Flower M A, al-Saadi A, Harmer C L, McCready V R, Ott R J
Thyroid Unit, Royal Marsden Hospital, Sutton, Surrey, UK.
Eur J Nucl Med. 1994 Jun;21(6):531-6. doi: 10.1007/BF00173041.
With the acknowledged problems associated with assessment of functioning thyroid mass and hence radiation dose, our policy had been to give 75 MBq iodine-131 at 6-monthly intervals to patients with Graves' disease until they became euthyroid. Since positron emission tomography (PET) has been available at this hospital, the radiation dose to the thyroid has been calculated with an accuracy of approximately 20%, the thyroid mass being determined from an iodine-124 PET scan. A dose-response study has been carried out on 65 patients who have received single or cumulative radiation doses of < 80 Gy. The results show that patients who receive a low radiation dose (< 20 Gy) at their first treatment have a high probability of remaining toxic at 12 months. In contrast, patients who receive higher radiation doses (> 40 Gy) at their first treatment have a high probability of control. The probability of becoming euthyroid increases more rapidly with increasing radiation dose than the probability of becoming hypothyroid. Following this dose-response study, a new treatment protocol has been introduced. A 124I PET tracer study prior to 131I therapy will be performed to enable a prescribed thyroid dose of 50 Gy to be delivered to patients with Graves' disease. Further 131I therapy will only be considered if patients are still toxic at 12 months.
鉴于公认的与功能性甲状腺肿块评估以及由此产生的辐射剂量相关的问题，我们的政策一直是每6个月给格雷夫斯病患者75兆贝克勒尔的碘-131，直到他们甲状腺功能正常。自从这家医院可以进行正电子发射断层扫描（PET）以来，甲状腺的辐射剂量已能精确计算，误差约为20%，甲状腺肿块通过碘-124 PET扫描确定。对65名接受单次或累积辐射剂量<80戈瑞的患者进行了剂量反应研究。结果表明，首次治疗时接受低辐射剂量（<20戈瑞）的患者在12个月时仍有毒性的可能性很高。相比之下，首次治疗时接受较高辐射剂量（>40戈瑞）的患者有很大的概率得到控制。甲状腺功能正常的概率随辐射剂量增加的速度比甲状腺功能减退的概率增加得更快。在这项剂量反应研究之后，引入了一种新的治疗方案。在进行碘-131治疗之前将进行碘-124 PET示踪剂研究，以便能给格雷夫斯病患者输送规定的50戈瑞甲状腺剂量。只有在患者12个月时仍有毒性的情况下才会考虑进一步的碘-131治疗。
