Wesche M F, Tiel-van Buul M M, Smits N J, Wiersinga W M
Department of Endocrinology, Academic Medical Centre, University of Amsterdam, The Netherlands.
Nucl Med Commun. 1998 Apr;19(4):341-6. doi: 10.1097/00006231-199804000-00008.
The activity of 131I to be administered as therapy to patients with thyroid disease is usually calculated from 24 h radioiodine uptake and thyroid volume. The aim of the present study was to compare thyroid volume, measured by scintigraphy and ultrasonography, to evaluate the impact of these methods on the calculated 131I dose. Forty patients (20 with diffuse toxic goiter and 20 with multinodular toxic or nontoxic goiter) were investigated. On the same day, thyroid volume was measured by ultrasonography (using transverse scans at 5 mm intervals) and by scintigraphy, using either the ellipsoid formula (SC-E: [symbol: see text]/6 x height x width x depth) or the Himanka formula (SC-H: 0.33 x (planimetric surface in pixels)3/2). With ultrasonography, the size of diffuse goiters was smaller than that of nodular goiters (median values and range: 18 ml (11-46) and 50 ml (14-198) respectively, P < 0.001). Both scintigraphic methods, however, failed to demonstrate a significant difference between diffuse and nodular goiter size. In patients with diffuse goiter, thyroid volume measured by SC-E did not differ from that measured by ultrasonography, whereas thyroid size was overestimated by 53% using the Himanka formula. In contrast, in patients with nodular goiter, thyroid volume measured by SC-H did not differ from that measured by ultrasonography, whereas the ellipsoid formula underestimated thyroid size by 48%. The overestimation of diffuse goiter size by the Himanka formula resulted in a relatively modest median excess of 96 MBq (range -118 to +248 MBq) of the calculated 131I dose. The underestimation of nodular goiter size by the ellipsoid formula resulted in a calculated dose that was 278 MBq lower (range -1624 to +141 MBq). The median calculated 131I dose based on the Himanka formula was not different from that based on ultrasound, but large differences in calculated 131I dose (up to 1280 MBq) were found in individual cases. In conclusion, thyroid volume can be assessed with accuracy by scintigraphy using the ellipsoid formula in patients with diffuse goiter. Wide differences, however, are observed in the size of nodular goiters measured by scintigraphy and ultrasonography.
作为甲状腺疾病治疗用的¹³¹I活度通常根据24小时放射性碘摄取量和甲状腺体积来计算。本研究的目的是比较通过闪烁扫描法和超声检查法测量的甲状腺体积，以评估这些方法对计算的¹³¹I剂量的影响。对40例患者（20例弥漫性毒性甲状腺肿和20例多结节性毒性或非毒性甲状腺肿）进行了研究。在同一天，通过超声检查（以5毫米间隔进行横向扫描）和闪烁扫描法测量甲状腺体积，闪烁扫描法使用椭圆体公式（SC-E：[符号：见原文]/6×高×宽×深）或希曼卡公式（SC-H：0.33×（像素平面面积）³/²）。超声检查显示，弥漫性甲状腺肿的大小小于结节性甲状腺肿（中位数及范围：分别为18毫升（11 - 46）和50毫升（14 - 198），P < 0.001）。然而，两种闪烁扫描法均未显示弥漫性和结节性甲状腺肿大小之间存在显著差异。在弥漫性甲状腺肿患者中，用SC-E测量的甲状腺体积与超声检查测量的结果无差异，而用希曼卡公式测量时甲状腺大小被高估了53%。相反，在结节性甲状腺肿患者中，用SC-H测量的甲状腺体积与超声检查测量的结果无差异，而椭圆体公式使甲状腺大小被低估了48%。希曼卡公式对弥漫性甲状腺肿大小的高估导致计算的¹³¹I剂量中位数相对适度地过量96兆贝可（范围 - 118至 + 248兆贝可）。椭圆体公式对结节性甲状腺肿大小的低估导致计算剂量低278兆贝可（范围 - 1624至 + 141兆贝可）。基于希曼卡公式计算的¹³¹I剂量中位数与基于超声检查的结果无差异，但在个别病例中发现计算的¹³¹I剂量存在很大差异（高达1280兆贝可）。总之，对于弥漫性甲状腺肿患者，使用椭圆体公式的闪烁扫描法可准确评估甲状腺体积。然而，闪烁扫描法和超声检查法测量的结节性甲状腺肿大小存在很大差异。
