| 胡俏俏,张艺宝,刘卓伦,张健,岳海振,吴昊.四种常见加速器晨检仪的性能比较[J].中华放射医学与防护杂志,2015,35(7):532-535 |
| 四种常见加速器晨检仪的性能比较 |
| Performance comparison of four common LINAC daily QA instruments |
| 投稿时间：2014-07-21 |
| DOI：10.3760/cma.j.issn.0254-5098.2015.07.012 |
| 中文关键词: 晨检 中心轴输出量 平坦度 对称性 |
| 英文关键词:Morning Check Central axis output Flatness Symmetry |
| 基金项目: |
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| 摘要点击次数: 2840 |
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| 中文摘要: |
| 目的 比较4种常见直线加速器晨检仪的性能差异。方法 用三维水箱、剂量仪和电离室测量并调整直线加速器剂量学参数,确保加速器的束流系统基本稳定,包括中心轴输出量(CAX)、射野平坦度(FLAT)和射野对称性(SYM)。对4种晨检仪LINA-C、 QUICK-C、BEAM-C和QA3,设置基准线,并对加速器进行检测和记录,比较各晨检仪的监测结果。依据TG 142报告要求,设置加速器剂量学参数(CAX和SYM)偏差,使用晨检仪检测,测试其灵敏度。结果 4种晨检仪的监测结果与三维水箱和剂量仪测得的基准值相比差异不大,CAX最大偏差为LINA-C的0.5%,FLAT最大偏差为QUICK-C的-0.45%, SYM最大偏差为BEAM-C的0.5%。4台晨检仪均能检测出设定的剂量学参数偏差。结论 各台晨检仪的稳定性均能满足日常检测需求。LINA-C只能提供CAX监测,QUICK-C、BEAM-C和QA3晨检仪除了能够满足AAPM的TG 142报告中的日常设备质量控制的要求,还提供了各自独特的附加功能。基准线的设置是晨检仪是否能准确监测直线加速器剂量学参数的关键因素。测量结果报警时,建议首先检查晨检仪的工作状况,不宜以晨检仪的监测结果直接调整直线加速器。 |
| 英文摘要: |
| Objective To compare the performances of four commercially available LINAC daily QA instruments. Methods The dosimetric stability of a LINAC including central axis output, flatness and symmetry were verified and fine-tuned using a 3-dimensional water phantom, dosimeters and ionization chambers. The baseline of the four instruments including LINA-C,QUICK-C,BEAM-C and QA3 were set thereafter. Daily measurements of LINAC were conducted with these instruments respectively and the results were compared. Arbitrary errors (CAX and SYM) beyond TG-142 tolerances were introduced to the LINAC to test the sensibilities of each instrument in detecting these changes. Results Relative to the baseline that were measured by the 3-dimensional water phantom and dosimeters, the results monitored by the four instruments were comparable. The maximum disparities of the CAX, FLAT, and SYM were 0.5% (LINA-C), -0.45% (QUICK-C), and 0.5% (BEAM-C), respectively. All checkers detected the known errors successfully. Conclusions The stabilities of all the four evaluated instruments met the requirements of daily QA for LINAC. LINA-C verifies CAX only. QUICKE-C, BEAM-C and QA3 can be used to perform all the daily QA protocols as suggested by AAPM TG 142 report. They also provide unique additional functions. The setup of baseline determines if the morning checkers could measure the LINAC dosimetric parameters correctly. When an error is alarmed by the morning checker, it is recommended to verify the performance of the instrument first rather than recalibrating the LINAC immediately. |
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