[An automatic 3D-locating couch for radiation therapy].

An intensity modulated method by scanning for the focusing therapy machine is introduced in this paper. At first, the 3-D model of the focus is delaminated through the treatment planning system, and the dose distributing of each lay is calculated by an inverse design method. Then, the exposure time of the focus at each position is determined and converted to a scanning parameter, such as position, speed and so on. Afterward, the focus continuously scans the tumor at different speeds along the planned track under the control of the computer. Consequently the point-by- point intensity modulation is achieved through the diversification of the scanning speed of the focus.