Richmond Neil D, Turner Robert N, Dawes Peter J D K, Lambert Geoff D, Lawrence Gill P
Regional Medical Physics Department, Newcastle General Hospital, Westgate Road, Newcastle upon Tyne NE4 6BE, UK.
Radiother Oncol. 2003 May;67(2):165-70. doi: 10.1016/s0167-8140(03)00008-2.
Fifteen consecutive patients had standard treatment plans generated using our departmental protocol and two further plans produced using either an asymmetric, or MLC shaped additional field, from each tangential direction. The mean percentage of the PTV receiving over 107% of the isocentre dose was 19.8% for the standard planned patients (95% confidence interval 12.3-27.4%). This was reduced to 6.0% for the asymmetric field technique (95% confidence interval 4.1-8.0%) and 5.3% for the MLC technique (95% confidence interval 2.8-7.7%). These high dose volume reductions were therefore significant at the 95% confidence level. It was also concluded that both alternative planning techniques offer the greatest potential when the standard plan indicated that more than 20% of the PTV would receive greater than 107% of the prescribed dose. Under these circumstances the segmented field techniques led to a reduction of at least 15 percentage points in this figure. It is this group of patients who stand to benefit most from application of these simple additional field techniques.
15名连续患者按照我们科室的方案生成了标准治疗计划，并从每个切线方向额外生成了两个计划，一个使用非对称野，另一个使用多叶准直器（MLC）成形野。标准计划患者中，接受等中心剂量107%以上的计划靶体积（PTV）的平均百分比为19.8%（95%置信区间12.3 - 27.4%）。对于非对称野技术，该比例降至6.0%（95%置信区间4.1 - 8.0%）；对于MLC技术，降至5.3%（95%置信区间2.8 - 7.7%）。因此，在95%置信水平下，这些高剂量体积的减少具有显著意义。研究还得出结论，当标准计划显示超过20%的PTV将接受超过规定剂量的107%时，两种替代计划技术都具有最大潜力。在这种情况下，分段野技术使该比例至少降低了15个百分点。正是这组患者最有可能从应用这些简单的额外野技术中受益。
