Dodd G D, Frank M S, Aribandi M, Chopra S, Chintapalli K N
Department of Radiology, The University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Dr., San Antonio, TX 78284, USA.
AJR Am J Roentgenol. 2001 Oct;177(4):777-82. doi: 10.2214/ajr.177.4.1770777.
The purpose of this study was to perform a computer analysis of the size of the thermal injury created by overlapping multiple thermal ablation spheres.
A computer-assisted design system was used to create three-dimensional models of a spherical tumor, a spherical tissue volume consisting of the tumor plus a 1-cm tumor-free margin, and individual spherical ablations. These volumes were superimposed in real-time three-dimensional space in different geometric relationships. The effect of the size and geometric configuration of the ablation spheres was analyzed with regard to the ability to ablate the required volume of tissue (tumor plus margin) without leaving untreated areas or interstices.
The single-ablation model showed that if a 360-degree 1-cm tumor-free margin is included around the tumor targeted for ablation, radiofrequency ablation devices producing 3-, 4-, and 5-cm ablation spheres can be used to treat 1-, 2-, and 3-cm tumors, respectively. The six-sphere model, in which six ablation spheres are placed in orthogonal planes around the tumor, showed that the largest tumor that may be treated with a 3-cm ablation device is 1.75 cm, whereas 4- and 5-cm ablation spheres can be used to treat tumors measuring 3 and 4.25 cm, respectively. The 14- sphere model showed that addition of eight more spheres to the six-sphere model increased the treatable tumor size to 3, 4.6, or 6.3 cm, depending on the diameter of the ablation sphere used. For treating larger tumors, we found a cylindrical model to be less efficient but easier to control.
Our computer analysis showed that the size of the composite thermal injury created by overlapping multiple thermal ablation spheres is surprisingly small relative to the number of ablations performed. These results emphasize the need for a methodic tumor ablation strategy.
本研究旨在对多个热消融球体重叠所造成的热损伤大小进行计算机分析。
使用计算机辅助设计系统创建球形肿瘤、由肿瘤加1厘米无瘤边缘组成的球形组织体积以及单个球形消融的三维模型。这些体积在实时三维空间中以不同的几何关系叠加。分析消融球体的大小和几何构型对消融所需组织体积（肿瘤加边缘）而不留下未治疗区域或间隙的能力的影响。
单消融模型显示，如果在靶向消融的肿瘤周围包含360度1厘米的无瘤边缘，产生3厘米、4厘米和5厘米消融球体的射频消融设备可分别用于治疗1厘米、2厘米和3厘米的肿瘤。六球体模型中，六个消融球体围绕肿瘤放置在正交平面上，结果显示，使用3厘米消融设备可治疗的最大肿瘤为1.75厘米，而4厘米和5厘米的消融球体可分别用于治疗直径为3厘米和4.25厘米的肿瘤。14球体模型显示，在六球体模型基础上再增加八个球体，可治疗的肿瘤大小增加到3厘米、4.6厘米或6.3厘米，具体取决于所用消融球体的直径。对于治疗较大肿瘤，我们发现圆柱形模型效率较低但更易于控制。
我们的计算机分析表明，相对于所进行的消融次数，多个热消融球体重叠所产生的复合热损伤大小出奇地小。这些结果强调了需要一种系统的肿瘤消融策略。
