Development of a computer-controlled moving bar (CCMB) conformal technique for neck irradiation

The development of an original conformal technique for neck cancer is in progress in our Institute. This technique uses a computer-controlled moving bar (CCMB): a portion of a blocking bar rotates during the rotation of the gantry in a 2 pi arc field in order to shield the spinal cord over the whole irradiated volume. This technique should solve in a relatively simple way some problems for different clinical situations when cervical node irradiation is required together with the primary tumor. The technique has been tested in an acrylic cylindrical phantom and in the humanoid RANDO phantom for two different irradiation conditions (neck completely bent and partially aligned).