Background and purpose: To investigate the feasibility and effectiveness of utilizing active breathing coordinator (ABC) in 3DCRT for HCC.
Materials and methods: A dosimetric comparison between the free-breathing (FB) plan and ABC plan in HCC 3DCRT was performed. Set-up errors and reproducibility of diaphragm position using ABC were measured, and patients' acceptance was also recorded.
Results: From April 2005 to February 2007, 28 HCC were irradiated with ABC and they tolerated ABC well. The mean dose to normal liver was reduced from 16.9Gy in FB plan to 14.3Gy in ABC plan. PTV for ABC and FB plans were 529cm(3) and 781cm(3), respectively, and V(23) were reduced from 45% to 30%. The predicted incidences of radiation-induced liver disease by Lyman model were 1% and 2.5%, respectively, in favor of ABC plan. The systematic and random errors for the ABC and FB plans were 1.2mm vs. 4.7mm, 1.6mm vs. 3.5mm, and 1.8mm vs. 2.7mm, respectively, in cranio-caudal, anterior-posterior, and left-right directions. The average intrafraction reproducibility of diaphragm position in cranio-caudal direction was 1.6mm, and the interfraction, 6.7mm.
Conclusions: The utilization of ABC in HCC 3DCRT is feasible, and can reduce liver irradiation.