Influence of Couch and Collimator on Dose Distribution of RapidArc Treatment Planning for Prostate Cancer in Radiation Therapy.
- Author:
Hyung Dong KIM
1
;
Byung Young KIM
;
Sung Jin KIM
;
Sang Mo YUN
;
Sung Kyu KIM
Author Information
1. Department of Physics, College of Science, Yeungnam University, Gyongsan, Korea.
- Publication Type:Original Article
- Keywords:
Prostate cancer;
RapidArc;
Dose distribution;
Radiation treatment planning
- MeSH:
Femur;
Photons;
Prostate;
Prostatic Neoplasms
- From:Korean Journal of Medical Physics
2012;23(2):99-105
- CountryRepublic of Korea
- Language:Korean
-
Abstract:
We investigated the influence of photon energy, couch and collimator angle differences between arcs on dose distribution of RapidArc treatment planning for prostate cancer. RapidArc plans were created for 6 MV and 10 MV photons using 2 arcs coplanar and noncoplanar fields. The collimator angle differences between two arcs were 0degrees, 15degrees, 30degrees, 45degrees, 60degrees, 75degrees and 90degrees. The plans were optimized using same dose constrains for target and OAR (organ at risk). To evaluate the dose distribution, plans were analyzed using CI (conformity index), HI (homogeneity index), QOC (quality of coverage), etc. Photon energy, couch and collimator angle differences between arcs had a little influence on the target and OAR. The difference of dosimetric indices was less than 3.6% in the target and OAR. However, there was significant increase in the region exposed to low dose. The increase of V15% in the femur was 6.4% (left) and 5.5% (right) for the 6 MV treatment plan and 23.4% (left), 24.1% (right) for the noncoplanar plan. The increase of V10% in the Far Region distant from target was 54.2 cc for the 6 MV photon energy, 343.4 cc for the noncoplanar and 457.8 cc for the no collimator rotation between arcs.
