Usage

The following rules apply to this value set:

1. Select the most specific term appropriate for a given situation.
2. Select the term that best describes the technique used, even if that term does not capture every detail of the technique. For example, image-guided intensity-modulated radiation therapy should be reported as IMRT because that category most closely aligns with the actual technique.

Mapping Between Vocabularies

The concepts in this value set are drawn in priority order first from SNOMED CT (SCT), then from UMLS Metathesaurus, and lastly, from the radiotherapy code system defined in this Implementation Guide. Missing SNOMED CT codes have been submitted for approval.

The following table shows potential mappings. This table may not be exhaustive and additional valid mappings may exist.

Notes:

1. SCT#434131000124108 ”Three dimensional conformal radiotherapy (procedure)” and UMLS#C0600521 “Radiotherapy, Conformal” are not matches because use of three-dimensional imaging in radiotherapy planning does not necessarily imply conformal dose distribution.
2. SCT#5304008 “Conventional X-ray therapy” implies two-dimensional, but is too specific in terms of modality.
3. Although superficially more specific, this is an acceptable match in many cases because boron is the most common neutron capture agent.

This value set includes codes based on the following rules:

• Include these codes as defined in http://snomed.info/sct

  Code	Display
  441799006	Intensity modulated radiation therapy (procedure)
  168524008	Radiotherapy - intraoperative control (procedure)
  169317000	Neutron capture therapy (procedure)

• Include these codes as defined in http://terminology.hl7.org/CodeSystem/umls

  Code	Display
  C3489631	Volumetric Modulated Arc Therapy
  C5236971	2D Conventional Radiotherapy

• Include these codes as defined in http://terminology.hl7.org/CodeSystem/radiotherapy

  Code	Display	Definition
  3D	Three Dimensional	Dose calculated with projection onto 3D imaging (e.g., CT or MR) delivered with either static aperture (Collimator, SRS Cone, Static MLC, blocks, etc) or non-IMRT/VMAT dynamic apertures (e.g., field-in-field, dynamic arc) using either single gantry angles or arcs.
  PPS	Particle Passive Scattering	In proton or carbon ion beam therapy, a technique where the beam is spread out to larger dimension using a scattering device such as lead foil.
  PSS	Particle Spot Scanning	In proton or carbon ion beam therapy, a technique where accelerated particles are focused into a small beam and then moved (scanned) over target regions in the patient.
  MIX	Mixed	Both photon and particle based beams are used to deliver the radiation therapy.