Castronovo F P
Departments of Radiology and Radiopharmacology, Massachusetts General Hospital, Harvard Medical School, Boston.
J Nucl Biol Med (1991). 1994 Mar;38(1):55-60.
Blocking the thyroid gland when administering radioiodinated materials is a common practice. Since pharmacologic quantities of potassium iodide (KI) in the range of 100-300 mg daily are usually administered for this purpose, the potential exists for iodide toxicity. Concomitant with the tracer administration is the risk produced from ionizing radiation. Reports in the literature demonstrated thyroid function abnormalities in patients administered iodides. Based on the latter observations the object of the present investigation is to determine the effectiveness of thyroid blocking with a lesser daily quantity of KI. Fifteen adult hip replacement patients (7 men, 8 women; 58.2 +/- 11.5 years) received 2.5 mg Ki orally every 12th hour twice daily 2 days prior to surgery and 125I-fibrinogen [(3,700 kBq)(100 microCi)], and each day up to 10 days thereafter. Thyroid and precordial counts were obtained daily and the latter two were used for calculating the 125I thyroid uptake. These data were used for estimating the thyroid blood disappearance and cancer risk. An attempt was made to compare the radiation risk to that from KI ingestion. The 125I% thyroid uptake for the study population (n = 15) was 1.83 +/- 1.25%. This compares to a thyroid uptake of 0.064 +/- 0.037% in a published report using 300 mg KI daily in the course of an 125I-fibrinogen test. The mean thyroid radiation dose for the study population was 6.09 cGy after receiving 5 mg KI daily. The specific risk estimate (SRE) for contracting thyroid cancer was calculated to be 4.5B-04. The NCRP calculated thyroid function risk after ingesting KI is 1-10E-07.(ABSTRACT TRUNCATED AT 250 WORDS)
在给予放射性碘化物质时阻断甲状腺是一种常见做法。由于通常为此目的每日给予100 - 300毫克范围内的药理剂量碘化钾（KI），存在碘中毒的可能性。与示踪剂给药同时存在的是电离辐射产生的风险。文献报道显示，接受碘化物治疗的患者存在甲状腺功能异常。基于后者的观察结果，本研究的目的是确定每日使用较少量KI进行甲状腺阻断的有效性。15名成年髋关节置换患者（7名男性，8名女性；年龄58.2±11.5岁）在手术前2天每天两次，每12小时口服2.5毫克KI，并给予125I - 纤维蛋白原[（3700 kBq）（100微居里）]，此后每天服用，持续至术后10天。每天获取甲状腺和心前区计数，后两者用于计算125I甲状腺摄取量。这些数据用于估计甲状腺血液清除率和癌症风险。试图将辐射风险与KI摄入风险进行比较。研究人群（n = 15）的125I甲状腺摄取率为1.83±1.25%。相比之下，在一篇发表的报告中，在125I - 纤维蛋白原测试过程中每日使用300毫克KI时，甲状腺摄取率为0.064±0.037%。研究人群在每日接受5毫克KI后，平均甲状腺辐射剂量为6.09 cGy。计算得出患甲状腺癌的特定风险估计值（SRE）为4.5B - 04。NCRP计算得出摄入KI后的甲状腺功能风险为1 - 10E - 07。（摘要截短至250字）
