| 孙蕴,尉可道,王建超,潘克梫.双能X射线骨吸收测量仪的辐射剂量评价[J].中华放射医学与防护杂志,2017,37(11):870-874 |
| 双能X射线骨吸收测量仪的辐射剂量评价 |
| Assessment of radiation dose in dual energy X-ray absorptiometry scanner |
| 投稿时间：2017-07-20 |
| DOI：10.3760/cma.j.issn.0254-5098.2017.11.014 |
| 中文关键词: 双能X射线骨吸收测量仪 辐射防护 入射体表剂量 |
| 英文关键词:Dual energy X-ray absorptiometry (DXA) scanner Radiation protection Entrance surface dose (ESD) |
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| 中文摘要: |
| 目的 评价双能X射线骨吸收测量仪（DXA）的辐射剂量。方法 使用美国Radcal公司多功能剂量仪（1 800 cc电离室）对美国Norland公司XR-800 DXA （笔形束扫描，100/46.8 kVp、1.3 mA）进行剂量检测，得到正位腰椎、髋关节、腕骨、下颌骨扫描的受检者入射体表剂量（ESD）；使用Radcal剂量仪对美国Hologic公司Discovery A DXA （扇形束扫描，140/100 kVp、2.5 mA）进行剂量检测，得到正位腰椎、髋关节扫描的受检者ESD；对比两种机器在不同扫描方式下骨密度检查受检者的ESD。使用美国Fluke公司451P巡测仪对这两台DXA仪器正位腰椎扫描分别在距床面模体中心1 m和地面高1 m处测量周围剂量当量率水平。结果 Radcal公司多功能剂量仪测得Norland XR-800 DXA受检者正位腰椎扫描的ESD为0.43 μGy （高速度）和0.73 μGy （标准速度），髋关节、腕关节、下颌骨扫描的ESD分别为1.93（初扫+测量扫描）、0.40和1.06 μGy （初扫+测量扫描）。Radcal多功能剂量仪测得Hologic Discovery A DXA受检者正位腰椎、髋关节扫描的ESD分别为65.6和63.9 μGy。Norland XR-800 DXA 4个检查部位在不同扫描方式和不同扫描速度下，受检者ESD均<2 μGy，Hologic Discovery A DXA正位腰椎及髋关节受检者ESD均<66 μGy，与两台机器的操作手册给出的数据基本一致。使用451P巡测仪对两台DXA周围剂量当量率测量显示，扇形束机器高于笔形束机器65倍。结论 受检者做骨密度检查的ESD是医用X射线检查项目中较低的，笔形束扫描DXA常规腰椎及髋关节的受检者ESD约为扇形束扫描DXA检查剂量的1/153~1/33。笔形束DXA扫描的工作人员接受的剂量可忽略不计，扇形束DXA扫描的工作人员接受的剂量<20 mSv/年的个人剂量限值。 |
| 英文摘要: |
| Objective To evaluate the radiation dose from a dual energy X-ray absorptiometry (DXA) study. Methods A Radcal multifunctional dosimeter (1 800 cc ionization chamber, USA) was used, for purpose of comparison, to measure the entrance surface doses (ESD) from Norland XR-800 DXA (pencil beam scan, 100/46.8 kVp, 1.3 mA) and from Hologic Discovery A DXA (fan beam scan, 140/100 kVp, 5.0 mA). Ambient dose equivalent rate at 1 m away from studied phantom center and at 1 m above floor was measured using the US 451P ionizaion chamber survey meter (Fluke, USA). ResultsThe ESD measured using a Radcal dosimeter for Norland XR-800 DXA was 0.43 μGy in high speed mode and 0.73 μGy in standard mode (AP spine), 1.93 μGy (hip), 0.40 μGy (wrist) and 1.06 μGy (mandible). The ESD measured for Hologic Discovery A DXA was 65.6 μGy (AP spine) and 63.9 μGy (hip). The ESD measured for Norland XR-800 at different scan types and scan speeds was <2 μGy while Hologic Discovery A DXA showed a result of <66 μGy (AP spine and hip scan), which were both consistent with the data given in their own respective operational manual. A comparison of DXA scanners with fan beam and pencil beam indicated that ambient equivalent dose rate, measured with 451P survey meter, from fan beam scan was 65 times that from pencil beam scan. Conclusions Compared with other medical X-ray studies, the ESD to the phantom undergoing a DXA study is relatively low. DXA pencil beam scan doses to lumbar spine and hip were about 1/153-1/33 of those from DXA fan beam scan. Pencil beam scan dose to DXA staff was negligible and fan beam scan dose to DXA staff was lower than the personal dose limits of 20 mSv per year. |
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