Architecture - HMIS Documentation

The radiology integration keeps HMIS independent of any particular PACS or modality vendor. HMIS exchanges normalized clinical messages with OIE; PACS-specific APIs remain inside OIE channels.

Component responsibilities

Component	Responsibility
HMIS	Orders, billing state, accession numbers, examination details, reporting, authorization, audit, and viewer links
OIE	Authentication, routing, PACS-specific API conversion, polling/webhooks, normalization, retries, and transport audit
PACS	Modality worklist, DICOM object storage, study indexing, DICOMweb, and study availability
Modality	Query the PACS worklist and send acquired DICOM objects directly to the PACS
Viewer	Retrieve studies from the PACS through DICOMweb
Mock modality	Local DICOM MWL and C-STORE simulation only

The modality does not send images through OIE. In the tested flow it performs DICOM MWL and C-STORE directly against the PACS. OIE handles control-plane integration between HMIS and PACS.

Vendor-neutral boundary

HMIS knows only the immutable pacs_code, accession number, normalized study identity, and a viewer URL template. It does not call Orthanc REST endpoints. The demo uses Orthanc, but a different PACS can be introduced by replacing these OIE adapter details:

the worklist publication destination;
the stable-study notification or polling mechanism;
PACS authentication and connection details;
the viewer URL template and DICOMweb deployment.

The HMIS worklist and study-ingestion API contracts remain unchanged.