The systematic and random errors determination using realtime 3D surface tracking system in breast cancer

13th South-East Asian Congress of Medical Physics 2015

物理学;医药卫生

Kanphet, J.^1,3 ; Suriyapee, S.^3 ; Dumrongkijudom, N.^2 ; Sanghangthum, T.^3 ; Kumkhwao, J.^3 ; Wisetrintong, M.^3

Medical Physics School, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand^1

Department of Radiological Technology, Faculty of Medical Technology, Mahidol University, Bangkok, Thailand^2

Department of Radiology, King Chulalongkorn Memorial Hospital, Thai Red Cross Society, Bangkok, Thailand^3

关键词: Deep inspiration breath hold;    High-efficiency;    Intrafraction motion;    Lateral directions;    Organ movements;    Patient setup errors;    Reproducibilities;    Systematic uncertainties;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/694/1/012005/pdf
DOI  :  10.1088/1742-6596/694/1/012005

学科分类：卫生学

来源: IOP

【 摘 要 】

The purpose of this study to determine the patient setup uncertainties in deep inspiration breath-hold (DIBH) radiation therapy for left breast cancer patients using real-time 3D surface tracking system. The six breast cancer patients treated by 6 MV photon beams from TrueBeam linear accelerator were selected. The patient setup errors and motion during treatment were observed and calculated for interfraction and intrafraction motions. The systematic and random errors were calculated in vertical, longitudinal and lateral directions. From 180 images tracking before and during treatment, the maximum systematic error of interfraction and intrafraction motions were 0.56 mm and 0.23 mm, the maximum random error of interfraction and intrafraction motions were 1.18 mm and 0.53 mm, respectively. The interfraction was more pronounce than the intrafraction, while the systematic error was less impact than random error. In conclusion the intrafraction motion error from patient setup uncertainty is about half of interfraction motion error, which is less impact due to the stability in organ movement from DIBH. The systematic reproducibility is also half of random error because of the high efficiency of modern linac machine that can reduce the systematic uncertainty effectively, while the random errors is uncontrollable.