As PACS has evolved over the last two decades, the technology has advanced to meet the needs of most - but not all - imaging modalities. General radiology PACS tend to focus on anatomical modalities like CT and MR. The primary reason for the cold shoulder? Nuclear medicine represents a different species with specific and unique needs.

"General radiology PACS don't provide the display functionality to support nuclear medicine studies. In addition, some PACS don't fully support DICOM for nuclear medicine for easy storage and retrieval of nuclear medicine studies," explains Bill Erwin, PhD, senior medical physicist with MD Anderson Cancer Center in Houston.

In some cases, frustrated nuclear medicine departments have cobbled together their own homegrown product to serve as the image management solution. In others, the department continues to rely on less than state-of-art solutions like storing images on CDs and magneto-optical (MO) drives. But some nuclear medicine departments have tapped into one of the few commercial solutions on the market - with promising results.

Several niche companies have developed nuclear medicine image management solutions geared to the unique needs of the specialty. Deploying such a solution can bring a number of benefits including complete soft-copy image management, improved workflow and access to nuclear medicine DICOM translation tools to facilitate a heterogeneous scanner environment. The hitch is to understand the facility's needs and the potential and limits of nuclear medicine image management solutions. In addition, smart departments also keep one eye on the future as the PET/CT explosion is driving changes across the nuclear medicine field.


The needs: At a glance

While most imaging modalities focus on anatomical representation, nuclear medicine displays images in many different ways. Static display does not suffice for dynamic nuclear medicine studies, planar gated studies, SPECT, PET or PET/CT, says Mike Georgiou, PhD, director of basic science operations-nuclear medicine at the University of Miami Hospital in Florida.  Nuclear medicine requires very specific display capabilities; the system must display grayscale or color, functional, quantitative and fusion data. For example, PET/CT image review is a complex process that entails viewing of transaxial, coronal and sagittal and maximum intensity projection (MIP) images. In addition, the physician should be able to easily triangulate the area of interest, obtain standard uptake values (SUVs) to determine metabolic uptake and change the display to PET and CT alone or both in a fused fashion.

Although nuclear medicine modality workstations provide processing and analysis tools for soft-copy interpretation and quantitative analysis, they can not store nuclear medicine images for the long-term. A nuclear medicine image management solution can provide that central archive. In addition, many systems incorporate DICOM translation tools to help hospitals integrate heterogeneous scanner environments.


Beyond the modality workstation

One of the primary reasons for turning to a nuclear medicine image management solution is to overcome the constraints of multiple modality workstations. "Modality workstations provide necessary processing and display tools, but they don't meet nuclear medicine image management needs beyond the modality," says Georgiou. That is, the workstations do not interact efficiently with the radiology PACS to provide networking integration, remote access to images or appropriate long-term data archiving.

Two years ago, University of Miami Hospital turned to Thinking Systems Corp.'s ThinkingPACS to meet the broader image management needs of its nuclear medicine department. "ThinkingPACS provides display and review flexibility, a departmental archive and remote access through its web-service capability," sums Georgiou.

The transition to soft-copy nuclear medicine image management has resulted in workflow gains as physicians no longer need to return to individual modality workstations to interpret studies. Thinking Systems provides the nuclear medicine processing packages of modality workstation, which facilitates one-stop reading.


Multi-purpose image management

MD Anderson Cancer Center has relied on Numa Inc.'s NumaStore as its nuclear medicine image management solution for more than 10 years; however, the system transcends the basic archive role. The unfortunate reality of DICOM-compliance is DICOM is not a strict standard. Each vendor can implement DICOM in its own dialect, making it difficult to exchange data among systems. NumaStore's DICOM implementation allows MD Anderson to store, retrieve and transfer images from multiple systems. This means if a physician prefers the acquisition features of one camera and the display functionality of a second vendor's workstation, he can have it both ways. "Numa-Store does not change DICOM data. We can take data from a vendor's system, store it in Numa, complete a DICOM-query/retrieve, and the data are returned unaltered," explains Erwin.

In addition, if a facility has older non-DICOM systems, Numa incorporates translators to convert and push data to a DICOM destination and the broader network. This feature facilitated MD Anderson's transition from film-based nuclear medicine to the soft-copy environment, says Erwin.

Although the DICOM translation capabilities provided by a nuclear medicine image management system can be a significant help in heterogeneous scanner facilities, it is not a perfect solution. "A site can run into incompatibilities," says Erwin. "We've had to write software or customize the display software to support different DICOM implementations on top of using Numa as a translator." That is, NumaStore's DICOM translation tools translate data to one level; however, it may not suffice for seamless data exchange. It's analogous to conversing in a foreign language. Generic translation software might facilitate conversation at one level, but more advanced skills are required for meaningful conversion. That's where human tweaking (and time) enters the picture.

