Terbium161QualityChecker

1. Scope

This document defines requirements and functional behaviour for Terbium161QualityChecker used to control: Terbium-161. The utility is intended for QC use and applies deterministic rules, not machine learning.

2. Execution modes

• Terbium161QualityChecker.exe — demo mode or help output.
• Terbium161QualityChecker.exe input.csv output.json — process user data and write result.

3. Key source-derived controls

• ℹ️ Utility checks critical parameters of terbium-161:
• • Radionuclidic purity (≥99.9%)
• • Terbium-160 impurity (≤0.1%) — CRITICAL!
• • Radiochemical purity (≥95%)
• • Residual gadolinium (≤10 ppm) — affects labeling efficiency
• • pH (1.0–2.5), endotoxins, sterility
• ⚠️ CRITICAL: Terbium-160 impurity >0.1% → chronic radiation burden (T½=72.3 days)!
• BatchNumber,ActivityMBq,RadionuclidicPurityPercent,Tb160ImpurityPercent,RadiochemicalPurityPercent,GadoliniumContentPPM,pH,EndotoxinsEU,SterilityTest,ProductType
• Example (sterility: 0=sterile, 1=contaminated):
• ⚠️ CRITICAL:
• • Radionuclidic purity ≥99.9% — ensures absence of other radioactive isotopes
• • Terbium-160 impurity ≤0.1% — CRITICAL! Tb-160 (T½=72.3 days) creates LONG-TERM RADIATION BURDEN to patient without therapeutic benefit. Requires strict control during production via Gd-160 irradiation.
• • Residual gadolinium ≤10 ppm — CRITICAL! Gadolinium (target material for Tb-161 production) is chemically identical to terbium and competes for binding sites in chelators (DOTA). High Gd content reduces specific activity of the final product and delivery efficiency to the tumor.
• • Radiochemical purity ≥95% — free Tb-161 accumulates in bones and liver, causing toxicity.
• • pH 1.0–2.5 — critical for stability of terbium chloride solution (prevents hydrolysis and colloid formation).
• • Endotoxins ≤175 EU/vial — critical for IV administration!
• • Sterility — MANDATORY for all parenteral forms!
• • Check of critical terbium-160 impurity (≤0.1%) — main radionuclidic purity parameter
• • Control of residual gadolinium (≤10 ppm) — unique parameter for Tb-161 affecting chemistry
• • Specific pH limits for lanthanide ion stability

4. URS — user requirements

5. input.csv contract

BatchNumber,ActivityMBq,RadionuclidicPurityPercent,Tb160ImpurityPercent,RadiochemicalPurityPercent,GadoliniumContentPPM,pH,EndotoxinsEU,SterilityTest,ProductType
TB161-TEST-001,5000.0,99.92,0.05,97.5,4.0,1.5,50.0,0,DOTATATE

6. FS — functional specification

7. output.json example

{
  "utilityId": "terbium161-quality-checker",
  "api": "Terbium-161",
  "overallStatus": "PASS|WARNING|FAIL",
  "sourceFile": "input.csv",
  "checks": [
    {
      "parameter": "BatchNumber",
      "value": "TB161-TEST-001",
      "status": "PASS|WARNING|FAIL",
      "message": "Rule-based check result"
    },
    {
      "parameter": "ActivityMBq",
      "value": "5000.0",
      "status": "PASS|WARNING|FAIL",
      "message": "Rule-based check result"
    },
    {
      "parameter": "RadionuclidicPurityPercent",
      "value": "99.92",
      "status": "PASS|WARNING|FAIL",
      "message": "Rule-based check result"
    },
    {
      "parameter": "Tb160ImpurityPercent",
      "value": "0.05",
      "status": "PASS|WARNING|FAIL",
      "message": "Rule-based check result"
    },
    {
      "parameter": "RadiochemicalPurityPercent",
      "value": "97.5",
      "status": "PASS|WARNING|FAIL",
      "message": "Rule-based check result"
    },
    {
      "parameter": "GadoliniumContentPPM",
      "value": "4.0",
      "status": "PASS|WARNING|FAIL",
      "message": "Rule-based check result"
    },
    {
      "parameter": "pH",
      "value": "1.5",
      "status": "PASS|WARNING|FAIL",
      "message": "Rule-based check result"
    },
    {
      "parameter": "EndotoxinsEU",
      "value": "50.0",
      "status": "PASS|WARNING|FAIL",
      "message": "Rule-based check result"
    }
  ],
  "criticalFindings": []
}

8. OQ/PQ test scenarios

9. QA/QC and change control

• Do not rename columns without validator update.
• Store input.csv, output.json, executable version and checksum.
• Before production use perform IQ/OQ/PQ or equivalent CSV/CSA verification.
• Critical radiopharmaceutical limits must be checked against the approved specification and local SOPs.