| 摘要 |
PROBLEM TO BE SOLVED: To provide a beam shaping assembly for neutron capture therapy that improves radiation flux and quality of a neutron source.SOLUTION: A beam shaping assembly 20 comprises: a beam inlet 21; a target 22; a moderator 23 adjoining to the target; a reflector 24 arranged around the moderator; a thermal neutron filter 25 adjoining to the moderator; a radiation shield 26 arranged inside the beam shaping assembly; and a beam outlet 27. Neutrons are produced by nuclear reaction between the target and an incident proton beam from the beam inlet, and the reflector leads the neutrons deviated from a main axis X1 to the main axis so as to enhance epithermal neutron beam intensity. The thermal neutron filter is used for absorbing thermal neutrons so as to avoid overdosing in a superficial normal tissue during therapy. The radiation shield is used for shielding leaking neutrons and photons so as to reduce dose of the normal tissue in a non-radiation region.SELECTED DRAWING: Figure 4 |
