Shortt C P, Fanning N F, Malone L, Thornton J, Brennan P, Lee M J
Department of Radiology, Beaumont Hospital, Dublin 9, Ireland.
Cardiovasc Intervent Radiol. 2007 Sep-Oct;30(5):922-7. doi: 10.1007/s00270-007-9093-7. Epub 2007 May 29.
To assess radiation dose to the thyroid in patients undergoing neurointerventional procedures and to evaluate dose reduction to the thyroid by lead shielding.
A randomized patient study was undertaken to evaluate the dose reduction by thyroid lead shields and assess their practicality in a clinical setting. Sixty-five patients attending for endovascular treatment of arteriovenous malformations (AVMs) and aneurysms were randomized into one of 2 groups a) No Thyroid Shield and b) Thyroid Lead Shield. Two thermoluminescent dosimeters (TLDs) were placed over the thyroid gland (1 on each side) at constant positions on each patient in both groups. A thyroid lead shield (Pb eq. 0.5 mm) was placed around the neck of patients in the thyroid lead shield group after the neurointerventional radiologist had obtained satisfactory working access above the neck. The total dose-area-product (DAP) value, number and type of digital subtraction angiography (DSA) runs and fluoroscopy time were recorded for all patients.
Of the 72 patients who initially attended for neurointerventional procedures, 7 were excluded due to failure to consent or because of procedures involving access to the external carotid circulation. Of the remaining 65 who were randomized, a further 9 were excluded due to; procedureabandonment, unfeasible shield placement or shield interference with the procedure. Patient demographics included mean age of 47.9 yrs (15-74), F:M=1.4:1. Mean fluoroscopy time was 25.9 min. Mean DAP value was 13,134.8 cGy x cm(2) and mean number of DSA runs was 13.4. The mean relative thyroid doses were significantly different (p< 0.001) between the unshielded (7.23 mSv/cGy2 x 105) and shielded groups (3.77 mSv/cGy2 x 105). A mean thyroid dose reduction of 48% was seen in the shielded group versus the unshielded group.
Considerable doses to the thyroid are incurred during neurointerventional procedures, highlighting the need for increased awareness of patient radiation protection. Thyroid lead shielding yields significant radiation protection, is inexpensive and when not obscuring the field of view, should be used routinely.
评估接受神经介入手术患者甲状腺所受的辐射剂量，并评估铅屏蔽对甲状腺的剂量降低效果。
开展一项随机患者研究，以评估甲状腺铅屏蔽对剂量的降低效果，并评估其在临床环境中的实用性。65名因动静脉畸形（AVM）和动脉瘤接受血管内治疗的患者被随机分为两组：a）无甲状腺屏蔽组和b）甲状腺铅屏蔽组。两组患者均在甲状腺的固定位置（两侧各一个）放置两个热释光剂量计（TLD）。在神经介入放射科医生获得颈部上方满意的操作通路后，给甲状腺铅屏蔽组患者的颈部围上一个甲状腺铅屏蔽（铅当量0.5毫米）。记录所有患者的总剂量面积乘积（DAP）值、数字减影血管造影（DSA）运行的次数和类型以及透视时间。
最初参加神经介入手术的72名患者中，7名因未同意或手术涉及颈外循环通路而被排除。在其余随机分组的65名患者中，又有9名因手术放弃、屏蔽放置不可行或屏蔽干扰手术而被排除。患者人口统计学特征包括平均年龄47.9岁（15 - 74岁），女性与男性比例为1.4:1。平均透视时间为25.9分钟。平均DAP值为13,134.8 cGy×cm²，平均DSA运行次数为13.4次。未屏蔽组（7.23 mSv/cGy²×10⁵）和屏蔽组（3.77 mSv/cGy²×10⁵）的平均相对甲状腺剂量有显著差异（p < 0.001）。与未屏蔽组相比，屏蔽组的甲状腺平均剂量降低了48%。
神经介入手术期间甲状腺会受到相当大的剂量照射，这凸显了提高患者辐射防护意识的必要性。甲状腺铅屏蔽可产生显著的辐射防护效果，成本低廉，且在不遮挡视野时应常规使用。
