Tc99mColloidChecker

Tc-99m Colloid Checker — Colloid phase control in technetium-99m radiopharmaceuticals

ℹ️  Utility performs DEEP colloid phase analysis with:
    • Current colloid percentage check (≤5% for most agents)
    • Stability prediction until end of shelf life (6-12 hours)
    • Trend analysis with previous measurements
    • pH and temperature impact assessment on colloid formation
    • Image quality impact evaluation for different study types

⚠️  CRITICAL: Colloids >5% accumulate in liver/spleen instead of target organ,
    reducing image quality and increasing radiation burden to patient!

Usage:
  Tc99mColloidChecker.exe                            → demo mode (console output)
  Tc99mColloidChecker.exe input.csv output.json      → analyze your data

Input format:
BatchNumber,ProductType,ColloidPhasePercent_Current,pH,MeasurementDateTime,RadiolabelingDateTime,StorageTemperatureC,PreviousColloidPhasePercent,PreviousMeasurementDateTime

Examples (optional parameters can be empty):
  TC99M-COL-2026-001,MDP,1.5,6.8,2026-03-18T10:00:00,2026-03-18T08:00:00,4.0,1.2,2026-03-18T09:00:00
  TC99M-COL-2026-002,Pyrophosphate,4.2,8.5,2026-03-18T10:00:00,2026-03-18T07:00:00,25.0,3.5,2026-03-18T08:30:00
  TC99M-COL-2026-003,DTPA,7.5,9.2,2026-03-18T10:00:00,2026-03-18T06:00:00,30.0,,

— WHY IS THIS NEEDED?
Colloid phase control is CRITICALLY IMPORTANT quality parameter for Tc-99m agents:
• Colloidal particles (10-500 nm) do not reach target tissues, but accumulate in RES (liver, spleen)
• Reduce image contrast and mask pathological lesions
• Increase radiation burden to patient without diagnostic benefit
• Form due to: incorrect pH, high temperature, prolonged storage, poor quality kits

⚠️  CRITICAL:
• Pharmacopoeial limit: ≤5% colloid phase (most agents, Ph. Eur. 2.14.1)
• Warning threshold: >3% — requires enhanced monitoring
• Risk mechanism: colloids → macrophage uptake in RES → liver/spleen accumulation →
  reduced target organ uptake → non-diagnostic study
• Accelerating factors: pH >7.5 or <4.5, temperature >25°C, storage >6 hours, oxidation

Key features:
• Colloid prediction until end of shelf life (6-12 hours) accounting for storage conditions
• Trend analysis with previous measurements (colloid formation rate %/hour)
• pH and temperature impact correction
• Image quality impact assessment for different study types:
  — Bone scintigraphy (MDP): colloids mask metastases in ribs/spine
  — Cardiac imaging (pyrophosphate): colloids reduce infarct contrast
  — Renal scintigraphy (DTPA/MAG3): colloids increase abdominal background
• Risk categorization: LOW / MEDIUM / HIGH / CRITICAL
• Specific recommendations for batch utilization

Prediction model:
• Base formation rate: 0.15%/hour at ideal conditions (pH 4.5-7.5, 2-8°C)
• pH correction: ×1.8 at pH 7.5-8.5, ×2.5 at pH >8.5
• Temperature correction: ×1.5 at >8°C, ×2.0 at >25°C, ×3.0 at >30°C
• Prediction = Current value + (Rate × Hours until expiry)

Image quality impact:
• Colloids >7.5%: NON-DIAGNOSTIC study — repeat administration required
• Colloids 5-7.5%: POOR quality — limited diagnostic value
• Colloids 3-5%: ACCEPTABLE — may require delayed imaging
• Colloids <3%: EXCELLENT quality — full diagnostic utility

💡 Practical tips:
1. Always check pH after labeling (ideal 4.5-7.5 for most agents)
2. Store labeled agents at 2-8°C — reduces colloid formation rate by 70%
3. For agents with colloids >3% increase monitoring frequency to hourly
4. At pH >8.0 verify correct buffer volume during labeling
5. Document all measurements for audits — this is a critical quality parameter

⚠️ Limitations:
• Prediction based on simplified model — actual conditions may vary
• Does not account for starting kit quality
• Does not replace official pharmacopoeial analytical method (paper chromatography)
• For agents with colloids >5% — immediate removal regardless of prediction

Data sources:
• Ph. Eur. Monograph 0148 — Technetium-99m radiopharmaceuticals
• USP General Chapter <823> — Radiopharmaceuticals for Positron Emission Tomography
• Journal of Nuclear Medicine Technology — Colloid formation in 99mTc-labeled agents (2019)
• EANM Guidelines for Radiopharmaceutical Preparation