Kawahara Daisuke, Toyoda Takatoshi, Yokomachi Kazushi, Fujioka Chikako, Nagata Yasushi
Department of Radiation Oncology, Institute of Biomedical & Health Sciences, Hiroshima University, Hiroshima City, Japan.
Radiation Therapy Section, Division of Clinical Support, Hiroshima University Hospital, Hiroshima City, Japan.
Pol J Radiol. 2023 Jun 7;88:e270-e274. doi: 10.5114/pjr.2023.128682. eCollection 2023.
To evaluate the absolute dose uncertainty at 2 different energies and for the large and small bowtie filters in dual-energy computed tomography (DECT).
Measurements were performed using DECT at 80 kV and 140 kilovoltage peak (kVp), and single-energy computed tomography (CT) at 120 kV. The absolute dose was calculated from the mass-energy absorption obtained from the half-value layer (HVL) of aluminium.
The difference in the water-to-air ratio of the mean mass energy-absorption coefficients at 80 kV and 140 kV was 2.0% for the small bow-tie filter and 3.0% for the large bow-tie filter. At lower tube voltages, the difference in the absorbed dose with the large and small bow-tie filters was larger.
The absolute dose uncertainty due to energy dependence was 3.0%, which could be reduced with single-energy beams at 120 kV or by using the average effective energy measurement with dual-energy beams.
评估双能计算机断层扫描（DECT）中两种不同能量以及大小两种蝴蝶结滤过器情况下的绝对剂量不确定性。
使用80 kV和140 kV峰值千伏（kVp）的DECT以及120 kV的单能计算机断层扫描（CT）进行测量。绝对剂量由铝半值层（HVL）获得的质能吸收计算得出。
对于小蝴蝶结滤过器，80 kV和140 kV时平均质能吸收系数的水空气比差异为2.0%，对于大蝴蝶结滤过器为3.0%。在较低管电压下，大小蝴蝶结滤过器的吸收剂量差异更大。
由于能量依赖性导致的绝对剂量不确定性为3.0%，通过120 kV的单能束或使用双能束的平均有效能量测量可以降低该不确定性。
