Build A DICOM Image Receiver: A Storage SCP Guide

Dec 1, 2025 by Alex Johnson 50 views

Welcome! This guide dives into the process of creating a Storage SCP (Service Class Provider) for receiving and storing DICOM (Digital Imaging and Communications in Medicine) files. This is a fundamental component in any Picture Archiving and Communication System (PACS) and is essential for managing medical imaging data. We'll explore the key aspects, features, and considerations involved in building a robust and reliable DICOM image receiver, all while keeping things clear and easy to understand.

Understanding the Basics: What is a Storage SCP?

So, what exactly is a Storage SCP? Think of it as a digital receptionist for your medical images. In the DICOM world, a Storage SCP is a server that accepts incoming DICOM files from other devices, known as Service Class Users (SCUs). These SCUs are typically modalities like MRI machines, CT scanners, or ultrasound devices, or even other PACS systems. The SCP's primary job is to receive these images, verify their integrity, and store them securely, often with associated metadata. Building a Storage SCP involves understanding and implementing the DICOM standard, including aspects like network communication, data encoding, and data storage. This is the cornerstone of any DICOM-compliant system. The goal is to create a system that can reliably and efficiently ingest DICOM images.

Building your own Storage SCP offers several advantages. You gain complete control over how images are stored, indexed, and managed. This allows for customization to meet your specific needs and integration with other systems. Furthermore, it gives you the flexibility to adapt to evolving standards and technologies in the medical imaging field. With this guide, we'll equip you with the knowledge and tools needed to create your own solution, offering flexibility and customization.

Key Purposes and Functions of a DICOM Image Receiver

The main goals of a DICOM Image Receiver are straightforward, yet crucial for effective medical image management. First and foremost, it needs to reliably receive DICOM images from various modalities or other SCUs. This involves establishing a secure connection, handling data transfer protocols, and ensuring that the images arrive intact. The Storage SCP acts as a central hub, receiving images from various sources and ensuring that they are stored safely. A key function is organizing these images in a structured directory, making retrieval and management easier. This structure can be hierarchical, based on patient information, study details, or other criteria, allowing for organized archiving. Simultaneously, a database is crucial for indexing these images. This index will store essential metadata, such as patient names, study dates, image types, and other relevant information. This indexing enables efficient searching, retrieval, and analysis of medical images.

Furthermore, an important function is to ensure that duplicates are handled correctly. The system must have the ability to detect whether an image already exists, preventing redundancy and ensuring data integrity. This involves comparing metadata and image characteristics. In the context of a Storage SCP, the ability to store DICOM images reliably and efficiently is paramount. Implementing robust storage solutions is essential for data security and efficient management.

Practical Usage and Command-Line Interface

Let's move to how to actually use a Storage SCP. The example store_scp command-line tool provides a straightforward way to interact with our DICOM image receiver. Let's break down some practical examples to show you how it works.

# Basic usage to start the server
store_scp 11112 MY_PACS --storage-dir ./received

This command initiates the Storage SCP on port 11112 and sets its AE Title to MY_PACS. Incoming DICOM images will then be stored in the ./received directory. This is the simplest form, perfect for getting started and testing basic functionality. The second command integrates database indexing, significantly enhancing the functionality.

# With database indexing
store_scp 11112 MY_PACS --storage-dir ./received --index-db ./pacs.db

This version adds database indexing using an SQLite database file at ./pacs.db. This enhances the receiver by providing quick search and retrieval based on image metadata. The final example allows for filtering based on SOP Class, providing more control over what images the server accepts.

# With specific SOP class filtering
store_scp 11112 MY_PACS --storage-dir ./received --accept "CT,MR,US"

Here, the server only accepts DICOM images from CT, MR, and US modalities, which provides more control over the types of images stored. Proper command-line options are important for efficient use. Understanding these options makes it easier to customize the Storage SCP to meet your requirements.

Diving into Features: Storage, Database, Access Control, and Monitoring

A solid Storage SCP should offer a rich set of features to ensure it is robust, secure, and user-friendly.

Storage Options

Flexibility in how the images are stored is crucial. Configurable storage directories allow the user to define the storage location that best suits their needs. A hierarchical file structure, such as Patient/Study/Series/Instance, helps in the easy organization and retrieval of images. This is very important. Furthermore, a configurable naming scheme provides flexibility in how images are named. The ability to customize these options allows for integration with existing systems. Using a well-organized directory structure is necessary for effective image management.

