Case Author(s): Michael Quinn, M.D. and Barry A. Siegel, M.D. , 03/30/98 . Rating: #D3, #Q4

Diagnosis: Perspiration Artifact on I-131 Scintigraphy

Brief history:

6-year-old girl with a history of papillary thyroid carcinoma referred for whole-body scintigraphy after a therapeutic dose of I-131.


Anterior and posterior whole-body images obtained 96 hours after I-131 administration are shown.

View main image(tr) in a separate image viewer

Full history/Diagnosis is available below

Diagnosis: Perspiration Artifact on I-131 Scintigraphy

Full history:

6-year-old girl with a history of metastatic papillary thyroid carcinoma status post thyroidectomy in June 1997. The patient has received three 25-mCi doses of I-131 for ablation of residual thyroid tissue: the first in June 1997, the second in December 1997, and the the third 4 days prior to this study. This imaging study was performed to evaluate for residual thyroid tissue.




There is accumulation of I-131 in the neck, salivary glands, gastrointestinal tract, and bladder. Additionally, there is subtle activity extending superiorly from atop the patients head in an unusual "fountain-like" fashion on the anterior image. On the posterior view, there is activity in a broad distribution over the back of the head just superior to the large focus in the neck.


The activity in the neck represents functioning thyroid tissue remaining in the thyroid bed and/or adjacent soft tissues. It may be residual normal thyroid tissue or tumor. No distant metastases were seen. The salivary gland, gastrointestinal tract, and bladder activity all reflect routes of physiologic excretion of I-131. The unusual activity extending above and behind the head was thought to be the result of yet another route of normal physiologic excretion, namely perspiration. Upon examining the patient, it was noted that she had her hair bound in a long braid. It was surmised that I-131 excreted via the sweat glands had remained in her hair.


To further evaluate this possibility, two further posterior images of head and neck were obtained. One of these was taken with the braid hanging down over her neck, while the other was taken with it raised above her head (see arrows). This demonstrated that the focus of activity indeed moved with the braid. This was confirmation of the presence of I-131 within hair matted by perspiration.

View followup image(tr). Posterior images of the head and neck are shown (left image: with the braid down and right image: with the braid up).

ACR Codes and Keywords:

References and General Discussion of Thyroid Scintigraphy (Anatomic field:Face, Mastoids, and Neck, Category:Other(Artifact))

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Case number: tr006

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