There is a RADIOBUTTON control (TYPE == 3).
 
Syntax:
Window.AddControl(id,3, X, Y, WIDTH, HEIGHT, "text");
Sample:
Window.AddControl(300,3,85,0,80,12,"First");
Description:
This RADIOBUTTON is not checked. A radio button consists of a round button and application-defined text (a label) that indicates a choice the user can make by selecting the button. An application typically uses radio buttons in a group box to permit the user to choose from a set of related, but mutually exclusive options.

X, Y, WIDTH, HEIGHT : - The horizontal base unit is equal to the average width, in pixels, of the characters in the system font; the vertical base unit is equal to the height, in pixels, of the font. Furthermore, each horizontal base unit is equal to 4 horizontal dialog units; each vertical base unit is equal to 8 vertical dialog units.

 
  GUI for script  
Content