Chaudhari Suresh, Deshpande Sudesh, Anand Vivek, De Sandeep, Saxena Sanjay, Dash A, Basu Mahua, Samant Preetam, Kannan V
Department of Radiation Oncology, P. D. Hinduja National Hospital and MRC, Mumbai, India.
J Med Phys. 2008 Jan;33(1):14-8. doi: 10.4103/0971-6203.39419.
Intraocular malignant lesions are frequently encountered in clinical practice. Plaque brachytherapy represents an effective means of treatment for intraocular lesions. Recently Radiopharmaceutical Division, BARC, Mumbai, has indigenously fabricated reasonable-cost I-125 sources. Here we are presenting the preliminary experience of dosimetry of sources, configuration of treatment planning system (TPS) and quality assurance (QA) for eye plaque therapy with Occu-Prosta I-125 seeds, treated in our hospital, for a patient with ocular lesions. I-125 seeds were calibrated using well-type chamber. BrachyVision TPS was configured with Monte Carlo computed radial dose functions and anisotropy functions for I-125 sources. Dose calculated by TPS at different points in central axis and off axis was compared with manually calculated dose. Eye plaque was fabricated of 17 karat pure gold, locally. The seeds were arranged in an outer ring near the edge of the plaque and in concentric rings throughout the plaque. The sources were manually digitized on the TPS, and dose distribution was calculated in three dimensions. Measured activity using cross-calibrated well-type chamber was within +/-10% of the activity specified by the supplier. Difference in TPS-calculated dose and manually calculated dose was within 5%. Treatment time calculated by TPS was in concordance with published data for similar plaque arrangement.
眼内恶性病变在临床实践中经常遇到。斑块近距离放射治疗是治疗眼内病变的一种有效方法。最近，孟买巴巴原子研究中心放射药物分部自主制造了成本合理的碘-125源。在此，我们介绍了我院使用奥克前列腺碘-125籽源对一名眼部病变患者进行眼部斑块治疗时，源剂量测定、治疗计划系统（TPS）配置和质量保证（QA）的初步经验。碘-125籽源使用井型电离室进行校准。使用针对碘-125源的蒙特卡罗计算径向剂量函数和各向异性函数配置了近距离放射治疗视觉TPS。将TPS在中心轴和离轴不同点计算的剂量与手动计算的剂量进行比较。眼部斑块在当地由17克拉纯金制成。籽源排列在斑块边缘附近的外环以及整个斑块的同心环中。在TPS上手动对源进行数字化，并计算三维剂量分布。使用交叉校准的井型电离室测量的活度在供应商规定活度的±10%以内。TPS计算剂量与手动计算剂量的差异在5%以内。TPS计算的治疗时间与类似斑块排列的已发表数据一致。
