GammaIndexAnalyzer

Gamma Index Analyzer

activity brachytherapy dosimetry source calibration TG-43

Gamma Index Analyzer — Dose Agreement Analysis (AAPM TG-218)

ℹ️ The utility calculates Gamma Analysis Pass Rate for RT plan verification (VMAT, IMRT, SRS).
ℹ️ Evaluates compliance with criteria (e.g., 3%/3mm), absolute number of failed points, and low dose threshold.
ℹ️ Processing: only the FIRST record in input.csv file.
⚠️ Critical for QA! High Pass Rate does not always guarantee absence of local errors. Utility warns about borderline values.

Usage:
GammaIndexAnalyzer.exe → demo mode
GammaIndexAnalyzer.exe input.csv output.json → analyze data (first record only)

Input format:
PatientID,PlanName,Criteria,TotalPoints,PassingPoints,ThresholdDosePercent,RequiredPassRate,MaxAllowedFailPoints

Example (criteria 3%/3mm, threshold 10%, required 95%):
PT-2026-PROSTATE-VMAT,Plan_Arc1_Rev2,3%/3mm,25400,24150,10.0,95.0,2000

— WHY IS THIS NEEDED?
During dose measurement with detectors (arrays, films), measured and calculated distributions are compared.
• Gamma index combines dose (%) and distance-to-agreement (mm) criteria.
• Pass Rate < 95% (for 3%/3mm) usually means unacceptable plan or measurement quality.
• Absolute failed points count is crucial for small fields (SRS) where 1% might be just few points in critical area.
• Automation eliminates manual counting errors from detector reports.
⚠️ CRITICAL:
• Low Dose Threshold: points with dose <10% often add noise and should be excluded.
• Criteria depend on treatment type: 3%/3mm (standard), 2%/2mm (SRS/SBRT), 5%/3mm (palliative).
• Local clusters of failures are more dangerous than scattered points, even if overall Pass Rate is high.
Critical parameters:
• Pass Rate: ≥95% (standard), ≥90–95% (SRS depending on protocol)
• Max failed points: absolute limit to prevent missing local hot spots
• Dose threshold: typically 10% of max dose
⚠️ Note: Utility assigns WARNING status if Pass Rate is within 1% of threshold, requiring physicist visual check. Result includes status (PASS/WARNING/FAIL) and bilingual recommendation (RU/EN).

input.csv

PatientID,PlanName,Criteria,TotalPoints,PassingPoints,ThresholdDosePercent,RequiredPassRate,MaxAllowedFailPoints
PT-2026-PROSTATE-VMAT,Plan_Arc1_Rev2,3%/3mm,25400,24150,10.0,95.0,2000

URS & FS — user requirements and functional specification

This document defines user requirements and functional specification for the quality-control utility. It supports deployment discussion, IQ/OQ preparation and QC workflow integration.

Utility: GammaIndexAnalyzerAPI / object: Gamma Index AnalyzerCategory: Radiation physics

1. Scope

The Gamma Index Analyzer utility is used for Gamma Index Analyzer. The actual input.csv is the source of truth for the input structure; control criteria are defined by the executable and the domain description.

The utility does not use machine learning; decisions are produced by deterministic rules.

Categories: Radiation physics

Tags: activity, brachytherapy, dosimetry, source calibration, TG-43

2. Execution modes

GammaIndexAnalyzer.exe                            → demo mode
GammaIndexAnalyzer.exe input.csv output.json      → analyze data (first record only)

3. Key controlled areas

activity, decay and radiochemical purity

4. Domain limits and critical parameters

⚠️ Critical for QA! High Pass Rate does not always guarantee absence of local errors. Utility warns about borderline values.
Pass Rate < 95% (for 3%/3mm) usually means unacceptable plan or measurement quality.
⚠️ CRITICAL:
Low Dose Threshold: points with dose <10% often add noise and should be excluded.
Criteria depend on treatment type: 3%/3mm (standard), 2%/2mm (SRS/SBRT), 5%/3mm (palliative).
Local clusters of failures are more dangerous than scattered points, even if overall Pass Rate is high.
Critical parameters:
Pass Rate: ≥95% (standard), ≥90–95% (SRS depending on protocol)
Max failed points: absolute limit to prevent missing local hot spots
Dose threshold: typically 10% of max dose
⚠️ Note: Utility assigns WARNING status if Pass Rate is within 1% of threshold, requiring physicist visual check. Result includes status (PASS/WARNING/FAIL) and bilingual recommendation (RU/EN).

