比较不同 NTCP 模型/参数，使用 PBC 算法与 AAA 的临床意义。
Clinical implications in the use of the PBC algorithm versus the AAA by comparison of different NTCP models/parameters.
机构信息
Medical Physics, PioXI Clinic and UOC Medical Physics, S Giovanni Calibita Fatebenefratelli Hospital, Rome, Italy.
出版信息
Radiat Oncol. 2013 Jul 4;8(1):164. doi: 10.1186/1748-717X-8-164.
PURPOSE
Retrospective analysis of 3D clinical treatment plans to investigate qualitative, possible, clinical consequences of the use of PBC versus AAA.
METHODS
The 3D dose distributions of 80 treatment plans at four different tumour sites, produced using PBC algorithm, were recalculated using AAA and the same number of monitor units provided by PBC and clinically delivered to each patient; the consequences of the difference on the dose-effect relations for normal tissue injury were studied by comparing different NTCP model/parameters extracted from a review of published studies. In this study the AAA dose calculation is considered as benchmark data. The paired Student t-test was used for statistical comparison of all results obtained from the use of the two algorithms.
RESULTS
In the prostate plans, the AAA predicted lower NTCP value (NTCPAAA) for the risk of late rectal bleeding for each of the seven combinations of NTCP parameters, the maximum mean decrease was 2.2%. In the head-and-neck treatments, each combination of parameters used for the risk of xerostemia from irradiation of the parotid glands involved lower NTCPAAA, that varied from 12.8% (sd=3.0%) to 57.5% (sd=4.0%), while when the PBC algorithm was used the NTCPPBC's ranging was from 15.2% (sd=2.7%) to 63.8% (sd=3.8%), according the combination of parameters used; the differences were statistically significant. Also NTCPAAA regarding the risk of radiation pneumonitis in the lung treatments was found to be lower than NTCPPBC for each of the eight sets of NTCP parameters; the maximum mean decrease was 4.5%. A mean increase of 4.3% was found when the NTCPAAA was calculated by the parameters evaluated from dose distribution calculated by a convolution-superposition (CS) algorithm. A markedly different pattern was observed for the risk relating to the development of pneumonitis following breast treatments: the AAA predicted higher NTCP value. The mean NTCPAAA varied from 0.2% (sd = 0.1%) to 2.1% (sd = 0.3%), while the mean NTCPPBC varied from 0.1% (sd = 0.0%) to 1.8% (sd = 0.2%) depending on the chosen parameters set.
CONCLUSIONS
When the original PBC treatment plans were recalculated using AAA with the same number of monitor units provided by PBC, the NTCPAAA was lower than the NTCPPBC, except for the breast treatments. The NTCP is strongly affected by the wide-ranging values of radiobiological parameters.
目的
回顾性分析 3D 临床治疗计划，以研究使用 PBC 与 AAA 的定性、可能的临床后果。
方法
使用 PBC 算法生成的 4 个不同肿瘤部位的 80 个治疗计划的 3D 剂量分布，使用 AAA 和 PBC 提供的相同数量的监测单位重新计算，并将其临床应用于每个患者；通过比较从已发表研究综述中提取的不同 NTCP 模型/参数，研究正常组织损伤的剂量-效应关系差异的后果。在这项研究中，AAA 剂量计算被视为基准数据。使用配对学生 t 检验比较使用两种算法获得的所有结果。
结果
在前列腺计划中，AAA 预测的晚期直肠出血风险的 NTCPAAA 值（NTCPAAA）对于 7 种 NTCP 参数组合中的每一种均较低，最大平均下降为 2.2%。在头颈部治疗中，涉及辐射性口干的腮腺照射风险的每种参数组合使用时，NTCPAAA 值均较低，从 12.8%（标准差=3.0%）到 57.5%（标准差=4.0%），而当使用 PBC 算法时，NTCPPBC 的范围从 15.2%（标准差=2.7%）到 63.8%（标准差=3.8%），具体取决于使用的参数组合；差异具有统计学意义。此外，在肺部治疗中，对于辐射性肺炎风险，NTCPAAA 也低于 NTCPPBC 的每个 8 组 NTCP 参数，最大平均下降为 4.5%。当使用卷积叠加（CS）算法计算的剂量分布计算 NTCPAAA 时，发现 NTCPAAA 平均增加了 4.3%。对于乳腺癌治疗后的肺炎发生风险，观察到截然不同的模式：AAA 预测的 NTCP 值更高。平均 NTCPAAA 值范围从 0.2%（标准差=0.1%）到 2.1%（标准差=0.3%），而平均 NTCPPBC 值范围从 0.1%（标准差=0.0%）到 1.8%（标准差=0.2%），具体取决于所选参数集。
结论
当使用与 PBC 提供的相同数量的监测单位的 AAA 重新计算原始 PBC 治疗计划时，除了乳腺癌治疗外，NTCPAAA 均低于 NTCPPBC。NTCP 受到广泛的放射生物学参数值的强烈影响。
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