3D打印个体化模体在胸部调强治疗计划中的剂量学研究OACSTPCD

Objective:To make an individual phantom that was printed by using three dimension(3D)technique,which could reflect the real situation of patient,and to analyze the computed tomography(CT)value and dose distribution of radiotherapy on each organ of the inside of the 3D-printed individual phantom.Methods:According to the localization of CT image of the patient,the empty shell of 3D structure of each organ were reconstructed and printed by using 3D technique.The CT value was used as basis to select the equivalent material of each organ to perform fill,which could obtain the individual phantom of chest that could appear the structural characteristics of patient.The treatment plan of patients were included in treatment plan group,and the plans which were transplanted to 3D-printed individual phantom from treatment plan of patients were included in phantom plan group.The dosimetric parameters of the plans of two groups were compared.Results:The average CT values of left and right lung,soft tissue,cancellous bone,compact bone and heart of the phantom plan group were respectively-709,-737,14,144,760 and 28 HU.The errors of the all CT values between phantom images and located images of patients were less than 16.7%.The exposure doses of normal tissues of radiotherapy plans on the images of two groups could meet the clinical requirements.The minimum dose(Dmin),mean dose(Dmean),the corresponding doses of 98%,50% and 2% target volumes(D98%,D50% and D2%),conformity index(CI),homogeneity index(HI),monitor unit(MU)of dosimetric parameters of the target region could meet the clinical requirements without statistically significant differences.There was significant differences in the maximum dose(Dmax)of the target region(t=2.678,P＜0.05).Among of these Dmax values,the Dmax value of phantom plan group was larger,which was(56.97±0.32)Gy.Conclusion:The CT value,tissue structure and spatial distribution of the phantom,which is finally designed,can emulate the chest of human body in radiotherapy.It has verified the feasibility that 3D-printed phantom is applied in measuring dose in the quality assurance of radiotherapy.