GammaCameraUniformityCheckForRenal

Utility description: Gamma Camera Uniformity Check For Renal

Gamma Camera Uniformity Check For Renal — Detector field uniformity check for renography

ℹ️  Utility evaluates detector sensitivity uniformity:
    • Integral uniformity (≤5%)
    • Differential uniformity (≤3%)
    • Statistical reliability (≥10 million counts)
    • Energy window centering (140 keV)

⚠️  CRITICAL: Non-uniformity >5% makes accurate Split Function calculation impossible!
    Difference in sensitivity between left and right kidney may be mistakenly taken for pathology.
    Test must be performed daily before starting clinical studies.

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

Input format:
CameraID,CheckDate,IntegralUniformityPercent,DifferentialUniformityPercent,TotalCounts,EnergyWindowCenterKeV,EnergyWindowWidthPercent,CollimatorType,MaxPixelCount,MinPixelCount

Example:
  GC-SIEMENS-01,2026-07-21,2.5,1.8,10000000,140,20,LEHR,1050,950

— WHY IS THIS NEEDED?
In quantitative renography (calculation of relative kidney function, Split Function), it is critically important that every pixel of the detector has the same sensitivity.
If one side of the detector "sees" better than the other, the software will show that one kidney is working worse, although the problem is with the camera.
• Integral uniformity shows general variations across the entire field.
• Differential uniformity shows local fluctuations (adjacent pixels).
• Low statistics (<10 million counts) create noise that masks real non-uniformity.

⚠️  CRITICAL:
• Integral uniformity ≤5% — NEMA standard for working cameras. For precision studies, ≤3% is desirable.
• Differential uniformity ≤3% — ensures no sharp local artifacts.
• Energy window strictly at 140 keV (Tc-99m) — window shift changes the pattern of radiation penetration through the collimator.
• LEHR (Low Energy High Resolution) collimator — standard for kidneys, as they are small and require high resolution.

Key features:
• Calculation of integral and differential uniformity from flood-field image data.
• Statistical significance check (number of accumulated counts).
• Tc-99m energy peak centering control.
• Analysis of max/min pixel signal ratio (search for "hot" or "dead" pixels).
• Compliance with NEMA NU-1 standards.

Critical parameters:
• Integral uniformity: ≤5.0%
• Differential uniformity: ≤3.0%
• Total counts: ≥10,000,000
• Energy window center: 135–145 keV
• Max/Min pixel ratio: <1.5

💡 Usage tips:
1. Uniformity test (Flood Field) is performed with a Co-57 point source or Tc-99m filled phantom.
2. The source should be at least 1.5–2 meters away from the collimator (for intrinsic/uniformity check).
3. If uniformity exceeds limits, perform Uniformity Correction via camera software.
4. Repeat the test after correction.
5. For renography, symmetry of the left and right halves of the detector is especially important.

⚠️ Note: Unlike general bone or lung imaging, where non-uniformity can be compensated by the eye, in renography we use mathematics. A 2-3% error in detector sensitivity will lead to a 2-3% error in kidney function calculation, which may change clinical decision (e.g., referral for surgery). Therefore, uniformity control is the foundation of trust in Tc99mRenal results.