Radiation therapy (or radiotherapy) uses ionizing radiation, generally as part of cancer treatment to control or kill malignant cells.

Data model

Definition of the Radiotherapy element
Field Type Multiplicity Description
modality OntologyClass 1..1 The modality of radiation therapy (e.g., electron, photon,…). REQUIRED.
body_site OntologyClass 1..1 The anatomical site where radiation therapy was administered. REQUIRED.
dosage int32 1..1 the total dose given in units of Gray (Gy). REQUIRED.
fractions int32 1..1 The total number of fractions delivered as part of treatment. REQUIRED.



Terms from the NCIT can be used to represent the modality of radiation therapy. Four examples are shown here:

The NCIT terms themselves specify whether the radiation therapy was administered externally or internally. For instance, NCIT terms from the Internal Radiation Therapy (NCIT:C15195) subhierarchy would be used to indicate a type of internal radiation therapy.


The anatomical site that was irradiated. An uberon term can be used.


The total dosage administered, indicated in units of Gray.


The number of fractions into which the radiation dosage was divided.