DVHComparator

DVH Comparator

activity brachytherapy dosimetry radiopharma source calibration TG-43

DVH Comparator — Dose-Volume Histogram Comparison (AAPM TG-218)

ℹ️ The utility compares key DVH metrics (D95, D2, V20, Mean, Max) between the current treatment plan and a reference plan (or clinical constraints).
ℹ️ Calculates absolute and relative difference checking against specified tolerances (% and absolute units).
ℹ️ Processing: only the FIRST record in input.csv file.
⚠️ Critical for planning QA! Unnoticed DVH changes can lead to tumor underdosing or Organs At Risk (OAR) damage.

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

Input format:
PatientID,StructureName,MetricType,PlanValue,RefValue,TolerancePercent,ToleranceAbsolute

Example (dose in Gy, volume in %, flexible tolerances):
PT-2026-LUNG-01,PTV_60,D95,58.5,60.0,3.0,1.0

— WHY IS THIS NEEDED?
During radiotherapy plan verification (VMAT, IMRT, SRS), physicist must ensure the plan has not degraded compared to approved reference or meets protocol.
• D95 (Coverage) — 95% of target volume must receive prescribed dose. Critical for tumor control.
• D2 / Max (Hot Spot) — maximum dose. Exceeding leads to tissue necrosis.
• V20 / Mean (OAR) — volume of organ receiving high dose. Critical for lungs, heart, kidneys.
• Automated comparison eliminates human factor when reading numbers from TPS.
⚠️ CRITICAL:
• Tolerances must match clinic protocol (typically 3%/3mm or 5% for dose).
• Different priorities for structures: for PAV avoid below minimum, for OAR avoid above maximum. Utility checks absolute deviation magnitude.
• Borderline values (>80% of tolerance) marked as WARNING for close attention.
Critical parameters:
• D95 (PTV): Deviation ≤ -3% (coverage reduction unacceptable)
• D2 (PTV): Deviation ≤ +5% (overheating unacceptable)
• V20 (Lung): Deviation ≤ +5% (pneumonitis risk)
• Mean Dose (Heart/Kidney): Strict mean dose control
⚠️ Note: Utility uses dual tolerance system (percentage and absolute). Plan passes (PASS) if deviation fits within at least one tolerance. Result includes status (PASS/WARNING/FAIL) and bilingual recommendation (RU/EN).

input.csv

PatientID,StructureName,MetricType,PlanValue,RefValue,TolerancePercent,ToleranceAbsolute
PT-2026-LUNG-01,PTV_60,D95,58.5,60.0,3.0,1.0

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: DVHComparatorAPI / object: DVH ComparatorCategory: Radiation physics

1. Scope

The DVH Comparator utility is used for DVH Comparator. 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, radiopharma, source calibration, TG-43

2. Execution modes

DVHComparator.exe                            → demo mode
DVHComparator.exe input.csv output.json      → compare data (first record only)

3. Key controlled areas

pH and physicochemical parameters
activity, decay and radiochemical purity

4. Domain limits and critical parameters

⚠️ Critical for planning QA! Unnoticed DVH changes can lead to tumor underdosing or Organs At Risk (OAR) damage.
⚠️ CRITICAL:
Tolerances must match clinic protocol (typically 3%/3mm or 5% for dose).
Different priorities for structures: for PAV avoid below minimum, for OAR avoid above maximum. Utility checks absolute deviation magnitude.
Borderline values (>80% of tolerance) marked as WARNING for close attention.
Critical parameters:
D95 (PTV): Deviation ≤ -3% (coverage reduction unacceptable)
D2 (PTV): Deviation ≤ +5% (overheating unacceptable)
V20 (Lung): Deviation ≤ +5% (pneumonitis risk)
Mean Dose (Heart/Kidney): Strict mean dose control
⚠️ Note: Utility uses dual tolerance system (percentage and absolute). Plan passes (PASS) if deviation fits within at least one tolerance. 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 DVH Comparator 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: pH and physicochemical parameters, 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-LUNG-01`	mandatory value; format and acceptability are checked by the utility
2	`StructureName`	text	as specified	Structure Name	`PTV_60`	mandatory value; format and acceptability are checked by the utility
3	`MetricType`	text	as specified	Metric Type	`D95`	mandatory value; format and acceptability are checked by the utility
4	`PlanValue`	decimal	as specified	Plan Value	`58.5`	mandatory numeric value; rule comparison is performed by the utility
5	`RefValue`	decimal	as specified	Ref Value	`60.0`	mandatory numeric value; rule comparison is performed by the utility
6	`TolerancePercent`	decimal	%	Tolerance %	`3.0`	mandatory numeric value; rule comparison is performed by the utility
7	`ToleranceAbsolute`	decimal	as specified	Tolerance Absolute	`1.0`	mandatory numeric value; rule comparison is performed by the utility

CSV example

PatientID,StructureName,MetricType,PlanValue,RefValue,TolerancePercent,ToleranceAbsolute
PT-2026-LUNG-01,PTV_60,D95,58.5,60.0,3.0,1.0

7. FS — functional specification

ID	Function	Implementation description
FS-001	CLI entry point	The executable `DVHComparator.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 DVH Comparator, 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": "DVHComparator",
  "api": "DVH Comparator",
  "batchNumber": "",
  "overallStatus": "PASS|WARNING|FAIL",
  "checkedAtUtc": "2026-05-18T00:00:00Z",
  "checks": [
    {
      "parameter": "PatientID",
      "value": "PT-2026-LUNG-01",
      "unit": "as specified",
      "status": "PASS|WARNING|FAIL",
      "message": "Rule-based check result"
    },
    {
      "parameter": "StructureName",
      "value": "PTV_60",
      "unit": "as specified",
      "status": "PASS|WARNING|FAIL",
      "message": "Rule-based check result"
    },
    {
      "parameter": "MetricType",
      "value": "D95",
      "unit": "as specified",
      "status": "PASS|WARNING|FAIL",
      "message": "Rule-based check result"
    },
    {
      "parameter": "PlanValue",
      "value": "58.5",
      "unit": "as specified",
      "status": "PASS|WARNING|FAIL",
      "message": "Rule-based check result"
    },
    {
      "parameter": "RefValue",
      "value": "60.0",
      "unit": "as specified",
      "status": "PASS|WARNING|FAIL",
      "message": "Rule-based check result"
    },
    {
      "parameter": "TolerancePercent",
      "value": "3.0",
      "unit": "%",
      "status": "PASS|WARNING|FAIL",
      "message": "Rule-based check result"
    },
    {
      "parameter": "ToleranceAbsolute",
      "value": "1.0",
      "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

Radiation Physics QC Suite

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

Open

Radiology QC Suite

QC package for radiology and diagnostic imaging: radiopharmaceuticals, PET/SPECT, contrast media, iodinated and gadolinium products, plus particle, sterility and endotoxin checks.

Open

RPH organ/system: cardiovascular

Myocardial perfusion, cardiac PET/SPECT, ventricular function, blood-pool and perfusion tracers.

Open

RPH organ/system: oncology and theranostics

Tumour imaging, PSMA/FAPI/receptor tracers, immuno-PET, targeted radionuclide therapy and radioembolization.

Open

RPH organ/system: pulmonary and ventilation

Lung perfusion, MAA, V/Q, aerosol, xenon ventilation, shunt and pulmonary dosimetry.

Open

RPH organ/system: renal and urinary

Renography, GFR/ERPF, renal uptake, DMSA/MAG3/DTPA and bladder-related workflows.

Open

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.

Open

RPH workflow: dosimetry and therapy planning

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

Open

RPH workflow: instruments, devices and radiation safety

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

Open