Rosado Paulo Henrique, Salata Camila, David Mariano Gazineu, Mantuano Andrea, Pickler Arissa, Mota Carla Lemos, de Almeida Carlos E
Brazilian National Ionizing Radiation Metrology Laboratory, Radioprotection and Dosimetry Institute (IRD), Rio de Janeiro, Brazil.
Department of Medical and Research Facilities, National Nuclear Energy Authority (CNEN), Rio de Janeiro, Brazil.
Med Phys. 2020 Nov;47(11):5802-5809. doi: 10.1002/mp.14473. Epub 2020 Oct 6.
For x-ray beams in the low and medium energy range, reference dosimetry is established in terms of air kerma. Fricke dosimetry has shown great potential in the absolute measurements of the absorbed dose to water for high-energy ranges. Therefore, the main purpose of this work was to compare the absorbed dose to water for medium-energy x-ray beams obtained through Fricke dosimetry with that obtained from the air kerma rate.
To determine the absorbed dose to water using Fricke dosimetry, the polyethylene bags methodology was chosen. Fricke solution was irradiated at four different beam qualities. The absorbed dose to water values obtained using Fricke dosimetry were compared to those obtained using the standard protocol, using the Z-score.
Values of the Z-score were <2 for all measurements of absorbed dose to water, which means that the values obtained using Fricke dosimetry are equivalent to those obtained using the reference protocol. The combined standard uncertainty for the absorbed dose to water obtained by Fricke dosimetry was lower than that obtained with the ionization chamber.
Chemical dosimetry using a standard FeSO solution has been demonstrated to be a potential option as a standard for the quantity absorbed dose to water for medium kV x-ray qualities.
对于低能和中能范围的X射线束，参考剂量学是根据空气比释动能来建立的。弗里克剂量学在高能范围内水吸收剂量的绝对测量中显示出巨大潜力。因此，这项工作的主要目的是比较通过弗里克剂量学获得的中能X射线束的水吸收剂量与从空气比释动能率获得的水吸收剂量。
为了使用弗里克剂量学确定水吸收剂量，选择了聚乙烯袋方法。弗里克溶液在四种不同的射束质下进行照射。使用Z分数将通过弗里克剂量学获得的水吸收剂量值与使用标准方案获得的值进行比较。
所有水吸收剂量测量的Z分数值均<2，这意味着使用弗里克剂量学获得的值与使用参考方案获得的值相当。弗里克剂量学获得的水吸收剂量的合成标准不确定度低于电离室获得的合成标准不确定度。
使用标准硫酸亚铁溶液的化学剂量学已被证明是作为中千伏X射线质水吸收剂量量值标准的一种潜在选择。
