The Quality Assurance Review Center (QARC), a research program within the University of Massachusetts Medical School, has provided radiotherapy quality assurance services, diagnostic imaging data management, and clinical research support across six continents for the past 25 years. For much of that time, the center relied on a primarily manual workflow for the identifying, receiving, and storage of hard-copy film. As medicine moved to a digital environment, QARC had to develop a method for accommodating the influx of DICOM images.
“In July of 2007, with a PACS containing over 6 million images, the QARC archive has exceeded 700 gigabytes (GB),” wrote the authors of an online paper available prior to publication in a forthcoming issue of the Journal of Digital Imaging.
The studies housed in the PACS represent a variety of modalities and diseases acquired from more than 850 different sites and arrive at QARC in many electronic formats, both with and without proprietary headers, according to the authors. The institution developed an image management system to accommodate data heterogeneity, which encompasses a patient database, DICOM image transfer software, and a PACS archive.
The database currently houses data for more than 40,000 patients over the past 30 years and is available to researchers worldwide. The heart of the successful development of the image portion of the database is DICOM image transfer software, Dicommunicator.
The application was initially written by Keith White, MD, of Primary Children’s Medical Center in Salt Lake City and also features a DICOM image viewer built using the DicomObjects toolkit provided by David Harvey, MD, of Medical Connections in Wales, U.K. It has been ported onto a web platform so that physicians at remote sites can retrieve and review images from QARC.
The last component of the QARC system is its archive, which includes an array of four 1.8 terabyte servers that hold more than 6 million DICOM image files.
Dicommunicator, donated by White to QARC in 2000, allows for DICOM images to be submitted to the center by email or CD. Demographic data (patient name and ID) is scrubbed from the images and is replaced with a study group, protocol, and patient registration number for investigative research purposes. It also maintains an audit history of submitted images that allows an originating institution to keep track of which studies have been sent to QARC.
According to the authors, Dicommunicator can directly interface and query/retrieve DICOM studies from eight different PACS vendors: Agfa HealthCare, Fujifilm Medical Systems, GE Healthcare, Dynamic Imaging (now part of GE), Carestream’s Kodak PACS, Philips Medical Systems, Siemens Medical Solutions, and Stentor (part of Philips).
“When images generated from remote Dicommunicator sites arrive at the QARC server, they are extracted from the emails using the same Dicommunicator software and stored in the QARC imaging archive,” the authors wrote.
Clinical research associates (CRAs) at QARC review submitted images to determine which of the studies meet central review endpoints. The authors noted that this manual intervention is critical as it may take numerous requests to obtain the correct data for submission to a particular study. In addition, CRAs may be able to resolve proprietary file or image quality issues before the data is integrated into the QARC PACS.
Once the DICOM files are imported into the PACS, the CRA resolves each study to a corresponding event and study on the patient’s electronic diagnostic record in the QARC database. Each study is uniquely linked to the event and study on the patient record by a study unique identifier (StudyUID) attribute associated with the images, according to the authors.
The center noted that the time required to manually copy and ship films to QARC has been eliminated with its system, expediting the time to data completion and allowing more rapid case review and feedback to the investigators and sponsors. In addition, the expense of copying and shipping films has been eliminated for participating institutions as has the cost of storing the films by QARC.