Raudabaugh Justin, Nguyen Giao, Lowry Carolyn, Januzis Natalie, Colsher James, Nelson Rendon, Yoshizumi Terry T
Medical Physics Graduate Program, Duke University, Durham, NC, USA.
Duke Radiation Dosimetry Laboratory, Duke University Medical Center, Durham, NC, USA.
Radiat Prot Dosimetry. 2018 Dec 1;182(3):352-358. doi: 10.1093/rpd/ncy072.
The purpose of this study was to validate a novel approach to estimating effective dose (E) in 'fast-kV switch dual energy computed tomography' using MOSFET detectors. The effective energy of the combined dual energy environment was characterized with the dual energy CT scanner and then MOSFETs were calibrated matching to the effective energy of the dual energy CT beam with a conventional CT beam. The calibration method was then experimentally validated by comparing the dose between MOSFET and an ion chamber (IC) using a standard CTDI body phantom. The measured doses of the MOSFET and IC were 17.1 mGy ± 3.8% and 17.1 mGy ± 0.4%, respectively. To measure organ doses, an adult anthropomorphic phantom loaded with 18 MOSFET detectors was scanned using a standard fast-kV switch dual energy abdomen/pelvis CT protocol. E was calculated by applying ICRP 103 tissue weighting factors as well as partial volume correction factors for organs that were not completely covered by the protocol field-of-view. E from the dual energy abdomen/pelvis CT was calculated to be 17.8 mSv ± 11.6%. This calculation was then compared to E from dose length product method, which yielded 14.62 mSv.
本研究的目的是验证一种使用MOSFET探测器在“快速千伏切换双能计算机断层扫描”中估算有效剂量（E）的新方法。利用双能CT扫描仪对组合双能环境的有效能量进行了表征，然后将MOSFET校准为与双能CT束的有效能量相匹配，使其等同于传统CT束的有效能量。然后，通过使用标准CTDI体模比较MOSFET和电离室（IC）之间的剂量，对校准方法进行了实验验证。MOSFET和IC的测量剂量分别为17.1 mGy±3.8%和17.1 mGy±0.4%。为了测量器官剂量，使用标准的快速千伏切换双能腹部/盆腔CT协议对装载有18个MOSFET探测器的成人人体模型进行扫描。通过应用ICRP 103组织权重因子以及对未被协议视野完全覆盖的器官的部分体积校正因子来计算E。双能腹部/盆腔CT的E计算值为17.8 mSv±11.6%。然后将该计算结果与剂量长度乘积法得出的E进行比较，后者为14.62 mSv。
