Pahlka Raymond B, Sonnad Jagadeesh R
INP-606 Everett Tower, University of Oklahoma Health Sciences Center, Oklahoma, OK 73190, USA.
Health Phys. 2006 Sep;91(3):227-37. doi: 10.1097/01.HP.0000214660.13440.64.
Currently, an accepted post-surgical treatment of patients with thyroid carcinoma is administration of an ablative dose of I. This treatment is well established based on extensive experience and modeling. However, for patients with renal disease, reduced iodine removal rates result in controversial thyroid doses and potentially excessive red bone marrow doses. There are differences of opinion regarding I dose recommendations ranging from a reduction in dose to an increase in dose compared with conventional amounts. Determination of suitable doses must take into account varying dialysis protocols and absorbed dose considerations to the thyroid and sensitive tissues such as red bone marrow. The specific aim of this study was to develop a simple yet comprehensive compartmental model for I kinetics in patients with thyroid carcinoma and end stage renal disease, which accounts for dialysis and provides absorbed dose estimates for the thyroid as well as the red bone marrow. STELLA, a compartmental modeling software program, was used to develop a kinetic model that includes the blood pool, thyroid, gastrointestinal tract, kidneys, bladder, and a conventional dialysis machine. Benchmarking was performed to demonstrate the validity of the model with data obtained from ICRP 30 and MIRD Dose Estimate Report No. 5. Iodine kinetics were simulated for normal patients, thyroid cancer patients, and patients with thyroid cancer and renal failure undergoing two standard types of dialysis, hemodialysis and continuous ambulatory peritoneal dialysis (CAPD). Results in this work show that thyroid doses to patients with thyroid cancer and renal failure on hemodialysis or CAPD are slightly higher than doses to patients with thyroid cancer and normal renal function. These results further indicate that red bone marrow doses to patients with thyroid cancer and renal failure on dialysis can be significantly higher than red bone marrow doses to patients with thyroid cancer and normal renal function, and thus these patients could benefit from a reduction in administered activity. Thyroid doses and red bone marrow doses to patients on standard hemodialysis depend on both dialysis frequency and the time interval between administration and first dialysis. The results in this study provide guidelines on how much activity a patient on dialysis should receive based on thyroid and red bone marrow absorbed dose (Gy MBq) considerations. This study should help to clarify some of the contradictory recommendations regarding I dose for thyroid carcinoma patients with renal failure.
目前，甲状腺癌患者术后公认的治疗方法是给予消融剂量的碘-131。基于广泛的经验和模型构建，这种治疗方法已得到充分确立。然而，对于肾病患者，碘清除率降低会导致甲状腺剂量存在争议，并且红骨髓剂量可能过高。关于碘-131剂量的建议存在不同观点，与常规剂量相比，有的建议降低剂量，有的则建议增加剂量。确定合适的剂量必须考虑不同的透析方案以及甲状腺和红骨髓等敏感组织的吸收剂量。本研究的具体目的是为甲状腺癌和终末期肾病患者开发一个简单而全面的碘-131动力学房室模型，该模型考虑了透析因素，并提供甲状腺以及红骨髓的吸收剂量估计值。使用房室建模软件程序STELLA开发了一个动力学模型，该模型包括血池、甲状腺、胃肠道、肾脏、膀胱和一台传统透析机。通过与国际辐射防护委员会（ICRP）第30号报告和医学内部辐射剂量（MIRD）剂量估计报告第5号中的数据进行对比，以证明该模型的有效性。对正常患者、甲状腺癌患者以及接受血液透析和持续非卧床腹膜透析（CAPD）这两种标准透析类型的甲状腺癌合并肾衰竭患者的碘动力学进行了模拟。这项研究的结果表明，接受血液透析或CAPD的甲状腺癌合并肾衰竭患者的甲状腺剂量略高于甲状腺癌且肾功能正常患者的剂量。这些结果进一步表明，透析的甲状腺癌合并肾衰竭患者的红骨髓剂量可能显著高于甲状腺癌且肾功能正常患者的红骨髓剂量，因此这些患者可能会受益于给药活度降低。接受标准血液透析患者的甲状腺剂量和红骨髓剂量取决于透析频率以及给药与首次透析之间的时间间隔。本研究结果提供了基于甲状腺和红骨髓吸收剂量（Gy/MBq）考虑，透析患者应接受多少活度的指导原则。这项研究应有助于澄清一些关于肾衰竭甲状腺癌患者碘-131剂量的相互矛盾的建议。
