Gott Katherine M, Potter Charles A, Doyle-Eisele Melanie, Lin Yong, Wilder Julie, Scott Bobby R
Lovelace Respiratory Research Institute, Albuquerque, NM, USA.
Sandia National Laboratories, Albuquerque, NM, USA.
Dose Response. 2020 Apr 3;18(2):1559325820916572. doi: 10.1177/1559325820916572. eCollection 2020 Apr-Jun.
US homeland security concerns regarding the potential misuse of some radiation sources used in radiobiological research, for example, cesium-137 (Cs), have resulted in recommendations by the National Research Council to conduct studies into replacing these sources with suitable X-ray instruments. The objective of this research is to compare the effectiveness of an X-RAD 320 irradiator (PXINC 2010) with a Cs irradiator (Gammacell-1000 Unit) using an established bone marrow chimeric model. Using measured radiation doses for each instrument, we characterized the dose-response relationships for bone marrow and splenocyte ablation, using a cytotoxicity-hazard model. Our results show that the X-RAD 320 photon energy spectrum was suitable for ablating bone marrow at the 3 exposure levels used, similar to that of Cs photons. However, the 320-kV X-rays were not as effective as the much higher energy γ rays at depleting mouse splenocytes. Furthermore, the 3 X-ray levels used were less effective than the higher energy γ rays in allowing the successful engraftment of donor bone marrow, potentially as a result of the incomplete depletion of the spleen cells. More defined studies are warranted for determining whether bone marrow transplantation in mice can be successfully achieved using 320-kV X-rays. A higher X-ray dose then used is likely needed for transplantation success.
美国国土安全部门对放射生物学研究中某些辐射源（例如铯 - 137（Cs））可能被滥用表示担忧，这导致美国国家研究委员会建议开展研究，用合适的X射线仪器替代这些辐射源。本研究的目的是使用已建立的骨髓嵌合模型，比较X - RAD 320辐照仪（PXINC 2010）和Cs辐照仪（伽马细胞 - 1000型）的有效性。利用每种仪器测量的辐射剂量，我们使用细胞毒性 - 危害模型来描述骨髓和脾细胞消融的剂量 - 反应关系。我们的结果表明，在使用的3个照射水平下，X - RAD 320的光子能谱适合于消融骨髓，与Cs光子的情况类似。然而，320 kV的X射线在耗尽小鼠脾细胞方面不如能量高得多的γ射线有效。此外，所使用的3个X射线水平在使供体骨髓成功植入方面不如能量较高的γ射线有效，这可能是由于脾细胞未被完全耗尽。需要进行更明确的研究来确定使用320 kV X射线是否能在小鼠中成功实现骨髓移植。可能需要使用更高的X射线剂量才能实现移植成功。
