dicom_flutter_radiology_kit

Drop-in clinical medical imaging kit for Flutter Web (Dart 3+ WasmGC, Skwasm/CanvasKit).

---

Overview

dicom_flutter_radiology_kit is a zero-jank, high-performance DICOM medical image streaming and rendering library built exclusively for Flutter Web applications. It provides direct WADO-RS / QIDO-RS DICOMweb streaming, WASM-powered Web Worker codec decoding for JPEG 2000 / HTJ2K off the main UI isolate, dynamic 16-bit scalar VOI LUT transformations, and interactive viewports with gesture controls and HUD overlays.

---

Key Features & Architecture

• Off-Thread Decoding: Never decode large JPEG 2000 / HTJ2K DICOM frames on the main UI thread. All heavy decoding is dispatched to Web Workers (web/j2k_worker.js) running WASM OpenJPEG/OpenJPH builds via package:web.
• Dynamic 16-Bit Scalar VOI LUT: Raw pixel data is preserved in original scalar formats (Int16List / Uint16List). Modality Rescale (Slope/Intercept) and VOI LUTs (Window Center/Width) are computed dynamically during rendering without truncation.
• WADO-RS Stream Processing: Efficiently parses DICOMweb REST multipart/related streams into discrete frame arrays.
• Skwasm / CanvasKit Viewport: High-performance Flutter DicomViewport widget featuring smooth pan, zoom, and window level gestures.

---

Quick Start

Add dicom_flutter_radiology_kit to your pubspec.yaml:

dependencies:
  dicom_flutter_radiology_kit: ^0.0.3

Basic Viewport Usage

import 'package:flutter/material.dart';
import 'package:dicom_flutter_radiology_kit/dicom_flutter_radiology_kit.dart';

class MedicalViewerPage extends StatefulWidget {
  const MedicalViewerPage({super.key});

  @override
  State<MedicalViewerPage> createState() => _MedicalViewerPageState();
}

class _MedicalViewerPageState extends State<MedicalViewerPage> {
  late final ViewportController _controller;

  @override
  void initState() {
    super.initState();
    _controller = ViewportController();
    _loadSampleFrame();
  }

  void _loadSampleFrame() {
    // 16-bit scalar pixel buffer (512x512)
    final rawPixels = Int16List(512 * 512);
    final frame = PixelFrame(
      rawPixels: rawPixels,
      width: 512,
      height: 512,
      rescaleSlope: 1.0,
      rescaleIntercept: -1024.0,
    );

    _controller.setFrame(frame);
    _controller.updateMetadata(
      patientName: 'DOE^JOHN',
      patientId: '123456',
      studyDescription: 'CT CHEST WITH CONTRAST',
    );
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: const Text('DICOM Flutter Radiology Kit Viewer')),
      body: DicomViewport(
        controller: _controller,
        showOverlay: true,
      ),
    );
  }
}

---

Document Walkthrough (Regulatory & Quality System)

To minimize regulatory friction for downstream medical device integrators seeking FDA 510(k) clearance or CE Mark (IEC 62304 / ISO 14971 / ISO 13485 compliance), dicom_flutter_radiology_kit provides formal documentation suites categorized by prefix:

• gsd_XXX (d for Design Controls) under doc/design/
• gsp_XXX (p for Procedures / SOPs) under doc/procedures/

Design Controls (gsd_XXX)

Document	Regulatory Standard	Description
gsd_000: Software Requirements Specification	IEC 62304 Cl. 5.2	Functional specifications, DICOM Transfer Syntaxes, 16-bit scalar preservation, performance benchmarks, and NEMA PS3.14 GSDF display rules.
gsd_010: System Design Specification	IEC 62304 Cl. 5.3 / 5.4	Software Architecture Description (SAD), subsystem decomposition (client, codecs, imaging, widgets), Web Worker thread boundaries, and VOI LUT equations.
gsd_020: Hazard Analysis & Risk Management	ISO 14971:2019 / IEC 62304 Cl. 7	Software Hazard Analysis Matrix identifying clinical hazards (detail loss, MONOCHROME1 inversion, WASM crashes) and software design risk controls.
gsd_030: Verification & Validation Plan	IEC 62304 Cl. 5.5 - 5.7	Verification test protocols across unit tests, browser Web Worker interop, and TG18 / SMPTE visual rendering accuracy validation.
gsd_040: Traceability Matrix	FDA Design Controls	Bi-directional matrix mapping Requirements (SRS) <-> System Design (SDS) <-> Hazards (ISO 14971) <-> Verification Tests (V&V).
gsd_050: Cybersecurity & SOUP BOM	FDA Cybersecurity Guidance	Software Bill of Materials (SBOM) for SOUP components (OpenJPEG WASM, Dart SDK, package:web), threat modeling, and PHI privacy rules.

Standard Operating Procedures (gsp_XXX)

Document	Regulatory Standard	Description
gsp_000: Software Development Procedure	IEC 62304 Cl. 5 / ISO 13485 Cl. 7.3	Standard Operating Procedure defining Safety Class B lifecycle phases, unit/integration verification, ISO 14971 risk controls, and release criteria.

---

Directory Structure

• lib/dicom_flutter_radiology_kit.dart: Main public barrel export.
• lib/src/client/: WADO-RS / QIDO-RS REST client (dicom_web_client.dart) and multipart stream reader (multipart_stream.dart).
• lib/src/codecs/: Decoders, Web Worker WASM bridge (wasm_worker_bridge.dart), and codec router (codec_router.dart).
• lib/src/imaging/: 16-bit PixelFrame, dynamic VoiLut pipeline, and WindowPresets.
• lib/src/widgets/: Flutter DicomViewport, ViewportController, and HUD Overlays.
• web/: j2k_worker.js, openjpegwasm.js, and openjpegwasm.wasm.
• doc/design/: Design Controls & 510(k) compliance documentation suite.
• doc/procedures/: Standard Operating Procedures (SOPs) for medical device software development lifecycle.

---

Medical & Diagnostic Disclaimer & Integrator Responsibility

---

Contact & Ownership

• Project Owner: GoSmart.Health
• Contact: compliance@gosmart.health

GitHub Resources

We welcome your contributions, sponsorships, questions, and discussions to this open-source project.

• Source Codes
• Issues
• Project Roadmaps
• Announcements and Discussions

---

License

Apache License 2.0. See LICENSE for full details.