Department of Physics, Royal Marsden NHS Foundation Trust, Sutton, Surrey, SM2 5PT, UK.
Eur J Nucl Med Mol Imaging. 2010 Feb;37(2):270-5. doi: 10.1007/s00259-009-1261-3. Epub 2009 Sep 4.
The aim of this study was to determine the range of absorbed doses delivered to thyroid remnants, blood, and red marrow from fixed administrations of radioiodine and to ascertain whether the success of ablation is more dependent on these absorbed doses than on the administered activity.
Twenty-three patients received 3,000 MBq radioiodine following near-total thyroidectomy. The maximum absorbed dose to remnants was calculated from subsequent single photon emission tomography scans. Absorbed doses delivered to blood and red marrow were calculated from blood samples and from whole-body retention measurements. The protein bound iodine (PBI) was also calculated.
Maximum absorbed doses to thyroid remnants ranged from 7 to 570 Gy. Eighteen of the 23 patients had a successful ablation. A significant difference was seen between the absorbed doses delivered to thyroid remnants, blood, and red marrow for those patients that had a successful ablation compared to those with a failed ablation (p = 0.030, p = 0.043 and p = 0.048, respectively). The difference between the PBI values acquired at day 1 and day 6 were also indicative of response (p = 0.074).
A successful ablation is strongly dependent on the absorbed dose to the thyroid remnant. Dosimetry-based personalized treatment can prevent both sub-optimal administrations, which entails further radioiodine therapy, and excessive administration of radioactivity, which increases the potential for radiation toxicity.
本研究旨在确定甲状腺残余组织、血液和红骨髓从固定放射性碘治疗中吸收剂量的范围，并确定消融的成功是否更依赖于这些吸收剂量，而不是给药活度。
23 例患者在近全甲状腺切除术后接受 3000MBq 放射性碘治疗。通过随后的单光子发射断层扫描计算残余物的最大吸收剂量。通过血液样本和全身滞留测量计算血液和红骨髓的吸收剂量。同时还计算了蛋白结合碘（PBI）。
甲状腺残余组织的最大吸收剂量范围为 7 至 570Gy。23 例患者中有 18 例消融成功。与消融失败的患者相比，成功消融患者的甲状腺残余组织、血液和红骨髓的吸收剂量有显著差异（p=0.030、p=0.043 和 p=0.048）。第 1 天和第 6 天获得的 PBI 值之间的差异也表明了反应情况（p=0.074）。
成功的消融强烈依赖于甲状腺残余组织的吸收剂量。基于剂量学的个体化治疗可以预防剂量不足的治疗，这需要进一步的放射性碘治疗，同时也可以防止放射性活度的过度使用，从而降低辐射毒性的风险。
