Klinik und Poliklinik für Nuklearmedizin, Universitätsklinikum Köln, Germany.
Z Med Phys. 2011 Dec;21(4):258-65. doi: 10.1016/j.zemedi.2011.04.006. Epub 2011 Jun 29.
Radioiodine therapy (RIT) for benign thyroid diseases in Germany requires the patient to stay in a nuclear medicine therapy ward for at least 48 hours and the dose to the thyroid to be computed from activity measurements performed during that stay. A major part of the total dose will be delivered after the patient's discharge from the hospital and thus has to be predicted through extrapolation with the effective half-life measured peri-therapeutically. We performed repeated thyroid uptake measurements on patients up to five months post therapy to investigate post-therapeutic changes in their effective half-lives and examine the dosimetric consequences. 12 patients (4 m, 8 f; age 36 - 76 y; 4 Graves' disease, 4 toxic adenoma, 3 toxic goitre, 1 non-toxic goitre) underwent late uptake measurements (1 - 7 meas., 13 - 154 d post administration, median 54 d, performed with thyroid probe resp. whole body counter at lower activities). Doses calculated from late measurements were compared to those predicted at discharge; half-lives calculated from the late measurement closest to the median delay (54 d) were compared to those determined at time of discharge. A cross-calibration between activity calibrator, thyroid probe, and whole body counter over an activity range from 52 MBq down to 45 Bq revealed linearity to within 6%, which was considered sufficient. In 9 out of 12 patients the achieved dose was within the range predicted at discharge. Averaged deviation between achieved and predicted dose was 3.1±2.2% (median 2.5%, range 0.7% - 7.2%). Averaged deviation between post- and peri-therapeutic half-lives was 5.1±3.9% (median 3.5%, range 1.3% - 12.5%). For n=5 patients discharged after 3 days, averaged deviations were greater (dose 4.0%, half-life 5.6%) than for those patients (n=7) who stayed in the hospital for a minimum of 4 days (dose 2.5%, half-life 4.8%). Excretion of iodine from the thyroid remains practically unchanged for at least two months after RIT. The dosimetric procedure implemented in our institution warrants a robust prediction of the post-therapeutic half-life and thus the actual achieved dose.
放射性碘治疗（RIT）用于德国的良性甲状腺疾病需要患者在核医学治疗病房至少停留 48 小时，并根据在此期间进行的活动测量来计算甲状腺的剂量。大部分剂量将在患者出院后给予，因此必须通过在治疗期间测量的有效半衰期的外推来预测。我们对接受治疗后 5 个月的患者进行了重复的甲状腺摄取测量，以研究治疗后有效半衰期的变化，并检查剂量学后果。12 名患者（4 名男性，8 名女性；年龄 36-76 岁；4 名格雷夫斯病，4 名毒性腺瘤，3 名毒性甲状腺肿，1 名非毒性甲状腺肿）接受了晚期摄取测量（1-7 次测量，接受放射性碘治疗后 13-154 天，中位数 54 天，使用甲状腺探头或全身计数器在较低活性下进行）。从晚期测量计算的剂量与出院时预测的剂量进行比较；从最接近中位数延迟（54 天）的晚期测量计算的半衰期与出院时确定的半衰期进行比较。在 52 MBq 至 45 Bq 的活性范围内，对活性校准器、甲状腺探头和全身计数器进行了交叉校准，结果表明线性度在 6%以内，这被认为是足够的。在 12 名患者中的 9 名中，实际剂量在出院时预测的剂量范围内。实际剂量与预测剂量的平均偏差为 3.1±2.2%（中位数 2.5%，范围 0.7%-7.2%）。治疗后和治疗期间半衰期的平均偏差为 5.1±3.9%（中位数 3.5%，范围 1.3%-12.5%）。对于在 3 天后出院的 n=5 名患者，平均偏差较大（剂量 4.0%，半衰期 5.6%），而对于在医院至少停留 4 天的 n=7 名患者（剂量 2.5%，半衰期 4.8%）。放射性碘治疗后至少两个月，甲状腺中碘的排泄基本保持不变。我们机构实施的剂量学程序可以可靠地预测治疗后半衰期，从而预测实际的治疗剂量。