Limits stated in the description must be verified against the current approved specification, pharmacopoeial monograph and registration dossier before production use.

5. URS — user requirements

ID	Requirement	Criticality	Acceptance criterion
URS-001	The system shall accept an `input.csv` file for Gamma Index Analyzer with the exact columns listed in the “Input data contract” section.	High	A file with the correct header is processed without manual editing; missing mandatory columns produce FAIL/import error.
URS-002	The system shall support execution without arguments in demo mode and execution with `input.csv output.json` for user data.	Medium	Both execution scenarios produce a predictable result or clear diagnostic error.
URS-003	The system shall perform rule-based controls for: activity, decay and radiochemical purity.	High	Each controlled parameter receives a status and message; the result does not depend on hidden Excel formulas or ML.
URS-004	The system shall preserve traceability between batch/lot, source values, applied rules and final verdict.	High	Output includes batch identifier, source values, parameter statuses and critical findings.
URS-005	The system shall generate machine-readable `output.json` for LIMS/ELN/MES, batch record and QA/QC review.	High	JSON contains overall status, check array, warnings, failures and source-file reference.
URS-006	The system shall support use in the client validation package: URS/FS, IQ/OQ preparation, installation and operational scenario checks.	High	The document, test scenarios and reproducible CSV/JSON flow are suitable for audit and internal approval.
URS-007	The system shall clearly separate technical data errors from specification nonconformities.	Medium	Schema/type errors are not mixed with pharmacopoeial deviations and are reported separately.

6. input.csv data contract

The source of truth for the input schema is the actual input.csv header. Column names are technical identifiers and are not translated.

#	Column	Type	Unit	Description	Sample	Control rule
1	`PatientID`	text	as specified	Patient ID	`PT-2026-PROSTATE-VMAT`	mandatory value; format and acceptability are checked by the utility
2	`PlanName`	text	as specified	Plan Name	`Plan_Arc1_Rev2`	mandatory value; format and acceptability are checked by the utility
3	`Criteria`	text	as specified	Criteria	`3%/3mm`	mandatory value; format and acceptability are checked by the utility
4	`TotalPoints`	decimal	as specified	Total Points	`25400`	mandatory numeric value; rule comparison is performed by the utility
5	`PassingPoints`	decimal	as specified	Passing Points	`24150`	mandatory numeric value; rule comparison is performed by the utility
6	`ThresholdDosePercent`	decimal	%	Threshold Dose %	`10.0`	mandatory numeric value; rule comparison is performed by the utility
7	`RequiredPassRate`	decimal	as specified	Required Pass Rate	`95.0`	mandatory numeric value; rule comparison is performed by the utility
8	`MaxAllowedFailPoints`	decimal	as specified	Max Allowed Fail Points	`2000`	mandatory numeric value; rule comparison is performed by the utility

CSV example

PatientID,PlanName,Criteria,TotalPoints,PassingPoints,ThresholdDosePercent,RequiredPassRate,MaxAllowedFailPoints
PT-2026-PROSTATE-VMAT,Plan_Arc1_Rev2,3%/3mm,25400,24150,10.0,95.0,2000

7. FS — functional specification

ID	Function	Implementation description
FS-001	CLI entry point	The executable `GammaIndexAnalyzer.exe` supports demo mode and `input.csv output.json` processing mode.
FS-002	CSV parser	The import module reads CSV, validates header, column presence/order, value count and encoding. Decimal values are expected with a dot separator.
FS-003	Field conversion	Each column is converted to the expected type: identifier, text, decimal number, date/time or boolean flag.
FS-004	Domain rule engine	For Gamma Index Analyzer, explicit rules are applied: range, minimum, maximum, absence of prohibited flag, data completeness or calculation-based check.
FS-005	Criticality handling	Critical violations produce FAIL; non-critical deviations and incomplete data produce WARNING; full conformance produces PASS.
FS-006	JSON writer	`output.json` stores overall status, per-parameter results, source values, warnings, failures and diagnostic messages.
FS-007	Integration contract	The CSV → JSON format is stable for invocation from LIMS/ELN/MES, scheduled task or wrapper service.
FS-008	Error handling	Schema error, missing file, non-numeric value or JSON write failure returns diagnosable error without silent PASS.