Database Integration

Database indexing is key to efficient image management. The ability to use an SQLite database enables easy indexing of metadata, enabling quick search and retrieval. Storing patient, study, series, and instance metadata is very important for effective management. This includes patient names, study dates, image descriptions, and much more. Duplicate detection is also extremely important, preventing redundant storage and ensuring data integrity. Duplicate detection is very important, because it prevents issues with data integrity.

Access Control

Security is paramount, and several access control mechanisms should be implemented. AE Title whitelisting restricts connections to only trusted sources, enhancing security. SOP Class acceptance filtering, as we've seen, allows the system to only accept certain image types, ensuring that only desired image types are stored. Furthermore, you can configure the maximum PDU size to control the size of incoming data packets. This prevents overloading the system and improves overall stability. Using such control features ensures that the Storage SCP is secure.

Monitoring

Monitoring features are crucial for managing the system's health and performance. Connection logging tracks all incoming connections and associated activities. Storage statistics provide insights into disk space usage and image storage trends. Real-time status display allows administrators to see active connections and storage activities, which makes troubleshooting easy. Thorough monitoring ensures that problems can be quickly detected and resolved.

Configuration Files: Customizing Your Setup

Configuration files are essential for configuring your Storage SCP without changing the code. Let's look at a YAML configuration file example. This file allows users to customize settings such as server port and AE title. We can also specify the storage directory and the desired naming scheme, whether it's hierarchical, flat, or date-based. The database settings can also be customized, including the path to the database file and whether to enable Write-Ahead Logging (WAL) mode for improved performance. The configuration file also defines which SOP Classes are accepted, increasing the control of image types to be stored.

# store_scp.yaml
server:
  port: 11112
  ae_title: MY_PACS
  max_associations: 10

storage:
  directory: ./received
  naming: hierarchical  # or flat, date-based
  
database:
  path: ./pacs.db
  wal_mode: true

accepted_sop_classes:
  - CT Image Storage
  - MR Image Storage
  - US Image Storage

Using configuration files provides a flexible and efficient means of managing the settings, avoiding code changes, and improving the maintainability of the Storage SCP.

Dependencies and Integration

Building a DICOM Image Receiver involves several dependencies and integrating with different parts of a PACS system. The pacs_network module handles the networking aspects, including the dicom_server and association management. The pacs_services module contains the core logic for the storage_scp. The pacs_storage module manages file storage and database indexing. Finally, the pacs_integration module acts as a connector, joining all the modules.

These modules provide a modular approach, improving code reuse, and simplifying maintenance. Effective dependency management is vital to ensure stability and reliable operation. This modular structure makes the entire system more manageable and scalable. Proper dependency management is essential for a stable and efficient system.

Ensuring Quality: Acceptance Criteria

To ensure your DICOM Image Receiver meets high-quality standards, the following acceptance criteria should be met. The system should receive and store files correctly, handling different image types and formats seamlessly. Database indexing must work accurately, allowing for efficient searching and retrieval of images. The system should handle concurrent connections, ensuring that multiple modalities can send images simultaneously without issues. Proper duplicate handling is essential to prevent data redundancy and maintain data integrity. Finally, the system must be compatible with standard DICOM tools, like dcmtk storescu, to ensure interoperability. The goal is to build a reliable and interoperable system.

Building Blocks: Files to Create

The project involves creating several key files to bring the Storage SCP to life. main.cpp is the entry point of the application, handling initialization and overall program flow. config.hpp will hold the configuration settings and data structures used throughout the application. CMakeLists.txt will define the build process, compiling the source code and linking necessary libraries. Implementing these files will create a functioning Storage SCP.

Conclusion: Your Path to a Robust DICOM Image Receiver

Building a DICOM Image Receiver can be a complex but rewarding project. From understanding the basics of a Storage SCP to implementing features like database indexing, access control, and monitoring, each step contributes to the development of a powerful system. By following the guidelines, you'll be well on your way to creating a reliable and efficient DICOM image receiver. Embrace the challenges, experiment with the features, and continually refine your solution to meet the ever-evolving needs of medical imaging. You've taken the first steps towards a robust PACS solution. Remember, thorough testing and continuous improvement are key to building a successful DICOM image receiver. Good luck!

For further reading and in-depth information on DICOM and PACS, please see the DICOM Standards Committee website: https://www.dicomstandard.org/. This is a great resource for staying up-to-date with industry standards and best practices.