, it is more important that the reading room be located in close proximity to patient examination areas and equipment. These requirements make it more challenging than the interpretation of images alone, which can be effectively performed even by remote telenuclear medicine. 2. Radiology departments have seen a substantial decline in “in person” consultations (ie, visits to the reading room) from referring physicians. This was documented in a study by Reiner et al,29 who documented an 82% reduction in the in-person consultation rate for general radiography and a 44% reduction for cross-sectional imaging despite an increase in overall volume after introduction of a PACS and the transition to filmless operation. This reduction has not been documented in nuclear medicine departments and, at least anecdotally in our experience, may be much less pronounced than in radiology. This finding suggests that it is important to have reading room environments for nuclear medicine that are sufficiently large to accommodate frequent clinician consultations and, when practical, to use projectors or mounted large-screen displays for image review purposes. 3. Nuclear medicine physicians currently require multiple workstations to perform image interpretation because of the lack of integration and consolidation of workstations as described in the previous section. This occurs much more often than with radiology- or cardiology-specific workstations. Any design of an image interpretation “cockpit” for nuclear medicine physicians must take this into consideration and make it as easy (and safe) as possible to move freely from one workstation to another. Improved workstations and/or greater use of image streaming from multiple servers to provide imaging applications is certain to occur in the future, and this will allow a nuclear medicine physician to use a single workstation for interpretation even when multiple user interfaces and software programs are required.

468 4. Imaging studies are more often reviewed and specified in advance for nuclear medicine studies and are often reviewed and modified during a study. This suggests greater need for rapid access to patient information and access to images as they are being acquired. Previous studies, prior reports, and information from the HIS and EMR should be readily available.

Computer Workstations Although digital nuclear medicine departments have been in existence for more than 30 years, many continue to rely on a largely paper-based workflow that is often a legacy of the original design of the departments. Paper is used for protocoling studies, for image requests, and often for review of previous reports and for patient or study information, such as reports from a cardiac stress study. Nuclear medicine departments— even those that call themselves “all digital”—should carefully review their paper-based and digital workflows for opportunities to reduce workflow steps,30 a process that can result in major improvements in efficiency and patient care. This redesign also offers the potential to reduce or redeploy personnel and save space previously associated with potentially outmoded processes and technologies (printers, fax machines, file storage, etc.). Nuclear medicine workstations are often configured inefficiently. Departments should strive to minimize the number of computer workstations required to achieve the necessary tasks by consolidating so that a single workstation can serve multiple purposes. Figure 1 shows only half of a University of Maryland Medical Center nuclear medicine reading room and highlights the difficulties associated with multiple workstations used for different systems, as well as lighting, sound, and ergonomic furniture challenges. On the basis of our experience,31 we recommend a 3-monitor workstation: 2 for image display and 1 for several functions that can be consolidated into a single workstation monitor, including worklists, review of the EMR, and for speech recognition or digital dictation. Liquid crystal display monitors have almost completely replaced cathode ray tube monitors for display of nuclear medicine as well as radiology imaging studies. Al-

Figure 1 Image of one half of the nuclear medicine reading room at the University of Maryland Medical Center shows only a third of our workstations and emphasizes ergonomic challenges in lighting, sound, and furniture. Note the use of a projector to mirror a workstation display on the wall. This is used for conference and teaching purposes. (Color version of figure is available online.)

N. Zemariame, N. Knight, and E.L. Siegel though nuclear medicine images do not require high-resolution displays, color monitors are typically used, which is currently not typical for standard PACS workstations. Just as the technologists perform regular quality control on the nuclear medicine cameras, it is important to perform similar assessment of the quality of monitors used in the nuclear medicine reading room. This can be accomplished with the use of a Society of Motion Picture and Television Engineers phantom or other test patterns that can assess for spatial and contrast display characteristics of the monitors. Other electronic devices, such as dictation equipment, telephones, and personal computers for access to the EMR and the Internet should be placed within easy reach of the radiologist without the need to move his or her chair.3,28

Room Lighting One of the most important design considerations in the reading room is lighting, both monitor brightness and ambient (background) lighting. One rule of thumb is that monitor brightness should be comparable to ambient lighting. During the past 20 years, monitor brightness has increased by a factor of 2 to 3 from ⬃150 cd/m2, which was the original ACR standard for monitor brightness. This has resulted in the ability to increase ambient light levels in nuclear medicine departments. Research performed at the Baltimore Veterans Affairs Medical Center has documented that optimization of monitor and ambient lighting can result in decreased image interpretation times, decreased fatigue, and improved accuracy in image interpretation.3 This difference in accuracy is particularly noteworthy, with a decrease in accuracy for interpretation of conventional radiographs from 85% to 74% in the presence of ambient lighting that was too bright. Additional lighting recommendations include the use of indirect incandescent light sources rather than overhead fluorescent lighting, which can cause flicker and result in glare. Monitors should be configured in a way that does not result in glare on other monitors in the room. Dimmable light sources are strongly preferred, with either incandescent light sources or light-emitting diode dimmable light sources appearing to be optimal. Task lighting can be used to minimize the need for high ambient room light and can allow the nuclear medicine physician to modify the lighting without leaving his or her chair. Our preference is also the use of light-emitting diode lighting, which uses a minimum amount of electricity and generates a minimum amount of heat. Of additional note, the use of a blue background has been documented to decrease stress levels in fish,32 and many believe this may be true in humans as well and may increase visual acuity in relatively low-light reading conditions.3