8. output.json contract

The output file must be suitable for automated processing, audit review and correlation with the source input.csv row.

{
  "utility": "GammaIndexAnalyzer",
  "api": "Gamma Index Analyzer",
  "batchNumber": "",
  "overallStatus": "PASS|WARNING|FAIL",
  "checkedAtUtc": "2026-05-18T00:00:00Z",
  "checks": [
    {
      "parameter": "PatientID",
      "value": "PT-2026-PROSTATE-VMAT",
      "unit": "as specified",
      "status": "PASS|WARNING|FAIL",
      "message": "Rule-based check result"
    },
    {
      "parameter": "PlanName",
      "value": "Plan_Arc1_Rev2",
      "unit": "as specified",
      "status": "PASS|WARNING|FAIL",
      "message": "Rule-based check result"
    },
    {
      "parameter": "Criteria",
      "value": "3%/3mm",
      "unit": "as specified",
      "status": "PASS|WARNING|FAIL",
      "message": "Rule-based check result"
    },
    {
      "parameter": "TotalPoints",
      "value": "25400",
      "unit": "as specified",
      "status": "PASS|WARNING|FAIL",
      "message": "Rule-based check result"
    },
    {
      "parameter": "PassingPoints",
      "value": "24150",
      "unit": "as specified",
      "status": "PASS|WARNING|FAIL",
      "message": "Rule-based check result"
    },
    {
      "parameter": "ThresholdDosePercent",
      "value": "10.0",
      "unit": "%",
      "status": "PASS|WARNING|FAIL",
      "message": "Rule-based check result"
    },
    {
      "parameter": "RequiredPassRate",
      "value": "95.0",
      "unit": "as specified",
      "status": "PASS|WARNING|FAIL",
      "message": "Rule-based check result"
    },
    {
      "parameter": "MaxAllowedFailPoints",
      "value": "2000",
      "unit": "as specified",
      "status": "PASS|WARNING|FAIL",
      "message": "Rule-based check result"
    }
  ],
  "criticalFindings": [],
  "sourceFile": "input.csv"
}

9. OQ/PQ test scenarios

ID	Scenario	Expected result
TC-001	Valid CSV with expected header and sample row	All rows are processed; output contains PASS/WARNING/FAIL and parameter-level detail.
TC-002	A mandatory input.csv column is missing	Import is rejected or the row receives FAIL with schema reference.
TC-003	A numeric field contains text or a blank value	Type conversion error is recorded; the result is not hidden as PASS.
TC-004	A parameter is outside specification or critical limit	Critical parameters produce FAIL; non-critical deviations produce WARNING according to the rule.

10. QA/QC, CSV and change control

Before production use, the client records executable version, checksum, specification/monograph version, test CSV, expected JSON and IQ/OQ results.
Column names must not be changed without updating the validator and test scenarios.
The source CSV, output.json and utility version should be stored together as an evidence package.
Any change in control rules must go through change control and repeated OQ scenario verification.

Included in packages

Andrology QC Suite

QC package for andrology: androgens, erectile-dysfunction medicines, BPH/prostate products, fertility and related hormonal checks.

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Radiation Physics QC Suite

Utilities for activity, dosimetry, brachytherapy sources, small-field corrections and TG-43 parameters.

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RPH use case: PET scanner state, gamma camera and radiation physics

The linked medical-device/radiation-physics layer: PET detector QC, normalization, AC map, cross-calibration, TOF, gamma-camera uniformity, source strength and staff dose.

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RPH workflow: dosimetry and therapy planning

Activity planning, absorbed dose, organ dose, lung shunt, preplanning and therapy verification.

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RPH workflow: instruments, devices and radiation safety

PET/gamma-camera state, calibration, detector QC, energy window, TOF, shielding and radiation safety.

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Urology QC Suite

QC package for urology: BPH, urolithiasis, overactive bladder, urinary-tract infection medicines and supporting antimicrobial QC checks.

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