MD Anderson also relies on NumaStore for a redundant nuclear medicine archive and permanent online mass storage for its gamma camera systems. "Before de-ploying NumaStore, we stored all of the data temporarily online on the acquisition system and permanently offline on CD or MO disks," notes Erwin.  


Interacting with the radiology PACS

An effective nuclear medicine image management solution not only meets the specific needs of the nuclear medicine department but also serves as a bridge to the radiology PACS - and often, the enterprise. At MD Anderson, nuclear medicine data are sent to both NumaStore and the radiology PACS. Referring physicians, who generally require simple views of nuclear medicine studies, view thumbnails and simple images on the radiology PACS. Nuclear medicine physicians can query and retrieve historical data from Numa-Store as they read current studies on their nuclear medicine interpretation station.

University of Miami Hospital employs a similar approach. The radiology PACS usually suffices for referring physicians. PET/CT is the exception to the rule because PACS workstations lack the display capabilities needed for anything but basic PET/CT viewing. For example, fused PET/CT studies cannot be viewed on a PACS workstation. Currently, some referring physicians visit the PET/CT reading room to view the images. To improve the situation, the hospital is evaluating several options, including Thinking Systems' web server capability and a PET/CT plug-in module for the radiology PACS.


A sound implementation

Deploying a nuclear medicine image management solution can bring significant benefits to the nuclear medicine department and across the enterprise. Facilities can pave the way for a smooth implementation by adhering to best practices. "Make sure the hardware and software of potential systems is up to date. Determine if the nuclear medicine system is a fully-fledged PACS with the capability and functionality of a general radiology PACS," recommends Georgiou. "In addition, make sure that the images generated by various nuclear medicine modalities display appropriately on the nuclear medicine PACS. The system also should provide all of the tools required by the nuclear medicine physician. From the institutional perspective, the nuclear medicine PACS must be capable of effectively, efficiently, appropriately and correctly interacting with the enterprise PACS. It should serve as a gateway to the radiology PACS," continues Georgiou.

"The technologist plays a vital role after deployment," adds Erwin. "Technologists must think of softcopy as digital film and ensure that all of the data are transmitted to the required destinations just as they ensured all of the necessary films were generated."


Looking forward: Integrating nuclear medicine into radiology PACS

The advent and demonstrated clinical utility of PET/CT could alter nuclear medicine image management. "The mainstream acceptance of PET/CT has changed the picture," confirms Erwin. "In the future, nuclear medicine may be a module on the larger PACS," adds Georgiou.

PET/CT is problematic for both interpreting radiologists and referring physicians across the continuum. In some departments, radiologists review PET/CT images on two or even three workstations. That's because the single workstation tied to the scanner may be optimized for functional viewing, which forces the radiologist to turn to a second workstation to read CT images. He may use a third station to dictate results. The process becomes even more complex when the radiologist needs to view prior studies.

At the same time, the process is not streamlined for referring physicians. Some oncologists and general practitioners may require the radiology report and key images. Other clinicians will demand standard uptake values. Oncologists completing advanced therapy planning require a higher degree of interaction, access to the entire image set and the ability to import data into therapy planning software.

These factors combine to create a need for some sort of marriage between PET/CT and the standard radiology or enterprise PACS. As more users need to view PET/CT studies, radiology PACS will be forced to incorporate nuclear medicine display capabilities. The wedding may be on the horizon.

Potential solutions include a hybrid PACS display that handles both functional and anatomic data or a third-party plug-in that offers the look and feel of integration with the PACS display. The third-party plug-in can serve as an integrated, single desktop solution that facilitates and streamlines viewing of PET/CT images. The solution also serves as a bridge or conduit that not only transmits images to the main PACS but also sends studies out to referring physicians.  


Conclusion

Nuclear medicine presents specific and specialized image needs, and general radiology PACS has tended to overlook nuclear modalities. But smaller, niche vendors have plugged the gap nicely with solutions tailor-made for nuclear medicine image management. "These companies understand nuclear medicine," opines Georgiou. "If we need a specialized modification, the company implements it in a very timely way," continues Georgiou.

Nuclear medicine image management solutions deliver on a number of fronts. For starters, they provide digital storage for the images, and they shuffle data to the main PACS. They also throw in nuclear medicine DICOM translation tools, making it easier to share data among disparate systems or bring older equipment into the digital storage era.

At the same time, nuclear medicine image management is very much a work in progress. PET/CT has altered the status quo, throwing a wrench in the system with new, broader viewing needs that encompass both function and anatomy. What's more, the masses are beginning to clamor to view the studies, yet standard PACS can't quite deliver. The writing is on the wall; PET/CT will pave the way for nuclear medicine. General vendors are exploring solutions like plug-in modules and hybrid displays to bring PET/CT pictures to the masses. New solutions will take time, says Erwin. "In the meantime, nuclear medicine departments have two choices: move and manage data across multiple systems or deploy a nuclear medicine PACS," concludes Erwin.