Saw C B, Suntharalingam N, Ayyangar K M, Tupchong L
Department of Radiation Oncology and Nuclear Medicine, Thomas Jefferson University Hospital, Philadelphia, PA 19107.
Int J Radiat Oncol Biol Phys. 1989 Oct;17(4):887-91. doi: 10.1016/0360-3016(89)90083-7.
Dose distributions of stereotactic brain implants performed by four institutions were analyzed. In these implants 192Ir or 125I sources were used. The analyses involved an evaluation of the isodose distributions in two orthogonal planes, the dose gradient outside, and the dose homogeneity within the target volume. Quantitative evaluation of the dose homogeneity was performed using three volumetric irradiation indices. The dose homogeneity was observed to improve as the number of catheters increased. However, the number of catheters used is influenced by neurosurgical considerations. Thus, it is necessary to make a compromise between dose homogeneity and the maximum number of catheters to be used. The dose gradient, a centimeter outside the target volume, was found to depend on the geometry of the implant and at distances beyond, it was found to depend on the type of radioisotopes used.
分析了四个机构进行的立体定向脑植入的剂量分布。在这些植入中使用了192Ir或125I源。分析包括评估两个正交平面中的等剂量分布、靶体积外部的剂量梯度以及靶体积内的剂量均匀性。使用三个体积照射指数对剂量均匀性进行定量评估。观察到随着导管数量的增加，剂量均匀性有所改善。然而，所使用的导管数量受到神经外科因素的影响。因此，有必要在剂量均匀性和要使用的导管最大数量之间做出折衷。发现靶体积外一厘米处的剂量梯度取决于植入物的几何形状，而在更远的距离处，发现它取决于所使用的放射性同位素的类型。
