This study aims to evaluate inter-fractional set-up errors in patients treated with distinct immobilization equipment (thermoplastic mask, knee-fix and feet-fix, wing board and vac-lok) for four anatomical regions inc...This study aims to evaluate inter-fractional set-up errors in patients treated with distinct immobilization equipment (thermoplastic mask, knee-fix and feet-fix, wing board and vac-lok) for four anatomical regions including brain, head and neck (HN), thorax and pelvis. Data of randomly selected 140 patients who were treated for four anatomical regions were obtained using Hi-Art Helical Tomotherapy (HT) system. Pre-treatment planning was based on automatic registration readings of computed tomography (CT) and mega-voltage computed tomography (MVCT) on a daily basis. Distinct immobilization equipment was used for varying anatomical regions. Individual mean set-up error (M), systematic error (Σ), and random error (σ) values were calculated through daily translational and rotational deviation values. The size of translational, systematic and random error was 1.31 - 4.93 mm for brain, 2.28 - 4.88 mm for HN, 4.04 - 9.90 mm for thorax, and 6.34 - 14.68 mm for pelvis. Rotational values were as follows: 0.06° - 0.73° for brain, 0.42° - 0.6° for HN, 0.48° - 1.14° for thorax and 0.65° - 1.05° for pelvis. The highest translational, systematic and random error value was obtained from the pelvic regional. The highest standard and random error value in pitch and roll was produced in the rotational direction of the pelvis (0.05° and 0.71°), while the highest error value in yaw was (1.14°) produced from thorax. Inter-fractional set-up errors were most commonly produced in the pelvis, followed by thorax. Our study results suggest that the highest systematic and random errors are found for thorax and pelvis. Distinct immobilization equipment was important in these results. Safety margins around the clinical target volume (CTV) are changeable for different anatomical regions. A future work could be developed to new equipment for immobilization because of the reduced margins CTV.展开更多
目的:探讨体质量指数(body mass index,BMI)对乳腺癌患者治疗中位移误差的影响,为乳腺癌放射治疗中计划靶区外放边界提供数据支持。方法:回顾性分析本中心乳腺癌治疗的患者153例,利用CBCT获取摆位误差,并对数据进行挖掘,计算出两组因BM...目的:探讨体质量指数(body mass index,BMI)对乳腺癌患者治疗中位移误差的影响,为乳腺癌放射治疗中计划靶区外放边界提供数据支持。方法:回顾性分析本中心乳腺癌治疗的患者153例,利用CBCT获取摆位误差,并对数据进行挖掘,计算出两组因BMI的不同而导致的误差和PTV外放的差别。结果:从左乳和右乳的摆位误差分析计算得出:在考虑BMI情况下,左乳在腹背Z方向的摆位误差随BMI的增大而略有增大。右乳在Rx方向的摆位误差随BMI的增大而增大。左乳中,腹背Z方向外扩边界随BMI增大而逐渐增大。右乳中,头脚Y方向外扩边界随BMI增大而增大。结论:医师可根据乳腺癌的左右位置和BMI的大小来判断Mptv的扩大或者缩小,从而为患者提供更个性化精准化治疗。展开更多
文摘This study aims to evaluate inter-fractional set-up errors in patients treated with distinct immobilization equipment (thermoplastic mask, knee-fix and feet-fix, wing board and vac-lok) for four anatomical regions including brain, head and neck (HN), thorax and pelvis. Data of randomly selected 140 patients who were treated for four anatomical regions were obtained using Hi-Art Helical Tomotherapy (HT) system. Pre-treatment planning was based on automatic registration readings of computed tomography (CT) and mega-voltage computed tomography (MVCT) on a daily basis. Distinct immobilization equipment was used for varying anatomical regions. Individual mean set-up error (M), systematic error (Σ), and random error (σ) values were calculated through daily translational and rotational deviation values. The size of translational, systematic and random error was 1.31 - 4.93 mm for brain, 2.28 - 4.88 mm for HN, 4.04 - 9.90 mm for thorax, and 6.34 - 14.68 mm for pelvis. Rotational values were as follows: 0.06° - 0.73° for brain, 0.42° - 0.6° for HN, 0.48° - 1.14° for thorax and 0.65° - 1.05° for pelvis. The highest translational, systematic and random error value was obtained from the pelvic regional. The highest standard and random error value in pitch and roll was produced in the rotational direction of the pelvis (0.05° and 0.71°), while the highest error value in yaw was (1.14°) produced from thorax. Inter-fractional set-up errors were most commonly produced in the pelvis, followed by thorax. Our study results suggest that the highest systematic and random errors are found for thorax and pelvis. Distinct immobilization equipment was important in these results. Safety margins around the clinical target volume (CTV) are changeable for different anatomical regions. A future work could be developed to new equipment for immobilization because of the reduced margins CTV.
文摘目的:探讨体质量指数(body mass index,BMI)对乳腺癌患者治疗中位移误差的影响,为乳腺癌放射治疗中计划靶区外放边界提供数据支持。方法:回顾性分析本中心乳腺癌治疗的患者153例,利用CBCT获取摆位误差,并对数据进行挖掘,计算出两组因BMI的不同而导致的误差和PTV外放的差别。结果:从左乳和右乳的摆位误差分析计算得出:在考虑BMI情况下,左乳在腹背Z方向的摆位误差随BMI的增大而略有增大。右乳在Rx方向的摆位误差随BMI的增大而增大。左乳中,腹背Z方向外扩边界随BMI增大而逐渐增大。右乳中,头脚Y方向外扩边界随BMI增大而增大。结论:医师可根据乳腺癌的左右位置和BMI的大小来判断Mptv的扩大或者缩小,从而为患者提供更个性化精准化治疗。
