Int J CARS (2013) 8:323–333 DOI 10.1007/s11548-012-0785-3 REVIEW ARTICLE DICOM relay over the cloud Luís A. Bastião Silva · Carlos Costa · José Luis Oliveira Received: 12 February 2012 / Accepted: 11 July 2012 / Published online: 9 August 2012 © CARS 2012 Abstract Purpose Healthcare institutions worldwide have adopted picture archiving and communication system (PACS) for enterprise access to images, relying on Digital Imaging Communication in Medicine (DICOM) standards for data exchange. However, communication over a wider domain of independent medical institutions is not well standardized. A DICOM-compliant bridge was developed for extending and sharing DICOM services across healthcare institutions without requiring complex network setups or dedicated com- munication channels. Methods A set of DICOM routers interconnected through a public cloud infrastructure was implemented to support med- ical image exchange among institutions. Despite the advan- tages of cloud computing, new challenges were encountered regarding data privacy, particularly when medical data are transmitted over different domains. To address this issue, a solution was introduced by creating a ciphered data channel between the entities sharing DICOM services. Results Two main DICOM services were implemented in the bridge: Storage and Query/Retrieve. The performance mea- sures demonstrated it is quite simple to exchange informa- tion and processes between several institutions. The solution can be integrated with any currently installed PACS-DICOM infrastructure. This method works transparently with well- known cloud service providers. Conclusions Cloud computing was introduced to augment enterprise PACS by providing standard medical imaging ser- vices across different institutions, offering communication privacy and enabling creation of wider PACS scenarios with suitable technical solutions. L. A. B. Silva (B ) · C. Costa · J. L. Oliveira Universidade de Aveiro—DETI/IEETA, Aveiro, Portugal e-mail: bastiao@ua.pt Keywords PACS · DICOM · Medical imaging · Telemedicine · Teleradiology · Cloud computing Introduction Collaborative work environments have greatly increased in healthcare in the past decade. This trend has changed proce- dures in healthcare institutions, so exchange of medical data across institutions has become common in several modali- ties [1]. Their importance has increased due to cost-savings for medical institutions and growth of applications, such as expert consultation, cooperative work and sharing of images between multiple image centres. Nowadays, picture archiving and communication system (PACS) is one of most valuable tools supporting medical decision and treatment procedures. A PACS is a key point in storing, retrieving and distributing medical images in the various steps of clinical practices. Digital Imaging Commu- nication in Medicine (DICOM) is a standard that supports the storage format of medical images and the distribution of medical imaging. Despite several institutions use of DICOM to distribute medical images, the inter-institutional usage of this standard is mainly supported by VPN connections. The only part of the DICOM complaint with Web 2.0 is WADO [2], which allows images retrieval over the Web, but storage and search are not supported. Web 2.0 compliant commu- nications over a wide domain composed of several medical institutions is still a challenge. Although the DICOM standards support SSL/TLS layers, i.e. encrypted channels that allow privacy in the transfer of electronic data, many medical devices do not support these features. This discourages users located outside an institu- tion from securely accessing the PACS archive only using DICOM with direct connections. Medical institutions often 123