Yang C M, Olsen K R, Schwade J G, Houdek P V, Markoe A M, Pisciotta V, Wu X
Department of Ophthalmology, Bascom Palmer Eye Institute, Miami, FL.
Exp Eye Res. 1993 Nov;57(5):577-85. doi: 10.1006/exer.1993.1162.
The dose rate effect of radiation by 125I plaque on choroidal melanoma and normal intraocular tissue was studied. In the first part of the experiment, high activity plaques (HAP) and low activity plaques (LAP) were implanted on rabbit eyes with experimental Greene choroidal melanoma to deliver a total dose of 10,000 cGy to the tumor apex. The mean dose rate calculated at 0.5 mm from the inner sclera in eight eyes with high activity plaques was 3341.5 cGy hr-1 (1 cGy = 1 rad) while that in ten eyes with low activity plaques was 239.9 cGy hr-1. For tumors less than 1.0 mm in height, both groups showed complete tumor regression at the tumor implantation site after plaque treatment. For tumors more than 1.0 mm in height, two out of two eyes in the low activity plaque group and one of four eyes in the high activity plaque group failed to show complete tumor regression. Both LAP and HAP were effective in eradicating tumors, but logistic regression analysis demonstrates that HAP was more effective than LAP when adjustment was made for initial tumor height (P = 0.032). Nine tumor control eyes without 125I plaque implantation demonstrated marked tumor growth within 3 weeks. In the second part of the experiment, 125I plaques were implanted on the sclera of 12 normal rabbits' eyes. Six received high dose rate plaque treatment, while the other six received low dose rate plaque treatment. Clinical and histologic examinations demonstrated more damaging effects to the normal chorioretinal tissues at the plaque implantation site in the high dose rate plaque group at 24 weeks of follow-up. These results suggest that high dose rate plaques are more effective than low dose rate plaques when tumor height is statistically controlled. However, high dose rate delivery increases the damaging effects on normal intraocular tissue.
研究了¹²⁵I敷贴器对脉络膜黑色素瘤及正常眼内组织的辐射剂量率效应。在实验的第一部分，将高活度敷贴器（HAP）和低活度敷贴器（LAP）植入患有实验性格林脉络膜黑色素瘤的兔眼，使肿瘤顶端接受的总剂量为10000 cGy。八只植入高活度敷贴器的眼睛，在距内巩膜0.5 mm处计算的平均剂量率为3341.5 cGy·hr⁻¹（1 cGy = 1拉德），而十只植入低活度敷贴器的眼睛的平均剂量率为239.9 cGy·hr⁻¹。对于高度小于1.0 mm的肿瘤，两组在敷贴器治疗后肿瘤植入部位均显示肿瘤完全消退。对于高度大于1.0 mm的肿瘤，低活度敷贴器组的两只眼睛中有两只、高活度敷贴器组的四只眼睛中有一只未显示肿瘤完全消退。LAP和HAP在根除肿瘤方面均有效，但逻辑回归分析表明，在对初始肿瘤高度进行校正后，HAP比LAP更有效（P = 0.032）。九只未植入¹²⁵I敷贴器的肿瘤对照眼在3周内显示出明显的肿瘤生长。在实验的第二部分，将¹²⁵I敷贴器植入12只正常兔眼的巩膜。六只接受高剂量率敷贴器治疗，另外六只接受低剂量率敷贴器治疗。临床和组织学检查表明，在随访24周时，高剂量率敷贴器组在敷贴器植入部位对正常脉络膜视网膜组织的损伤作用更大。这些结果表明，在对肿瘤高度进行统计学控制时，高剂量率敷贴器比低剂量率敷贴器更有效。然而，高剂量率照射会增加对正常眼内组织的损伤作用。
