TOPAS & GATE Proton & Hadrontherapy Monte Carlo (.topas, .mac)

@modelscript/topas (languages/topas) provides native WebAssembly GLR parsing, Geant4 geometry hierarchy and parent-child bounding-box containment verification, Bortfeld (1997) analytical Bragg peak depth-dose and Spread-Out Bragg Peak (SOBP) evaluation, DAEBuilder lowering, and OpenSCAD / Modelica projections for TOPAS (Tool for Particle Simulation) and GATE proton, carbon-ion, and flash radiotherapy beamline configurations.

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Supported Extensions & Standards

Extension	Format	Description
.topas, .txt	TOPAS Parameter File	Typed Geant4 parameter system (s: string, d: double with units, i: integer, b: boolean, dv:/sv: vectors) for Ge/, So/, Sc/, and Ph/
.mac	GATE / Geant4 Macro	Command-stream macro (/gate/world/daughters/..., /gate/source/..., /gate/actor/...) for medical physics Monte Carlo

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Key Capabilities

1. Typed Geometry (Ge/), Beam Sources (So/) & Dose Scorers (Sc/)

• Parses hierarchical CSG beamline components (TsBox, TsCylinder, TsSphere, TsRangeModulator, TsPropeller, TsMultiLeafCollimator, water phantoms, and patient CT volumes), particle sources (Proton, Carbon12, Electron, Photon), and DoseToMedium / LETd scorers.

2. Analytical Bortfeld Bragg Peak & Range Calculation

• Computes the continuous-slowing-down range $R_0=\alpha E_0^p$ in water ($\alpha \approx 0.0022\text{ cm}\cdot {\text{MeV}}^{-p}$, $p\approx 1.77$ for protons), distal $80\mathrm{\%}$ dose falloff ($R_{80}$), peak-to-plateau ratio, and full depth-dose curves $D(z)$ (computeBraggPeakDepthDose).

3. 3D Nozzle CSG & Modelica Projections

• Projects TOPAS/GATE treatment nozzles and water phantoms into OpenSCAD 3D CSG geometry (topasToScad) and Modelica beamline dosimetry models (topasToModelica).

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Pre-Flight Diagnostics

10 rules9 error1 warning

Code	Rule	Severity	Message
M9601	topas-type-prefix-mismatch	error	Parameter '<fullPath>' value '<rawVal>' does not match declared TOPAS type prefix '<typePrefix>:'.
M9602	topas-unresolved-parent-component	error	Geometry component '<compName>' references undeclared parent volume '<parentName>'.
M9603	topas-non-positive-geometry-dimension	error	Geometry component '<compName>' has invalid dimension: <detail>.
M9604	topas-child-exceeds-parent-bounds	error	Child geometry '<childName>' protrudes outside parent '<parentName>' along <axis>-axis ('<childExtent> mm' > '<parentHalfExtent> mm').
M9605	topas-undefined-material	error	Component '<compName>' references unknown material '<materialName>' not found in Geant4/NIST materials or custom 'Ma/' definitions.
M9606	topas-invalid-beam-energy	error	Particle source '<sourceName>' has invalid beam energy specification: <detail>.
M9607	topas-circular-include-file	error	Circular or self-referential includeFile chain detected: '<cycleChain>'.
M9608	topas-scorer-missing-component	error	Scorer '<scorerName>' has invalid configuration: <detail>.
M9609	topas-vector-length-mismatch	error	Vector parameter '<fullPath>' declares length '<declaredCount>' but provides '<actualCount>' elements.
M9610	topas-duplicate-parameter-assignment	warning	Parameter '<fullPath>' is assigned multiple times in the same file without 'change' override prefix.

Generated from languages/topas/src/lints/rules.ts. All languages →

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CLI Usage

# Inspect TOPAS/GATE geometry components, beam sources, and scorers
msx topas inspect ProtonNozzle.topas

# Validate parent-child bounding box containment, materials, and beam energy
msx topas validate ProtonNozzle.topas

# Compute analytical Bortfeld Bragg peak range (R0, R80) and depth-dose curve
msx topas bragg-peak ProtonNozzle.topas

# Project treatment nozzle and phantom geometry to OpenSCAD or Modelica
msx topas to-scad ProtonNozzle.topas > ProtonNozzle.scad
msx topas to-modelica ProtonNozzle.topas > ProtonNozzle.mo