Journal of radiological science and technology (대한방사선기술학회지:방사선기술과학)

Korean Society of Radiological Science (대한방사선과학회)
권호 표지

Consideration on Measured Patients Dose of Three-Dimensional and Four-Dimensional Computer Tomography when CT-Simulation to Radiation Therapy

방사선치료를 위한 CT 검사 시 3DCT와 4DCT에 대한 피폭선량 고찰

  • Park, Ryeong-Hwang (Department of Radiation Oncology, Yonsei Cancer Center, Yonsei University Health System) ;
  • Kim, Min-Jung (Department of Radiation Oncology, Yonsei Cancer Center, Yonsei University Health System) ;
  • Lee, Sang-Kyu (Department of Radiation Oncology, Yonsei Cancer Center, Yonsei University Health System) ;
  • Park, Kwang-Woo (Department of Radiation Oncology, Yonsei Cancer Center, Yonsei University Health System) ;
  • Jeon, Byeong-Cheol (Department of Radiation Oncology, Yonsei Cancer Center, Yonsei University Health System) ;
  • Cho, Jeong-Hee (Department of Radiation Oncology, Yonsei Cancer Center, Yonsei University Health System) ;
  • Yoo, Beong-Gyu (Department of Radiotechnology, Wonkwang Health Science University) ;
  • Lee, Jong-Seok (Department of Radiotechnology, Wonkwang Health Science University)
  • 박령황 (연세의료원 암센터 방사선종양학과) ;
  • 김민정 (연세의료원 암센터 방사선종양학과) ;
  • 이상규 (연세의료원 암센터 방사선종양학과) ;
  • 박광우 (연세의료원 암센터 방사선종양학과) ;
  • 전병철 (연세의료원 암센터 방사선종양학과) ;
  • 조정희 (연세의료원 암센터 방사선종양학과) ;
  • 유병규 (원광보건대학교 방사선과) ;
  • 이종석 (원광보건대학교 방사선과)
  • Received : 2011.10.31
  • Accepted : 2011.12.09
  • Published : 2011.12.30
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Abstract

This study was to measure the patient dose difference between 3D treatment planning CT and 4D respiratory gating CT. Study was performed with each 10 patients who have lung and liver cancer for measured patient exposure dose by using SOMATON SENSATION OPEN(SIMENS, GERMANY). CTDIvol and DLP value was used to analyze patient dose, and actual dose was measured in the location of liver and kidney for abdominal examination and lung, heart and spinal cord for chest examination. Rando phantom were used for the experiment. OSLD was used for in-vitro and in-vivo dosimetry. Increasing overall actual dose in 4D respiratory gated CT-simulation using OSLD increase the dose by 5.5 times for liver cancer patients and 6 times for lung cancer patients. In CT simulation of 10 lung cancer patients, CTDIvol value was increased by 5.7 times and DLP 2.4 times. For liver cancer patients, CTDIvol was risen by 3.8 times and DLP 1.6 times. The accuracy of treatment volume could be increased in 4D CT planning for position change due to the breaths of patient in the radiation therapy. However, patients dose was increased in 4D CT than 3D CT. In conclusion, constant efforts is required to reduce patients dose by reducing scan time and scan range.

방사선치료를 위한 CT 검사 시 동일 환자에 대하여 3차원영상과, 호흡주기영상을 획득하기 위한 컴퓨터단층촬영에서 환자의 피폭선량을 측정하고자 SOMATON SENSATION OPEN(SIEMENS, GERMANY)을 이용하여 내원환자 중 폐암환자 10명, 간암환자 10명의 CT 검사 시 피폭선량을 측정했다. 환자가 받는 피폭선량은 The volume CT dose index(CTDIvol), Dose Length Product(DLP)를 이용하여 분석하였으며 각각의 장기들이 받는 피폭선량의 실측은 환자의 장기를 대상으로 할 수 없어 Rando 팬텀을 이용 흉부검사 시 폐와 심장, 척수를, 복부검사 시 간과 신장의 위치를 선택하여 in-vitro와 in-vivo 계측이 가능한 광유도발광선량계(Optically Stimulated Luminescent Dosimeter, Landauer, Inc., USA)를 이용하여 측정하였다. 폐암환자의 CT 검사 시 10명의 CTDIvol값은 5.7배, DLP값은 약 2.4배, 간암환자의 CTDIvol값은 3.8배, DLP값은 약 1.6배의 값을 나타내었고, OSLD를 이용한 실측정치 역시 폐암환자의 경우 6배, 간암환자의 경우 5.5배의 차이를 보이는 등 4DCT 검사에서 전체적인 피폭선량의 증가를 볼 수 있었다. 방사선치료 시 호흡에 의한 치료부위의 위치변화를 4DCT 검사를 이용하여 움직임을 보정하여 치료계획시 치료용적의 정확성을 높일 수 있으나 4DCT 검사로 인한 환자의 피폭선량 증가를 고려하여 검사시간과 검사범위를 줄여 피폭선량을 감소시키기 위한 노력이 필요하다.

Keywords

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