Frequently Asked Questions

Table of Contents

• SOP Class Support
  • Which SOP classes are supported?
  • How do I add a new SOP class?
• Transfer Syntax Questions
  • How do I add a new transfer syntax?
  • What if the receiver doesn't support my transfer syntax?
• Security Questions
  • How do I enable TLS for DICOM connections?
  • Does pacs_system support audit logging?
• Integration Questions
  • How do I integrate with a hospital PACS?
  • DICOMweb services?
• Storage Questions
  • What storage backends are available?
• Performance Questions
  • How do I tune for high-throughput ingestion?
• AI Integration
  • How does AI integration work?
• Conformance Testing
  • How do I run conformance tests?

SOP Class Support

Which SOP classes are supported?

27 SOP classes covering the major clinical workflows: CT, MR, US, XA, NM, PET, RT, SR (Structured Report), SEG (Segmentation), MG (Mammography), CR (Computed Radiography), SC (Secondary Capture), Patient/Study Root Q/R, Modality Worklist, MPPS, Storage Commitment, Print, UPS, PIR, XDS-I.b. See README for the full list.

How do I add a new SOP class?

Derive from services::sop_class_base, register the UID with sop_class_registry, and implement the service callbacks. Existing SOP class implementations in sources/services/ serve as templates.

Transfer Syntax Questions

How do I add a new transfer syntax?

Implement a codec that satisfies the codec_interface — encode() produces encoded bytes from pixel data, decode() reverses it. Register via codec_registry::add(uid, factory). The existing JPEG, JPEG 2000, HTJ2K, JPEG-LS, and RLE codecs show the pattern.

What if the receiver doesn't support my transfer syntax?

During association negotiation, the SCU proposes all supported transfer syntaxes per presentation context. The SCP picks one it can handle. If there's no overlap, the presentation context is rejected and the SCU must either convert on the fly (see dcm_conv) or abort.

Security Questions

How do I enable TLS for DICOM connections?

Set tls_enabled = true in the association config and provide certificate paths:

config.tls_enabled = true;
config.tls_cert = "/etc/pacs/cert.pem";
config.tls_key = "/etc/pacs/key.pem";
config.tls_ca = "/etc/pacs/ca.pem";

See examples/secure_dicom/ for a full working example.

Does pacs_system support audit logging?

Yes — audit events are emitted via logger_system's structured log sinks. Every C-STORE, C-FIND, C-MOVE, and login event produces a structured record suitable for SIEM ingestion.

Integration Questions

How do I integrate with a hospital PACS?

1. Coordinate AE titles, IP, port with the hospital's imaging IT team.
2. Register your AE at the hospital PACS and vice versa.
3. Agree on SOP classes and transfer syntaxes.
4. Test with echo_scu (simplest) before attempting store or query.
5. Verify audit logs match the hospital's compliance requirements.

DICOMweb services?

Yes — pacs_system ships with pacs_web library supporting WADO-RS (retrieve), STOW-RS (store), and QIDO-RS (query) via the Crow REST framework. See the pacs_web/ module.

Storage Questions

What storage backends are available?

• File storage — local filesystem, one file per object (default)
• SQLite indexing — metadata index for fast Q/R
• AWS S3 — cloud blob storage (optional, PACS_WITH_AWS_SDK)
• Azure Blob — cloud blob storage (optional, PACS_WITH_AZURE_SDK)
• HSM — hierarchical storage management integration hooks

Performance Questions

How do I tune for high-throughput ingestion?

1. Use async storage (file_storage with write-behind buffering).
2. Increase the network thread pool (network_system settings).
3. Enable pipeline mode in the DIMSE handler — multiple DIMSE commands per association.
4. Use a lock-free job queue for incoming objects (default in release builds).
5. See docs/performance/ for benchmark data.

AI Integration

How does AI integration work?

pacs_ai provides an ai_service_connector that forwards DICOM objects to an AI endpoint and receives results as SR (Structured Report) or SEG (Segmentation) objects. The results are then stored alongside the source objects and made retrievable via Q/R.

Conformance Testing

How do I run conformance tests?

pacs_system's test suite includes DCMTK interop tests that verify wire-level compatibility with the reference DCMTK implementation. Run ctest -R dcmtk to execute them. For formal conformance, use a third-party validator like DVTk.