Author: Oleksandr Orlov, Co-Founder and CTO, Andersen
Healthcare imaging platforms process large structured data objects: DICOM files, imaging orders, radiologist findings. They work at high volumes, matching clinical needs. These platforms operate in real time and across networks spread over different locations. A radiologist reading studies across several states depends on sub-second image retrieval. A clinic coordinator scheduling an imaging order depends on the immediate system response.
These demands create architectural tension. High availability demands distributed redundancy; compliance calls for controlled data flows. Performance at scale requires horizontal architecture; HIPAA demands that horizontal architecture not introduce uncontrolled data surfaces (NIST, 2024). Delivery speed needs familiar and maintainable technology stacks. Clinical reliability requires validating these stacks against real-world healthcare loads before they go live.
This article describes the Constrained Scaling Model (CSM), a decision framework I developed to guide architectural planning for healthcare platforms operating under simultaneous scalability, compliance, and clinical reliability constraints. Existing software architecture practice tends to approach these as sequential concerns: design the system against performance and cost criteria, then verify it against regulatory requirements. The difficulty software architects face in tracing and transforming regulatory requirements at the architecture level stems largely from the absence of established design mechanisms for doing so. The CSM's contribution is to narrow that gap by treating compliance and clinical reliability as parallel inputs to every significant architectural decision, evaluated at the same point as performance and cost.
The Clinical Context and Its Engineering Implications
Teleradiology allows radiologists to read imaging studies (MRI, CT, ultrasound, X-ray) for facilities where they are not physically present. In the United States, a significant portion of hospitals and outpatient imaging centers can’t sustain continuous on-site radiology coverage. Teleradiology fills that gap. A national teleradiology network routes imaging orders from hundreds of facilities to radiologist pools working across several time zones. Turnaround time for urgent studies is measured in minutes.
The platform enabling such a workflow is a clinical support system. It changes what “acceptable downtime” or “sufficient test coverage” means in clinical reality. Engineers who haven’t worked in such environments often underestimate this fact. I address it as the first development constraint, prior to any technical decision-making.
Three engineering implications follow directly:
- Availability is a clinical requirement
The system must tolerate component failure without service interruption because a radiologist’s access to a study can't wait for a system to recover.
- Data integrity is a clinical accuracy standard
A failed migration that introduces data inconsistencies is a potential contribution to a diagnostic error.
- Observability is a safety mechanism
A system that can’t detect its internal failures faster than clinical staff can is a system that can’t protect patients from the consequences of those failures.
The ProScan Engagement: System State at Intake
At the start of the project, the platform was built on a legacy system architecture. Such a configuration was appropriate for the platform’s original scale. But as the network grew, it became a constraint. At the volume Proscan’s network required, the company observed four failure modes:
- Query performance degraded non-linearly with data volume growth;
- Data integrity depended on application-layer enforcement, which was applied inconsistently across the system;
- The database configuration poorly supported horizontal scaling of read-heavy workloads;
- The absence of a normalized data model made cross-facility reporting computationally expensive.
The user base at intake was in the range of several thousand active users. The network’s growth course planned for the platform to support 10,000 active users in the near term, with architectural capacity for more than 20,000. The existing architecture had no strategy to withstand that scale.
The new platform was designed to meet HIPAA Security Rule controls — encryption of ePHI at rest and in transit, access control with audit logging, breach detection, and response capability — which the legacy system didn’t fully address (HHS OCR, 2023). Technical safeguards existed in some layers and were absent in others.
The Constrained Scaling Model
I created the Constrained Scaling Model, which prescribes a decision sequence: before making any significant architectural decision, a team should evaluate three constraints in parallel.
| Constraint | What to Evaluate | Common Failure |
|---|---|---|
| #1. Clinical Reliability | Does this decision maintain or improve the system’s ability to support uninterrupted clinical workflows? | A decision that improves performance but introduces a new failure mode fails this constraint regardless of performance characteristics. For example, a dependency on a third-party service with weaker availability guarantees or a caching layer that can serve stale data to a radiologist. |
| #2. Compliance Conformance | Does this decision maintain full conformance with applicable regulatory requirements, including those that will apply to the evolved system? | A microservice extraction that improves scalability but creates a new data flow demanding encryption and audit logging is incomplete until those controls are in place. Teams should evaluate compliance conformance against the future state, not the current one. |
| #3. Operational Maintainability | Does this decision produce a system that the client’s engineering team can operate, maintain, and extend independently? | A technically sound solution that needs specialized knowledge to maintain is a vendor dependency in engineering form (ISO/IEC 27001:2022). |
These three constraints are assessed before performance optimization, cost efficiency, or delivery speed. In clinical systems, a performance gain that compromises clinical reliability or compliance conformance is a defect with a delayed presentation.
