Dosimetric comparison of volumetric modulated arc therapy with robotic stereotactic radiation therapy in hepatocellular carcinoma.
OBJECTIVE
To compare volumetric modulated arc therapy of RapidArc with robotic stereotactic body radiation therapy (SBRT) of CyberKnife in the planning and delivery of SBRT for hepatocellular carcinoma (HCC) treatment by analyzing dosimetric parameters.


METHODS
Two radiation treatment plans were generated for 29 HCC patients, one using Eclipse for the RapidArc plan and the other using Multiplan for the CyberKnife plan. The prescription dose was 60 Gy in 3 fractions. The dosimetric parameters of planning target volume (PTV) coverage and normal tissue sparing in the RapidArc and the CyberKnife plans were analyzed.


RESULTS
The conformity index was 1.05 ± 0.02 for the CyberKnife plan, and 1.13 ± 0.10 for the RapidArc plan. The homogeneity index was 1.23 ± 0.01 for the CyberKnife plan, and 1.10 ± 0.03 for the RapidArc plan. For the normal liver, there were significant differences between the two plans in the low-dose regions of V1 and V3. The normalized volumes of V60 for the normal liver in the RapidArc plan were drastically increased when the mean dose of the PTVs in RapidArc plan is equivalent to the mean dose of the PTVs in the CyberKnife plan.


CONCLUSIONS
CyberKnife plans show greater dose conformity, especially in small-sized tumors, while RapidArc plans show good dosimetric distribution of low dose sparing in the normal liver and body.
Department of Radiation Oncology, Korea Institute of Radiological and Medical Sciences, Seoul, Korea.
Eun Kyung
EK
Paik
Department of Radiation Oncology, Korea Institute of Radiological and Medical Sciences, Seoul, Korea.
Mi-Sook
MS
Kim
Department of Radiation Oncology, Dongnam Institute of Radiological and Medical Sciences, Busan, Korea.
Chul Won
CW
Choi
Department of Radiation Oncology, Korea Institute of Radiological and Medical Sciences, Seoul, Korea.
Won Il
WI
Jang
Department of Radiation Oncology, Korea Institute of Radiological and Medical Sciences, Seoul, Korea.
Sung Hyun
SH
Lee
Department of Radiation Oncology, Korea Institute of Radiological and Medical Sciences, Seoul, Korea.
Sang Hyoun
SH
Choi
Department of Radiation Oncology, Korea Institute of Radiological and Medical Sciences, Seoul, Korea.
Kum Bae
KB
Kim
CyberKnife Center, Korea Institute of Radiological and Medical Sciences, Seoul, Korea.
Dong Han
DH
Lee
Hepatocellular carcinoma; Radiosurgery; Robotic radiosurgery; Volumetric modulated arc therapy