Imaging devices need to link with older DICOM versions
New imaging equipment is usually compliant with the latest version of DICOM, but making sure that new equipment communicates with legacy devices is often overlooked in purchasing. If you have a modality that was installed in the early 1990s and connects to a workstation or other device, there is a chance that this connectivity is based on ACR-NEMA 2.0, the predecessor to the DICOM standard.
If the equipment you already own supports DICOM 3.0 rather than ACR-NEMA 2.0, there is a good chance that equipment you purchase today will communicate with it.
Be cautious, however. In the case of many ultrasound, nuclear medicine, and computed radiography systems, the DICOM 3.0 implementation has changed.
Compatibility between devices can be determined during the setup for a DICOM connection, when both devices negotiate their capabilities. For example, a workstation might support the receipt of CT and MR, but not ultrasound, since that modality requires different software and often hardware (i.e., color display). The negotiation process clarifies the capability of the receiving device, whether these are old or new versions of ultrasound, nuclear medicine, or CR.
Vendors also specify these capabilities in their DICOM conformance statements.
For some modalities, this is a nonissue. For example, fundamental changes have not been made to the CT storage service, which allows a CT scanner to send images using DICOM to a workstation.
The National Electrical Manufacturers Association (NEMA) has made the 1998 version of the DICOM standard available free at its Web site (www.nema.org). End users, universities, and other PACS implementers, who might otherwise not have been able to afford the purchase of this standard, now have free access. Paper copies can still be purchased (see the NEMA Web site for details).
The standard consists of 14 parts. Part 2 (how to write and interpret a DICOM conformance statement), 3, and 4 (specifying DICOM objects such as images) and services (such as Store, Print) are the most worthwhile to end users.
-By Herman Oosterwijk, president, OTech Inc. (firstname.lastname@example.org)