The following problem sometimes arises in the radiation treatment of a pathological area in the human body. Due to the nonuniformity of thickness and the difference of density of the tissue passed by the radiation energy, the radiation dose in the target area may not be uniform. To avoid such a situation, this paper considers a method in which the attenuation configuration of the radiation in passing through the body is estimated in detail. A three‐dimensional block is placed between the radiation source and the target area to realize the radiation treatment with the dose correction. The design method for the three‐dimensional block, i.e., the compensation filter for the correction, is discussed. First, the CT value for each density voxel obtained by the continuous tomography of X‐ray CT image is converted into the absorption coefficient of the high‐energy X‐ray for treatment. Then the values of the voxels passed from the radiation generator to the pathological area are summed up, and the radiation dose in the target areas is calculated. The three‐dimensional shape of the compensation filter, which can correct adequately the dose distribution, is determined based on the tissue‐air dose ratio obtained from the actual measurement. The block is constructed based on the shape data. By the experiment using a phantom, the nonuniformity of the dose is reduced approximately from 10 percent to 3 percent. In the simulation for the application to the biological object, the area of high dose distribution fits the target area, indicating the effectiveness of the dose correction.
All Science Journal Classification (ASJC) codes
- Theoretical Computer Science
- Information Systems
- Hardware and Architecture
- Computational Theory and Mathematics