Saw C B, Suntharalingam N
Department of Radiation Oncology, University of Pittsburgh School of Medicine, PA 15213.
Int J Radiat Oncol Biol Phys. 1991 Jan;20(1):135-9. doi: 10.1016/0360-3016(91)90149-x.
Quantitative assessment of interstitial implants is proposed using volume versus dose curves and four well-defined dosimetric parameters. The volume versus dose curves, both differential and cumulative, provide quantitative data on the volumes of tissues irradiated to different doses. They also offer a qualitative assessment of the variations in dose delivery. The dose nonuniformity ratio (DNR) quantitatively determines the degree of dose nonuniformity specific to the implant configuration. The dose rate at which the DNR shows a minimum value, if selected as the treatment dose rate, gives an optimized dose distribution. The three volumetric irradiation indices are formulated with respect to a well-defined target volume. They offer quantitative data on the extent to which the implant delivers the prescribed dose to the target volume. These dosimetric parameters determine the degree of coverage of the target volume, dose homogeneity within the target volume, and irradiation of tissues outside the target volume. The method of quantitative assessment is demonstrated using, as examples, an ideal Ir-192 double-plane implant and an actual clinical Ir-192 double-plane breast implant.
提出使用体积-剂量曲线和四个定义明确的剂量学参数对间质植入物进行定量评估。体积-剂量曲线，包括微分曲线和累积曲线，提供了关于接受不同剂量照射的组织体积的定量数据。它们还对剂量传递的变化进行定性评估。剂量不均匀率（DNR）定量确定特定植入物配置的剂量不均匀程度。如果选择DNR显示最小值时的剂量率作为治疗剂量率，则可得到优化的剂量分布。三个体积照射指数是相对于一个定义明确的靶体积制定的。它们提供了关于植入物向靶体积输送规定剂量的程度的定量数据。这些剂量学参数决定了靶体积的覆盖程度、靶体积内的剂量均匀性以及靶体积外组织的照射情况。以理想的铱-192双平面植入物和实际临床铱-192双平面乳腺植入物为例，展示了定量评估方法。
