DICOM-RT Radiation Oncology & Clinical Dosimetry (.rtplan, .rtstruct, .rtdose)

@modelscript/dicom-rt (languages/dicom-rt) provides native WebAssembly parsing, QUANTEC Organ-at-Risk (OAR) dose constraint and Multi-Leaf Collimator (MLC) leaf/gantry kinematics verification, cumulative and differential Dose-Volume Histogram (DVH) integration, Linear-Quadratic BED / EQD2 biological dose calculation, DAEBuilder lowering, and OpenSCAD / SysML v2 projections for DICOM Radiotherapy (RTPLAN, RTSTRUCT, RTDOSE) treatment plans.

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Supported Extensions & Standards

Extension	Format	Description
.rtplan	DICOM RT Plan	External-beam photon/electron/proton beam geometry, gantry/couch/collimator angles, MLC control points, and fraction groups
.rtstruct	DICOM RT Structure Set	3D anatomical contours for Planning Target Volumes (PTV, CTV, GTV) and Organs at Risk (OAR)
.rtdose	DICOM RT Dose	3D dose grid arrays and cumulative/differential Dose-Volume Histogram (DVH) curves

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Key Capabilities

1. Cumulative DVH, ICRU 83 Homogeneity & Paddick Conformity

• Evaluates $D_{98\mathrm{\%}}$, $D_{95\mathrm{\%}}$, $D_{50\mathrm{\%}}$, $D_{2\mathrm{\%}}$, $D_{\text{mean}}$, and $V_{x\text{Gy}}$ across Target and OAR structures:$${\text{HI}}_{\text{ICRU 83}}=\frac{D_{2\mathrm{\%}}-D_{98\mathrm{\%}}}{D_{50\mathrm{\%}}},{\text{CI}}_{\text{Paddick}}=\frac{(T{V}_{\text{PIV}}{)}^2}{TV\times PIV}$$

2. Linear-Quadratic Biological Dose ($\text{BED}$ & $\text{EQD2}$)

• Computes Biologically Effective Dose and Equivalent Dose in $2\text{ Gy}$ fractions for tumor targets ($\alpha /\beta \approx 10\text{ Gy}$) and late-responding normal tissues ($\alpha /\beta \approx 2\text{–}3\text{ Gy}$):$$\text{BED}=nd(1+\frac{d}{\alpha /\beta }),\text{EQD2}=\frac{\text{BED}}{1+\frac{2}{\alpha /\beta }}$$

3. QUANTEC Safety Verification & OpenSCAD / SysML v2 Projections

• Checks spinal cord, brainstem, optic chiasm, parotid, lung, heart, rectum, and bladder doses against clinical QUANTEC limits, verifies MLC leaf bank non-interdigitation/overtravel, and projects beam apertures to OpenSCAD (dicomRtToScad) and SysML v2 (dicomRtToSysML2).

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Pre-Flight Diagnostics

10 rules9 error1 warning

Code	Rule	Severity	Message
M9201	dicom-rt-missing-target-volume	error	Treatment plan '<planLabel>' contains no clinical target volume ROI ('PTV', 'CTV', or 'GTV').
M9202	dicom-rt-mlc-leaf-overlap	error	MLC leaf pair '<pairIndex>' on beam '<beamName>' control point '<cpIndex>' has bankA='<bankA> mm', bankB='<bankB> mm' (gap '<value> mm' < minimum '<MIN_MLC_LEAF_GAP_MM> mm').
M9203	dicom-rt-mlc-speed-exceeded	error	MLC leaf pair '<pairIndex>' on beam '<beamName>' between control points '<cpFrom>' and '<cpTo>' travels at '<value> mm/s', exceeding physical motor limit '<value> mm/s'.
M9204	dicom-rt-gantry-couch-collision	error	Gantry angle '<gantryDeg> deg' and non-coplanar couch angle '<couchDeg> deg' on beam '<beamName>' control point '<cpIndex>' enter the gantry-couch collision hazard zone.
M9205	dicom-rt-oar-dose-constraint-violated	error	Organ-at-Risk '<roiName>' <metricKind> dose '<value> Gy' exceeds QUANTEC clinical constraint '<value> Gy'.
M9206	dicom-rt-non-monotonic-cum-meterset	error	Control point cumulativeMetersetWeight sequence on beam '<beamName>' is invalid: <detail>.
M9207	dicom-rt-unclosed-roi-contour	error	CLOSED_PLANAR contour slice at z='<zSlice> mm' in ROI '<roiName>' has '<vertexCount>' vertices (minimum 3 required).
M9208	dicom-rt-unresolved-frame-of-reference	error	<modalitySource> FrameOfReferenceUID '<sourceUid>' does not match plan FrameOfReferenceUID '<planUid>'.
M9209	dicom-rt-invalid-beam-meterset	error	TREATMENT beam '<beamName>' has invalid delivery parameters (metersetMu='<metersetMu>', energyMeV='<energyMeV>'); both must be > 0.
M9210	dicom-rt-ptv-underdosage	warning	Target volume '<roiName>' D95% '<value> Gy' is below 95% of prescribed dose '<value> Gy' (minimum '<value> Gy').

Generated from languages/dicom-rt/src/lints/rules.ts. All languages →

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CLI Usage

# Inspect RTPLAN prescription, fractions, anatomical structures, and beams
msx dicom-rt inspect ProstateVMAT.rtplan

# Validate QUANTEC OAR dose limits, MLC leaf gaps, and gantry clearance
msx dicom-rt validate ProstateVMAT.rtplan

# Compute DVH metrics (D95, D2, HI, CI) and Linear-Quadratic BED / EQD2
msx dicom-rt dosimetry ProstateVMAT.rtplan

# Project treatment beams and ROI contours to OpenSCAD or SysML v2
msx dicom-rt to-scad ProstateVMAT.rtplan > ProstateVMAT.scad
msx dicom-rt to-sysml ProstateVMAT.rtplan > ProstateVMAT.sysml