SU-E-T-622: The Individual Internal Target Volume for Kidney Carcinoma: 4D-CT Vs 3D-CT Associated with Active Breathing Control (ABC)

Abstract

Purpose: To research the feasibility of using 3D‐CT associated with ABC in determination of the individual Internal Target Volume (ITV) and margins from Gross Target Volume (GTV) to ITV for kidneycarcinoma. Methods: 44 kidneycarcinoma patients (left‐superior, right‐superior, left renal hilum, right renal hilum were 12, 12, 10, 10 respectively) were enrolled. All the patients had completed the 4D‐CT scans and the 3D‐CT scans associated with ABC (three ways of breathing: Free Breathing (FB), End Inspiration Hold (EIH), End Expiration Hold (EEH)). 4D‐CT images were sorted into 10 phases based on the breathing cycle and the maximum intensity projection (MIP) was constructed which were respectively labeled as CT0, CT10…CT90 and CTMIP; 3D‐CT images were labeled as CTFB, CTEIH, CTEEH. The GTVs were manually contoured on CT0, CT20, CT50, CTMIP, CTFB, CTEIH, CTEEH and labeled as GTV0, GTV20, GTV50, GTVMIP, GTVFB, GTVEIH, GTVEEH. GTV0, GTV20 and GTV50, GTVEIH and GTVEEH were respectively merged into ITV1, ITV2. The volume and the position of GTVs and ITVs were calculated and compared. The volume of ITVFB‐1, ITVFB‐2 which was obtained according to the margins and margins were calculated and compared. Results: The motion of kidneycarcinoma measured between 4D‐CT images and 3D‐CT images was not significantly different. There were no significant difference in volume and position among ITV1 and ITV2; There were no significant difference in the margins from GTVFB to two ITVs and the volume of ITVFB‐1, ITVFB‐ 2. Conclusions: Compared with the 4D‐CT, the application of 3D‐CT associated with ABC in determination of the individual ITV and margins from GTV to ITV for kidneycarcinoma was feasible, safe and sufficient. And, the margins of kidneycarcinoma need a non‐uniform and individual extent in kidneycarcinoma of different position.