Records the dominant modality of radiation therapy used to deliver the clinically most significant regional dose to the primary volume of interest during the first course of treatment.

Radiation treatment frequently is delivered in two or more phases that can be summarized as regional and boost treatments. To evaluate patterns of radiation oncology care, it is necessary to know which radiation resources were employed in the delivery of therapy. For outcomes analysis, the modalities used for each of these phases can be very important.

00	No radiation treatment
20	External beam, NOS
21	Orthovoltage
22	Cobalt-60, Cesium-137
23	Photons (2-5 MV)
24	Photons (6-10 MV)
25	Photons (11-19 MV)
26	Photons (> 19 MV)
27	Photons (mixed energies)
28	Electrons
29	Photons and electrons mixed
30	Neutrons, with or without photons/electrons
31	IMRT
32	Conformal or 3-D therapy
40	Protons
41	Stereotactic radiosurgery, NOS
42	Linac radiosurgery
43	Gamma Knife
50	Brachytherapy, NOS
51	Brachytherapy, Intracavitary, Low Dose Rate (LDR)
52	Brachytherapy, Intracavitary, High Dose Rate (HDR)
53	Brachytherapy, Interstitial, Low Dose Rate (LDR)
54	Brachytherapy, Interstitial, High Dose Rate (HDR)
55	Radium
60	Radio-isotopes, NOS
61	Strontium - 89
62	Strontium - 90
80*	Combination modality, specified
85*	Combination modality, NOS
98	Other, NOS
99	Unknown

Note: For tumors diagnosed prior to January 1, 2003, the codes reported in this data item describe any radiation administered to the patient as part or all of the first course of therapy.

*Codes 80 and 85 describe specific converted descriptions of radiation therapy coded according to Volume II ROADS, and DAM rules and should only be used to record regional radiation for tumors diagnosed prior to January 1, 2003.