Beam quality is changed about magnetic field of bending magnet. Evaluation of beam quality using PDD(Percentage Depth Dose) at 10cm depth at recommendation of AAPM(America Academy of Pain Medicine). However this evaluation shows fragmentary element. Therefore this study is applied to three value, 10cm divided by 5cm depth PDD, 20cm divided by 10cm depth PDD, 30cm divided by 20cm depth PDD, at change the magnetic field. PDD is measured at magnetic field changed ±1%, ±2% at 6MV(Mega Voltage), 10MV photon. The plan technique is 3 portal plan using Core-Plan at human pelvic phantom. Conventional and presented methods are compared at maximum and minimum dose. The presented method increased discernment of relieve the unequal distribution and energy area than conventional method. Henceforth, application of presented method will be considered. Development of energy measurement method and detector miniaturization will be needed about continuous study.

Abstract
 1. 서 론
 2. 대상 및 방법
  2.1 대상
  2.2 방법
 3. 결 과
  3.1 선량평가 오차비교
  3.2 선량평가 기준비교
  3.3 오차에 따른 기준비교
 4. 고찰 및 결론
 5. Reference
 저 자 소 개

• 김정호(건양대학교병원 방사선종양학과) | Jeong-Ho Kim
• 유세종(건양대학교병원 영상의학과) | Se-Jong Yoo Corresponding author
• 박명철(건양대학교병원 영상의학과) | Myeong-Cheol Park
• 배석환(건양대학교 방사선학과) | Seok-Hwan Bae
• 김기진(건양대학교병원 핵의학과) | Ki-Jin Kim