Environmental Controls One area that is often overlooked in reading room design is control of environmental conditions, such as heating, cooling, and ventilation. The importance of these and of innova-

Redesigning the nuclear medicine reading room

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Noise and Sound Protection Distractions from noise originate from other workers’ faceto-face conversations (65%), other workers’ telephone conversations (62%), telephones ringing (55%), and office equipment (18%).34 Additional source of noise include departmental overhead paging systems, visiting clinicians, and ventilation systems. Noise has become especially critical after the introduction of speech recognition systems, which typically try to interpret background sounds as words. To diminish noise, reading rooms should have sound-absorbing material in all walls and dividers and should also have acoustic paneling and carpeting. A sound-masking system that generates “noise” in the general frequency range of the human voice works surprisingly well to attenuate noise associated with medical imaging equipment (such as an MRI scanner) without deleteriously affecting speech recognition performance.24

Ergonomics

Figure 2 Individual environmental controls for ventilation and temperature controls. (A) Adjustable controls for ventilation and heating. (B) Ventilation and heating system located below the desk with floor duct. (Color version of figure is available online.)

tive designs in this area have been highlighted by work from the Robert L. Preger Intelligent Workplace laboratory at Carnegie Mellon University, which was funded by an industrial consortium.33 Ventilation controls provide airflow, heating, and air conditioning that are user controlled, as demonstrated in Figure 2 in an Intelligent Workplace demonstration project. Keeping the room temperature comfortable is also an important factor in maintaining productivity. Sources of heat include computers, incandescent lighting, the number of people in the room, computer monitors, and any number of peripheral devices the users may bring into the room with them. Although the optimal industrial work temperature range is 17°-24°C, the reported most comfortable temperature is 25.6°C (78.1°F).33 Radiologists may actually be more productive at temperatures slightly colder than those with which they are most comfortable. Thus, rooms should include workstations with individual controls for each workstation user.

Poorly designed furniture can results in eye strain, fatigue, low back pain, and occupational repetitive stress disorders. Two common types of upper-extremity compressive neuropathies associated with repetitive stress disorder from using a computer mouse or track ball are carpal (median nerve) and cubital (ulnar nerve) tunnel syndromes. These have been reported with increased frequency in radiologists using a PACS workstation.35 In addition to being a source of repetitive stress disorders, the mouse and (less often) trackball used by nuclear medicine physicians are relatively inefficient devices for tasks such as image navigation and review. Sherbondy et al36 compared the ability of a trackball with that of other input devices (a mouse, tablet, and jog-shuttle wheel) to find 25 different vascular targets in 3 CT angiography datasets. They found that the trackball was significantly slower than the tablet and marginally slower than the jogshuttle wheel. Weiss et al37 used automated audit logs to evaluate CT interpretation times with detailed structured reporting using the RollerMouse (Fig. 3) and compared those times with those for a game controller and a conventional mouse. They found a 5% reduced interpretation time using the game pad and a 41% reduction in interpretation time using the RollerMouse (Contour Design, Inc, Windham, NH), with no significant changes in accuracy of measurement or detection of pathology. The U.S. Occupational Safety and Health Administration provides extensive recommendations and references for keyboards, on work-related musculoskeletal disorders, on the need for strategic breaks using computer monitors, on furniture ergonomics, and on other challenges associated using computer workstations and monitors.38 These recommendations include the need for chairs to have adjustable height/ armrests with lumbar support and that keyboards should be adjustable in height/position with keyboard trays. The Occupational Safety and Health Administration also recommends keeping the relative positions of the monitor and the body within optimal parameters. The optimal viewing distance

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Figure 3 The use of the RollerMouse (Contour Design, Inc, Windham, NH) was associated with a substantial reduction in interpretation time in comparison with a conventional mouse and game pad. (Color version of figure is available online.)

should be 24-36 inches, to decrease eyestrain, whereas the optimal viewing angle should be 10°-20°, with the observer looking down at the center of the monitor.

Conclusions The design, redesign, or upgrade of a nuclear medicine reading room has received relatively little attention in the nuclear medicine literature but is becoming an increasingly complex process that represents an opportunity to improve efficiency, efficacy, and safety. To achieve an optimal design, it is critical to ensure that all the information required to make a diagnosis and to communicate findings effectively is readily and rapidly accessible. It is also important to optimize the factors that affect human performance to minimize distraction from unwanted noise, glare, and other lighting issues as well as optimize comfort and minimize strain and injury to nuclear medicine practitioners. The practice of nuclear medicine can be both cognitively and physically stressful and demanding and, given the amount of time spent in the reading room, it is essential to take the time to plan a pleasant and low-stress yet highly connected and interoperable environment.

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