A new radiation system known as the TomoTherapy Hi-ART system was introduced into our hospital in October 2010. This system combines helical intensity-modulated radiotherapy (IMRT) with an integrated image guidance system by means of a megavoltage-CT. This image-guided IMRT enables us to deliver appropriate doses to tumors with good conformality while avoiding sensitive structures in an accurate manner. Patients having tumors in the head, neck, abdomen and pelvis would be good candidates for this treatment. In our hospital, a total of about 150 patients were treated with the helical tomotherapy in 2011.
  However, in the helical tomotherapy, low-dose areas would be spread wide, compared with conventional radiotherapy.Low dose irradiation to large volumes of the lung would increase the risk of radiation pneumonitis, thus planning for thoracic regions such as chest wall and mediastinum might be difficult. In such cases, another strategy “TomoDirect” might be more useful. That allows us to create treatment plans just like conventional radiotherapy using static gantry positions, combined with simultaneous couch movement. Over 20 patients were treated with TomoDirect in 2011.