This paper discusses how to choose irradiation field and irradiation process.

Generally, a square or rectangular single field or a plurality of fields are used for irradiation.

General irradiation is the earliest radiation therapy method, and generally it adopts square or rectangular single field or multi-field irradiation. Its irradiation range is large, so it does great harm to normal tissues and organs. Although there are new methods now, they are still applicable to the treatment of some diseases.

According to the development history of radiotherapy, the main radiotherapy methods are: general radiotherapy (2DRT), three-dimensional conformal radiotherapy (3DRT), intensity modulated radiotherapy (IMRT), respiratory gated radiotherapy, image-guided radiotherapy (IGRT) and computer-controlled precise radiotherapy.