Gammex RMI designed the 469 IMRT phantom based on research conducted by the University of Wisconsin medical physics researchers**. The 469 IMRT Phantom offers simple, highly reliable dose validation of complex 3D treatment plans. The principle behind the Gammex IMRT Phantom is to create a film spiralgram of the treatment dose along a mathematically precise path to obtain a 3 dimensional sampling of a treatment plan.

For treatment plan verification, a 7 x 43 cm strip of film is loaded into the phantom by sliding it into the slot from the locating pin position until it contacts the ion chamber adapter. The plan is then executed on the phantom. After the film is developed, it is compared to the predicted treatment plan. (**Medical physics research group: Paliwal Bhudatt, Wolfgang Tomé; Susan Richardson and T. Rockwell Mackie)