Dosimetric study of intensity modulated direct aperture optimization radiation therapy for testicular seminoma / 医疗卫生装备

ABSTRACT

Objective To compare the field-matching techniques and dosimetric characteristics in the target area of testicular seminoma including the abdominal and pelvic cavities between direct aperture optimization intensity modulated radiation therapy (DAO-IMRT) and 3D conformal radiation therapy (3D-CRT),and to analyse the advantages and disadvantages of DAO-IMRT.Methods DAO-IMRT and 3D-CRT plans were designed with Pinnacle treatment planning system for 7 testicular seminoma patients,and the characteristics of both the irradiation methods were analyzed and evaluated by means of the parameters like dose homogeneity indexes,dose volume histograms and etc.Results DAO-IMRT had the hot and cold volumes in the target areas both significantly smaller than those by 3D-CRT,while the conformity index and homogeneity index superior to those by 3D-CRT.The mean doses (Dmean) by DAO-IMRT of the organs at risk (OAR) except the left femur head were all lower than those by 3D-CRT,aud the V15 values of liver,double kidney,small intestine and rectum by DAO-IMRT were statistically lower than those by 3D-CRT (P＜0.01).3D-CRT had the V5 values of OAR all lower than those by DAO-IMRT,in which the differences of double kidney,small intestine,bladder,left femur head and normal tissues were significant statistically (P＜0.05).The monitor units by DAO-IMRT roughly doubled when compared with those by 3D-CRT,and the difference was also significant (P＜0.01).Conclusion DAO-IMRT with easy operation and high reliability can avoid the connection of fields in the target area of testicular seminoma,and is superior to 3D-CRT in dosimetry.