What Is a Radiology Information System (RIS)?

A radiology information system (RIS) is the software platform a radiology or medical-imaging department uses to run its operational workflow — scheduling exams, tracking orders from request through signed report, and handling the department-specific billing and resource-management tasks that sit around an imaging study. It is a distinct system from a PACS (picture archiving and communication system), which stores and displays the actual diagnostic images, and from the hospital’s general EHR/HIS, which holds the whole longitudinal patient chart across every department, not just imaging.

Core RIS functions

Across vendors, a system only counts as a RIS if it covers the imaging-specific operational workflow, not just image storage. The functions that define it are:

• Patient scheduling and registration for imaging exams — booking a modality slot (X-ray, CT, MRI, ultrasound, nuclear medicine), pre-authorization tracking, and patient/exam-prep instructions.
• Order and exam tracking — assigning an accession number to each study so it can be followed from the referring order through acquisition, interpretation, and final report, and linked back to the correct patient encounter.
• Radiologist reporting and dictation workflow — routing studies to a reading worklist, supporting speech-recognition or template-based dictation, structured-reporting fields, and report sign-off.
• Results distribution — delivering the finalized report (and often a link to the images) back to the referring clinician, typically through an HL7 interface into the hospital’s EHR.
• Procedure-based billing and coding — capturing CPT/procedure codes and charge data tied to each completed exam.
• Departmental resource and equipment management — tracking modality utilization, technologist assignments, and exam volume for staffing and capacity planning.

RIS vs. PACS

RIS and PACS are the two systems most often confused because they’re used together on nearly every study and are frequently sold, and sometimes deployed, as a combined “RIS/PACS” product. The functional split is:

• RIS manages the workflow and data about the exam: who the patient is, what was ordered, when it happened, what the report says, and how it gets billed.
• PACS manages the images themselves: DICOM-format acquisition, storage, retrieval, and display, typically archived long-term for the regulatory retention period that applies to diagnostic imaging.

A facility can technically run a PACS without a RIS (viewing and archiving images with no structured scheduling/reporting workflow around them), but that setup can’t support billing, order tracking, or a reporting worklist — which is why most imaging departments run both, integrated so the accession number in the RIS matches the study identifier in the PACS.

RIS vs. HIS/EHR

The hospital information system (HIS) or electronic health record is the patient’s full record across every department — labs, medications, notes, and orders from every service line, not just imaging. RIS is scoped narrowly to the radiology department’s own operational workflow. The two are connected, not interchangeable: the HIS/EHR typically sends the imaging order into the RIS via an HL7 interface, and the RIS sends the finalized report back the same way once a radiologist signs it. A facility’s imaging order and result data therefore usually touch three systems in sequence — HIS/EHR (order originates, report lands) → RIS (workflow, scheduling, reporting) → PACS (image storage/display) — connected by HL7 messaging for the order/report data and DICOM for the image data itself.

How facilities select and procure a RIS

RIS selection is an imaging-IT infrastructure decision, not a routine purchase, because the system sits in the critical path between ordering a study and a clinician receiving a diagnosis. Facility/IT buyers typically evaluate:

• Integration depth with the facility’s existing EHR/HIS and PACS — whether the vendor has a proven HL7/DICOM interface to those specific systems, not just interface capability in the abstract.
• Combined RIS/PACS vs. best-of-breed — many large EHR vendors now offer an integrated imaging module (sold as part of the broader EHR contract) as an alternative to a standalone, imaging-specialist RIS/PACS vendor; each path trades integration simplicity against imaging-specific workflow depth.
• Regulatory and data-retention requirements that apply to diagnostic imaging records in the facility’s jurisdiction, since the RIS is usually the system of record for the audit trail around an exam (who ordered it, who read it, when it was reported).
• Reporting/dictation workflow fit for the radiology group’s actual reading pattern (on-site, teleradiology, or a mix), since this is the part of the system radiologists interact with directly, every study, every day.
• Total cost of ownership — licensing model, interface-build costs to existing systems, and ongoing support, evaluated the same way as any other clinical/lab information-system procurement (see purchasing cooperative and vendor selection criteria for the general procurement framework this decision follows).

Because this is a competitive vendor market rather than a single-standard product category, CASRAI does not recommend or rank specific RIS vendors on this page; facility IT and radiology leadership should run the evaluation against their own integration and workflow requirements, generally via a formal RFP process consistent with the facility’s standard IT procurement controls.

Frequently asked questions

What is RIS in healthcare?

In healthcare specifically, RIS refers to the same radiology information system described above: the software a hospital or imaging center’s radiology department uses to schedule exams, track orders and reports, and manage imaging-related billing — as distinct from PACS (image storage) and the hospital’s general EHR (the full patient record).

What are some radiology information system vendors?

RIS is a competitive commercial software market with both standalone imaging-IT specialists and RIS/PACS modules offered by larger enterprise EHR vendors; specific product offerings and market positioning change over time, so facility buyers should evaluate current vendors directly against their own integration and workflow requirements rather than relying on a fixed list. See “How facilities select and procure a RIS” above for the evaluation criteria to apply regardless of which vendors are under consideration.

What’s the relationship between HIS and RIS in radiology?

HIS (hospital information system, or more broadly the EHR) holds the patient’s complete record across all departments and is where an imaging order typically originates. RIS is the department-specific system that manages that order once it reaches radiology — scheduling, tracking, and reporting the exam — then sends the finalized report back to the HIS/EHR via an HL7 interface. HIS is facility-wide; RIS is radiology-department-scoped.