Figure 1
The PMMA cylindrical phantom pendant from the hole in the patient support; in the background the rectangular beam entrance window can be seen. (a) A flat piece of radiochromic film is positioned in the middle of the phantom to record the 2D distribution of the incident air kerma. (b) A radiochromic film strip is wrapped around the phantom using adhesive tape; its central part shows a thin blackened rectangular area where the SR beam is incident on the phantom. |