# 📐 L2 Spec — X-ray Angiography (DSA) Mismatch-Only Spec
**ID:** `L2-039-001` · **Status:** ⊙ Testnet (genesis catalog)
**Parents:** ⬆ Principle [`L1-039`](/artifact/l1/L1-039)
> **🎯 Tolerance (ε):** expression
> **⚖ Difficulty score:** 0.5 · **Delta tier:** 5
> **⛓ On-chain block:** 41553374
---
## 1. Domain Ω
**Type:** `range`
| Parameter | Unit | Range |
|---|---|---|
| H | px | 512 |
| W | px | 512 |
| Fps | — | 1 – 60 |
| Kvp | — | 60 – 120 |
| Scatter | — | 0.0 – 0.3 |
| Pixel um | µm | 50 – 300 |
| Patient motion | — | 0.0 – 0.3 |
| Contrast timing | — | 0.0 – 0.5 |
| Misregistration | — | 0.0 – 5.0 |
| Dose per frame ugy | — | 0.5 – 50 |
## 2. Tolerance (ε)
**Type:** `fn`
```
20.0 + 2.0 * log10(dose_per_frame_uGy / 0.5) - 6.0 * contrast_timing - 8.0 * misregistration / 5.0
```
## 3. Difficulty
| Property | Value |
|---|---|
| Difficulty score | 0.5 |
| Delta tier | 5 |
## 4. Fingerprint
`276597431e37147bd1ae72d0fa5ba35a795b32eef9dd223f4897bdf3d25f220f`
## 5. On-chain Registration
- **Chain hash:** `0x46358ee3d27dd2f03070fbda9ff10d36286df367e0015268133cc6460cffef8e`
- **Chain tx hash:** `0x34ea34ce925481f44ef4afbeeea97a4969d6cf1f314da0d8e2bc41879b456e45`
- **Chain block:** `41553374`
---
## File Mapping
This bundle consists of: `L2-039-001.md`, `L2-039-001.json`.
| File | Role | How to regenerate |
|------|------|-------------------|
| `L2-039-001.md` | Source of truth — edit this | Human or LLM |
| `L2-039-001.json` | Structured metadata for the registry | LLM regenerates from the sections above |
**Prompt for your LLM after editing this Markdown:**
> Read the attached Markdown. Regenerate the sibling `.json` so every field matches.
> Preserve the schema documented in the rows above.
> Output each file in its own fenced code block tagged with the filename.
> Output only the JSON object.
_This Markdown was auto-synthesized from the catalog row for `L2-039-001`._
_Edit it, regenerate the JSON, and submit at [/submit](/submit) to claim the artifact._