Integrating Open Source PACS in Research One Step at a Time
 
Authors:
Nipun D. Patel, MS, Beth Israel Deaconess Medical Center
 
Background:
Picture Archiving and Communication Systems (PACS) have been utilized at hospitals since 1990 to handle radiology images.[1,2,3] Using PACS has resulted in significant improvements in the work-flow and productivity of clinical and radiology practices. Medical imaging is frequently used in research labs, and a number of research labs own imaging equipment like MicroCT (Scanco Medical, Switzerland). In addition, due to the highly collaborative nature of medical research, there is a tremendous amount of data exchange between laboratories. Unfortunately, PACS are almost never utilized in non-traditional research labs using such imaging equipment and generating varied image based data. There may be several reasons for this trend including, but not limited to, increased expense, unconventional workflow, lack of DICOM[4] compliance, lack of necessary resources and, above all, lack of awareness. The goal of the present work is to propose a model for research labs that would utilize existing open source tools to allow for integration of data generated from various research based imaging systems and provide a central repository to access and view data. The proposed model will rely on harnessing the robustness and flexibility of the applicable open source systems for addressing the needs of a research lab. Open source systems and tools are proposed here, because these would be most suitable for the research environment due to their zero-cost, robustness and possibility of expert inputs from users with varied experience in using these tools for different applications.[5,6,7] Additional advantages of open source systems include a very high level of unbiased dialogue for problem solving and an easy venue to learn and understand varied issues in such applications. Finally, getting inexpensive commercial support for actively used open source system is a viable option. For the proposed application of the open source systems, the costs associated with higher fidelity can be limited because research labs can be more tolerant to downtime when compared with radiology or clinical practices. Due to the reasons discussed previously, DCM4CHEE[8,9] enterprise level PACS system is chosen. The aim to this work is to develop a “Research PACS” to handle the needs of the research workflow as outlined above. The overall project is broken down into the following steps:

1. Data Acquisition: This step can be the most problematic in a research lab setting, especially because of non-compliance with the DICOM 3.0 requirement.
2. Data Query: Searching for image data that can originate from animal studies or in vitro studies with non-uniform nomenclature.
3. Appending additional documentation: This step is extremely crucial for research applications due to the extreme variability between studies conducted in a research lab.
 
Evaluation:
A DCM4CHEE system (an enterprise version of DCM4CHEE)[8] has been setup in our network as our PACS engine that connects with an Ultrasound Machine (HDI 5000, Philips, USA). Open source Debian Linux Server acts as our operating system, although DCM4CHEE is a multiplatform PACS. Linux was employed because of its superior reliability[6] and low cost. This system allows us to view the data through the browser or download data using any software that has the capability of communicating with a PACS. Freely available software applications such as KPACS, OSIRIX[5,10] are being used to view the data. We have chosen the DCM4CHEE[8,9] system due to its low cost, ability to easily modify, and the excellent support available through forums.
 
Figure 1
Figure 1: A schematic setup with PACS system
 

The communication scheme with the Ultrasound machine is as shown in Figure 1 above. The UltraSound machine used here is designed to communicate with PACS and is fairly simple to implement due to the lower size of the data generated in our application. However, MicroCT 40 (Scanco Medical, Switzerland) systems running on the OpenVMS platform can generate DICOMs that may not be DICOM 3.0 compliant. Also, there is no communication ability available to communicate with the PACS and, therefore, an intermediate tool needs to be developed to push data into the PACS. One possible solution is to upload data from the MicroCT system to a data server (in our case linux server hosting DCM4CHEE) as a data folder which can then be read by DCM4CHEE. This solution allows us to push the data to the PACS system with an inexpensive solution. The Peripheral Quantitative Computer Tomography (PQCT) (XCT Research SA+, Stratec Biomedical, Germany) system in our research lab currently generates only proprietary image data. The vendor has provided header information which is utilized to manually import the raw data in Analyze™ (Mayo Clinic, U.S.A) which is not freely available. The imported data is then converted into DICOM and the patient/sample information is re-entered and data is sent to PACS. Once the data is in PACS we can use the web browser to look at the data. We have used Oviyam Dicom Viewer to obtain a better interface through the browser. In addition, data can also be downloaded or uploaded using desktop applications such as K-PACS, Osirix etc. Overall setup is shown in Figure 1.
 
Discussion:
The Ultrasound system and the PACS were successfully connected and the data was easily viewed using K-PACS, as well as with the internet browser Firefox. The integration of the PQCT system was slightly more challenging primarily due to the lack of DICOM data. Analyze™ was used to convert the raw data into DICOM which were successfully pushed to DCM4CHEE. However, the disadvantage of this method is the necessity for user intervention. The MicroCT system was able to export the image data into the PACS by inserting the data server between the PACS and the MicroCT as we lacked direct communication capabilities between the two systems.

The approach in this work was to begin with a robust Picture Archiving system (DCM4CHEE) and modify it as per our requirements. The major hurdle encountered was importing data from the different imaging modalities as they are either non-compliant with DICOM 3.0 or lack the capability to generate DICOM format images (PQCT). Currently, direct communication between the MicroCT or PQCT and the DCM4CHEE has not been possible due to the non-compliance of the image data with DICOM 3.0. Several open source tools[11] are available that can be used to fill this void. Conquest PACS (open source software) can be used to correct for the DICOM header and make the images compliant. In addition a research setting will need a tremendous amount of documentation. A document can be appended to the DICOM converter tool to organize the documents along with their image data. Apart from the technical challenges, user training will present another challenge due to the diverse nature of the projects.. Our overarching goal is to have a single tool that can be used for MicroCT and PQCT to communicate with PACS. As we progress towards our goal it is our hope to add key pathology images and add naming nomenclature and indexing to the database to afford a rich search capability. The search capability will prove crucial for our setup due to the variety of the data we hope to store in our “Research PACS”
 
Conclusion:
Open Source PACS can provide great benefits to the research community as experienced by the clinical community. The issues with the imaging equipment presented here showcase the type of complexities that may be encountered when building a PACS system for research settings. In this scenario a single vendor solution may not be possible. Hence, an open source solution when chosen carefully can help mitigate the costs and enhance utilization and innovation.
 
Acknowledgement:
I would like to thank Dan Buckland from Massachusetts Institute of Technology and Harvard Medical School for his assistance with the ultrasound machine.
 
References:
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