Linux in medical devices: why?
Today, more and more medical device manufacturers are looking to enhance their products with advanced features like connectivity and user-friendly touch screen interfaces. These enhancements require integrating new software stacks for networking, connectivity, data management, and more.
In the medical field, device manufacturers typically have two options:
- they can either rely on certified software layers
- or redevelop everything from scratch.
While Linux isn’t certified software, that doesn’t mean it can’t be used. In fact, Linux is a great option to develop these advanced features.
However, these additions bring complexity and risk, making it challenging to develop and maintain these systems while complying with industry regulations like IEC62304.
Let’s explore how we can use Linux in medical devices while remaining compliant.
Linux, a great solution to build advanced medical device features
Linux is a mature operating system that has been developed over many years. It offers the ability to maintain a device in production, providing a certain level of reliability and stability. This makes Linux an excellent choice for building advanced features in medical devices.
Let’s delve into the strengths of this solution:
Regular system updates & Long-Term Support (LTS)
One of the reasons Linux is considered a mature operating system is its regular updates. As an open-source product, it benefits from an extremely active community that provides updates on a frequent basis. These updates come in cycles of three months, six months, one year, and two years, with both regular and long-term support (LTS) versions. The LTS versions offer maintenance, and vulnerability fixes for up to two years at the kernel level, which, while short in the lifecycle of a medical product, ensures that updates are constant consideration.
Multi-hardware support
Linux supports a wide range of hardware. It allows for easy pre-integration on diverse types of processors and hardware components, making it a versatile choice for medical devices.
Advanced security framework
Linux offers multiple security features and frameworks, including libraries for certificate management and secure connectivity with other servers. This extensive range of security options ensures that medical devices can maintain high standards of data protection.
Multi-GUI development frameworks support
When it comes to graphical user interfaces (GUIs), Linux offers several development solutions. Frameworks like Qt are widely used and maintained, available both as open-source and with commercial licensing options for guaranteed maintenance.
Additionally, developers can use frameworks like Slint and Flutter for graphical development, and web-based interfaces can be integrated with web browsers.
This flexibility in GUI development allows for a wide range of user experiences and interface designs.
Multiple languages supported
Linux supports a variety of programming languages, from C++ and Java to more modern and robust languages like Rust. This extensive selection of languages and frameworks provides developers with the flexibility to choose the best tools for their needs and constraints.
Feature-rich
Linux is not just about graphical interfaces; it also offers rich implementations of connectivity protocols and multimedia content. For example, displaying a video for instructional purposes during product installation can be easily achieved. While the quality of the OS port on a specific processor and the associated drivers plays a significant role, the OS itself is feature rich.
In brief, Linux offers flexibility and reliability, making it an excellent framework for developing advanced medical devices.
Main medical compliance constraints
1. IEC 62304
IEC 62304 is an international standard by the International Electrotechnical Commission (IEC). It depicts lifecycle requirements for developing medical software and software within medical devices.
It necessitates the following actions from medical device manufacturers (non exhaustive):
- Risk analysis
- Requirement coverage
- Architecture & implementation verification
- SOUPs management
- And more.
2. Software of Unknown Provenance (SOUP)
SOUP (Software of Unknown Provenance, or Pedigree) refers to software not developed in-house and over which the company has no control. This software has been developed for general purposes without consideration for use in a medical context.
That’s why Linux is considered SOUP, requiring careful management, starting with a risk analysis and a reflection on the system architecture.
Segmented architecture to achieve compliance
To bypass the limitations of Linux for medical device compliance, segmented architecture to separate responsibilities among software layers offer a privileged solution. Here is an example of segmented architecture you could implement in your system:
Relying on certified MCU managing life-critical features
Properly separating responsibilities among software layers and system components is key to managing risk and integrating SOUP effectively.
For example, in a connected syringe, real-time decisions about dosage should not be managed by Linux. Instead, certified layers or in-house development on MCUs should oversee these critical functions. An additional MCU can serve as a failsafe, ensuring decisions are accurate and actions are controlled .
Using Linux for advanced and non-critical features
An abstraction layer can allow Linux to send information while critical decisions are verified by the MCU. This approach ensures responsibilities are clearly defined, enabling the development of modern features like connectivity and user-friendly interfaces without compromising safety.
Best practices for developing medical devices advanced features with Linux
While Linux is a powerful and versatile OS, developing Linux in medical products with it requires careful consideration and adherence to best practices. Here are some key points to keep in mind:
Choosing the right Linux distribution
The first step in developing a medical product with Linux is selecting the appropriate distribution. In the Linux world, a distribution is a collection of software packages that form your Linux system.
Well-known distributions like Debian and Ubuntu are often used in server contexts, but they also have specialized versions for embedded systems.
At The Embedded Kit, we believe in tailored solutions, and for embedded Linux, Yocto is a highly recommended choice. Yocto allows you to customize your distribution to meet the specific needs of your product development.
Consult our comparison of Linux distributions for embedded systems.
Quality and cybersecurity
In the medical field, two critical aspects are quality and cybersecurity. Simplifying the target system can enhance both. For example, if you do not need IPv6 or Bluetooth, do not include those stacks.
This is easier with Yocto, which allows you to control the size and components of your system, making it easier to manage vulnerabilities. You can generate a Software Bill of Materials (SBOM) to track the versions of all software included in your system, ensuring precise control over its content.
Cybersecurity is a significant concern, especially in the medical field. European directives and industry standards push manufacturers towards robust cybersecurity measures. Best practices include:
- Secure boot: Ensures that only authenticated software runs on your system, creating a chain of trust from hardware to application.
- Secure storage: Protects confidential medical and technical information.
- System updates: Regular updates are essential to fix vulnerabilities and maintain security.
- Minimal image: Fewer components mean fewer potential vulnerabilities.
- Least privilege: Limit system and application privileges to reduce the risk of exploitation.
- Containerization: Adds layers of protection and encapsulation to your system.
Yocto excels in providing these cybersecurity features, making it a strong choice for Linux medical device development.
Quality assurance practices are crucial and widely applicable, not just in the medical field. Implementing continuous integration ensures ongoing compilation and quality checks. Automated testing and static code analysis are also essential practices that help maintain high-quality standards in embedded systems, including those running Linux.
Don't forget about maintenance
Launching a product is just the beginning. Ongoing maintenance is vital to ensure long-term reliability and security. This includes identifying vulnerabilities, conducting risk and impact analyses, and implementing updates, as necessary, for your software layers including Linux in medical devices.
Focus on risk & impact analysis for medical devices
When a vulnerability is identified, it is crucial to assess its risk and impact. In the medical context, frequent updates may not be feasible, so it is essential to balance the need for fixes with the potential impact on the system. Automated testing routines can help revalidate changes quickly, ensuring that updates do not introduce new issues.
