Comparison of dose verification among three radiotherapy techniques / 中华放射肿瘤学杂志

ABSTRACT

Objective To study if the dose verification technique for three dimensional conformal radiation therapy ( 3 DCRT) can be applied for simplified intensity modulation radiation therapy ( sIM RT). Methods From 1988 patients treated by sIMRT in our department,12 were chosen randomly for the study. For each case,3 differert plans of 3DCRT,sIMRT,and IMRT were worked out with Pinnacle TPS,and the dose verification for each plan was carried out with Elekta Precise LA by using 2D diode-matrix of MapCHECK Model 1175. Results For slMRT,the overall average percentages of pass points for DD(DTA) 2% (2 mm) ,3% (3 mm)and 4% (4 mm) were 90.5% ,94.8% and 98.2% reapectively,which were slightly worse when comparing with those of 3DCRT with deterioration of 1.9% (t=2.19,P=0.040) ,1.0% (t= 1.52,P=0.144) and 0.2% (t=0.05,P=0.623), but slightly better comparing with those of IMRT with increment of 2.1% (t=2.17,P=0.041) ,1.5% (t=2.62,P=0.016) and 1.5% (t=3.68,P=0.001) for 2% (2 mm) ,3% (3 mm) and 4% (4 mm) ,respectively. Conclusions The sIMRT technique simplifies the complicated dose verification procedure of I MRT. When the sIMRT technique is formally used, the procedure of dose distribution verification for 3DCRT can be used directly for slMRT.