Coia L, Galvin J, Sontag M, Blitzer P, Brenner H, Cheng E, Doppke K, Harms W, Hunt M, Mohan R
University of Pennsylvania School of Medicine, Philadelphia, PA.
Int J Radiat Oncol Biol Phys. 1991 May 15;21(1):183-92. doi: 10.1016/0360-3016(91)90177-6.
The role of three-dimensional (3-D) treatment planning in the definitive treatment of carcinoma of the larynx with radiation was evaluated at four institutions as part of an NCI contract. A total of 30 different treatment approaches were devised for two patients with larynx cancer. CT scans were obtained for both patients and various treatment planning tools were employed to optimize beam arrangements and to evaluate the resulting dose distribution. The effect on dose distribution of a number of factors was also examined: 1) the use of dose calculation algorithms which correct for tissue inhomogeneities, 2) the variation of the CT numbers used for inhomogeneity corrections to simulate inaccuracies in the knowledge of the CT numbers, and 3) the modification of beam energy. A multitude of data was used in plan evaluation and a numerical score was given to each plan to estimate the tumor control probability and the normal tissue complication probability. We found 3-D treatment planning to be of potential value in optimizing treatment plans in larynx cancer. Improved target coverage was achieved when complete information describing 3-D geometry of the anatomy was utilized. In some cases, the treatment planning tools employed, such as the beam's eye view, helped devise novel beam arrangements which were useful alternatives to standard techniques. We found little effect of change in CT number on dose distributions. A comparison between dose distributions calculated with tissue inhomogeneity corrections to those calculated without this correction showed little difference. We did find some improvement in the dose to the primary tumor volume at lower beam energies, but with an increased larynx volume potentially receiving doses above tolerance.
作为美国国立癌症研究所（NCI）一项合同的一部分，四家机构对三维（3-D）治疗计划在喉癌根治性放射治疗中的作用进行了评估。针对两名喉癌患者共设计了30种不同的治疗方案。为两名患者均进行了CT扫描，并使用了各种治疗计划工具来优化射束布置并评估由此产生的剂量分布。还研究了许多因素对剂量分布的影响：1）使用校正组织不均匀性的剂量计算算法；2）用于不均匀性校正的CT数值变化，以模拟CT数值知识中的不准确情况；3）射束能量的改变。在计划评估中使用了大量数据，并为每个计划给出一个数值分数，以估计肿瘤控制概率和正常组织并发症概率。我们发现三维治疗计划在优化喉癌治疗计划方面具有潜在价值。当利用描述解剖结构三维几何形状的完整信息时，可实现更好的靶区覆盖。在某些情况下，所使用的治疗计划工具，如射束视场，有助于设计新颖的射束布置，这是标准技术的有用替代方案。我们发现CT数值的变化对剂量分布影响很小。对经组织不均匀性校正计算的剂量分布与未经校正计算的剂量分布进行比较，差异不大。我们确实发现在较低射束能量下，原发肿瘤体积的剂量有所改善，但潜在接受高于耐受剂量的喉部体积增加。
