通过靶向规划 CT 降低 CT 透视引导下腰椎疼痛注射的患者辐射暴露
Reducing Patient Radiation Exposure From CT Fluoroscopy-Guided Lumbar Spine Pain Injections by Targeting the Planning CT.
机构信息
1 Department of Radiology, Duke University Medical Center, Box 3808, Durham, NC 27710.
2 Department of Radiation Oncology, Duke University Medical Center, Durham, NC.
出版信息
AJR Am J Roentgenol. 2016 Feb;206(2):390-4. doi: 10.2214/AJR.15.14436.
OBJECTIVE
CT fluoroscopy-guided lumbar spine pain injections typically include a preprocedural planning CT that contributes considerably to patient dose. The purpose of this study was to quantify the degree of radiation exposure reduction achieved by modifying only the planning CT component of the examination.
MATERIALS AND METHODS
A retrospective review was performed of 80 CT fluoroscopy-guided lumbar spine injections. Forty patients were scanned with a standard protocol using automatic tube current modulation (method A). Another 40 patients were scanned using a new technique that fixed the tube current of the planning CT to either 50 or 100 mA on the basis of the patient's anteroposterior diameter and that reduced the z-axis coverage (method B). Dose-length products (DLPs) were compared for the two methods.
RESULTS
The mean maximal tube current for the planning CT was 435.0 mA for method A and 67.5 mA for method B. The mean z-axis was shorter for method B at 6.5 cm than for method A at 9.6 cm (p < 0.0001). The mean DLP for the planning CT was 11 times lower for method B than for method A: 27.9 versus 313.1 mGy × cm, respectively (p < 0.0001). When method B was used, the mean DLP for the total procedure (i.e., planning CT plus CT fluoroscopy components) was reduced by 78%. There was no significant difference between methods A and B in CT fluoroscopy time (p = 0.37). All procedures were technically successful.
CONCLUSION
A nearly fivefold reduction in radiation exposure can be achieved in CT fluoroscopy-guided lumbar spine pain injections through modifications to the planning CT alone.
目的
CT 透视引导下腰椎疼痛注射通常包括术前计划 CT，这对患者剂量有很大影响。本研究的目的是通过仅修改检查的计划 CT 部分来量化实现的辐射暴露减少程度。
材料和方法
对 80 例 CT 透视引导下腰椎注射进行回顾性研究。40 例患者采用自动管电流调制标准方案（方法 A）进行扫描。另外 40 例患者采用新技术进行扫描，该技术根据患者的前后直径将计划 CT 的管电流固定在 50 或 100 mA，并减少 z 轴覆盖范围（方法 B）。比较两种方法的剂量长度乘积（DLP）。
结果
方法 A 中计划 CT 的平均最大管电流为 435.0 mA，方法 B 中为 67.5 mA。方法 B 的平均 z 轴比方法 A 的 9.6 cm 短 6.5 cm（p < 0.0001）。方法 B 的计划 CT 的平均 DLP 比方法 A 低 11 倍：分别为 27.9 与 313.1 mGy × cm（p < 0.0001）。当使用方法 B 时，总程序（即计划 CT 加 CT 透视组件）的平均 DLP 降低了 78%。方法 A 和 B 之间的 CT 透视时间没有显著差异（p = 0.37）。所有程序均技术成功。
结论
通过仅修改计划 CT 即可在 CT 透视引导下腰椎疼痛注射中实现辐射暴露减少近五倍。
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