Radiology and Medical Imaging | Moana Digital Health

Overview

Moana PACS (moana-pacs) is a dedicated Picture Archiving and Communication System that operates as a production-ready service within the Moana platform. It integrates imaging orders placed by clinicians in the EHR, DICOM image storage in the Orthanc server, cloud archiving in AWS S3 with automated cost tiering, radiologist reporting, and synchronisation of imaging studies back to the HAPI FHIR server into a single end-to-end workflow.

Medical imaging infrastructure has historically been one of the most expensive and technically complex components of a health system digital strategy. Proprietary PACS systems require substantial upfront capital, vendor-locked storage infrastructure, and specialist IT support that most health systems in the Pacific Islands and comparable environments cannot sustain. Moana PACS changes that equation by building imaging capability directly into the same platform that manages clinical records, laboratory, and pharmacy, using open-standard DICOM protocols, open-source Orthanc as the image management engine, and cloud object storage for long-term archiving at a fraction of traditional PACS storage costs.

The result is a radiology infrastructure that a facility can stand up without a separate capital procurement, without a separate vendor contract, and without a separate IT team, while still meeting the standards expected of a production clinical imaging system. Images are encrypted at rest. Access is governed by role. Radiologist reports are linked directly to the patient record. Studies are available to authorised clinicians anywhere in the network through presigned URLs with configurable time-to-live settings.

The system accepts all standard DICOM modalities. No modality filtering is applied at the gateway. A facility beginning with digital X-ray acquires the same platform infrastructure that will support CT, MRI, ultrasound, and mammography as imaging capacity grows.

Core Capabilities

Imaging Order Workflow

Clinicians place imaging requests directly from the patient's clinical encounter, selecting the required modality, body region, and clinical indication. The order is transmitted to the radiology worklist immediately, eliminating paper request forms and the delays, losses, and transcription errors they introduce. Order status is tracked through five stages: draft, submitted, scheduled, in-progress, completed, and reported. The ordering clinician receives automatic notifications when the study is completed and when the radiologist's report is available, eliminating the need for manual follow-up on investigation results.

DICOM Storage and Orthanc Integration

Medical images are received from imaging equipment via the DICOM C-STORE protocol and stored in the Orthanc PACS server. Orthanc provides standards-compliant DICOM Query-Retrieve (C-FIND and C-MOVE) for integration with any DICOM-compliant imaging modality. Studies are simultaneously synced to the Moana PACS database, where they are indexed by patient, study date, modality, and accession number, and uploaded to AWS S3 for long-term cloud archiving. The Orthanc web viewer provides browser-based access to DICOM studies for radiologists without requiring a separate workstation application.

AWS S3 Cloud Archiving with INTELLIGENT_TIERING

All DICOM files are uploaded to AWS S3 and organised under the INTELLIGENT_TIERING lifecycle policy, which automatically moves studies between storage tiers based on access frequency without any manual management required. Studies accessed within 30 days remain in the frequent-access hot tier. Studies not accessed for 30 days move to the infrequent-access tier at lower cost. Studies not accessed for 90 days move to the archive tier at minimal cost. For health facilities managing years of accumulated imaging data, this automated tiering provides the long-term archiving capability required by clinical governance and medico-legal retention requirements, at a storage cost that scales with actual usage rather than requiring upfront capacity planning.

Secure Presigned URL Access

DICOM image files are never publicly exposed. Access to imaging studies is provided through presigned URLs generated on demand by the PACS service. Each presigned URL is cryptographically signed, grants access to a single study, and expires after a configurable time-to-live window, with a default of 15 minutes. This ensures that access to patient imaging data is always governed by the authentication and authorisation layer, and that URLs cannot be bookmarked, shared, or reused beyond their intended access window. All image access events are logged in the audit trail.

Supported Modalities

The Orthanc DICOM gateway accepts all standard imaging modalities without modality filtering. Confirmed modality support includes digital X-ray (DX and CR), computed tomography (CT), magnetic resonance imaging (MRI), ultrasound (US), mammography (MG), nuclear medicine (NM), positron emission tomography (PT), and fluoroscopy (RF). Modality worklist integration allows imaging equipment to pull patient and order details automatically from the PACS worklist, eliminating manual patient demographic entry at the imaging console and reducing the risk of study mislabelling.

Radiologist Reporting Workflow

Radiologists access studies through the Orthanc web viewer from any authorised workstation. Radiology reports, including structured findings and clinical impression, are authored and submitted within the Moana PACS interface, directly against the imaging request record. Submitted reports are immediately available to the ordering clinician through the patient record, with a notification confirming report availability. Reports are versioned: if a radiologist amends a report after initial submission, both the original and amended versions are retained with timestamps and authoring clinician attribution.

FHIR ImagingStudy Synchronisation

Every completed imaging study is synchronised to the HAPI FHIR server as an ImagingStudy resource, making imaging data available to any FHIR-compliant system participating in the broader health information exchange. The ImagingStudy resource includes the study instance UID, modality, number of series and instances, and a reference to the presigned URL for secure image access. This synchronisation ensures that imaging data participates fully in the FHIR-based interoperability layer that national digital health strategies in the Pacific and Southeast Asia are building toward.

Role-Based Access Control

Access to imaging studies and reporting functions is governed by a five-level role model. Administrators manage system configuration, storage settings, and user access. Radiologists have full access to the reading worklist and can author, submit, and amend reports. Doctors can place imaging orders and view completed reports and images for their patients. Nurses can view imaging order status. Service accounts support machine-to-machine integration with FHIR and external systems. Each role sees only the functions and data appropriate to their clinical responsibility.

Who Uses This Module

Radiologists and Reporting Clinicians

Access the imaging worklist, view DICOM studies via the Orthanc viewer, and submit structured radiology reports linked to the imaging request.

Requesting Clinicians

Place imaging orders from the clinical encounter. Receive notifications on study completion and report availability. Access images and reports from the patient record.

Radiographers and Imaging Technicians

Manage the imaging worklist. Confirm studies as complete on acquisition. Monitor DICOM storage and upload status.

IT Administrators

Manage Orthanc configuration, S3 storage settings, presigned URL expiry configuration, and FHIR synchronisation monitoring.

How This Connects to the Rest of Moana

Imaging orders originate in Clinical Care Management and are linked to the patient encounter from the moment of ordering. Completed studies and radiologist reports are written back to the patient record automatically, making them part of the longitudinal clinical history. ImagingStudy resources sync to the HAPI FHIR server, making imaging data available to the broader interoperability layer. Billing entries for imaging services are generated automatically from completed studies. The PACS service is independent of the EHR backend and can be deployed separately for facilities that require imaging infrastructure without the full clinical record system.

Standards and Interoperability

The PACS service implements the DICOM standard for image storage, retrieval, query, and worklist management. ImagingStudy resources are structured to FHIR R4. Presigned URL access is secured via AWS Signature Version 4. AES-256 SSE encryption is applied to all objects at rest in S3. The Orthanc engine supports DICOM C-STORE, C-FIND, C-MOVE, and standard DICOM tag metadata. Images and reports are linked to the patient longitudinal record via the imaging request workflow.