Study on Absorbed Dose Determination of Electron Beam Quality for Cross-calibration with Plane-parallel Ionization Chamber.
- Author:
Jeong Eun RAH
1
;
Dong Oh SHIN
;
So Hyun PARK
;
Hojin JEONG
;
Ui Jung HWANG
;
Sung Hwan AHN
;
Young Kyung LIM
;
Dong Wook KIM
;
Myonggeun YOON
;
Dong Ho SHIN
;
Se Byeong LEE
;
Tae Suk SUH
;
Sung Yong PARK
Author Information
1. Proton Therapy Center, National Cancer Center, Korea. cool_park@ncc.re.kr
- Publication Type:Original Article
- Keywords:
Electron beam;
Absorbed dose to water calibration coefficient;
Plane-parallel ionization chamber;
Cross-calibration;
Beam quality
- MeSH:
Electrons;
Water
- From:Korean Journal of Medical Physics
2009;20(2):97-105
- CountryRepublic of Korea
- Language:Korean
-
Abstract:
Absorbed dose to water based protocols recommended that plane-parallel chambers be calibrated against calibrated cylindrical chambers in a high energy electron beam with R50>7 g/cm2 (E> or =16 MeV). However, such high-energy electron beams are not available at all radiotherapy centers. In this study, we are compared the absorbed dose to water determined according to cross-calibration method in a high energy electron beam of 16 MeV and in electron beam energies of 12 MeV below the cross-calibration quality remark. Absorbed dose were performed for PTW 30013, Wellhofer FC65G Farmer type cylindrical chamber and for PTW 34001, Wellhofer PPC40 Roos type plane-parallel chamber. The cylindrical and the plane-parallel chamber to be calibrated are compared by alternately positioning each at reference depth, zref=0.6R50-0.1 in water phantom. The DW of plane-parallel chamber are derived using across-calibration method at high-energy electron beams of 16, 20 MeV. Then a good agreement is obtained the DW of plane-parallel chamber in 12 MeV. The agreement between 20 MeV and 12 MeV are within 0.2% for IAEA TRS-398.
