A Method of Segment Weight Optimization for Intensity Modulated Radiation Therapy

Key words: 
• intensity modulated radiation therapy /
• conjugate gradient method /
• precise radiotherapy system /
• segment weight

Abstract: The error caused by leaf sequencing often leads to planning of IntensityModulated Radiation Therapy(IMRT) arrange system couldn’t meet clinical demand. The optimization approach in this paper can reduce this error and improve efficiency of planmaking effectively. Conjugate Gradient algorithm was used to optimize segment weight and readjust segment shape， which could minimize the error anteriorposterior leaf sequencing eventually. Frequent clinical cases were tasted by precise radiotherapy system， and then compared DoseVolume histogram between target area and organ at risk as well as isodose line in computed tomography(CT) film， we found that the effect was improved significantly after optimizing segment weight. Segment weight optimizing approach based on Conjugate Gradient method can make treatment planning meet clinical request more efficiently， so that has extensive application perspective.