This sequencing is the model’s central methodological departure from standard practice. Most healthcare modernization efforts consider compliance a late-stage checkbox and absorb the cost of that choice well after the architecture is fixed. The CSM relocated the point at which compliance and clinical reliability are addressed — from validation after the fact to constraint at the moment of decision.
Architectural Decisions and Their Rationale
#1. Database Architecture: Document to Relational
The migration from a legacy system architecture to a relational one was the highest-risk element of the partnership with ProScan. Normalized data models support radiology query patterns more efficiently than document stores at high volume. Referential integrity imposed at the database layer prevents data inconsistency that application-layer enforcement can’t prevent at scale. Flexible document structures can’t match the accuracy of an audit of a relational schema with defined access controls.
The migration sequencing demanded a more conservative approach than standard practice. A team can’t migrate medical records with techniques that tolerate partial data loss or temporary inconsistency. Migration from the legacy system was conducted through file-based transfer, beginning from the first days of the development phase. The source data's full scope and complexity were not fully known at project start — a condition I treated as a risk to be mapped and monitored throughout, rather than resolved before work began. The team tested rollback procedures before the cutover window opened.
#2. Service Architecture: Microservices and Event-Driven Communication
Service decomposition was chosen against the CSM's clinical reliability constraint. In a monolithic architecture at this scale, a failure in one module can affect unrelated clinical workflows. Decomposition isolates failure domains.
The core imaging workflow uses event-driven communication rather than synchronous patterns. Synchronous calls between services create availability chains — if one service depends on another synchronously, its availability is bounded by the dependency. In a platform with dozens of services, those chains compound. Event-driven communication decouples services temporally, allowing workflows to continue during partial system degradation.
Events carrying protected health information require encryption in transit, access controls, and audit logging. These controls were specified at the architecture level, before the development of any services.
#3. Technology Stack and Observability
The CSM's operational maintainability constraint guided the choice of the technology stack. It included Java and Spring Boot for backend services, React and TypeScript for the frontend, Amazon Aurora PostgreSQL for structured data, and AWS cloud infrastructure following AWS healthcare architecture guidance. I evaluated each option based on a single question: is it possible for ProScan's engineering team to maintain this system without Andersen's involvement? When maintainability wasn't clear, the team opted for the standard choice, even when innovative options were available.
The monitoring layer includes more than 40 discrete services. Alerting thresholds are calibrated to clinical workflow timing — not to generic infrastructure metrics — because the two do not coincide. An alert set for response times over two seconds doesn’t matter if a radiologist needs images in under one second. The practical standard is simpler: the system should detect and flag degradation before any clinical user experiences it as an interruption. If clinical staff identify a problem before the monitoring layer does, the monitoring layer has not done its job.
Quality Assurance Under Compliance Pressure
Quality assurance in a HIPAA-regulated clinical system operates under constraints that standard enterprise approaches do not address. Three practices I regard as non-negotiable in this environment:
#1. Compliance Review at the Specification Stage
A compliance engineer must evaluate compliance requirements before implementation:
- Findings at the specification stage produce a specification change;
- Findings at the code review stage cause code changes;
- Findings at the audit stage call for architectural changes.
The cost differential is not linear. In a clinical system, late-stage findings affect the reliability of a platform people depend on for diagnostic decisions.
#2. Testing Against the Full Scope of Clinical Workflows
A test suite that covers typical usage patterns but not clinical edge cases is insufficient. Healthcare platforms tend to fail under the conditions that matter most clinically: high-concurrency access during peak imaging hours, concurrent multi-facility load, large binary object retrieval under degraded network conditions. Such scenarios demand thorough testing. Manual approval gates at every stage promotion and production deployment keep human judgment in the loop. This helps verify changes before they impact systems with clinical dependencies.
