en Radiation Biology Radiation Biology تحقيق بديع Original Research <div style="text-align: justify;"><span style="font-size:10pt"><span style="text-justify:newspaper"><span style="text-kashida-space:50%"><span style="line-height:119%"><span style="font-family:Calibri"><span style="color:black"><span lang="en-US" style="font-size:9.0pt"><span style="font-family:Calibri"><span style="color:#1f497d"><span style="font-style:italic"><span style="font-weight:bold"><span style="language:en-US">Background</span></span></span></span></span></span><span lang="en-US" style="font-size:9.0pt"><span style="font-family:Calibri"><span style="color:#1f497d"><span style="font-weight:bold"><span style="language:en-US">:</span></span></span></span></span> <span lang="en-US" style="font-size:9.0pt"><span style="font-family:Calibri"><span style="language:en-US">To evaluate the effects of probe positioning on radioactive iodine uptake (RAIU) measurements and 131I quantification in Graves disease (GD) patients. </span></span></span><span lang="en-US" style="font-size:9.0pt"><span style="font-family:Calibri"><span style="color:#1f497d"><span style="font-style:italic"><span style="font-weight:bold"><span style="language:en-US">Materials and Methods: </span></span></span></span></span></span><span lang="en-US" style="font-size:9.0pt"><span style="font-family:Calibri"><span style="language:en-US">We performed a cross-sectional study in GD patients between May 9 and June 27, 2013. 24 hr-RAIU was measured. Measurement A was the reference measurement and was obtained with the probe parallel to the bottom of the thyroid cartilage. Measurements B, C, D, and E were obtained by moving the probe 2.5 cm to the left, 5 cm to the left, 2.5 cm vertically upward, and 5 cm vertically upward, respectively. The </span></span></span><span lang="en-US" style="font-size:5.9939pt"><span style="font-family:Calibri"><span style="language:en-US">¹³¹</span></span></span><span lang="en-US" style="font-size:9.0pt"><span style="font-family:Calibri"><span style="language:en-US">I doses were calculated. Non-reference measurements were compared with measurement A using the paired t-test or Wilcoxon signed-rank test. </span></span></span><span lang="en-US" style="font-size:9.0pt"><span style="font-family:Calibri"><span style="color:#1f497d"><span style="font-style:italic"><span style="font-weight:bold"><span style="language:en-US">Results: </span></span></span></span></span></span><span lang="en-US" style="font-size:9.0pt"><span style="font-family:Calibri"><span style="language:en-US">A total of 63 GD patients (17 men, 40.3&plusmn;13.6 years old) were enrolled. Among them, 57 patients had 24 hr-RAIU measurement and 37 patients chose the </span></span></span><span lang="en-US" style="font-size:5.9939pt"><span style="font-family:Calibri"><span style="language:en-US">¹³¹</span></span></span><span lang="en-US" style="font-size:9.0pt"><span style="font-family:Calibri"><span style="language:en-US">I treatment. Significant changes were observed in 24 hr-RAIU and </span></span></span><span lang="en-US" style="font-size:5.9939pt"><span style="font-family:Calibri"><span style="language:en-US">¹³¹</span></span></span><span lang="en-US" style="font-size:9.0pt"><span style="font-family:Calibri"><span style="language:en-US">I dose between measurement A (24 hr-RAIU 60.40&plusmn;12.67% and median </span></span></span><span lang="en-US" style="font-size:5.9939pt"><span style="font-family:Calibri"><span style="language:en-US">¹³¹</span></span></span><span lang="en-US" style="font-size:9.0pt"><span style="font-family:Calibri"><span style="language:en-US">I dose 8.17 mCi) and measurement E (24 hr-RAIU 48.67&plusmn;11.74% and median </span></span></span><span lang="en-US" style="font-size:5.9939pt"><span style="font-family:Calibri"><span style="language:en-US">¹³¹</span></span></span><span lang="en-US" style="font-size:9.0pt"><span style="font-family:Calibri"><span style="language:en-US">I dose 9.50 mCi) (P<0.05). In one patient, the 24 hr-RAIU was 20.3% lower in measurement E compared with that in measurement A, resulting in a 30 mCi increase in the calculated 131I dose. </span></span></span><span lang="en-US" style="font-size:9.0pt"><span style="font-family:Calibri"><span style="color:#1f497d"><span style="font-style:italic"><span style="font-weight:bold"><span style="language:en-US">Conclusions: </span></span></span></span></span></span><span lang="en-US" style="font-size:9.0pt"><span style="font-family:Calibri"><span style="language:en-US">The vertically upward movement by a distance of a radius of the collimator could affect the 24 hr-RAIU measurement and thus cause inaccurate calculation of the </span></span></span><span lang="en-US" style="font-size:5.9939pt"><span style="font-family:Calibri"><span style="language:en-US">¹³¹</span></span></span><span lang="en-US" style="font-size:9.0pt"><span style="font-family:Calibri"><span style="language:en-US">I dose.</span></span></span></span></span></span></span></span></span></div> Thyroid function tests, iodine radioisotopes, Graves’ disease, data accuracy. 309 313 http://ijrr.com/browse.php?a_code=A-10-1-1175&slc_lang=en&sid=1 J. Zeng 7900319475328460026880 7900319475328460026880 No Department of Endocrinology, Fifth Medical Center of Chinese PLA General Hospital, Beijing 100071, China T. Zhang 7900319475328460026881 7900319475328460026881 No Department of Endocrinology, Fifth Medical Center of Chinese PLA General Hospital, Beijing 100071, China Y. Yang 7900319475328460026882 7900319475328460026882 No Department of Endocrinology, Fifth Medical Center of Chinese PLA General Hospital, Beijing 100071, China J. Wang 7900319475328460026883 7900319475328460026883 No Department of Endocrinology, Fifth Medical Center of Chinese PLA General Hospital, Beijing 100071, China X. Han 7900319475328460026884 7900319475328460026884 No Department of Endocrinology, Fifth Medical Center of Chinese PLA General Hospital, Beijing 100071, China Q. Guo 7900319475328460026885 7900319475328460026885 No Department of Endocrinology, Fifth Medical Center of Chinese PLA General Hospital, Beijing 100071, China Y. Fang fangyi5zhongxin@163.com 7900319475328460026886 7900319475328460026886 Yes Department of Endocrinology, Fifth Medical Center of Chinese PLA General Hospital, Beijing 100071, China