Prediction error and required internal margin provided for irregular respiratory movements: a phantom study
Prediction error and required internal margin provided for irregular respiratory movements: a phantom study
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为不规则呼吸运动提供的预测误差和所需的内部裕度：一项模型研究
DOI：
10.1007/s11604-015-0418-1
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发表时间：
2015
期刊：
影响因子：
2.1
通讯作者：
H. Sakurai
中科院分区：
文献类型：
--
作者：
N. Fukumitsu;H. Numajiri;K. Ohnishi;M. Mizumoto;T. Aihara;H. Ishikawa;T. Okumura;K. Tsuboi;T. Terunuma;T. Sakae;H. Sakurai
目的估计不规则呼吸运动的预测误差和所需的内缘。材料与方法利用运动模体制备了28种不规则运动模式。对于不规则周期运动，每4个周期在基线运动数据中插入一个2.0-5.0 s的周期（3.5 s周期，6 mm振幅）。此外，每四个周期在不规则数据点中插入一个2.5-4.5 s的周期，以产生更复杂的不规则性。对于不规则振幅运动，在基线呼吸运动数据中插入3.0-9.0 mm的振幅。此外，每4个周期在不规则数据点中插入4.0-8.0 mm的振幅，以产生更复杂的不规则。利用实时位置管理（RPM）和四维CT （4DCT）系统获取运动目标图像。计算了基线图像的位移和补偿不规则运动所需的余量。结果采样不规则比周期不规则更容易失去稳定的位置，需要更大的边缘来补偿图像再现性的降低。当目标以较为复杂的不规则幅度运动时，会产生较大的位移和所需的裕度。结论RPM和4DCT系统存在预测误差的风险，这可能是由于呼吸运动的复杂幅度不规则性造成的。
PurposeTo estimate the prediction error and required internal margin provided for irregular respiratory movements.Materials and methodsTwenty-eight patterns of irregular movement were prepared using a moving phantom. For irregular cycle movement, a cycle of 2.0–5.0 s was inserted into the baseline movement data (3.5-s cycle, 6-mm amplitude) every four cycles. In addition, a cycle of 2.5–4.5 s was further inserted into one of the irregular data points every four cycles to produce more complicated irregularity. For irregular amplitude movement, an amplitude of 3.0–9.0 mm was inserted into the baseline respiratory movement data. In addition, an amplitude of 4.0–8.0 mm was further inserted into one of the irregular data points every four cycles to produce more complicated irregularity. Images of the moving target were acquired using a real-time position management (RPM) and four-dimensional CT (4DCT) system. The displacement from the baseline image and required margin to compensate for irregular movement were calculated.ResultsAmplitude irregularity tended to lose stable placement and need larger margins to compensate for the reduction of image reproducibility than cycle irregularity. There was a large displacement and required margin when the target moved with more complicated irregular amplitude.ConclusionThe RPM and 4DCT system has a risk of prediction error, which may result from the complicated amplitude irregularity of respiratory movement.