#3. Separation of Deployment from Release
A team must validate changes made to the production infrastructure before any clinical workflow relies on them. It’s usually hard to reproduce the behavior of a system under real clinical load and real data conditions in staging. Separating deployment and activation allows engineering teams to confirm production behavior before exposure. This way, they can reverse a deployment without clinical users experiencing its effects.
Conclusions
The novelty of the Constrained Scaling Model lies in the systematic prioritization of clinical reliability and regulatory compliance as primary architectural inputs, evaluated in parallel with performance and cost at the point of every high-impact design decision. In standard enterprise practice, a team selects an architecture based on performance and cost. Then, they determine what controls to add to meet compliance. In clinical systems, this sequence produces architecture where compliance is added to a structure that was not intended to support it. It’s auditable on paper but fragile in operation.
The CSM reverses that sequence. Applied to the ProScan engagement, the model produced outcomes across several measurable dimensions:
- Architectural rework was reduced because clinical reliability and compliance constraints were evaluated before implementation;
- No critical compliance findings emerged at the audit stage — the point at which such findings are most expensive to remediate;
- The platform's scalability grew without a corresponding increase in operational risk, because the architecture was designed for the evolved system's regulatory and performance requirements from the outset;
- Query processing improved once the relational architecture replaced a configuration that scaled poorly under read-heavy clinical workloads;
- Operational overhead in ongoing maintenance decreased, since the technology stack and monitoring architecture were selected against long-term maintainability;
- A team evaluates compliance and clinical reliability constraints before making any technical decision;
- Despite the resulting architectures taking longer to create, they are also substantially cheaper to operate, audit, and extend because the compliance controls are load-bearing, not decorative.
None of these outcomes is attributable to a single technical decision. They are the product of treating compliance and clinical reliability as design inputs — the principle that distinguishes the CSM from the sequence most healthcare technology organizations still follow. The directional logic is supported by broader industry data: organizations that integrate compliance measures from the start of development report revision cost reductions of up to 30%, and early automated compliance testing can improve non-compliance detection rates by as much as 60%. The framework absorbed the costs of late discovery before the project began.
The technical decisions described in this paper — relational database architecture, microservice decomposition, event-driven communication, conservative technology stack selection, and observability as a safety property — show how the CSM applies to specific engineering choices. No single decision is novel in isolation. Their consistent application within a single decision framework, from the first specification through production deployment, is what produces clinical-grade software at enterprise scale.
For engineering leaders in healthcare, the practical implication is the same as the one I have drawn from every regulated-market engagement: the framework must precede the project. Organizations that apply the CSM or equivalent constraints from the start of architectural planning will find that compliance, performance, and delivery speed reinforce each other. Organizations that treat compliance as a final checkpoint will find that it undermines all three.
References
- Gardazi, S. U., & Shahid, A. A. (2017). Compliance-Driven Architecture for Healthcare Industry. International Journal of Advanced Computer Science and Applications. https://thesai.org/Publications/ViewPaper?Volume=8&Issue=5&Code=IJACSA&SerialNo=71
- HHS Office for Civil Rights. (2023). HIPAA Enforcement Highlights. U.S. Department of Health and Human Services. https://www.hhs.gov/hipaa/for-professionals/compliance-enforcement/data/enforcement-highlights/index.html
- ISO/IEC 27001:2022. Information security, cybersecurity and privacy protection — Information security management systems — Requirements. International Organization for Standardization. https://www.iso.org/standard/27001
- MoldStud Research Team. (2025). The Impact of Regulatory Changes on the Healthcare Software Development Lifecycle. https://moldstud.com/articles/p-the-impact-of-regulatory-changes-on-the-healthcare-software-development-lifecycle-key-challenges-and-strategies
- NIST. (2024). Special Publication 800-66r2: Implementing the HIPAA Security Rule: A Cybersecurity Resource Guide. National Institute of Standards and Technology. https://csrc.nist.gov/pubs/sp/800/66/r2/final
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