摘要
目的：研究CTDI100表征CT检查所致辐射剂量的准确性。方法使用长杆电离室测量不同准值宽度、螺距以及管电压下体模内剂量分布曲线并计算CT剂量效率。结果 CT剂量效率范围为79%～94%，其中，中心位置的CT剂量效率范围为79%~87%，边缘4个位置的CT剂量效率范围为79%～94%，加权CT剂量效率范围为82%～90%。准直宽度与螺距越大，CT剂量效率越低；CT剂量效率受管电压影响不明显。结论CTDI100与CTDI∞之间存在一定差异，CTDI100、CTDIw表征CT检查所致辐射剂量的准确度随准直宽度和螺距的增大而降低。
Objective To explore the accuracy ofCTDI100 in evaluating radiation dose of CT examination. Methods Dose distribution curves of the phantom under the conditions of different collimation widths, pitches and tube voltages were measured with long-pole ionization chamber and thenCTDI100 and CTDI∞were calculated to evaluate the dose efficiency of CT examination.Results The range of CT radiation dose efifciency was 79%~94%. The range of CT radiation dose efifciency located at the center was 79%~87% and that of CT radiation dose efifciency located at margins was 79%~94% while that of weighted CT radiation dose efifciency was 82%~90%. The longer the collimation widths and pitches, the lower the CT radiation dose efifciency. The inlfuence of tube voltages on CT radiation dose efifciency was unconspicuous.Conclusion There were certain differences betweenCTDI100 andCTDI∞ in evaluating radiation dose of CT examination. The accuracy ofCTDI100 andCTDIw in evaluating radiation dose of CT examination would be decreased as the increasement of collimation widths and pitches.
出处
《中国医疗设备》
2014年第11期41-42,71,共3页
China Medical Devices
基金
国家自然科学基金项目资助(81372923)
国家科技支撑计划课题(2011BAI02B02)
